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Relationship between Food, Fat, Sexual Maturation, and Spawning Time of Baltic Herring (Clupea harengus membras) in the Archipelago Sea
Abstract
The effect of nutritional status on gonad maturation and timing of spawning was examined in the Baltic herring (Clupea harengus membras) in the Archipelago Sea. Fish were collected from overwintering areas in December and from the spawning grounds in May–July. Muscle fat content, amount of mesenteric fat, and condition factor were used as indicators of nutritional status of fish. In winter, fish were highly variable with substantial individual variation in nutritional status, gonad stage, gonad weight, and gonadosomatic index (GSI). Gonad weight was related to fat content, suggesting a close relationship with fish nutritional status and maturation rate. Spawning fish were separable into early and late spawners according to fat content, gonad weight, and GSI but not according to length. The spawning shoals consisted of mixtures of fish of all sizes. I concluded that in the study area, individual maturation cycles vary and timing of spawning is primarily determined by the feeding conditions prior to spawning.
... Tämän tutkimuksen tarkoituksena oli tuottaa tietoja Saaristomereltä pyydetyn silakan rasvapitoisuudesta, rasvojen laadusta ja muista kalan ominaisuuksista, joilla on merkitystä sekä kuluttajille että silakkaa jalostaville yrityksille. Saaristomereltä pyydetyn silakan lihaksen ja mädin rasvapitoisuudesta on tietoja saatavilla 1970-luvulta lähtien (Kaitaranta & Linko 1984;Linko et al. 1985;Rajasilta 1992;Aro et al. 2000) ja erillisten tutkimusten lisäksi on tehty säännöllistä seurantaa Airistolla lisääntyvän silakan lihaksen ja mädin rasvapitoisuudesta (Rajasilta et al. 2018;2021). Koska tutkimustuloksia rasvan määrän ja koostumuksen vaihtelusta Saaristomeren eri osissa ei juurikaan ole saatavilla, näytteet pyrittiin ottamaan siten, että sekä trooli-että rysäkalan ominaisuuksien vertailu alueiden välillä oli mahdollista ja tuloksia voitiin myös vertailla aikaisempiin tutkimustuloksiin. ...
... Saaristomeren silakan lihaksen rasvapitoisuutta on tutkittu v. 2020 tehdyn tutkimuksen lisäksi talvikautena 1988 ja 2017 ja Airistolla kutevasta kalasta vuosittain 1980-luvun lopulta alkaen vuosittain (Rajasilta 1992;Rajasilta et al. 2018). Sekä talvi-että lisääntymiskautena saadut tulokset osoittavat, että kalan rasvapitoisuus on selvästi pienentynyt tutkimusjakson aikana (Kuva 9). ...
... Toisaalta myös yksilöiden väliset erot ovat pienentyneet ja kalasta on siten tullut sekä koon että rasvapitoisuuden suhteen tasalaatuisempaa verrattuna 1980-luvun tilanteeseen. Talvikaudella 1988 tehdyssä tutkimuksessa, jossa näytteet otettiin Gullkronan ja Iniön merialueiden lisäksi myös kahdelta muulta alueelta Saaristomeren eri osista, kalojen koko ja lihaksen rasvapitoisuus vaihtelivat huomattavasti yksilöittäin, mutta alueiden välillä ei eroja havaittu (Rajasilta 1992 Varhaisin lounaisrannikolta pyydetystä silakasta tehty tutkimus lihaskudoksen rasvahappokoostumuksesta on vuodelta 1976 (Linko et al. 1985). Keskeisten rasvahappojen osalta kalan rasvahappoprofiili näyttää pysyneen varsin samankaltaisena tämän tutkimuksen tuloksiin verrattuna (kuva 10), mutta huomattavin muutos näyttäisi tapahtuneen pitkäketjuisten, monityydyttymättömien rasvahappojen kohdalla. ...
In this study, the fat content and fatty acid composition of the Baltic herring muscle and eggs were investigated in the Archipelago Sea during 2020-2021. Fish samples were collected from the trawl catches in winter and from the trap net catches of spawning herring in two different areas. All fish were analysed on individual basis to find out the seasonal and spatial variation in the Archipelago Sea. In addition, pooled samples of overwintering and spawning herring were investigated for the concentration of dioxins, which regulate the use of herring in human consumption.
Herring of the Archipelago Sea was typically small in size (mean length 15-16 cm) regardless of the season and fishing area. Large-sized individuals (> 20 cm) were not found in the samples taken in winter and their number was low also in the trap net samples (1-2 % of all fish in the sample). In all, the herring of the Archipelago Sea seemed to form a rather homogeneous population as for the size structure, fat content and fatty acid composition. The largest differences were due to the reproductive phase, as the fat content of the muscle tissue was somewhat higher in the overwintering fish (mean 2-3 %) than in those collected at the spawning time (mean 1.5 %). Fat content varied substantially among the individual fish independently on fish size. Lipids of the fish fillet were composed of about 40 fatty acids, of which the major ones were the palmitic acid (16:0), oil acid (18:1n-9) and the long-chain polyunsaturated fatty acids EPA (20:5n-3) and DHA (22:6n-3). EPA and DHA formed on average 35-38 % of the herring lipids during the winter, and they were equally important also in the lipids of spawning fish, representing some 35-40 % of all fatty acids found in the muscle tissue. Herring eggs contained only little fat (mean concentration 1 %), and the fatty acid composition indicated a high proportion of EPA and DHA in the FA-profile of the herring rom. The level of dioxins in the herring fillet was low (0.52-0.55 pg/g) in the samples taken in winter. In spawning fish, the concentrations were somewhat higher (2.1 – 4.8 pg/g), but the dioxin levels didn’t exceed the limit set by the European Commission for human food also in these samples.
The comparison with the earlier results on the Archipelago Sea herring indicated that the fat content of the muscle tissue has decreased from the average 7-8 % to the present 2-3 % in the winter samples, and from 3-4 % to the present 1-2 % in the samples taken at the spawning season. The herring of the Archipelago Sea thus contains less fat than for instance in the 1980s, but the lipids mainly consist of high-quality fatty acids essential for the human health. The reason for the change is not fully understood, but most likely it is connected to the decline of the water salinity in the Baltic Sea.
... Herring is the dominant planktivorous fish in this sea area and an important commercial fishery target with annual landings of about 100 000 tonnes. As an abundant species, having a relatively high content of lipid and PUFA in the muscle tissue (Linko et al. 1985;Rajasilta 1992a;Szlinder-Richert et al. 2010), herring contribute substantially to ecosystem energy cycles, and its lipids affect all species consuming it, including humans (Aro et al. 2000;Arts et al. 2001). Large-scale variations in the Baltic ecosystem have revealed the role that hydroclimatic factors and food competition plays in the regulation of growth, condition, and recruitment of herring (Axenrot and Hansson 2003;Casini et al. 2010Casini et al. , 2011Lindegren et al. 2011), suggesting that the same environmental factors could influence also the biochemical properties of this species. ...
... The lipid data were collected during 1987-2006 from the Archipelago Sea (Fig. 1), where, beginning in the 1980s, the herring population was monitored with annual samplings on the spawning grounds ). In addition to routine measurements of fish, the muscle tissue lipid content was determined from spawning females (Rajasilta 1992a), providing a data set spanning 19 years. Declining salinity, high variation in winter temperature, and increasing herring stock during this period offered an opportunity for assessing the influence of the major environmental factors and intraspecific food competition on herring lipid reserves. ...
... Spawning herring sampling for the lipid analyses was conducted annually in the Archipelago Sea (60 o 23=N, 22 o 06=E) from (Table 1). The first lipid analyses were made from both sexes of spawning and overwintering herring (Rajasilta 1992a), but the monitoring was focused on spawning females due to the association between their lipid content and offspring production . Samples were taken from early spawning fish, as, in the study area, the muscle tissue lipid content differs between early spawning (Maymiddle of June) and late spawning herring (at the end of June and onwards; Rajasilta 1992a). ...
Global climate change can affect the energy content of fish by altering their lipid physiology and lipid consumption. We investigated the effects of different environmental stressors on the lipid content of the Baltic herring (Clupea harengus membras) from spawning ground samples that were collected annually in the northern Baltic Sea. During 1987-2014, the average lipid content in herring muscle decreased from 5-6% (w.wt.) to 1.5% (w.wt.). Generalized linear mixed models (GLMMs) indicated that sea water salinity and the size of the herring stock explained best the declining trend of lipid content. We estimated that the amount of the lipid storage incorporated in the spawning stock decreased by approximately 45% during the study, with respective energy content decreases. Fatty acid composition analysis revealed that herring lipids contained a high proportion of EPA (20:5n-3) and DHA (22:6n-3), which originated from its main summertime prey, Limnocalanus macrurus. The results illustrate various climate change-induced processes leading to changes in the lipid content of the Baltic herring and, consequently, to changes in the energy flows of the northern Baltic ecosystem
... The Airisto Inlet is one of the main spawning areas of C. harengus in the Archipelago Sea [ Fig. 1(a)]. It spawns in the littoral zone between early May and the end of July (Rajasilta, 1992). After spawning, the fish migrate to their feeding areas offshore and live there until the next reproduction. ...
... The fat content was expressed as percentage (%) of the wet or dry mass of the muscle. Clupea harengus also store fat in the body cavity (Rajasilta, 1992), but in spawning fish, visceral fat was not found. The fat content determined in this study is thus a measure of the energy left after growth, metabolic demands and reproduction (build-up and maturation of gonads and migration to the spawning grounds). ...
... In this study, females invested in gonadal production even when resources had to be taken from the body store, which suggests that in the first place, C. harengus tend to reproduce every year. Skipped spawning is usually explained by low physical condition of a female, but in the study area, even females having low condition factor and minor fat stores can have developing ovaries in winter and the same situation is found among reproducing females at spawning time (Rajasilta, 1992). This suggests that skipped spawning actually conserves resources other than proteins, such as vitamins or hormones, which also have to be transported into the ovaries (Ayson & Lam, 1993;Fontagné-Dicharry et al., 2010). ...
The trade-off between somatic growth and reproduction in the female Baltic herring Clupea harengus was investigated from 1984 to 2002. During the study period, growth decreased, as a consequence of decreasing salinity and weakening of feeding conditions. Production of muscle and ovarian tissue decreased in repeat spawners, but investment in reproduction took an increasing amount of the total production of new tissues. This suggested that a shift in allocation to reproduction takes precedence over body growth in the reproductive strategy of C. harengus. The process also indicated one possible mechanism leading to dwarf forms in fish populations.
... At any given time during the wintering period and spawning season I G tended to increase with body lengths in the range 27-31 cm, whereas insignificant differences in I G were found between body lengths in the range 32-37 cm (Fig. 7). This length specific relationship was observed both in males and females, although the males were at a higher maturity level in the wintering area in accordance with other studies on Pacific herring (HAY 1985;WARE & TANASICHUK 1989) and Atlantic herring (BLAXTER & HOLLIDAY 1963;MCQUINN 1989;RAJASILTA 1992;BRADFORD 1993a). The fact that the relation between fish length and I G was maintained in the spawning stock throughout the wintering and spawning season, implies that the delayed spawning time in the smallest fish was most likely induced by delayed onset of maturation rather than a slower maturation rate. ...
... It is possible that spawning waves may occur on the basis of differences in the individual condition. SLOTTE & AL (1999) demonstrated an increase in maturity level (I G ) with the condition or energy level of the herring (Fig. 9), which is supported by other studies on captive herring (HAY & al. 1988;Ma & al. 1998) and wild herring (ANEER 1985;HENDERSON & ALMATAR 1989;RAJASILTA 1992). RAJASILTA (1992) found that fish with high muscular fat reserves had reached maturity stage 3 already in December and would become early spawners, whereas those with low fat content were supposed to spawn significantly later. ...
... SLOTTE & AL (1999) demonstrated an increase in maturity level (I G ) with the condition or energy level of the herring (Fig. 9), which is supported by other studies on captive herring (HAY & al. 1988;Ma & al. 1998) and wild herring (ANEER 1985;HENDERSON & ALMATAR 1989;RAJASILTA 1992). RAJASILTA (1992) found that fish with high muscular fat reserves had reached maturity stage 3 already in December and would become early spawners, whereas those with low fat content were supposed to spawn significantly later. Correspondingly, lower energetic status may also be the reason for delayed spawning in the recruits compared to the repeat spawners. ...
The size at first spawning is comparatively larger in Norwegian spring spawning herring (Clupea harengus L.) than in other herring stocks in the Atlantic and Pacific oceans. This is probably an adaptation to a life with long seasonal migrations between wintering-, spawning-and feeding grounds. The present paper presents empirical data and model results suggesting that also historic long-term shifts and annual variations in migrations and distribution pattern may be attributed to size dependency.
... Several studies indicate that herring reproductive traits are influenced by the feeding conditions which precede spawning. The amount of food available for herring females can influence the timing of reproduction ( Aneer, 1985;Rajasilta, 1992) but it may also affect fecundity ( Hay et al., 1988). Bradford and Iles (1992) show that herring females getting energy for gonadal development directly from food produce a higher number of eggs than those which draw on stored energy. ...
... These fish mature later and thus also spawn later. Obviously, individual herrings may change their spawning time according to the energy reserves ( Anokhina, 1971;Rajasilta, 1992) but as the herring spawning pattern seems to be relatively constant in the Baltic Sea at the time-span of several years ( Aneer, 1985), this phenomenon is of minor importance at annual level. Evidently, the reproductive properties of the herring cannot be considered without taking into account the production cycle of the Baltic Sea and timing of herring spawning in this environment. ...
... The main spawning months of the Archipelago Sea herring are May and June, although there is still some spawning in July and August ( Rajasilta et al., 1993). The spawning shoals are mixtures of different sized fish (13-25 cm; Rajasilta, 1992) but the proportion of large fish in a shoal varies. In our samples collected in 1988, 1989, 1997 and 1998, the mean length was constant over the season, whereas the samples of the years 1990 and 1991 showed that there were more large fish in the first spawning shoals than in the later ones. ...
Trends with spawning time in the ovarian weight of the Baltic herring (Clupea harengus membras) were studied from samples collected over the spawning season in 1988-1991, 1997 and 1998 in the Archipelago Sea, northern Baltic. Usually, ovarian weight was related to the size composition of the spawning shoals but there was also variation unrelated with female length. In the latter cases, ovarian weight first decreased in the beginning of the spawning season with decreasing fish length but it then increased again in the middle of the season, irrespective of length. In such years, the piecewise regression analysis suggested a breakpoint for the ovarian weight between the dates 14 June and 30 June. At the later part of the spawning season, ovarian weight was associated with temperature conditions and onset of zooplankton production, which suggests that environmental factors modify the reproductive properties of the herring in the Baltic Sea. 2001 International Council for the Exploration of the Sea
... The physiological dynamic of fishes varies according to their life history, in which growth and reproduction processes reflect these variations due to the high-energy demand in each life stage (Rajasilta, 1992;Olson et al., 2016;Hatzonikolakis et al., 2021). Herein, the adult individuals prioritize reproduction over growth to ensure an efficient reproductive period, which is determined by the quality of gametes and fecundity (Marshall et al., 1999;Tocher, 2003;Zudaire et al., 2014;Barneche et al., 2018). ...
... Although the liver works as a storage organ, it also plays a key role in the metabolism of nutrients and their mobilization to or from other organs (Tocher, 2003;Polakof et al., 2012;Hiraoka et al., 2019). In fact, the liver dynamic of swordfish could allow storing essential nutrients in the muscle and use them in reproductive periods or when food is scarce (Rajasilta, 1992;Bradford, 1993;Zudaire et al., 2014;Yasuda et al., 2021). Thus, the gonad, that stands out for its high-energy demand, can perform efficiently its somatic development (Henderson et al., 1984;Marshall et al., 1999;Tocher, 2003). ...
The temporal dynamics of energy reserves are associated with the physiological processes (i.e., reproduction) in marine fishes, in which storage organs play a key role for efficient energy investment. We evaluated the temporal (i.e., seasons) and intra-individual (i.e., organs) dynamics of adult female swordfish (Xiphias gladius) during its feeding period off the Chilean coast in the southeastern Pacific Ocean (SEPO). The biochemical composition (i.e., lipids, proteins, and glucose), energy content and fatty acid profile of the muscle, liver and gonad were evaluated during the austral autumn, winter, and spring. Our results showed principally an intra-individual effect in both the muscle and liver in the autumn and spring. Herein, a trend of higher amounts of lipids and total energy were found in the muscle, while the liver showed greater protein and glucose contents. Consequently, the muscle showed a higher saturated, monounsaturated, and polyunsaturated fatty acid contents than the liver. Although the gonad showed no significant temporal effect in the lipids and proteins contents, an increasing trend of each biochemical constituent, fatty acid group and gonadosomatic index were found from autumn to winter. Consistently, the glucose and total energy content as well Fulton's condition factor were significantly higher in winter. These findings reflect the spatial-temporal physiological dynamic of swordfish based on the storage of energy reserves in different organs during its feeding period. In this way, the products obtained from swordfish could have an added value depending on the season and capture zone, which could benefit the exploitation and regulation measures of this resource under an ecological approach of conservation and sustainability in the SEPO.
... The herring of the Archipelago Sea (referred as AS; Figure 1) are capital-breeders, which acquire their energy resources during the summer and autumn, store them as lipids in the muscle tissue and develop their gonads during winter, when lipids are transported into the ovary (Vuorela et al., 1979;Rajasilta, 1992). The AS herring reproduce from May to mid-July on shallow bottoms, and show a constant pattern in the use of the spawning beds in our study area (Rajasilta et al., 1993). ...
... Finally, with model C, we studied the effect of female traits (lipid reserves and length) on the log-transformed egg lipid content. In spawning Baltic herring, lipids are found in the muscle and ovarian tissue only, as the visceral lipid depositions formed during the feeding period are depleted before the reproduction (Rajasilta, 1992). The female's total lipid reserves were therefore expressed as the sum of the total content of lipids in muscle and ovary (Fish Total, mg), and the percentage of ovarian lipids of the total (index OL, %) was calculated to indicate the partitioning of lipids between the ovarian and somatic production (e.g., Calow, 1985;Zera and Harshman, 2001). ...
In fish, the lipid resources of the female form a link between the environment and progeny, contributing to the contents of the egg yolk. Variation of the environmental conditions is therefore expected to affect the egg quality via maternal pathways, reflecting the female’s response to the environmental factors before spawning. We investigated the content of lipids and thyroid hormones in the ovary and eggs of the Baltic herring during 1988–2019, when salinity of the Baltic Sea first declined and then stabilized to a lower level, and winters varied between severe and mild. The total lipid resources of spawning females decreased by 40–50% during the study, and the ovarian lipid concentration followed this trend resulting in a decrease of the lipid content of eggs. The concentration of thyroid hormones in the ovary suggested a hormonal response in females to salinity and winter temperature and was observable also in the content of thyroid hormones in the eggs. A change in the egg lipid content took place approximately around 1998 (SE ± 3 years) suggesting that in declining salinity, egg quality was associated with salinity and intrinsic factors in the female, i.e., fecundity and amount of lipids deposited into the ovary. However, during the period of stable salinity, egg quality was mainly limited by the female’s lipid resources. As also the body size of the females decreased over the years, it is suggested that small body size can be a key phenotypic trait to reduce the environmental impact on egg quality in variable environmental conditions.
... The first explanation would imply a switch of spawning season from spring spawning to autumn spawning for females with otoliths of the spring hatch type; or, less drastical, that Central Baltic herring are part of a spawning continuum rather than two distinct spawning populations. Switching of spawning season and spawning continuums between two consecutive spawning seasons has been observed in Newfoundland herring (McQuinn, 1997) as well as Baltic herring (Aneer, 1985;Anokhina, 1971;Rajasilta, 1992), and suggested as theoretically possible in North Sea autumn-and winter-spawning herring (van Damme et al., 2009). This indicates that herring are not necessarily confined to spawning only in the same season they were hatched; and although McQuinn (1997) assumes that once an individual herring has spawned for the first time, it remains fixed as that spawner type for the rest of its life, others have suggested a more plastic approach to spawning type fidelity (Rajasilta, 1992). ...
... Switching of spawning season and spawning continuums between two consecutive spawning seasons has been observed in Newfoundland herring (McQuinn, 1997) as well as Baltic herring (Aneer, 1985;Anokhina, 1971;Rajasilta, 1992), and suggested as theoretically possible in North Sea autumn-and winter-spawning herring (van Damme et al., 2009). This indicates that herring are not necessarily confined to spawning only in the same season they were hatched; and although McQuinn (1997) assumes that once an individual herring has spawned for the first time, it remains fixed as that spawner type for the rest of its life, others have suggested a more plastic approach to spawning type fidelity (Rajasilta, 1992). ...
Herring (Clupea harengus) is a capital breeder that stores energy reserves in muscle tissue. Individual potential fecundity relies on the size and weight of female fish. Poor condition during the maturation process can lead to a heavy down-regulation of fecundity through atresia and, in the extreme, cause skipped spawning. Herring in the Central Baltic Sea exist in a variable environment where food availability fluctuates substantially. Compared to other herring populations their condition is generally poor. In the present study, the oocyte dynamics and fecundity in relation to the condition of Central Baltic herring was investigated. A modern stereological method, the physical fractionator, was used to quantify the number of oocytes in previtellogenic (PG), cortical alveoli (CA) as well as successive vitellogenic (VT1 and VT2) stages in central Baltic herring during ovarian maturation. The potential fecundity, i.e. the number of VT2 oocytes, was low compared to other Atlantic stocks but the relative potential fecundity was higher. The latter decreased by 71% when comparing early-maturing individuals with CA oocytes and late-maturing individuals with VT2 oocytes, suggesting a substantial down-regulation of fecundity. Although determined as spring spawners by otolith hatch type, 15% of the randomly sampled females were characterized by oocytes in CA stage in the prespawning period, indicating skipped spawning. The condition of these females was poor, which might have resulted in skipped spawning. Ovary weight was a good predictor of potential fecundity within maturing stages of females. Combined with estimates of skipped spawning, this ovary weight could be used to estimate egg production thereby improving Central Baltic herring stock-recruitment models.
... Spawning of Baltic herring occurs when the water temperature is 5–15C (Oulasvirta et al., 1985) and is normally most intense in early May at a temperature of 5–9C, but occurs even in July–August (Aneer, 1979;Oulasvirta et al., 1985;Rajasilta, 1992). It has been shown that herring spawn early in warm springs (Ware and Tanasichuk, 1989;Rajasilta, 1992) and, in our study year (1993), the spring surface water temperatures were more than 2C warmer than normal (U. ...
... Spawning of Baltic herring occurs when the water temperature is 5–15C (Oulasvirta et al., 1985) and is normally most intense in early May at a temperature of 5–9C, but occurs even in July–August (Aneer, 1979;Oulasvirta et al., 1985;Rajasilta, 1992). It has been shown that herring spawn early in warm springs (Ware and Tanasichuk, 1989;Rajasilta, 1992) and, in our study year (1993), the spring surface water temperatures were more than 2C warmer than normal (U. Larsson, pers. ...
Growth rates, hatch-date distributions and seasonal changes in energy content of larval and juvenile herring (Clupea harengus), the major Baltic Sea zooplanktivore, were studied in a coastal area. The first microstructure (ring) shown in the otoliths (sagittae) was formed at the end of the yolk-sac stage. The following rings occurred regularly and showed a pattern corresponding to daily growth rings, as described in the literature, and we used these rings to age the fish. The average growth rate was estimated al 0.37 mm d(-1) and 0.58 mm d(-1) for larval and metamorphosed herring, respectively. The overall growth for ail young stages could be described with a fourth order polynomial relationship between length and age. Estimated hatching dates were distributed between March and June. This is earlier than normally assumed for the northern Baltic Sea and was probably caused by an early and warm spring in 1993. Our data indicate the highest survival for herring spawned from end of April to the middle of May. In terms of seasonal and yearly fluctuations in body composition, there was an increase in energy content from 2200 to 2800 J g(-1) wet weight and 2900 to 4800 J g(-1) wet weight for larval and metamorphosed herring, respectively, with nearly constant energy content during metamorphosis. (C) 1996 International Council for the Exploration of the Sea
... From the foregoing, we note that the chemical composition of fish varies according to many factors, especially the species, fishing season, sex, and the period of sexual maturity. This is confirmed by several studies, where it was found that the chemical composition of fish changes and is related to many different factors such as temperature, location, reproductive cycle, diet, age, size, sex, and other factors [19,20,21]. ...
The effects of seasonal and sexual differences and Total Lenght on the chemical composition of the Red Sea goatfish Parupeneus forsskali caught from the marine waters of Lattakia Governorate were investigated. Moisture, crude protein, crude fat, and ash were determined as a percentage of the fish muscles. The results revealed that the autumn season was the highest in terms of nutritional components (protein 22.08%, fat 9.78%, ash 2.42% of fresh fish muscle), While the Summer season was the lowest (protein 19.32%, fat 5.46%, ash 1.20%). The results also showed the superiority of females in the values of the nutritional components over males, where the values were for females (protein 22.3%, fat 8.9%) and males (protein 20.7%, fat 6.8%), while The results also showed the superiority of males in the values of ash over females of ash (male 1.5%, female 1.3%). Regarding the body length factor, the results showed a significant positive relationship between an increase in Total length and an increase in protein and fat and a significant inverse relationship with both ash and moisture content.
... This confirms that the chemical composition of fish varies according to many factors, especially the fishing season, sex, and the period of sexual maturity. This is confirmed by several studies, where it was found that the chemical composition of fish changes and is related to many different factors such as temperature, location, reproductive cycle, diet, age, size, sex, and other factors [17][18] [19]. The round sardines is considered to be a fatty fish [20] where the fat content is > 5% and this fat is stored mainly in the muscles (Bougis, 1952) [21], and this can be attributed to the relatively high activity of this species, which requires a large amount of energy which is in agreement with (Yuan et al) [22]. ...
The effects of seasonal and sexual differences on the biochemical composition of
the Round Sardinella fish species S. aurita caught from the marine waters of
Lattakia Governorate were investigated. Moisture, crude protein, crude fat, and ash
were determined as a percentage of the fish muscles. The results revealed that the
autumn season was the highest in terms of nutritional components (protein 19.88%,
fat 11.80%, ash 3.50% of fresh fish muscle), While the Spring season was the
lowest (protein 19.53%, fat 7.74%, ash 1.04%). The results also showed the
superiority of females in the values of the nutritional components over males,
where the values were for females (protein 20.9%, fat 11.2%) and males (protein
20.3%, fat 9.3%), while the results also showed the superiority of males in the
values of ash over females of ash (male 1.7%, female 1.2%).
... The physicochemical properties like protein, moisture, fat and ash content vary within species, and it depends upon many factors. The variations can be due to season, temperature, breeding location, age, size and maturity of the species [28,29]. The present analysis results were similar to Perez-Velazquez et al. [10] which reported that the nutritional profile of various ray species and their physiochemical properties ranges between 27.77 and 28.21 (protein), 6.78 and 7.66 (crude fat), 5.26 and 5.94 (moisture) and 940 and 9.70 (ash). ...
Fish oils are well-known sources of polyunsaturated fatty acid (PUFA) and docosahexaenoic acid (DHA), widely used in the food industry as nutritional supplements, as well as in the pharmaceutical industry. In this present study, ray fish Himantura marginata (Blackedge whipray) were collected from Nagapattinam fishing harbour, and oil from the livers was extracted by the BUME method. The percentage of oil yield was recorded as 83 ± 2.8 from the above method. The proximate composition such as total protein (26.51 ± 0.34%), crude fat (7.58 ± 0.16%), moisture (7.08 ± 0.13%) and ash content (8.63 ± 0.45%) was calculated by standard AOAC method. The physical properties were recorded as follows: specific gravity at 28 ℃, 1.03 ± 0.02 g cm⁻³; refractive index, 1.430; saponification value, 176.90 ± 1.24 mg KOH/g oil; iodine value, 148.79 ± 2.07 mg I2/100 g; density, 0.927 ± 0.06 g/mL; carotenes, 3.68 mg/100 g oil; α-tocopherol 9.34 mg/100 g oil; and colour, yellowish. Fatty acid profiling of the liver oil was performed by using gas chromatography with flame ionization detector (GC-FID); it exhibited 22 different types of fatty acids including saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The elemental analysis of liver oil was performed by inductively coupled plasma mass spectrometry, and the values are analysed in triplicate.
... The amount of fat deposited around the gut was inversely correlated with gonad weight of herring (Clupea harengus membras) (Rajasilta, 1992). High mesenteric fat index (MFI) in the farmed female yellow catfish has a negative correlation with gonad somatic index (GSI) (Hu et al., 2021). ...
Nutritional components and feeding strategies are multifarious amongst different producers, whereas they are just designed for fish farming but not suitable for improving the reproductive performance of broodfish. Yellow catfish (Pelteobagrus fulvidraco), an omnivorous species, is one of the important aquaculture fish in China. In order to improve the reproductive performance of female yellow catfish (119.86—134.54 g), four feeding strategies (0.5%, 0.75%, 1% and 1.5% BW/d) and three dietary protein levels (34%, 40% and 46%) were examined, respectively, in the two separate trials. The females with moderate feed restriction (1%) showed significant lower mesenteric fat index (MFI) and higher gonadosomatic index (GSI) than the satiation group (1.5%) and excessive feeding restriction groups (0.5% and 0.75%). Females with high MFI were difficult to be artificially propagated and showed a high mortality rate, whilst the fish at 1.0% feeding rate displayed low mortality rate and high ratios of spawned fish, as well as high percentages of fertilization and hatching. Meanwhile, the offspring of 1.0% feeding rate group showed a low malformation rate and high survival rate. Multiple spawning in the same breeding season are applied in yellow catfish to reduce the number of parent fish and increase the fry production, and gonadal recrudescence after spawning might be affected by different nutrient values including dietary protein levels. In the second trail, female yellow catfish were fed with 34%, 40% and 46% crude protein diet at 1% feeding rate for the second spawning, and the best reproductive and breeding performances were observed in the fish group with 46% crude protein diet. These results demonstrate that 1% feeding rate is optimum for the spawning and reproductive performance of female yellow catfish for the first artificial spawning, and 46% dietary protein group had the best reproductive performances in the second spawning.
... Fish can store energy in their liver or viscera to meet the requirements of spawning activities. The energy required for spawning by northern pike Esox lucius is derived from the liver (Diana & Mackay, 1979), while Baltic herring use energy stored in viscera for reproduction (Rajasilta, 1992). Liver weight has been used as an indicator for assessing energy allocation during the life cycles of many fish species (Diana & Mackay, 1979;Iker, Hilario, Maitane, & Nathalie, 2014;Pulliainen & Korhonen, 1990;Smith, Paul, & Paul, 1990). ...
... Fish can store energy in their liver or viscera to meet the requirements of spawning activities. The energy required for spawning by northern pike Esox lucius is derived from the liver (Diana & Mackay, 1979), while Baltic herring use energy stored in viscera for reproduction (Rajasilta, 1992). Liver weight has been used as an indicator for assessing energy allocation during the life cycles of many fish species (Diana & Mackay, 1979;Iker, Hilario, Maitane, & Nathalie, 2014;Pulliainen & Korhonen, 1990;Smith, Paul, & Paul, 1990). ...
The reproductive characteristics of a commercially important sparid fish used in aquaculture
systems, the yellowfin seabream Acanthopagrus latus, were described based
on 938 specimens caught by various fisheries in the waters off western Taiwan from
January 2016 to September 2017. Based on macroscopic appearances, gonadosomatic
indices and histological examinations of the gonad tissues, the spawning season
of this species was identified to be from September to December. This species is an
asynchronous spawner, with an estimated mean fecundity of 2,444,787 ± 1,205,991.
The sex ratio was significantly different from 0.5, and females predominated in most
size classes and months. The sizes at 50% maturity were estimated to be 29.7 and
21.0 cm FL for females and males respectively. Although A. latus is believed to be a
protandrous hermaphrodite in many geographical locations, the possibility of being a
rudimentary hermaphrodite could not be excluded in this study. The positive correlations
found between the fecundity and length, weight and age of the individuals and
implications of these results with respect to their inshore migration pattern and the
stock enhancement success were addressed.
... Therefore, during the evaluation of physiological condition of fish in different periods of the annual cycle, it is important to have data on the dynamics of the content of the metabolism products in the muscles and the organs. The study of the biochemical changes in the organism of hydrobionts in the pre-spawning and spawning periods allows more complete revelation of the process of reproduction and also prediction of the terms and duration of the spawning, and therefore the productivity of individuals (Krivobok & Tarkovskaya, 1960;Rajasilta, 1992). The literature mostly reveals the seasonal changes in the parameters of metabolism of marine fish (Gorbatenko & Lazhentsev, 2016;Romotowska et al., 2016;John Kiran et al., 2017;Kosker et al., 2018;Hossain et al., 2019). ...
The aim of this research was to study the dynamics of metabolism in the body of bream Abramis brama (L.) at different periods of the annual cycle: pre-spawning, spawning, post-spawning and feeding. The object of the study was 55 male and 53 female bream aged 9–13 years, to reduce the effect of age on the studied parameters. Individuals were measured, weighed, gender was determined, gonad maturity stage, age; the condition factor and organ indices were calculated. The content of moisture, dry matter, lipids, proteins, ash and nitrogen-free extracts (NFE) in the muscles, liver and gonads of male and female bream have been analyzed. The lowest coefficients of condition factor were found in bream during the autumn feeding season, the highest in males during spawning, in females before and after spawning. In the muscle tissue of male and female bream the content of metabolic products in the feeding period and before spawning differed slightly. In the spawning period, the muscles of males exceeded the muscle tissue of females in lipid content by more than two times. In the annual cycle of the bream, the ovaries contain more protein than the testes. The bream of different sex revealed differences in the intensity of metabolic processes during the maturation of gonads: in males, energy costs are more pronounced after wintering before spawning, while in females, during spawning. The main energy reserve in the form of lipids in the annual cycle changes more significantly in the body of male bream than in females. Ovarian maturation requires more metabolite reserves than maturation of the testes, however, males have increased expenditure associated with reproductive behaviour during spawning. Therefore, the total energy contribution to reproduction may be the same for female and for male bream. Bream’s liver and muscle tissue can serve as a source of energy during food shortages and during spawning. In the annual cycle, the condition factor of bream increases due to an increase in the moisture content in the muscles.
... The chemical composition of livers varied among species probably in response to a variety of factors (diet, age, size, sex, physiological state, etc.)(Bandarra, Batista, Nunes, Empis, & Christie, 1997;Rajasilta, 1992;Wouters, Molina, Lavens, & Calderon, 2001). These factors could also explain the differences between the present results and those reported by other authors (Navarro-Garcia, Pacheco-Aguilar,Bringas-Alvarado, & Ortega-Garcia, 2004;Navarro-Garcia et al., 2009;Ould El Kebir et al., 2003;Sellami et al., 2014). ...
Abstract
The increase in world fish lipid request has made necessary the search for new fish species rich in
polyunsaturated fatty acid (PUFA) that could be used as raw material for oil production. In this
study, liver oils from the deep-sea sharks Mustelus mustelus, Squalus acanthias, and Rhinobatos
cemiculus were extracted and analyzed to describe their lipids characteristics. Lipid contents of
shark livers ranged from 64.245 to 69.57%. Among minerals, potassium and sodium were the most
abundant while unsaturated fatty acids (FAs) were dominant exceeding 55% of the total FAs.
Omega-3 PUFA (x-3 PUFA) profiles exhibited a dominance of eicosapentaenoic acid and docosahexaenoic
acid. This study suggests that shark livers, actually considered as waste, may be an
attractive source of x-3 PUFAs and a good source of carotenoids and phenolic compounds.
Practical applications
The production of EPA and DHA concentrates from residual sources of marine oils has unexplored
potential of use in food industry and oil-based nutraceutical production for obtaining health benefits
can be achieved. The economic activities of fish residues can reduce inappropriate excessive
fishing, reducing imports of fish oils while contributing to the ecosystem balance.
KEYWORDS
in vitro digestibility, lipids, nutritional quality, polyunsaturated fatty acids, radical scavenging activity,
sharks by-products
... The chemical composition of livers varied among species probably in response to a variety of factors (diet, age, size, sex, physiological state, etc.)(Bandarra, Batista, Nunes, Empis, & Christie, 1997;Rajasilta, 1992;Wouters, Molina, Lavens, & Calderon, 2001). These factors could also explain the differences between the present results and those reported by other authors (Navarro-Garcia, Pacheco-Aguilar,Bringas-Alvarado, & Ortega-Garcia, 2004;Navarro-Garcia et al., 2009;Ould El Kebir et al., 2003;Sellami et al., 2014). ...
The increase in world fish lipid request has made necessary the search for new fish species rich in polyunsaturated fatty acid (PUFA) that could be used as raw material for oil production. In this study, liver oils from the deep-sea sharks Mustelus mustelus, Squalus acanthias, and Rhinobatos cemiculus were extracted and analyzed to describe their lipids characteristics. Lipid contents of shark livers ranged from 64.245 to 69.57%. Among minerals, potassium and sodium were the most abundant while unsaturated fatty acids (FAs) were dominant exceeding 55% of the total FAs. Omega-3 PUFA (x-3 PUFA) profiles exhibited a dominance of eicosapentaenoic acid and docosa-hexaenoic acid. This study suggests that shark livers, actually considered as waste, may be an attractive source of x-3 PUFAs and a good source of carotenoids and phenolic compounds. Practical applications The production of EPA and DHA concentrates from residual sources of marine oils has unexplored potential of use in food industry and oil-based nutraceutical production for obtaining health benefits can be achieved. The economic activities of fish residues can reduce inappropriate excessive fishing, reducing imports of fish oils while contributing to the ecosystem balance. K E Y W O R D S in vitro digestibility, lipids, nutritional quality, polyunsaturated fatty acids, radical scavenging activity , sharks by-products
... Research on seasonal protandry has provided evidence that this phenomenon may positively affect male fitness in several ways. Protandry may result in a higher number of sired offspring because early-arriving females are commonly in prime body condition and may produce more offspring than late-arriving females 11,43 . In mating systems where pairs are formed early in the season, the early-arriving male may form more than one pair in the mating season 21 or may achieve more offspring via extra-pair paternity 37 . ...
In polygynandrous mating systems, in which females limit reproductive success, males can increase their success by investing in courtship. Earlier arrival at the spawning ground compared to when females arrive may increase their opportunities in competitive mating systems. In this study, we used passive telemetry to test whether a male minnow known as the asp, Leuciscus aspius, times its arrival at spawning grounds relative to the arrival of females. Males arrived in a model stream approximately five days earlier than females on average and left four to five days later than females over two years. Both sexes performed a daily migration between a staging ground (standing water, low energy costs) and the fluvial spawning ground (high energy costs). Fish abundance peaked twice a day, with a major peak at sunset and a minor peak at sunrise and with the evening peak abundance for males occurring 1 hour 40 minutes earlier than that of females. The number of females on the spawning ground never exceeded the number of males. While the degree of protandry is hypothesized to be influenced by the operational sex ratio (ranging from 0.5 to 1 in our study), our data did not support this theory.
... Interspecific competition between native and non-native fish species in high-elevation, shallow lakes has been observed through both competition between omnivores for similar food items [23] and predation by one fish species on another fish species [24]. Feeding habits can influence important life history characteristics of fishes; including growth, egg quality and quantity, and timing of spawning that determine the ultimate success of populations [25][26][27]. A greater understanding of seasonal foraging dynamics could greatly enhance managers' ability to conserve native fish populations in the face of non-native fish introductions. ...
Introduction of non-native species is a leading threat to global aquatic biodiversity. Competition between native and non-native species is often influenced by changes in suitable habitat or food availability. We investigated diet breadth and degree of trophic niche overlap for a fish assemblage of native and non-native species inhabiting a shallow, high elevation lake system. This assemblage includes one of the last remaining post-glacial endemic populations of adfluvial Arctic grayling (Thymallus arcticus) in the contiguous United States. We examined gut contents and stable isotope values of fish taxa in fall and spring to assess both short- (days) and long-term (few months) changes in trophic niches. We incorporate these short-term (gut contents) data into a secondary isotope analysis using a Bayesian statistical framework to estimate long-term trophic niche. Our data suggest that in this system, Arctic grayling share both a short- and long-term common food base with non-native trout of cutthroat x rainbow hybrid species (Oncorhynchus clarkia bouvieri x Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis). In addition, trophic niche overlap among Arctic grayling, hybrid trout, and brook trout appeared to be stronger during spring than fall. In contrast, the native species of Arctic grayling, burbot (Lota lota), and suckers (Catostomus spp.) largely consumed different prey items. Our results suggest strong seasonal differences in trophic niche overlap among Arctic grayling and non-native trout, with a potential for greatest competition for food during spring. We suggest that conservation of endemic Arctic grayling in high-elevation lakes will require recognition of the potential for coexisting non-native taxa to impede well-intentioned recovery efforts.
... Simultaneously, condition factor continuously decreased throughout the season, and the decreasing was more prominent in females than males (Fig. 8). Condition factor is fatness of the fish and indicates individual fat condition (Bolger and Connolly 1989;Rajasilta 1992). Condition factor fluctuates seasonally and starts to decrease after fish have depleted the fat body for reproduction during the spawning season. ...
Pacific bluefin tuna Thunnus orientalis occur in the south-western North Pacific spawning ground from April to July. All females and males occurring there are thought to be involved in the spawning event, but details of their occurrence are not well understood. A daily fishing port survey was conducted at Ishigaki Island (24°21’N, 124°09’E), Yaeyama Islands, during the entire fishing season (April to July) between 2009 and 2014 to assess sexual differences in the timing of occurrence and physiological condition for reproduction of Pacific bluefin tuna. In total, males (n = 566) outnumbered females (481, chi-squared test, P < 0.01) and had a larger body size (mean ± SD = 229 ± 18 cm fork length in male, 220 ± 18 cm in female, Welch’s t-test, P < 0.001). Estimated ages were not different between sexes; 6–25 years for females and 6–24 years for males. Males tended to occur earlier in the spawning ground (median date = 20 May) than females (24 May, Mann–Whitney U-test, P < 0.05). Gonadosomatic indices of both sexes increased from mid April, beginning of the fishing season, had higher values in late May to early-mid June, and then decreased. Fat body index and condition factor of both sexes decreased during the fishing season, and loss of body weight was more prominent in females. Sexual differences in the occurrence in the spawning ground are thought to relate with the reproductive activity and the condition factor.
... Fat content and fatty acid composition Fresh fillets were found to have a high relative lipid content (6.83 AE 0.94%) compared with the 1.3 AE 0.12% reported for raw golden grey mullet fillets (Ghelichpour & Shabanpour, 2011). This large variation in relative lipid contents may be due to a variety of factors including fishing area, fishing season, spawning period (Nielsen et al., 2005) or fish size and gender (Rajasilta, 1992). The lipid content of fillets was significantly affected (P < 0.05) by hot smoking (Fig. 4) with smoked fillets having a higher lipid content than fresh ones (11.47% ...
The combined effects of hot smoking and added quince polyphenol (0.8% and 1.6% v/w) on the quality attributes of mullet (Mugil cephalus) fillets were evaluated. Biochemical parameters that were monitored in the fillets during 75 days of storage (4 ± 1 °C) included trimethylamine (TMA-N), volatile basic nitrogen (TVB-N), fatty acids and amino acids. Data were submitted to principal component analysis (PCA) which revealed that the smoking process combined with polyphenols' treatment was negatively correlated with TVB-N, TMA-N, lipids, indices of lipid quality (index of atherogenicity (IA); index of thrombogenicity (IT)) and storage time. Health concern related to the flesh content of polycyclic aromatic hydrocarbons (PAHs) following hot smoking was also evaluated, and analysis showed that the sum of 4 of the PAHs (chrysene, benzo(b)fluoranthene, benz(a)anthracene and BaP) remained far below the maximum limit set by the European Commission. Sensory analysis revealed that the smoked mullet fillet treated with a low dose of polyphenols was a very acceptable new product.
... Finally, several studies (e.g. Aneer, 1985; Rajasilta, 1992) have established a relationship between reproductive activities of herring and fish condition. The effects of fish condition on the maturation and spawning cycles was tested using estimates of herring condition from least-squares analyses of weight–length relationships as recommended by Cone (1989) and described by Winters and Wheeler (1994). ...
A simple technique based on seasonal changes in gonad weights was used to describe key events in the spawning and maturation cycle of spring-spawning herring in the north-west Atlantic. Analysis showed that there were quite large inter-annual variations in the timing and duration of the maturation and spawning periods. The initial maturation process, which begins in the fall, is controlled mainly by phenotypic factors related to the size composition and condition of the adult population. The final maturation process, which begins in the spring and whose trajectory determines spawning times, is cued by January sea temperatures. The results contradict the general opinion that herring have a relatively fixed spawning season that is restricted to a brief 4-6 week period. Rather, the plasticity in spawning and maturation cycles of spring-spawning herring suggests that herring recruitment may not be a passive affair but an adaptive process in which Atlantic herring modify their reproductive activities to match expected environmental conditions during larval emergence.
... The long standing interest in fish lipids stems from the important roles lipids play in the life histories and physiology of fish 3 . Fatty acid compositions of fish lipids have been investigated for decades 4 and much of the early lipid research was directed at determining the commercial value of fish oils 5 and understanding how fat content relates to various life history functions 6 . Many studies have established that fatty acid analysis also has utility as a stock identification tool or for the purpose of population structure analysis. ...
Populations of Megalaspis cordyla (horse mackerel) from four areas, two each from the east (Digha and Mandapam regions in the Bay of Bengal) and west (Cochin and Mumbai regions of the Arabian Sea) coasts of the Indian peninsula were studied using a chemometric method based on fatty acid composition of their heart tissue. Heart tissue from the specimens from each location was collected and preserved, analyzed by the fatty acid profile method, comprising methanolysis, gas chromatography, and multivariate statistics. The profile showed difference between southern and northern populations in both the coasts. Trend was more obvious in the case of saturated fatty acids and poly unsaturated fatty acids; the southern population with high content of saturated fatty acids and the northern populations with high content of poly unsaturated fatty acids.
... 로 간과 내장에 저장하여 생식활동에 이용한다 (Diana and Mackay, 1979;Rajasilta, 1992 656 (12,053-32,817) 35,415 (20,247-53,164) 43,103 (38,720-46,004) 81,600 (62,208-104,246) 38,321 (12,053-104,246) 4,174 (2,133-5,834) 7,599 (5,292-11,467) 11,429 (10,756-12,386) 13,813 (12,051-16,600) 7,550 (2,133-16,600) 2,762 (2,460-3,327) 3,106 (2, 945) 3,077 (2,289) 3,440 (2,830) 3 ...
The reproductive ecology of the glowbelly, was examined using 637 specimens collected monthly from January to December 2006 in the coastal waters off Gori, Korea. The specimens ranged in standard length (cm, SL) from 2.9 to 11.4cm for female, 2.7 to 10.5cm for male. The gonadosomatic index (GSI) of female was highest in September and decreased until December, and the spawning season lasted from August to November. The monthly sex was not different significantly (-test, p>0.05). The size at 50% maturity was estimated at 6.0cm SL. was multiple spawner that spawn on more than one occasion in a single spawning season, and the maximum egg diameter was 0.75mm. Fecundity (F) ranged from 12,052 to 104,246 eggs, with the mean of 38,321 eggs. The relationships between fecundity and standard length (cm, SL), body weight (g, BW) were estimated as (=0.7970) and (=0.7992), respectively.
... In fact, since the early 1990s the concentration of sprat into the north-eastern Baltic Proper triggered strong densitydependent effects that resulted in a drastic decrease in body condition in this area. In other studies, condition has been related to lipid reserves and therefore to fecundity in Baltic clupeid fish [22,31]. A low body condition would then also imply a reduced per-capita reproductive output [32]. ...
Spatio-temporal density-dependent processes are crucial regulatory factors for natural populations. However, there is a lack of studies addressing spatial density-dependence in fish growth. A previous investigation has suggested spatio-temporal density-dependence in body condition of Baltic sprat. Here, we used different techniques, such as centre of gravity, distance, and homogeneity indices, to better characterize the spatial and temporal variations in sprat density and body condition in the Baltic Proper. Our results evidenced a negative spatio-temporal co-variation between the centres of gravity of density and maximum condition. In the 1980s-early 1990s both centres were located in the middle of the Baltic Proper. From the mid 1990s the centres progressively separated in space, as the sprat population moved towards the north-eastern Baltic Proper, and the centre of maximum condition towards the south-western areas. Moreover, at low abundances, sprat density and condition were homogeneously distributed in space, whereas at high abundances both density and condition showed pronounced geographical gradients. The ecological processes potentially explaining the observed patterns were discussed in the light of the Ideal Free Distribution theory. We provide evidence that the shift in the spatial distribution of cod, the main predator of sprat, has been the main factor triggering the overall spatial changes in sprat density, and thus condition, during the past thirty years. The spatial indices shown here, synthesizing the spatio-temporal patterns of fish distribution, can support the implementation of the EU Marine Strategy Framework Directive.
... In our samples, the majority of fish were at the prespawning stage, but no doubt good physical condition helps a fish to recover from the physiological stress caused by spawning. At spawning time, the fat reserves and condition of the Baltic herring are at their lowest level (Rajasilta, 1992), but fish weight and condition can respond rapidly to feeding, especially if the oil content of food is high (Chua and Teng, 1982;Young et al., 2005). It is not known how this affects the herring's survival, but the period after spawning could likely form the bottle-neck when those individuals that are in a poor condition and unable to replenish their energy reserves are eliminated from the population. ...
The stomach contents of the herring (Clupea harengus membras L.) from the Bothnian Sea, northern Baltic, were analysed during spring 2011 and 2013. The stomachs were full of Limnocalanus macrurus in May and June, and an improvement in the condition of herring was observed when fish started to feed on this prey. The analyses showed that Limnocalanus is currently an important link between lower trophic levels and Baltic herring in the Bothnian Sea.
... Consistent latitudinal patterns of interspecific spawning seasonality are also often lacking (Robertson 1991). Finally, several recent studies describe correlations between seasonal shifts in the adult environment and temporal patterns of reproduction (Fishelson et al. 1987, McClanahan 1988, Montgomery et al. 1989, Robertson 1990, Rajasilta 1992). Although pelagic conditions might still be driving seasonal peaks of spawning in such cases (i.e. if periods of maximal egg or larval survival coincide with optimal environmental conditions for adult reproduction ), these results encourage further study of the 'adult' factors influencing seasonal reproduction of coral reef fishes. ...
Little is currently known about the temporal linkage between naturally occurring food levels and patterns of growth, reproduction, and feeding behavior by fishes on coral reefs. This study examines seasonal changes in these variables for populations of the herbivorous striped parrotfish Scarus iserti on 2 reefs in the San Bias region of Panama. Although less than 3 km apart, these populations experience notably different environmental conditions during Panama's annual cycle of rainfall and drought. In response to lower rainfall and higher dry-season winds and wave action, the renewal rate and standing crop of the striped parrotfish's algal food fell on a semi-exposed reef while rising on a more protected reef. Opposite trends occurred when wind and waves abated with the return of the wet season. In response, parrotfish on the 2 reefs showed opposite patterns of seasonal growth and reproduction, indicating that reef-associated environmental conditions determine seasonal peaks of reproduction for these fish. This result challenges the notion that planktonic conditions encountered during early life-history stages generally drive seasonal reproduction by coral reef fishes.
... Timing of maximum spawning in many north-temperate stocks varies annually due to variation in ocean temperature (Lambert 1987 and references therein; Hutchings and Myers 1994), age and size structure (e.g., Hutchings and Myers 1994; Marteinsdottir and Björnsson 1999), or a combination thereof (Carscadden et al. 1997). Spawning time in Baltic herring (Clupea harengus membras) can be a function of the feeding conditions experienced prior to spawning (Rajasilta 1992), and the same can be said of captive Pacific herring (Clupea harengus pallasi; Hay et al. 1988) and Atlantic cod (Gadus morhua; Kjesbu and Holm 1994). Photoperiod (Rijnsdorp and Vingerhoed 1994; Norberg et al. 1995) and tidal phase (e.g., Hay 1990) also appear to influence spawning time. ...
Different fish stocks of the same species are defined by spatial and temporal differences in spawning, though spawning time can vary within and among stocks. Here we address spawning time variation in Icelandic summer-spawning (ISS) Atlantic herring (Clupea harengus). We do so by examining influencing factors that include variation in stock size structure, spawning experience (recruit vs. repeat spawners), spawning stock biomass (SSB), sea temperature, and combinations thereof. Our results, based on temporal variation in ovary weight (OW), relative ovary weight (RG), and maturation stage, across a time series of nearly 50 years and eight length classes of ISS herring, show that spawning occurs over a relatively invariant 30-day period defined by day-of-the-year. Logistic regression analyses and temporal development in OW and RG show that maximum spawning invariably occurs on day-of-the-year 200 ± 15 days, and seasonal variation in mesenteric fat content is physiologically consistent with the timing. We show that the smaller recruit spawners tend to spawn ~17 days later, on average, than the larger repeat spawners. Spawning occurs ~7 days later when SSB is greater than the long-term average, and spawning may be delayed by as much as 10 days during periods of colder than average ocean temperature.
... Although this theory is supported by the observed differences in the morphology, otolith characteristics, and life history traits of herring spawning at different times of the year (Parrish and Saville 1965;Postuma 1974), evidence from otolith morphometrics suggests that herring spawned during one season often occur in spawning aggregations in a different season (Messieh et al. 1989;McQuinn 1997a). Within populations of herring and other marine fish species, variation in timing of spawning has been linked to condition, size, age, and nutritional status of individual fish, as well as environmental conditions before the onset of spawning (Rajasilta 1992;Slotte 1999;Wieland et al. 2000). Such evidence highlights the phenotypic plasticity of reproductive traits and contradicts the premise that timing of spawning can maintain segregation of stocks in the absence of other barriers to gene flow. ...
Considerable debate surrounds the issue of reproductive exchange between subunits of marine fish populations. Discrete population theories predict that spawning time and location are predetermined during larval life and that spawning season fidelity and natal homing maintain population integrity. Conversely, spawning assemblages may represent interconnected subgroups within metapopulations with social transmission of spawning behaviours facilitating mixing. This study examines spawning season fidelity in three subpopulations of Atlantic herring (Clupea harengus) with overlapping distributions. Autumn- and winter-spawned fish were collected from spawning and feeding grounds in the Irish and Celtic seas. Hatching season was determined using otolith microstructure and was compared with season of spawning as indicated by visual gonad inspection. Spawning assemblages in the Irish Sea consisted almost exclusively of autumn-spawned fish, despite extensive mixing with winter-spawned fish during the juvenile phase. The available evidence suggests that in Celtic herring, the season and location of spawning are not learned from repeat-spawning adults, but are predetermined, possibly through larval imprinting. The seasonal components showed distinct patterns of gonad development, and estimated rates of spawning season switching were below 10%. Although this exchange rate will facilitate some gene flow, mixing of subgroups is limited. This has important implications for management of seasonal spawning populations.
... Without additional data, such as histological descriptions or oocyte size, GSIs are often not reliable measures to distinguish reproductively inactive but mature females from immature females during the non-spawning season (West, 1990). In fish, the energy required for spawning may be derived from liver oil reserves (Diana and Mackay, 1979) or the viscera (Rajasilta, 1992); in this work, the HSI values showed no clear trend related to spawning. This species is voracious, with a high feeding activity (Palko et al., 1982) that does not decrease during the spawning period (Olson and Galván-Magaña, 2002). ...
... In contrast, a number of studies have shown that there is no consistent relationship between fat content and the body length. For example, Rajasilta (1992) reported a positive correlation between muscle fat content and body length in the Baltic herring (Clupea harengus). Likewise, Slotte (1999) noted a similar relationship in spawning herring, but not in over-wintering herring. ...
Anchovy is a key species in the Yellow Sea ecosystem. An accurate estimate of anchovy abundance is vital for the management
of the anchovy stock and measurement of the ecosystem response to changes in anchovy abundance. However, the acoustic fish
abundance estimate may be biased by 30%–40% if the fat-content induced target strength variation is not taken into account.
We measured the monthly variation in the fat content of anchovy (Engraulis japonicus) in the Yellow Sea, and evaluated the potential effect of variation in fat content on the acoustic assessment of anchovy
abundance. The fat content of anchovy varied seasonally, with two maxima and two minima in a year. The highest fat content
(14.75%) was measured in the pre-spawning period in May, and the lowest fat content (2.48%) was measured during the post-spawning
period in October. Fat content appeared to correlate with water content, but not body size. Assuming that the target strength
is decreased by 0.2dB for every 1% increase in fat content, the seasonal difference in the target strength of anchovy may
be as high as 2.45 dB. Given this, the acoustic abundance estimate may be biased by between 43% and 76%. Our results highlight
the need for more information on the changes in fat content of fishes whose abundance is estimated by acoustic surveys.
Keywordfat content–water content–target strength–acoustic estimation–anchovy–the Yellow Sea
... No significant differences were found in relative fecundity, fertilisation rates or blastomere morphology scores. Deficiencies in the nutritional status of broodfish can reduce production of granular oocytes in plaice (Horwood et al., 1989), and alter the plasma levels of 17h-oestradiol and the timing of spawning in captive sea bass (Cerdá et al., 1994), and modify individual maturation cycles and the timing of spawning in the Baltic herring (Rajasilta, 1992). Navas et al. (1993) reported poor egg quality and spawning performance in sea bass fed artificial diets, with these effects worsening over a 2-year period, and suggested that nutritional deficiencies in the artificial diets were the cause of the impaired performance. ...
Two series of experiments were conducted to assess whether the trash fish-based diet traditionally used by the industry for broodstock halibut could be replaced by a formulated pelleted feed and to investigate the effects of docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (AA) on halibut fecundity, blastomere morphology and fertilisation and hatching rates.In the first experiment, two formulated broodstock feeds (one containing Krill meal and one supplemented with tuna orbital oil, which provided higher dietary levels of DHA and AA), gave similar performances (Relative fecundity 9557±3462 and 10,551±2166, fertilisation rate 40.0±6.4% and 40.0±9.1%, respectively) to that of a fish fed a trash fish-based diet (Relative fecundity 11,782±1873, fertilisation rate 41.0±4.0%). In a second experiment, the spawning performance and egg quality of two groups of broodstock maintained on two formulated diets, each containing different levels of AA (1.8% and 0.4%) was compared over two successive spawning seasons. The diet with the higher (1.8%) level of AA resulted in significantly higher (p<0.05) fertilisation rates (59.0±5.8%), blastomere morphology scores (14.2±0.4) and hatching rates (51.0±3.6%) compared to those on the 0.4% AA diet (31.0±4.9%, 12.5±0.3 and 28.0±5.7%, respectively). The eggs selectively accumulated DHA up to 30% of the total fatty acids. DHA/EPA and EPA/AA ratios of 2 and 4 in the eggs respectively were associated with improved egg and larval quality, similar to that achieved by fish maintained on the trash fish-based diets.
The effects of seasonal differences on the chemical composition of the
Marblid Spinefoot fish species Siganus rivulatus caught from the marine
waters of Lattakia Governorate were investigated. moisture, crude protein,
crude fat, and ash were determined as a percentage of the muscles of the
caught fish. The results showed that the Spring season was the highest in
terms of nutritional components (protein 19.18%, fat 4.06%, ash 1.82%),
while the Winter season was the lowest (protein 18.24%, fat 2.3%) and
autumn for ash (1.5%), As for the summer season, the values were (protein
18.87%, fat 3.23%, ash 1.92%). regarding the size factor, the results showed
a significant positive relationship between size increase and an increase in
protein and fat and a significant inverse relationship with both ash and
moisture content.
Temperature modifies the reproductive success of fish, yet, in many species, we lack the information on its role in the early development. In this study, the effect of temperature on the relation between maternal traits (length, age, somatic condition, and muscle lipid and ovarian thyroid hormone concentrations), egg quality (fertilization success, development rate, mortality, and hatching success), and offspring traits (size-at-hatch, yolk sac size, and proportion of malformations) were studied in Baltic herring (Clupea harengus membras) in the northern Baltic Sea. The experiments were conducted at an ambient temperature of 7°C and at an elevated temperature of 14°C using 5 to 15 females and 3 replicates per female. The results indicate that elevated temperature may result in a faster developmental rate, a lower early-stage mortality and hatching success, smaller size-at-hatch, a larger yolk sac size and a higher amount of larval malformations when compared to an ambient temperature. The egg and offspring traits were also associated with the maternal traits, indicating especially that thyroid hormones play a mediating role in the physiological processes.
The effects of seasonal and sexual differences on the chemical composition of the gold gray mullet fish species C. auratus caught from the marine waters of Lattakia Governorate were investigated. Moisture, crude protein, crude fat and ash were determinated as a percentage of the muscles of the caught fish. The results revealed that the autumn season was the highest in terms of nutritional components (protein 22.02%, fat 10.58%, ash 2.38%), while the summer season was the lowest (protein 20.56%, fat 4.68%, ash 1.72%). The results also showed the superiority of females in the values of the nutritional components over males, where the values were for females (protein 21.54%, fat 7.9%) and males (protein 21.12%, fat 7.3%), while the ash values did not show significant differences between males and females
The reproductive biology of a commercially important sparid, the goldlined seabream Rhabdosargus sarba, was determined from examination of 802 specimens (443 females, 232 males, 68 fish of undifferentiated sex, and 59 bisexual fish) collected by fisheries operating in the central waters of the Taiwan Strait (henceforth “central Taiwan Strait”) from January to December 2016. Previous studies undertaken in other parts of the world have yielded conflicting information on the reproductive biology of this species. Based on macroscopic appearance, the gonadosomatic index, and histological examination of the gonad tissues, the spawning season of this species in the central Taiwan Strait was determined to be from December to March. R. sarba is an asynchronous spawner, with a mean estimated fecundity of 825,078 ± 431,672 eggs. The sex ratio, 0.66, was significantly different from 0.5, and females predominated in most size classes and monthly samples. Size at 50% maturity was estimated to be 23.7 and 20.9 cm fork length for females and males, respectively. Ovotestes were identified in both young and adult individuals, which suggests that R. sarba is a rudimentary hermaphrodite in the central Taiwan Strait. This finding is similar to that for conspecifics reported from Australia, but differs from those reported for other geographical regions. Monthly variation in the condition factor and in the hepatosomatic index indicated that the energy reserves of the muscles and liver may be closely linked to the spawning activity of this species.
1. Environmental factors in the bay water are very similar to the
environmental conditions of the Mediterranean coast, but they
are directly affected by El-Umoum Drain water which in turn led
to the deterioration of these factors.
2. The results showed an increase in heavy metals concentrations
when approaching to El-Umoum Drain which indicates to the
main source of these elements in the bay water; due to the
increasing in the agricultural and industrial waste and sewage
which directly discharged without treatment.
3. Accumulation of heavy metals in the bay waters was less than the
permissible levels.
4. Accumulation of heavy metals in the bay sediments was
represented as the following: Fe> Zn> Pb> Ni > Cu > Cd.
5. Nickel ion concentrations in the target organs (gills, kidneys,
liver, muscles and skin) of the examined fish were higher than
the permissible ones.
6. Cu, Zn and Pb in the muscles of Alepes djedaba were lower
than the permissible levels while, Cd, Fe and Ni were higher
than the permissible ones.
7. Cu, Zn, Fe and Cd in the muscles of Diplodus sargus were
lower than the permissible levels while, Pb and Ni were higher
than the permissible ones.Summary
337
8. Cu, Zn and Cd in the muscles of Siganus rivulatus were lower
than the permissible levels while, Fe, Pb and Ni were higher
than the permissible ones.
9. Iron, lead, nickel and zinc in the different organs of fish species
(Alepes djedaba, Diplodus sargus and Siganus rivulatus)
increased with the increasing length of these species.
10. The highest values of heavy metals in the different organs of
these fish were recorded for iron and zinc. While, the lowest
values were recorded for cadmium ions.
11. Concentrations of copper, iron and nickel in the muscles of
Diplodus sargus was lower than the other organs. The highest
values of these metals were recorded in the liver.
12. The highest values of total proteins in the target organs (kidney,
liver and muscle) of Alepes djedaba and Diplodus sargus were
recorded in the kidneys and the lowest value occurred in the
muscles.
13. The highest values of total proteins in the target organs of the
examined species (Alepes djedaba and Diplodus sargus) were
recorded during spring and the lowest value occurred during
winter.
14. Total proteins, lipids and carbohydrates in the target organs of
the examined species increase with the increasing length of
these fishes
The duration and timing patterns of spawning seasons among marine teleosls tishes over broad geographic ranges from the polars to the equator has been reviewed. The review was based on 206 studies In order to evaluale potenlial patterns of the length or timing of spawning seasons in relation to tatitude, habitats and taxonomic groupings patterns.
The total food consumption of herring Clupea harengus L. and sprat Sprattus sprattus (L.), the dominant zooplanktivorous fish in the Baltic Sea, was estimated from published data on abundances, growth, mortality rates and diets using a bioenergetics model. The annual food consumption was 5.0 x 10(7) tonnes for herring and 2.4 x 10(7) tonnes for sprat. For herring ca 90 % of the food consumed was zooplankton and the rest mysids and benthos. Larvae and young-of-the-year (YOY) of sprat and herring accounted for 50 and 45 % of the total consumption respectively. Peak consumption rates occurred in August-September. Our estimate for annual consumption of zooplankton by clupeids in the Baltic sea is 4 times higher than previous estimates. One major explanation for this is that we included the consumption by YOY and 1 yr old fish. Our simulations also show that a diet shift, from a mix of zooplankton, mysids and amphipods to only zooplankton, could have a significant effect on fish growth rate. At a fixed biomass consumption, the lower energy density of zooplankton would mean that this shift would decrease growth by about 25 % for older age groups. This decrease is similar to that observed in the Baltic Sea in the late 1980s.
Fatty acid composition, oil content, free fatty acid content, and peroxide value of Baltic herring (Clupea harengus membras) and two processed products (fried fillets and fish burgers) were investigated. The highest oil content of the fillets was found in autumn (10%), at the time when the free fatty acids had their minimum (1.4%). The main fatty acids were oleic (18-23%), palmitic (17%), palmitoleic (8-12%), and docosahexaeneoic (8-10%) acids. The proportion of saturated fatty acids was a constant 23% all year around, whereas mono- and polyunsaturated acids varied from 34 to 39% and 33 to 37%, respectively. During processing the oil content doubled and the fatty acid composition changed to the pattern of the rapeseed oil used for frying. Oleic acid was a major fatty acid in the products comprising over 40% of the total fatty acids. The proportion of n-3 acids decreased during processing but the total amount of polyunsaturated acids remained fairly constant.
The reproductive biology of Psenopsis anomala was examined from semimonthly trawl samples collected in northeastern Taiwan. Male P. anomala matured at 157 mm fork length (FL) and females were mature at 168 mm FL. Sex ratio of P. anomala was skewed toward females during the spawning season but was dominated by males in non-spawning seasons. Females also dominated the large size classes. The spawning season of P. anomala began in March and lasted for about 6 months (to August). P. anomala decreased in body condition before and during spawning, then increased in condition after spawning, and reached peak condition in early winter (December). The hepatosomatic index increased during late winter (February), peaked in May prior to peak spawning in June–August and decreased to its lowest value immediately after spawning. The patterns indicate that P. anomala reduced feeding activity and used reserved energy in muscle and liver for spawning. The fecundity of P. anomala ranged from 43 to 155 thousand eggs, with a mean of 80 thousand eggs. Batch fecundity ranged from 25 to 62 thousand eggs, which is 31–46% of total fecundity. P. anomala in northeastern Taiwan matured at a smaller size, were more fecund and exhibited an earlier and more protracted spawning season than those found off Japan and in the East China Sea. Geographical variations in reproductive biology suggest that P. anomala is able to adjust phenotypic response to environmental conditions that vary with latitude.
It is a well known fact that the lipid (oil) extracted from various fish species can be of industrial benefit if properly extracted and processed. In this study herring fish oil was analyzed using quantitative and qualitative analysis in other to provide an assessment of the quality of the oil for industrial purposes. This work focuses on the production of oil from frozen herring fish (Clupea harengus) as the raw material readily available on the market, by evaluating by the oil using chemical and physical analysis and refining the oil by degumming, neutralizing, drying, and decolorizing. The experimental results revealed that the rate of extraction increases with time until maximum extraction took place using an average size of 780 µm. Every 10.64 g of dried sample used has about 4.34 g of oil extracted for five hours. The extracted herring fish oil contains two essential unsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which could be of great industrial importance.
Hufnagl, M., and Peck, M. A. 2011. Physiological individual-based modelling of larval Atlantic herring (Clupea harengus) foraging and growth: insights on climate-driven life-history scheduling. – ICES Journal of Marine Science, 68: 1170–1188.
A physiological individual-based model for the foraging and growth of Atlantic herring (Clupea harengus) larvae was constructed, validated using laboratory and field data, tested for parameter sensitivity, and used to examine
climate-driven constraints on life-history scheduling. Model scenarios examined how natural (phenological and magnitude) changes
in key environmental factors (temperature, prey, and photoperiod/daylength) affected the estimates of survival and growth
of spring- and autumn-spawned larvae. The most suitable hatching seasons agreed well with the periods of larval abundance
in Northeast Atlantic waters. Modelled survival is unlikely in June, July, and November. Mean annual temperature, prey concentration,
and composition significantly influenced larval growth of both autumn and spring spawners. The model suggested that climate-driven
changes in bottom-up factors will affect spring- and autumn-spawned larvae in different ways. It is unlikely that autumn-spawning
herring will be able to avoid unfavourable conditions by delaying their spawning time or by utilizing more northern spawning
grounds because of limitations in daylength to larval growth and survival. Conversely, earlier spawning in spring, or later,
midsummer spawning will be tightly constrained by match–mismatch dynamics between larvae and zooplankton production.
The sensory properties of marinated herring produced immediately post mortem of raw material from different fishing ground and seasons were described and related to biological, biochemical and functional properties. Subtle variation was encountered in the appearance of whole marinated herring fillets. Fishing ground did not influence the odor, flavor or texture, but there was an apparent effect of season on the sensory profile. The sensory properties were influenced by body weight, but not by age, sex and gonad maturity. The influence of varying lipid content, water content and liquid holding capacity resulted in similar effects showing the high correlation between these properties. The results indicated that variation in sensory quality observed by the industry is not primarily due to the parameters fishing ground and season.
This study was conducted to clarify the seasonal variation of the chemical composition of the Tunisian Sardinella aurita with a focus on the total lipid content. The chemical composition showed a large fluctuation over years in response to various factors. For the entire fish, lipid content was lower in July (2.50%), but higher in November (10.25%). It varies with seasons in inverse proportion to water content. Interestingly, it was found that red muscle have much higher lipid content than white muscle and the entire fish body. The major fatty acids in S. aurita lipids were palmitic acid, palmitoleic acid, eicosapentaenoic acid, docosahexaenoic acid and myristic acid. Palmitic acid comprised the main proportion (23.9%). The high amounts of saturated and monounsaturated fatty acids in the screened species are almost in agreement with other studies. Moreover, the percentage of omega-3 fatty acids (25%) was very similar to that in oil production commercial fish.
Regional and interannual variations in spawning activity of Pacific saury Cololabis saira during the northward migration in spring were investigated for 1995–1997 in the north-western Pacific. Only females with a large body size (≥270–290 mm knob length) appeared to spawn. Almost all females in this cohort were actively spawning in a region of sea surface temperature (TSS) >18° C, the proportion of active spawners appeared positively related to TSS in a region of 13° C < TSS≤ 18° C, and no females were spawning in the region of TSS≤13° C. Although this relationship between spawning activity and TSS was common in all years, the distribution of females in the large-size cohort among the regions varied interannually. Consequently, the proportion of active spawners among adult females showed considerable interannual variations.
The objective of this study was to investigate the seasonal cycle of condition, nutrition and gonad development, as well as
the magnitude of seasonal variations in energy content of somatic and gonad tissues in juveniles, males and females of Sclater's
barbel, Barbus sclateri, from the upper Guadalete River (south Spain). The influence of reproductive cycle on somatic changes
was also investigated and discussed. Measurements of condition factor (K), somatic index (SI), gonadosomatic index (GSI) and
somatic and gonad energy content (J g-1 dw) were made in individual specimens taken from the Guadalete River monthly for 12 months. This freshwater ecosystem is
characterised by strong seasonal fluctuations in water and flow level, temperature and food supply. It was found that in general
juveniles, males and females of barbel exhibited a similar condition, nutrition and somatic energy cycle throughout the year,
with the highest values in spring and the lowest in summer. Depletion of K, SI and somatic energy storage from spring until
mid-summer seems to be associated with high metabolic demands during this period, and in adult fish also with spawning-related
activity. The gonad index and energy content of the gonad were the highest in April and the lowest in summer for both sexes.
Spawning took place during late spring – early summer, with fish quiescent by mid summer. The energy required for ovarian
development (3970 J g-1 dw) was greater than the one for testes development (2763 J g-1 dw). Data on gonad energy content indicated a period (March to April) of intense energy accumulation (64% males and 37% females)
which was related to the decline in the average somatic energy content in males and females. The somatic energy content was
linearly related to K and SI. In the same way, GSI correlated positively with gonad energy. Linear trends were found between
somatic parameters (K, SI and energy content) and gonad parameters (GSI and energy content).
The energy of the body components and the energy costs of spawning and overwintering in the bay anchovy Anchoa mitchilli, the most abundant fish in Chesapeake Bay, were studied to determine seasonal variability during the different stages of its life cycle. Bimonthly samples were collected by trawl from April 1990 through October 1991. Fish condition and body energy levels fluctuated seasonally, and were related to anchovy size. Energy equivalents (cal g-1 dry wt) was highest in December, before the overwintering period. The somatic weight component increased by 32 to 33% and total body weight by 26% during the spawning season, indicating that feeding not only met energy requirements of daily spawning but also provided surplus energy for growth. The overwintering loss of energy was 33 to 35% of total body calories, and was primarily derived from deposit fat in somatic and visceral tissues.
Maturation rates (measured as the change in the gonosomatic index (GSI) with time) over the last month of the annual maturation cycle were estimated for male and female herring in British Columbia, between 1982–87. The data were analyzed to determine interannual and interregional differences in the maturation rate and its influence on spawning time. The data also indicated that in some areas herring spawned in discrete waves — the largest fish tended to spawn first and the smaller fish in subsequent waves. Each spawning wave lasted about 5–6 d and the interwave interval varied from 8–26 d in the Strait of Georgia. General equations were developed to describe gonadal growth over the entire maturation cycle. These equations accounted for the observed differences in: (1) the maturation rates between the sexes (males initially mature faster), (2) the interregional and interannual variation in the timing of spawning (herring tend to spawn later at higher latitudes, and earlier than normal when its warmer), and (3) provide an explanation for spawning waves. All of these phenomena derive from the fact that the instantaneous rate at which the gonad grows during the maturation cycle in both sexes depends on the weight of the fish, and the daily sea temperature.
Approximately 3 mo before spawning, Pacific herring (Clupea harengus pallasi) were captured and transferred to experimental netpens varying in fish density, cover, and feeding regimes. Fecundity decreased as the fish ripened. Concurrently, ovary weight and egg weight increased and somatic weight decreased. Length-specific fecundities of fed and unfed fish were similar, but the unfed fish had higher weight-specific fecundities, corresponding to a greater loss of somatic tissue during impoundment. Feeding accelerated the rate of maturity, and fed fish spawned earlier with heavier eggs than unfed fish. Relative fecundity (eggs per gram) was highest among the unfed fish. Reduction in preovulatory egg number probably was a consequence of follicular atresia (observed but not quantified here). Age-, length-, and weight-specific fecundity of impounded herring varied within the range observed for naturally maturing populations (1974 and 1980). Fecundity in impounded fish varied no more than observed in nature: there was a greater difference in age-, length-, and weight-specific fecundity between years than there was between experimental treatments. We suggest that reduction in the number of maturing oocytes occurs naturally and reflects a mechanism that allows herring to adjust their egg size and egg number according to energetic resources and environmental conditions.
Approximately 3 mo before spawning, Pacific herring (Clupea harengus pallasi) were captured and transferred to experimental netpens and subjected to different holding conditions: high, medium, and low densities; with and without covers; and fed and not fed. Mortality during impoundment was low. There were no detectable effects of density or cover, but feeding accelerated spawning time and promoted gonadal growth. Fed fish had significantly higher somatic weights, gonad weights, and condition factors and significantly lower gonosomale indices than unfed fish. Water content increased in all fish from about 70%, at the beginning, to about 75% when the fish were ripe. Consequently, total body weight increased in all females, and somatic weight decreased, but the decrease was feast in the fed fish. No significant differences in the percentages of total protein and ash in the carcass were found during impoundment, but the levels of fat and free fatty acids showed a progressive decrease. Glycogen levels in the muscle and liver were higher in fed herring. Oocyte maturation was normal. Preovulatory atresia of vitellogenic oocytes was observed in all groups. Egg diameters of fed females were slightly larger than those of unfed fish. The evidence for winter feeding in Pacific herring is evaluated.
The Atlantic herring (Clupea harengus) stock complex is confusing from the perspectives of both evolutionary biology and systematics. There are numerous ecologically and morphologically divergent stocks classified as species, subspecies, races, tribes, etc. with an unknown degree of genetic differentiation and reproductive isolation between them. The genetic population structure of herring from the Scandinavian waters was analysed electrophoretically. The pattern for distribution of genetic variation was compared to that of the morphological characters most frequently used for stock classification, i.e., the number of vertebrae and keeled scales.Fish were collected from 17 locations distributed from the northern Gulf of Bothnia to the north-east Atlantic off the west coast of Norway. The genetic analysis was based on 17 electrophoretic loci, 13 of which were variable. There are statistically significant allele frequency heterogeneities, but there is a conspicuously small amount of genetic differentiation, even between stocks classified as representing different subspecies. More than 99 per cent of the total gene diversity was found within populations, and genetic distances are typically of the order of 0001. The genotypic distribution of the total material is very similar to the one expected if all the samples had been drawn from a single panmictic population. There appears to be no association between the variation of morphological characters and that at electrophoretic loci, and this is true for the variation between as well as within samples. Data suggest that stocks either diverged rather recently or that the amount of gene flow between groups of fish classified as stocks has been large enough to prevent substantial differentiation, and that morphologic and ecologic divergence may to a large extent be environmentally induced.
Changes in the wet weights and lipid contents of muscle, liver and gonad were determined in male and female Mallotus villosus in Balsfjorden, northern Norway, in 1981, from January, when gonadal development becomes noticeable, until May when the fish are spawning. Fatty acid compositions of tissue lipids were also determined. Over 4 mo prior to spawning, the weight of muscle in female capelin decreased by 32% while the weight of the ovary increased exponentially by 830%. In males the weight of the muscle remained constant and that of the testis decreased slightly. The lipid contents of the muscle of both males and females decreased by 76% over the period and an inverse relationship existed between the water and lipid contents of muscle in both sexes. Male liver weight remained constant over the period of study whereas female liver weight increased transiently by 300% between January and March. 38% of the lipid lost from female muscle was accounted for by lipid deposited in ovary whereas negligible amounts of the lipid lost from male muscle was accounted for by lipid in the testis. Gonadal lipid was always richer in polyunsaturated fatty acids than muscle lipid and, immediately prior to spawning, 42% of the fatty acids in ovarian lipid were polyunsaturated. Muscle lipid of males and females showed a progressive increase in the percentage of the long-chain monoenes 20:1 and 22:1 between January and May. It is concluded that male capelin catabolise more of their muscle lipid reserves than females in the 4 mo prior to spawning and that most of the lipid catabolism in males is associated with physical activity. Conversely, females deposit much more of their muscle lipid in gonads than males, although considerable selectivity occurs in the mobilisation of fatty acids from muscle lipid into ovarian lipid. Additionally, biosynthesis of gonadal constituents accounts for a considerable proportion of the lipid catabolised in females.
The behavior of individual, juvenile pink salmon toward novel prey (Artemia salina) under laboratory conditions is described. Two aspects of predatory behavior, namely latency time to initial prey-capture attempt and prey-capture success, are quantified in relation to chronological age and feeding experience. Initially, mean latency time declined slightly with increasing age up to Day 19 (post-emergence from gravel), but increased sharply to an asymptote with further aging. Mean percentage capture success gradually increased from 7.88% on Day 1 to 92.9% on Day 45. Prior feeding experience on the prey resulted in a decline (to a stable level) in mean latency time in experienced fish compared to control fish. Mean percentage capture success was not significantly altered by prior feeding experience on the prey.
Publisher Summary This chapter discusses the behavior and physiology of herring and other clupeids. The various characteristics of clupeids are discussed. The Clupeidae are found in all habitats from fresh water, for example some Pomolobus and Harengula species, to sea water. Many of them are anadromous such as Alosa, Caspiolosa and Pomolobus. The family contains species that lay demersal eggs offshore (herring), demersal eggs in shallow water (Clupea pallasii) and pelagic eggs (Sardinops). The basic structure and composition of the gametes is discussed. The herring sperm is of major importance. In the body of the parent herring the gametes are maintained in a relatively favorable environment. The embryonic development of the herring is reviewed. The rate of development is closely linked with temperature, for example at 14° C gastrulation begins 22 hr after fertilization, whereas at 11.5°C the eggs after 22 hr are still in the blastula stage. The anatomy and development of the skeleton and organ systems after hatching is studied in herring.
The two mainindigenous herring (Clupea harengus L.) stocks in the Skagerrak and the Kattegat, the Skagerrak Spring Spawners (SSS) and the Kattegat Spring Spawners (KSS) have been studied regarding percentage number spawning at age, biomass and length increment, and gonad maturity cycle for the years 1969, 1971 and 1973–1976. The SSS were significantly (p < 0.01) longer and had a larger biomass at a fixed age than the KSS. Both stocks showed a strong seasonal variation in biomass with minimum in the first quarter and maximum normally in the third quarter of the year. The maturation cycle was different between the sexes: the recruited males of both stocks passed the winter in pre-maturity Stage IV, whereas the gonads of the females successively developed from Stage III to Stage IV during that time.
Herring Clupea harengus often spawns in waves which result in a succession of larval cohorts. First-time (recruit) spawners generally spawn later than repeat spawners and it is suggested that spawning proceeds consecutively through year classes from oldest to youngest due to differential maturahon. Further, it is suggested ~t 1s the large reproductive contribution of dominant year classes that gives the appearance of spawning waves; thus the number and relative size of these waves relates directly to the age structure of the reproductive population. In this paper historical data on the Norwegian spring-spawning herring stock are reworked in support of the hypothesis. An age-specific progression through annual maturation stages is demonstrated. This relation gives mean time of spawning by age which, combined with information on the age frequency distribution and age-specific fecundity, allows prediction of the duration of the spawning season and the intensity of spawning over time. Predictions agree well with observations made at actual spawning sites. Furthermore, it is probable that recruitment is, in part, dependent on the age structure of the mature population. The higher the number of age classes in the reproductive populahon the greater appears the likelihood of good recruitment.
Most British Columbia herring begin sexual maturation in the late summer and become sexually mature in the subsequent March or April. As they mature, most stocks migrate from summer feeding grounds to overwintering areas and then to shallow nearshore spawning areas. Also, newly recruited, sexually maturing fish join the adult spawning stocks, either on the summer or winter grounds. These events occur in an unpredictable environment. Consequently, reproduction in Pacific herring may be viewed as a biological problem of maintaining synchrony and precision; specifically the synchronous maturation of 1) males and females and 2) the recruit spawners with the adult fish that have spawned in previous years. Generally, the warmer the temperature, or lower the latitude, the earlier the maturation and spawning time. There are some notable exceptions that indicate local adaptation to other environmental cues. Food supply can affect the maturation rate. Egg density in Pacific herring is controlled by a biological feedback mechanism involving milt concentration and hydrographic factors. Earlier spawners tend to be larger and there is a positive relationship between female size and egg size, a tendency consistent with other herring stocks and species. Size-adjusted fecundity, when compared among different regions and years, is strikingly uniform within British Columbia. On a broad geographic scale (California to Alaska), size-specific fecundity declines with latitude. Total egg number is higher at early stages of maturation and decreases as spawning time approaches. -from Author
Complexities of herring (Clupea harengus) stocks previously alluded to are here explored in detail. Analysis of polymodal larval populations of both herring and capelin (Mallotus villosus) from a number of localities reveals the presence of a succession of larval cohorts over time. Separation of these cohorts in time and space is quantified and similarities and differences between species are indicated. The concept of "feeding range" can be applied in explanation of this cohort phenomenon. I suggest that this reproductive strategy serves to limit intraspecific competition and divides a limited food supply more equitably among the total larval population.
Chemical signals (pheromones) have been shown to be involved in schooling, territorial marking, species, sex and individual recognition, courtship, the induction of physiological readiness for mating, and in parent–young interactions. Alarm substances released from damaged skin elicit avoidance behavior. Pheromones may also be involved in homestream recognition in some anadromous species. Most pheromones investigated act as "releasers"; a few "priming" effects have been observed. In most of the chemically mediated interactions surveyed it is not clear that communication in a generally accepted sense is involved, or whether fish are simply responding adaptively to those metabolic products which inevitably "leak" into the environment and only fortuitously provide "information" to conspecifics. In a few cases, specializations in chemical secretions or secretory structures indicate that they have evolved for communication. It is proposed that a combination of factors — the availability of a wide array of soluble biochemical products, the diffuse nature of the sites from which such products might be released, and the lack of strong selection for complex chemical messages — has resulted in the relatively simple "unritualized" systems of chemical communication which appear to be characteristic of fish.Key words: chemical signals, pheromones, reproduction, schooling, homing, parental behavior, fright reaction
It is well established that the lipid content of the herring Clupea harengus from the waters around the British Isles and Ireland undergoes a marked seasonal cycle, being highest during the summer months of active feeding and lowest after a winter fast (Wood, 1958; lies & Wood, 1965; Lovern & Wood, 1937; Molloy & Cullen, 1981; Wallace, 1986). In the case of spring-spawning herring, the minimum lipid content coincides with the spawning period and the depletion of lipid over winter corresponds with the development of gonads (Lovern & Wood, 1937).
Allozyme markers have been used to investigate the genetic structure of stocks of herring. Results from these studies show little genetic differentiation between the recognised stocks. Much of the traditional evidence for discrete stocks, based on morphometrics, spawning times and tag returns, is shown to be weak and based on a typological concept. In fact this evidence indicates the occurrence of gene flow between neighbouring spawning aggregations. It is suggested that the herring stock is a transient sub-division and has no taxonomic or evolutionary status.
The contamination of Baltic herring and pike from six different areas of the Turku archipelago (the southwestern coast of Finland) with DDT and its metabolites DDE and DDD, and PCBs (polychlorinated biphenyls) was studied. Herring muscle contained on average 0·38 ppm Σ DDT and 0·31 ppm PCBs on a fresh tissue basis. However, the values obtained for individual fish specimens showed large variations, depending mainly on the differences in the fat content of the fish. The range of DDT and PCB concentrations in herring from the Turku archipelago was similar to that found in herring from the Gulf of Bothnia.Pike muscle contained on average only 0·04 ppm DDT compounds and 0·05 ppm PCBs on a fresh weight basis. The results show local differences in the residue concentration of the fish. The chlorinated hydrocarbons were found to accumulate in the liver and ovary of the pike and, to a lesser degree, in the testis and kidney. In the ovary fat the Σ DDT concentration rose to 100 ppm and that of PCBs to 190 ppm.
Finnish fisheries research, ISSN 0301-908X, vol. 10, 1-48 For the purpose of fisheries management in the northern Baltic Sea, an investigation was made of the possible existence of separate herring groups deviating from each other in growth or morphology. The growth of Baltic herring in 1974-1988 was studied on the basis of the mean size, length distributions and the von Bertalanffy growth parameters of 199 678 fish. The morphometric and meristic variation of 474 one-year-old herring was examined by multivariate methods, using thirteen morphological variables. The migrations of Baltic herring were studied by tagging 76 289 fish in 1975-1988. In managing the fisheries, it would be advisable to use small management areas when the herring are on the spawning grounds, and to extend the units for the autumn migration.
Triglycerides and phospholipids dominate in Baltic herring flesh lipids throughout the plankton growth season though at the same time plankton species and their lipids vary considerably. Wax esters and fatty alcohols do not exist in significant amounts in Baltic herring flesh or plankton. Saturated fatty acids exist in equal proportions in herring and plankton lipids whereas monoenoic acids are more dominant in herring and polyunsaturated acids in plankton lipids, respectively. The component alkyl chains are similar in both fish and plankton fatty acids, thus suggesting the planktonic origin. During the period of abundant availability of plankton the changes in the fatty acids of the herring depot fat are related to the changes in the plankton lipid composition.
1.1. Spring-spawning herring were maintained in captivity without food for a period of 4 months.2.2. Survival was lowest in those fish in which fat reserves were lowest at commencement of the experiment. Fifty per cent of this sample were still alive after 78 days, indicating a high resistance to starvation.3.3. The survivors were considerably emaciated, and biochemical analyses indicated a large reduction in the proportions and amounts of organic constituents with an increase in the proportions of water and ash.4.4. It appears that emaciation during starvation may prove less hazardous at the population level than the effect of prolonged starvation on reproductive capacity in ensuing maturation cycles.
L m d cohort succession in herring (Ckupea hrengus) md capelin (Malkobss vilHosus)
- T C Lbribert
LBRIBERT, T. C. 1984. L m d cohort succession in herring (Ckupea hrengus) md capelin (Malkobss vilHosus). Can. J. Fish. Aquat. Sci. 41: 1552-1564.
Maturation of Baltic and White &a hewing with specid reference to variations in fecundity md egg diameter. Ram. Pa-V
- L Anomma
ANOmmA, L. 1971. Maturation of Baltic and White &a hewing with specid reference to variations in fecundity md egg diameter. Ram. Pa-V. W6un. Cons. Int. Explsr. Mer 160: 12-17.
Occur-rence of DDT and PCB compunds in Baltic hewing and pike from the Twku Archipfago
- R R Limo
- J Uitamnta
- And L. E R O ~ N Rantamaki
LIMO, R. R., J. UITAMNTA, 9. RANTAMAKI, AND L. E R O ~ N. 1974. Occur-rence of DDT and PCB compunds in Baltic hewing and pike from the Twku Archipfago. Envbn. Pollut. 7: 193-207.
Composition of hod of the Baltic herring (CHupes harengus v. membrus L.), fourhorn sculpin (Myoxocephalus qdricormis L.) and eel-pout (Zoarces viviparus L.) from deep soft bottom trawling in the Ask6-Landsort area during two consecutive yem. Merentutkimuslaitok-sen julk./Havsforskningsinstt Skr
- G Aneer
ANEER, G. 1978. Composition of hod of the Baltic herring (CHupes harengus v. membrus L.), fourhorn sculpin (Myoxocephalus qdricormis L.) and eel-pout (Zoarces viviparus L.) from deep soft bottom trawling in the Ask6-Landsort area during two consecutive yem. Merentutkimuslaitok-sen julk./Havsforskningsinstt Skr. 239: 846-154. 1985. Some speculations about the Baltic herring (Ckupea hrengus membras) in connection with the eutrqhi@ation of the Baltic Sea. Can.
Age and growth Methods for assessment of fish production in fresh waters
- T B Bagenal
- F W And
- Tbsch
BAGENAL, T. B., AND F. W. TBSCH. 1978. Age and growth, p. 101-136. %m T. Bagend [ed.] Methods for assessment of fish production in fresh waters. IBP Handbook No. 3. Blackwell Scientific hblieations, Oxford.
Ice winters 198 1-85 along the Finish coast
- S &liosaari
- A And
- Seina
&LIOSAARI, S., AND A. SEINA. 1987. Ice winters 198 1-85 along the Finish coast. Finn. Mar. Res. 254: 3-63.
Spawning shod structure and spawning time of the herring (Clupea harengus) in the northeastern pxt of the Both-wian Bay
- pihtqnen
- L ~obnsuu
$%PIHTQNEN, L., AND 0. ~OBNSUU. 1984. Spawning shod structure and spawning time of the herring (Clupea harengus) in the northeastern pxt of the Both-wian Bay. Bothnim Bay Rep. 3: 3-12.
Age md growth studies on the Baltic herring, Clupea hremgus, in the northeastern part of the Bothnian Bay
- O Joensuu
- L H A H T Q ~ N And
JOENSUU, O., AND L. H A H T Q ~ N. 1984. Age md growth studies on the Baltic herring, Clupea hremgus, in the northeastern part of the Bothnian Bay. Bothnian Bay Rep. 3: 21-30.
Statview 5 12 f user's mmual. Brain-power, Inc., Cdabasas, CA. 180 p. FGmI Statistics on fishing a d fish farming in Finland in 1985
- D S Feldman
- J And
- F ~ I ~ H Gagnon
- Game
- ~ ~ S T H T W E ) Fisheries
- Fisheries
- Division
FELDMAN, D. S., AND J. GAGNON. 1986. Statview 5 12 f user's mmual. Brain-power, Inc., Cdabasas, CA. 180 p. FGmI ( F ~ I ~ H GAME AND FISHERIES R ~ s m a e ~ ~ S T H T W E ), FISHERIES DIVISION. 1989. Statistics on fishing a d fish farming in Finland in 1985. Suom. KdataEous 55: 39-137.
The effect of the ferry traffic on fish md fisheries in the SW archiplags of FinlandIn Finnish Quantitative study of the Baltic herring eggs m d larvae in the northern part of the Gulf sf Riga and principal factors determining their survivd. Fish. Pees. Board Cm
- M P Ryman
- U Lagercranz
- L Andbwssbn
- R Chakrabbrty
- R Rbsenbewg And
~ A S I L T A, M. 1982. The effect of the ferry traffic on fish md fisheries in the SW archiplags of Finland. h b l. k p. Biol. Univ. Twku 4: 1-73. (In Finnish; Swedish s u m q ) RANNAK, L. A. 1959. Quantitative study of the Baltic herring eggs m d larvae in the northern part of the Gulf sf Riga and principal factors determining their survivd. Fish. Pees. Board Cm. TrmsI. Ser. 238: 15 p. RYMAN, N., U. LAGERCRANZ, L. ANDBWSSBN, R. CHAKRABBRTY, AND R. RBSENBEWG. 1984. Lack sf mnespndence between genetic and mor-phologic variability patterns in Atlantic heming (Clqea hrengus).
The behaviour md phys-iology of herring md other clupids
- J H S And
- F G T Hqlliibay
B L A X T ~, J. H. S., AND F. G. T. HQLLIIBAY. 1963. The behaviour md phys-iology of herring md other clupids. Adv. Mar. BioE. 1 : 26 1-393.
Studies on the herring in the south-western Finland
- E Helevama
HELEVAMA, E. 1912. Studies on the herring in the south-western Finland. Suom. Kalatdllsus 1: 19-59. (In Finnish)
SASISTAT uses's guide, release 6.03 edition. SAS Institute k c Stock discreteness in herrings: a con-ceptud revolution
- Sas T N S ~ ~ Inc P Smith
- P J And
SAS T N S ~ ~ INC. 1988. SASISTAT uses's guide, release 6.03 edition. SAS Institute k c., Cay, NC. 1028 p. SMITH, P. J., AND A. J A ~ S O N. 1986. Stock discreteness in herrings: a con-ceptud revolution. Fish. R e. 4: 223-234.
Physicd features of the Bdtic Sea
- P Malkki
- And
MALKKI, P., AND TAMSALU. 1985. Physicd features of the Bdtic Sea. Ann. M a. Wes. 252: 1-110.