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The Effects of light intensity on growth and survival of cuttlefish (Sepia officinalis) hatchlings and Juveniles
Aquaculture Research
Abstract
The effects of three light intensities (100, 350 and 1200 lux) on cuttlefish hatchling rearing performance was studied in black tanks. A total of 270 cuttlefish with a mean wet weight (MWW) of 0.089 ± 0.012 g were used in the experiment, which was undertaken during the first 50 days after hatching (hatchling stage plus the transition to the juvenile stage). According to results of the present study, light intensity is an important factor for growth and survival consistency in cuttlefish rearing. All three light intensity groups displayed exponential growth. The effect of days, light intensity and their interaction only displayed differences (P < 0.05) between light groups in terms of mean wet weight. The 100 lux light intensity promoted the best absolute values of total biomass and total mortality. We believe that the higher mortality observed in 1200 lux reared cuttlefish during the first 10 days after hatching (DAH) was due to light intensity and individual adaptation to light conditions. Therefore, the 100 lux light intensity, obtained with daylight spectrum bulbs, is recommended for cuttlefish rearing during the first 50 DAH. This light setup promotes higher growth and survival rates and lower energetic costs, which are key aspects to consider in a cuttlefish hatchery.
... Among environmental factors, light is a key environmental parameter that can greatly affect the culture performance of marine larvae, especially for larvae that are visual predators, such as fish and cephalopods (e.g., Márquez et al., 2007;Pedro Cañavate et al., 2006;Puvanendran and Brown, 2002;Sykes et al., 2014;Tur et al., 2018;Villamizar et al., 2011). For example, larvae of pike-perch (Sander luciperca) had higher survival when reared under dim light conditions, but the highest growth was measured at higher light intensities, suggesting a trade-off between maximal growth and higher survival (Tielmann et al., 2017). ...
... Similar to octopuses, the survival of larvae and juveniles from other cephalopods, such as the common cuttlefish (Sepia officinalis) can be affected by light intensities (Koueta and Boucaud-Camou, 2003;Richard, 1975;Sykes et al., 2014). For example, survival and growth of S. officinalis juveniles and adults were affected by light intensities . ...
Research aimed at resolving commonly observed high mortalities in the culture of octopus paralarvae has largely focused on their nutritional requirements, while zootechnical aspects have been somewhat disregarded. Light conditions are a key environmental factor often involved in the successful larval culture of many marine organisms, with little known about the optimal light conditions for the growth and survival of cultured octopus paralarvae. This study evaluates the behavior (positive or negative phototaxis) of newly-hatched O. tetricus paralarvae aged 0 days when held under four different light sources (blue – 460 nm, green – 517 nm, pale blue – 460-517 nm, white – 440-530 nm). To test phototaxis behavior, 200 newly-hatched paralarvae were placed in a kreisel tank (12 l volume), held in darkness for 30 minutes before exposed to one of the light sources above and the distribution of the paralarvae within the tank recorded with a video camera at 0, 15 and 25 min among the bottom, middle and top layers of the kreisel tank. Light intensity was highest in the top layer for all four light sources and decreased by up to 49% and 54% in the middle and bottom layer of the kreisel tank, depending on the wavelength of each light source. Newly-hatched paralarvae were evenly distributed among the three tank layers for the four light sources at 0 min. In contrast, the majority (52.1-57.8%) of paralarvae were found in the top layer at 15 min and 25 min for all four light sources. The results demonstrate that newly-hatched O. tetricus paralarvae show positive phototaxis towards blue, green and white light, which is important knowledge required to provide O. tetricus paralarvae with suitable culture conditions.
... Sykes et al. [5] obtained increased growth and survival in cuttlefish hatchlings with the use of black tanks, which promoted a lower light intensity condition due to lower light reflections within the rearing tank. This study led those authors to test the use of different light intensities in black tanks, with the best results being achieved at low light intensities [31]. Both factors contributed to the weaning of Sepia officinalis from the first day after hatching on frozen food [32]. ...
... The different treatments shared a similar photoperiod of 12L:12D. Incident light was measured by pointing the sensor up towards the light source, while reflective light was measured by pointing the sensor down towards the tank [31]. In addition, to avoid abrupt changes in artificial light intensity, the light was switched on at 50% intensity at 8:30 a.m. and only increased to 100% intensity after 30 min. ...
High paralarvae mortality is a major bottleneck currently hindering the control over the lifecycle of common octopus (Octopus vulgaris Cuvier, 1797). It is believed that this problem might be related to either zoo-technical and/or nutritional aspects. The present paper is focused on the study of different zoo-technical aspects related to light conditions on the rearing of paralarvae, including the effects of polarization in prey ingestion, the use of a blue filter to simulate natural conditions, and the use of focused light to avoid reflections of the rearing tank’s walls. In the first experiment, O. vulgaris paralarvae ingestion of Artemia sp. and copepods (Tisbe sp.) was assessed under either normal or polarized light. In the second experiment, the effect of a blue filter with natural light or focused artificial light on growth and mortality was assessed over 15 days of rearing. Ingestion rate was not influenced by light polarization. Nonetheless, a significantly higher ingestion of Artemia sp. with respect to copepods was observed. The blue filter promoted the use of natural light conditions in Octopus paralarval culture, while focused light reduced the collision of the paralarvae against the walls. However, no significant differences were found in paralarval growth nor survival.
... Besides temperature, diet and the above mentioned water quality parameters, other biotic and abiotic factors may have an effect on culture success, which highlights the need to determine standard conditions for optimum growth and survival (Uriarte et al. 2011;Estefanell, Roo, Fern andez-Palacios, Izquierdo & Socorro 2012). Few parameters have been examined, among which salinity (Villanueva, Moltschaniwskyj & Bozzano 2007), type and colour of tanks (Sykes, Domingues, M arquez & Andrade 2011), and light type, photoperiod and intensity Sykes, Quintana & Andrade 2014), but their effects on the formation of hard structures are practically unknown in cephalopods (Villanueva, Arkhipkin, Jereb, Lefkaditou, Lipinski, Perales-Raya, Riba & Rocha 2003). High luminosity has been observed to positively contribute to female growth rate, maturation and spawning (Iglesias et al. 2000). ...
... High luminosity has been observed to positively contribute to female growth rate, maturation and spawning (Iglesias et al. 2000). In the case of benthic hatchlings (up to 50-days old) of Sepia officinalis, however, the use of low light intensity was more beneficial to growth and survival than the use of high intensity (Sykes et al. 2014). In the present study, a slight decrease in light intensity was observed at times during the second week, although variation in intensity during the day (morning/afternoon) was higher in that period. ...
Octopus vulgaris is a viable candidate for commercial aquaculture, but rearing procedures might stress individuals and result in diminished growth and survival. This study investigated the relationship between possible stress sources (tank transposition and syphoning) when rearing O. vulgaris paralarvae and the deposition pattern of growth increments in their beak microstructure. Light intensity at the facility was heterogeneous, and accounted for with an experimental design consisting of blocks without replicates. Growth and survival were estimated and possible effects of handling were tested for both parameters. Increments and stress marks were counted in 120 paralarval upper jaws (UJ), and the number of UJs with a mark on the day of stress application (day 8) was quantified. Differences in light intensity, diet quantity and total number of marks in the UJ were also compared between treatments. Growth and survival were statistically similar between treatments, although the control treatment showed a tendency for higher survival rates. Age at first increment deposition coincided with day 1 of experiment, and a 1 increment day−1 deposition rate was validated for the experiment duration. The number of stress marks was significantly different between the control and other treatments, indicating that handling might cause stress and that marks can be used as a biomarker for stress, although the occurrence of stress marks on day 8 was not significantly different. Light intensity and diet might have also been relevant stressors and confounded the results. The results herein presented are important for improving rearing conditions for O. vulgaris paralarvae.
... Sykes et al. (2006b) previously recommended to rear cuttlefish in the hatching tank (Fig. 11.4a) but currently the use of hatching baskets (Fig. 11.4b), preferably in black (Fig. 11.4c; Sykes et al. 2011), or raceway tanks (Fig. 11.4d) is suggested. The use of low light intensities during this stage is also suggested (Sykes et al. 2013c). These conditions of tank colour, light intensity and similar seawater physical conditions with respect to embryonic development should be maintained to promote appropriate welfare conditions, lower mortality rates and normal growth and development. ...
... There is no known minimal amount of light necessary for this stage but recent results recommended 100 lx at the air-water interface of the tank (Sykes et al. 2013c), provided by daylight (450-650 nm) fluorescent bulbs. From published data, only Koueta and Boucaud-Camou (2003) studied the effect of photoperiods in hatchlings and suggested that cuttlefish hunts more during daylight. ...
This chapter reviews the importance of the European cuttlefish, Sepia
officinalis, as a potential species for aquaculture and its applications. It provides an
overview of cuttlefish culture, its current state of art and future trends. Present cuttlefish
culture-related research and recently developed technologies are described.
This includes a description of the culture systems for the different life stages, broodstock
and egg acclimatization to captivity and management, hatchlings, juvenile
and adult-rearing methodologies. Values of fecundity and fertility obtained in different
culture conditions (variables include tanks, stocking densities, sex ratios and
food); a characterization of different types of cuttlefish egg morphology; growth
rates, mortality, feeding rates and food conversions at the hatchling and juvenile
stages (including live, frozen and artificial diets); and a comparison between different
growout setups are presented. Finally, current bottlenecks are enumerated,
prospects for future research are suggested and an overview of whole animal use by
the industry is given.
... Interestingly, we have found that silicate concentration is one of the main drivers of community composition in Demospongiae and Hexactinellida. Recent studies have revealed the effect of light regimes on growth of cuttlefish (Fiorito et al., 2014;Sykes et al., 2014), distribution of Ascidiacea (Shenkar and Swalla, 2011) and symbiosis activities of Anthozoa (as the acquisition of both ammonium and nitrate in is a light-dependent process) (Furla et al., 2005), which might explain the importance of light in the distribution of these taxa in this study. Some studies have also highlighted the role of currents in shifting the community compositions and distributions of epibenthic megafauna such as echinoderms, supporting our findings in this study (Roy et al., 2014;Lacharité and Metaxas, 2018). ...
Establishing management programs to preserve the benthic communities along the NW Pacific and the Arctic Ocean (AO) requires a deep understanding of the composition of communities and their responses to environmental stressors. In this study, we thus examine patterns of benthic community composition and patterns of species richness along the NW Pacific and Arctic Seas and investigate the most important environmental drivers of those patterns. Overall we found a trend of decreasing species richness toward higher latitudes and deeper waters, peaking in coastal waters of the eastern Philippines. The most dominant taxa along the entire study area were Arthropoda, Mollusca, Cnidaria, Echinodermata, and Annelida. We found that depth, not temperature, was the main driver of community composition along the NW Pacific and neighboring Arctic Seas. Depth has been previously suggested as a factor driving species distribution in benthic fauna. Following depth, the most influential environmental drivers of community composition along the NW Pacific and the Arctic Ocean were silicate, light, and currents. For example, silicate in Hexactinellida, Holothuroidea, and Ophiuroidea; and light in Cephalopoda and Gymnolaemata had the highest correlations with community composition. In this study, based on a combination of new samples and open-access data, we show that different benthic communities might respond differently to future climatic changes based on their taxon-specific biological, physiological, and ecological characteristics. International conservation efforts and habitat preservation should take an adaptive approach and apply measures that take the differences among benthic communities in responding to future climate change into account. This facilitates implementing appropriate conservation management strategies and sustainable utilization of the NW Pacific and Arctic marine ecosystems.
... Newly hatched Sepia officinalis can predate on the mysid Mesopodopsis slabberi at light intensities as low as 25 lx of white light (Márquez et al., 2007a) or simply when the aquatic medium contains bioluminescent microalgae (Fleisher and Case, 1995). Both results, together with the absence of a significant effect on hatchling growth and survival with light intensities ranging between 100 and 1200 lx (Sykes et al., 2014), point to a wide range of light intensity tolerance in this species. In the case of O. vulgaris, the importance of light intensity for the feeding success of 1-day old paralarvae preying on Artemia sp. was established by Márquez et al. (2007b). ...
... The species tolerates a wide temperature range (10-32 C; Domingues et al. 2001a, Domingues et al. 2002. Hatchlings should be reared in black tanks (Sykes et al. 2011), at low incident light intensities (100 lux) or reflective light intensities below 10 lux (Sykes et al. 2013), and at densities less than 500 hatchlings/m 2 (Sykes et al. 2003). Figure 3 shows a common seawater system setup with 10-L raceway tanks in a flowthrough system, which may hold 500 cuttlefish hatchlings through this stage, depending on temperature. ...
En France la seiche commune Sepia officinalis est élevée en eau claire alors qu’elle a évolué dans un environnement naturel où la turbidité de l’eau varie saisonnièrement et quotidiennement. Cette thèse tente de voir si l’élevage dans des conditions proches du milieu naturel (i.e turbides) ne permet pas d’améliorer les conditions de vie des seiches en laboratoire. Nous avons démontré que la préférence pour le milieu turbide est âge dépendante : les jeunes seiches préfèrent l’eau claire et les plus âgées l’eau turbide. Le comportement prédateur des seiches n’est pas modifié en milieu turbide sauf pour le groupe élevé en turbidité forte où le comportement prédateur est moins performant en eau turbide. Les seiches adaptent leur camouflage à la turbidité de l’eau de leur environnent. L’environnement d’élevage joue probablement sur la façon dont les seiches perçoivent la turbidité. La turbidité impacte également l’ensablement, un comportement défensif pourtant peu dépendant des stimuli visuels. Nous avons également montré un effet de l’expérience individuelle et du milieu d’élevage sur l’adaptation à la turbidité. A l’âge de 7 jours les seiches élevées dans une eau turbide développent des capacités visuelles supérieures en eau claire (sensibilité à la polarisation) et en eau turbide (contraste d’intensité). Nos résultats préliminaires semblent suggérer que la seiche utilise préférentiellement la modalité olfactive en eau turbide. La couleur de l’œuf, le site de ponte et le milieu d’élevage influencent les capacités visuelles de seiches juvéniles et conditionnent leur sensibilité et leur adaptation à la turbidité. Chez une espèce d’eau claire, Sepia pharaonis la turbidité influence les capacités visuelles mais les individus semblent limités dans les réponses adaptatives qu’ils peuvent produire pour se camoufler dans un milieu turbide. L’ensemble de nos résultats montrent que la turbidité du milieu, lorsqu’elle est modérée, est un élément d’enrichissement qui pourrait être utilisée afin d’améliorer les conditions d’élevage de la seiche commune.
Photoperiod is a key environmental indicator for regulating embryonic development, individual growth and physiological processes in aquatic animals. In this study, differences in embryonic development and performance of newly hatched cuttlefish juvenile exposed to five different cycles of lightdark (L:D): constant light, 18L:6D, 12L:12D, 6L:18D cycles, and constant darkness were evaluated. Prolonged exposure to light induced an accelerated rate of embryonic development, particularly after the red-bead stage. Principal component analysis (PCA) revealed that red-bead stage, heartbeat, endoskeleton formation, pigment appear, and six increments of cuttlebone were the main factors contributing to the embryonic development. Meaning that the duration time of these five stages were significantly different when exposed to photoperiod regimes, which may determine the duration of the incubation period of the embryos. Long term light has also affected the incubation parameters with an increased rate in hatching and shortened the incubation and hatching periods in the 12–24-h day length range. However, constant light and darkness environment appeared to have a greater effect on the stress of embryonic development, mainly reflected in the yolk shed ratio and the inking rate in the egg capsule. Moreover, the increase in the day length has contributed to improve the growth and survival of juveniles in the 12–18-h day length range; however, juveniles exposed to constant light and darkness experienced worse results in terms of growth, tissue glycogen content, digestive enzymes of the digestive glands, and metabolic enzymes of the muscles. These finding suggest that prolonged light exposure accelerates the process of embryonic development, maximum feeding time is not necessarily a condition of optimal growth, and inappropriate light cycles can disturb the body’s endogenous controls. Therefore, the optimal photoperiod for the embryos development and juvenile growth of Sepia pharaonis were 12 h and 12–18 h of day length, respectively. These results are useful for increasing the production of this species during embryo incubation and juveniles rearing in aquaculture practice.
The impact of individual size differences on social interactions and social groups are being increasingly recognized by researchers in different disciplines, but studies on cephalopods are still scanty. A two-stage trial was conducted to evaluate the effect of size ratios on growth and physiology of juvenile pharaoh cuttlefish (Sepia pharaonis). Juvenile cuttlefish were divided into two size groups (large (L): weight 1.0 ± 0.08 g, mantle length 1.5 ± 0.1 cm; small (S): weight 0.3 ± 0.05 g, mantle length 0.8 ± 0.1 cm), and groups with the following size-based ratios (L:S) were established: 0:30, 3:27, 6:24, 9:21, 12:18, 15:15, and 30:0. During the first phase of the 4-week trial, the growth parameters indicated that small cuttlefish experienced growth depression at the size ratio of large cuttlefish >9:21, which seemed to be irreversible. When large cuttlefish were removed from the 9:21 group, compensatory growth occurred, and define specific growth rate was significantly higher than that in other groups (P < .05). The occurrence of low levels of glycogen in tissue and of stress-induced physical damage indicated size dominance affects feeding, that small individuals were suppressed by larger individuals, and that small cuttlefish suffer from malnutrition, especially at the size ratios of 12:18 and 15:15. Expression of arginine kinase (AK) and heat shock protein 90 (HSP90) implied that the size ratio of 9:21 was a turning point; exceeding this ratio, resulted in significantly decreased growth performance and physiological activity. In summary, the differences in size seem to be a direct consequence of social dominance where the larger cuttlefish are aggressive against smaller individuals, resulting in suppressed growth, and were closely related to cannibalism and size-dependent mortality. This study provides evidence of size dominance in cuttlefish with implications for ethical and welfare considerations when using cephalopods as experimental animals and aquaculture practice.
Ensuring the health and welfare of animals in research is paramount, and the normal functioning of the digestive tract is essential for both. Here we critically assess non- or minimally-invasive techniques which may be used to assess a cephalopod's digestive tract functionality to inform health monitoring. We focus on: (i) predatory response as an indication of appetitive drive; (ii) body weight assessment and interpretation of deviations (e.g., digestive gland weight loss is disproportionate to body weight loss in starvation); (iii) oro-anal transit time requiring novel, standardized techniques to facilitate comparative studies of species and diets; (iv) defecation frequency and analysis of fecal color (diet dependent) and composition (parasites, biomarkers, and cytology); (v) digestive tract endoscopy, but passage of the esophagus through the brain is a technical challenge; (vi) high resolution ultrasound that offers the possibility of imaging the morphology of the digestive tract (e.g., food distribution, indigestible residues, obstruction) and recording contractile activity; (vii) needle biopsy (with ultrasound guidance) as a technique for investigating digestive gland biochemistry and pathology without the death of the animal. These techniques will inform the development of physiologically based assessments of health and the impact of experimental procedures. Although intended for use in the laboratory they are equally applicable to cephalopods in public display and aquaculture.
Maintenance of health and welfare of a cephalopod is essential whether it is in a research, aquaculture or public display. The inclusion of cephalopods in the European Union legislation (Directive 2010/63/EU) regulating the use of animals for scientific purposes has prompted detailed consideration and review of all aspects of the care and welfare of cephalopods in the laboratory but the information generated will be of utility in other settings. We overview a wide range of topics of relevance to cephalopod digestive tract physiology and their relationship to the health and welfare of these animals. Major topics reviewed include: (i) Feeding cephalopods in captivity which deals with live food and prepared diets, feeding frequency (ad libitum vs. intermittent) and the amount of food provided; (ii) The particular challenges in feeding hatchlings and paralarvae, as feeding and survival of paralarvae remain major bottlenecks for aquaculture e.g., Octopus vulgaris; (iii) Digestive tract parasites and ingested toxins are discussed not only from the perspective of the impact on digestive function and welfare but also as potential confounding factors in research studies; (iv) Food deprivation is sometimes necessary (e.g., prior to anesthesia and surgery, to investigate metabolic control) but what is the impact on a cephalopod, how can it be assessed and how does the duration relate to regulatory threshold and severity assessment? Reduced food intake is also reviewed in the context of setting humane end-points in experimental procedures; (v) A range of experimental procedures are reviewed for their potential impact on digestive tract function and welfare including anesthesia and surgery, pain and stress, drug administration and induced developmental abnormalities. The review concludes by making some specific recommendations regarding reporting of feeding data and identifies a number of areas for further investigation. The answer to many of the questions raised here will rely on studies of the physiology of the digestive tract.
The aim of this experiment was to determine the optimal initial food for hatchling cuttlefish and to investigate the influence of dietary composition on the growth, survival, and nutritional composition of cultured juvenile cuttlefish, Sepia pharaonis. Six experimental food groups were designated: Artemia nauplii, Calanus sinicus, frozen Hyperacanthomysis brevirostris, Ampithoe valida, H. brevirostris, and subadult Artemia. The results showed that survival, growth body biochemical composition of juvenile cuttlefish were significantly affected by experimental diets (P < 0.05). The optimum initial food was H. brevirostris, yielding a growth rate as high as 6.39%/d and survival rate reaching 81%. Growth rate was significantly positively correlated with dietary protein, Lys, Met, Phe, Iie, Leu, Trp, Arg, Gly, Eicosapentaenoic acid (EPA), Docosahexaenoic acid (DHA), and 16:0 (P < 0.05). Survival was significantly positively correlated with dietary protein, Lys, Met, Phe, Val, Thr, Iie, Leu, Trp, Arg, Gly, EPA, DHA, and 16:0 (P < 0.05). The dietary protein, lipid, Met, Val, Thr, Leu, 18:0, and EPA were prone to accumulation within the body of juvenile cuttlefish (P < 0.05). These results demonstrate that juvenile cuttlefish exhibited the best growth rates and survival when fed a diet that supplied high-protein, low-fat, and larger quantities of Lys, Met, Phe, Val, Thr, Iie, Leu, Trp, Arg, Gly, EPA, DHA, and 16:0.
Experiments designed to measure the effect of LED (light–emitting diode) light wavelength on the growth of fingerling rockfishes (Sebastes inermis) were conducted. Fingerling rockfishes (average body weight of individual: 1.13g) were divided into two groups by wavelength of the LED light [light power: 1,620 mW; wavelength: 518 nm (green color), 622 nm (red color)]. Triplicate groups of 180 individuals were reared over 7 weeks. Lighting duration was 14 hours from 06:00 to 20:00. A water tank exposed on the natural light in a room through the windows was used as a control. At results of the first experiment [initial average body weight (BW) of individual: 1.13 g; standard deviation (SD): 0.13 g], the final individual BW exposed on the green color was increased 0.39 g than the red color, and decreased 0.12 g than the natural light in the room. At results of the second (initial individual BW: 5.07 g; SD: 0.70 g) and the third experiment (initial individual BW: 10.67 g; SD: 0.67 g), the final individual BW exposed on the green color was increased 1.07 g and 2.55 g than the red color, respectively, and increased 0.57 g and 0.84 g than the natural light, respectively. The relative growth rate of the green color was higher about 8% significantly (p<0.05) than the natural light. In the case of the red color the relative growth rate was lower significantly (p<0.05) than the natural light.
This article presents a review on growth of the cuttlefish (Sepia officinalis) under laboratory conditions as well as in wild populations. Growth in captivity under different conditions relating to culture density, prey type and den-sity, temperature and tank size is reported. Growth studies using artificial feeds are also reported. Growth in wild populations is focused upon considering recent re-sults based on age-size frequency distributions and biochemical indices, where some new data are given. The effect of some environmental factors on growth is also reported.
Light is a key environmental factor that synchronizes all life-stages of fish, from embryo development to sexual maturation. The underwater photo-environment is complex since light characteristics (i.e. intensity, photoperiod and spectrum) depend on the absorbance properties of the water column. The aim of this paper is to review the effects of artificial lighting conditions on the performance, development and welfare of some fish larvae of commercial interest. Reviewed results show that larvae were significantly affected by light characteristics. For example, European sea bass and sole larvae achieved the best performance, and showed fastest development and lowest degree of deformity under a light/dark cycle using blue light (half-peak bandwidth = 435–500 nm), conditions which were the closest to their natural aquatic environment. However, constant light (LL) or constant darkness (DD) was shown to negatively affect normal larval development and resulted in increased malformations and poor survival in most of the studied species. Similar results have been observed in other fish larvae such as Atlantic cod, which performed better under short wavelengths (blue and green). These findings highlight the role of lighting conditions during the early development of fish larvae and should be taken into account for the optimization of rearing protocols in fish hatcheries as juvenile supply is one of the main production bottlenecks.
Abstract This investigation examined the effects of live prey availability on growth and survival of Sepia officinalis. Two independent experiments, comprising two feed rations each, were performed, using adequate prey size. In the first experiment, cuttlefish hatchlings were fed live mysids, Paramysis nouvelli [(feed ratio I (fr I)], at 15% body weight per day (bw day−1) (fr I15) and 30% bw day−1 (fr I30). In the second experiment, juvenile cuttlefish were fed live Atlantic ditch shrimp, Paleomonetes varians (fr II), under the same experimental design. In both experiments, the final mean weight, feeding rate and instantaneous growth rate were higher when animals were fed feed ratio fr II15 and fr II30 (30% bw day−1). The results indicate that prey availability influenced weight gain, irrespective of the prey used, during the first 2 months of cuttlefish life cycle. This effect seems to be more noticeable when a certain limit of prey is achieved. For cuttlefish fed fr II, the optimal prey density is thought to be under 2.5 g prey L−1 (i.e. 14 shrimp L−1). Results indicate that cuttlefish can withstand prey densities up to 120 mysids L−1 for cuttlefish up to 3 weeks old and 19 shrimps L−1 for cuttlefish up to 6 weeks old.
This investigation examined the effect of prey condition on the growth and survival of juvenile cuttlefish (Sepia officinalis). In the first group, cuttlefish were fed with daily captured live Palaeomonetes varians from the wild [daily prey (DP)], the second group was fed 5 days stocked and starved P. varians [starved prey (SP)], while in the third group, cuttlefish were fed 8 days stocked P. varians fed with an artificial diet [fed prey (FP)]. Mean instantaneous growth rate (IGR) was 2.8±1% body weight day−1 (bw day−1), 3.3±1.1% bw day−1 and 4.9±0.5% bw day−1 for SP, DP and FP respectively. At the end of the experiment, final weight gain (Wg) was 121±21.6%, 153.8±17.3% and 295±29.8% for SP, DP and FP respectively. No significant differences were found (P>0.05) between growth curves for every group tested, or for the food conversions between those same groups (P>0.05), but statistical differences (P<0.05) were found in IGR between DP vs. FP and SP vs. FP. Mortality was 2 and 1 for SP and DP respectively. Results indicate that prey starvation should not be considered when feeding juvenile cuttlefish, as prey can only be stocked if proper artificial diets are provided, to obtain optimal growth.
7) We are grateful to Dawn Golden for manually coding behaviors videotaped in Experiment 1. We thank for their assistance in the computerized scoring of hours upon hours of videotape. James Fenwick and Guy Steucek generously provided statistical advice; responsibility for any errors in the analyses remains ours. Care and maintenance of animals was graciously provided by the staff of the National Resource Center of the University of Texas Medical Branch in Galveston, Texas, and the Marine Resources Center of the Marine Biological Laboratory in Woods Hole, Massachusetts. Funding for this project was provided by the Sholley Foundation (RTH), the Millersville University Faculty Grants Committee (JGB), NIH grant 5F32HD07686 (JGB), NSF grant IBN 9419566 (RTH), and BSF grant 1999040 (NS). All experiments and animal maintenance were in compliance with U.S. law and institutional internal regulations concerning animal care.
The present article provides an overview of cuttlefish culture, its current state of art, and future trends. Present cuttlefish culture related research, recently developed technologies (like culture systems, maternity/nursery and juve-nile and adult proceedings) are described. Finally, current problems and prospects for future research are discussed. The increase of the human population has led to a greater demand for fishery products, and there-fore intensified diversification of fish catches. Al-though there has been a decline in fish consump-tion and production in developed countries, global fish consumption has doubled since the beginning of the 1970's (Delgado et al. 2003). During this pe-riod, aquaculture production followed this increase and has risen from 6 to 30% of total fishery pro-duction (Delgado et al. 2003). Landings from worldwide aquaculture increased rapidly in the last decade, to approximately 10–15% per year. Ac-cording to FAO (2002), total aquaculture in 1996 was 26.7 million tons, and in 2001 increased to 37.5 million tons. Rapid growth was due to the combined effects of an increasing world popula-tion, decreasing catches from traditional fisheries (Caddy & Griffiths 1995), and changing consumer preferences in developed countries (Lem & Shehadeh 1997, Tacon 1997). Ultimately, this was reflected in world fish catches, including cephalo-pods. Between 1950 and 1970, cephalopod land-ings increased from 20 million tons (Mt) to 70 Mt (Amaratunga 1983). At present, cephalopod spe-cies represent an important seafood supply for hu-man consumption worldwide. According to FAO (FAO 2002, 2004), cephalopods contribute approx-imately 14% of the world fisheries. The fast de-cline of the worldwide fish stocks, as well as the technological advances over the last 15 years, and decreased prices of commonly cultured species, makes the development of technology for rearing and culture of new species profitable, indeed nec-essary (FAO 2004). High commercial value of the cephalopods, particularly in the Asian and Medi-terranean markets, and some aspects of cephalopod biology and physiology make them good candi-dates for aquaculture (Kunisaki 2000, Ruíz-Cappillas et al. 2002). It is also known that cephalopod consumption is increasing in the American market. Thus, an overall increase in world cephalopod consumption is predicted, since an open market with high growing potential is fore-seen in the future. These facts indicate that increas-ing efforts to start semi-intensive and intensive cul-ture of cephalopod species like the European cuttlefish (Sepia officinalis) and the common octopus (Octopus vulgaris) should be made. The top five countries in fish consumption (above 40 kg/head/year; Iceland, Japan, Portugal, Norway and Spain) (European Communities 2004) are also those searching for greater diversification of edible fish species. In these countries, there is an existing market for cephalopod catches. In fact, Japan is the principal consumer of cephalopods, with cuttlefish being the most appreciated and val-ued species (Boucaud-Camou 1990). Therefore, cephalopod production for human consumption in these countries is advantageous, since their short life cycles and fast growth rates imply lower pro-duction periods and associated costs. Also, the non-edible parts of cephalopods, which make up approximately 30% of the animal, can be used for fish meal or bait. According to Kreuzer (1984), the conversion of non-edible parts into products of higher value would also be economically beneficial. In the case of cuttlefish, there is potential for further exploitation, particularly with regard to the production of undersized individuals allowed by DGPA (Portuguese Fisheries and Agriculture De-partment), which would reduce the impact of ille-gal catches on this species from the natural envi-ronment. For example, the smallest individuals are considered a delicacy and have the highest com-mercial value in Portugal. The main reason for this increasing demand is that cephalopods in general
The effects of culture density on growth and survival of juvenile cuttlefish were tested. Groups of 1, 3 and 5 hatchlings were placed in small containers with bottom surface of 80 cm2, obtaining individual densities of 125, 375 and 625 cuttlefish m–2, respectively. Additionally, groups of 5 hatchlings were placed in containers with 2 different bottom areas (80 and 240 cm2), providing culture densities of 625 and 42 cuttlefish m–2, respectively. A total of 120 hatchlings were used and experiments lasted for 40 days. No differences were found in growth between any of the densities tested throughout the experiment until 35 days old. After this, cuttlefish placed in isolation grew significantly larger. A second experiment was conducted in a flow through system, using two rectangular tanks with bottom surface of 0.5 m2. Two groups of 25 cuttlefish hatchlings were used in this experiment, which lasted for 40 days. Both groups were fed live juvenile shrimp (Crangon crangon) during the first 5 days. Afterwards, one group was fed live fish fry of different species, while the other continued to be fed shrimp. After day 10 and until the end of the experiment, hatchlings fed shrimp grew significantly larger than those fed fish fry. Survival of hatchlings fed shrimp or fish fry after 40 days was of 100% and 68%, respectively. Total protein content of both prey types was similar. Therefore, the higher polar lipid content, especially due to the higher phosphatidylcholine and phosphatidylethanolamine levels observed in the shrimp, compared to fish fry could possibly be one of the major factor to explain the significantly higher growth rates for S. officinalis juveniles fed shrimp. Also, the percentage of polar lipids in the shrimp (47.4%) was closer to the one of juvenile cuttlefish (38.1%) than the composition of polar lipids in fish fry (10.4%). This could also be an important factor to explain the poor growth and survival obtained when feeding fish fry to the cuttlefish.
The culture of Sepia officinalis hatchlings and juveniles at different densities and enriched environments was investigated. Experiments were conducted to
determine effects of culture density and the use of a substrate on growth and survival. Experiment I studied the effect of
three different densities (52, 515 and 1544 hatchlings m−2). Experiment II tested the effects of the enriched environment, using a sandy bottom with pvc shelters. Experiment III tested
the effects of density on growth, survival, feeding rates and food conversions. Cuttlefish were fed live grass shrimp at rates
of 20% body weight per day (BW d−1). Grass shrimp (Palaemonetes varians) was supplied ad libitum as food in all experiments. In experiment I, growth was different between the three densities, with highest growth for density
of 515 hatchlings m−2. IGR was of 8.8, 9.6 and 9.2% BW d−1 for the three densities tested, respectively. Both groups of experiment II had similar growth. IGR was of 10.1 and 9.7% BW
d−1 for enriched and non-enriched environments, respectively. Densities of 10, 45 and 120 juvenile m−2 were used in experiment III. Significant differences in feeding rates were only found between densities of 10 and 120 cuttlefish
m−2 during the last week. Results indicate that culture of cuttlefish hatchlings could be done in a non-enriched environment,
with densities not exceeding 500 hatchlings m−2 and minimum bottom areas of about 600 cm2. Densities of 120 juveniles m−2 in a minimum area of about 1083 cm2 should be considered for juveniles between 5 and 25 g.
Twoexperiments were conducted to determine the effects ofArtemia sp. or mysids on growth and survival ofS. officinalis hatchlings, and their effect throughout thelife cycle. For experiment I, for the first 20 days, one group was fed adultArtemia sp. and the other was fed mysid shrimp(Paramysis nouvelli). Eggs laid by females in both groupswere counted and weighed, and hatchlings were weighed, to determine differencesin both groups. For experiment II, during the first 10 days, one group was fedArtemia sp. and the other was fed mysids (P.nouveli). After the period of differentiated feeding, the 2 groupsinexperiment I were fed grass shrimp (Paleomonetes varians)to 70 days old, and dead crabs (Carcinus maenas)afterwards. Cuttlefish in experiment II were fed grass shrimp from day 10 untilthe end of the experiment. For both experiments, hatchlings fed mysids grewsignificantly bigger (p < 0.01)="" and="" survival="" was="" higher.="" for="" experiment="" i,eggs="" laid="" by="" females="" fed="" mysids="" and="" the="" hatchlings="" born="" from="" these="" eggs="" werebigger="" (p="">< 0.001)="" compared="" to="" the="" group="" fed="">Artemiasp.initially. Individual fecundity was slightly higher for females in the groupfedArtemia sp. (163 eggs female–1) than forthe group fed mysids (144 eggs female–1). Egg laying startedatthe age of 125 days and lasted 45 days in both groups. Time between first egglaying day and first hatchlings to be born was 21 days. The last female to die(after spawning) in both groups was 167 days (less than 6 months old).
In two separate experiments, haddock (Melanogrammus aeglefinus) larvae were raised under different photoperiods (24L : 0D or 15L : 9D), or different combinations of tank colour (black or white) and light intensity (1.1 mol s–1 m–2 or 18 mol s–1 m–2). Growth (0.8% day–1 in standard length; 2.9% day–1 in body area) and survival (2%) were not significantly different between photoperiod treatments after 35 days. Larval survival was greater in white versus black tanks after 41 days (2% versus l%, respectively). Growth of larvae was impaired in black tanks at low (1.1 mol s–1 m–2) light intensity (0.8% day–1 in standard length and 2.2% day–1 in body area versus 1.1% day 21 in standard length and 3.1% day–1 in body area, for all other treatments). Transmission and reflection of light was low in black tanks at low incident light, and there was very little upwelling light. The resultant poor prey to background contrast probably resulted in larvae being unable to consume sufficient food to sustain a level of growth comparable to that in other treatments.
The life cycle of cuttlefish fed ad libitum exclusively on live grass shrimp (Palaemonetes varians) was studied during 5 consecutive generations. Different culture temperatures promoted different (P<0.05) exponential growth for each life cycle, being summer generations shorter than those of winter. Higher temperatures promoted higher IGR’s and mortality, while lower temperatures promoted increased life span, reproduction stages, total fecundity and total egg biomass. Increased generations also seemed to increase fertility. A “hybrid” generation promoted the best results in terms of hatchling weight, individual fecundity and fertility. Mean egg weight was related to female size and embryonic development took longer at lower temperatures. Brood stock sex ratios seemed to be temperature related. All of these culture aspects were also compared between themselves in order to establish future brood stock methodologies. Grass shrimp proved to be a good diet for the culture of cuttlefish throughout the life cycle. The use of only one species reduces costs and labor associated to cuttlefish culture.
Light compares a complex of external and ecological factors, including colour spectrum, intensity and photoperiod. Light characteristics are very specific in an aquatic environment and light is extremely variable in nature. `Receptivity' of fish to light profoundly changes according to the species and the developmental status. Specific photoreceptor cells are present in both eye and pineal. If it is easy to change the light in experimentation and to observe the effects on fish growth, it is much more difficult in nature to make such determinations. In larvae, many studies have been dedicated to the influence of intensity and photoperiod on growth: generally, species need a minimal threshold intensity to be able to develop normally and grow. This is probably related to the aptitude to localize, catch and ingest prey. Light is also indispensable for body pigmentation, an important phenomenon involved in early development and growth. Too intense light can be stressful or even lethal. A few species are able to develop and grow at very low intensities or, sometimes, in the absence of light. Generally, long daylength improves larval rearing quality. The synergistic effect of `food availability-daylength' appears to be determining at this stage. In older fish, there is very little information about the influence of light `quality' but more about intensity and much more about photoperiod. Light intensity effects are not so clear and depend on the species and the experimental procedures: it is probably not an important factor for growth stimulation. Daylength appears much more important. Many species, including both marine species and salmonids, react to photoperiod treatments and long daylength stimulates growth. The most studied species is the Atlantic salmon, which is very sensitive, both during the freshwater stage, with the parr–smolt transformation very dependent on the photoperiod, and also in sea water. In this last condition, lighting also influences early maturation. An important point is to be certain that light affects fish growth through a better food conversion efficiency and not just through stimulated food intake. Also included in this review is a discussion about the endolymph–otolith system, which is very sensitive to daylight and seasonal cycles and a review of the present knowledge on the involvement of light influence on hormone levels (melatonin, somatotropin, thyroid hormones and other hormones).
Consumption rate and feeding success of newly hatched paralarvae of the cephalopod Octopus vulgaris preying on Artemia larvae were investigated in relation to visual conditions and prey density. Each paralarva was tested individually using
a small-scale experimental setup; consumption over one day was measured at 20°C. A factorial experiment was designed to investigate
the effects on the consumption rate of two predictor variables: illumination/background (three levels: 7.5 Wm−2 white light + white background, 7.5 Wm−2 white light + blue background, darkness) and prey density (four levels: 2.35, 4.70, 9.40 and 14.10 Artemia metanauplii ml−1). Consumption rate varied significantly between different conditions of illumination and prey density. Light enhanced consumption
rate, but different backgrounds yielded similar rates. The maximal consumption rate under illumination was close to 16 Artemia paralarva−1 day−1, and it was around 5 Artemia paralarva−1 day−1 for assays in darkness. The predatory efficiency, measured as the proportion of prey consumed, was significantly affected
by prey density, pointing to a type III functional response. The number of nonfeeding paralarvae was significantly higher
in darkness and at low prey density.
Fourteen extraocular eye muscles are described in the decapods Loligo and Sepioteuthis, and thirteen in Sepia; they are supplied by four eye muscle nerves. The main action of most of the muscles is a linear movement of the eyeball, only three muscles produce strong rotations. The arrangement, innervation and action of the decapod eye muscles are compared with those of the seven eye muscles and seven eye muscle nerves in Octopus. The extra muscles in decapods are attached to the anterior and superior faces of the eyes. At least, the anterior muscles, and presumably also the superior muscles, are concerned with convergent eye movements for binocular vision during fixation and capture of prey by the tentacles. The remaining muscles are rather similar in the two cephalopod groups. In decapods, the anterior muscles include conjunctive muscles; these cross the midline and each presumably moves both eyes at the same time during fixation. In the squids Loligo and Sepioteuthis there is an additional superior conjunctive muscle of perhaps similar function. Some of the anterior muscles are associated with a narrow moveable plate, the trochlear cartilage; it is attached to the eyeball by trochlear membranes. Centripetal cobalt fillings showed that all four eye muscle nerves have fibres that originate from somata in the ipsilateral anterior lateral pedal lobe, which is the oculomotor centre. The somata of the individual nerves show different but overlapping distributions. Bundles of small presumably afferent fibres were seen in two of the four nerves. They do not enter the anterior lateral pedal lobe but run to the ventral magnocellular lobe; some afferent fibres enter the brachio-palliovisceral connective and run perhaps as far as the palliovisceral lobe.
Invertebrate rhodopsins activate a G-protein signalling pathway in microvillar photoreceptors. In contrast to the transducin-cyclic GMP phosphodiesterase pathway found in vertebrate rods and cones, visual transduction in cephalopod (squid, octopus, cuttlefish) invertebrates is signalled via Gq and phospholipase C. Squid rhodopsin contains the conserved residues of the G-protein coupled receptor (GPCR) family, but has only 35% identity with mammalian rhodopsins. Unlike vertebrate rhodopsins, cephalopod rhodopsin is arranged in an ordered lattice in the photoreceptor membranes. This organization confers sensitivity to the plane of polarized light and also provides the optimal orientation of the linear retinal chromophores in the cylindrical microvillar membranes for light capture. Two-dimensional crystals of squid rhodopsin show a rectilinear arrangement that is likely to be related to the alignment of rhodopsins in vivo.Here, we present a three-dimensional structure of squid rhodopsin determined by cryo-electron microscopy of two-dimensional crystals. Docking the atomic structure of bovine rhodopsin into the squid density map shows that the helix packing and extracellular plug structure are conserved. In addition, there are two novel structural features revealed by our map. The linear lattice contact appears to be made by the transverse C-terminal helix lying on the cytoplasmic surface of the membrane. Also at the cytoplasmic surface, additional density may correspond to a helix 5-6 loop insertion found in most GPCRs relative to vertebrate rhodopsins. The similarity supports the conservation in structure of rhodopsins (and other G-protein-coupled receptors) from phylogenetically distant organisms. The map provides the first indication of the structural basis for rhodopsin alignment in the microvillar membrane.
We tested color perception based upon a robust behavioral response in which cuttlefish (Sepia officinalis) respond to visual stimuli (a black and white checkerboard) with a quantifiable, neurally controlled motor response (a body pattern). In the first experiment, we created 16 checkerboard substrates in which 16 grey shades (from white to black) were paired with one green shade (matched to the maximum absorption wavelength of S. officinalis' sole visual pigment, 492 nm), assuming that one of the grey shades would give a similar achromatic signal to the tested green. In the second experiment, we created a checkerboard using one blue and one yellow shade whose intensities were matched to the cuttlefish's visual system. In both assays it was tested whether cuttlefish would show disruptive coloration on these checkerboards, indicating their ability to distinguish checkers based solely on wavelength (i.e., color). Here, we show clearly that cuttlefish must be color blind, as they showed non-disruptive coloration on the checkerboards whose color intensities were matched to the Sepia visual system, suggesting that the substrates appeared to their eyes as uniform backgrounds. Furthermore, we show that cuttlefish are able to perceive objects in their background that differ in contrast by approximately 15%. This study adds support to previous reports that S. officinalis is color blind, yet the question of how cuttlefish achieve "color-blind camouflage" in chromatically rich environments still remains.
From among hatchlings, juvenile cuttlefish Sepia officinalis of 200 mg were divided into two groups fed with two different diets: natural live prey and PUFA (polyunsaturated fatty acids) enriched natural live prey. After 10 days of rearing, juvenile cuttlefish previously fed on the enriched diet easily accepted natural frozen prey and their survival was better, while juvenile cuttlefish previously fed with normal prey were resistant to frozen prey and showed high mortality. After 10 days of rearing with the enriched diet, when changed to a diet of alternatively frozen prey and live prey, an adjustment period with lower growth is observed. These results show that when juvenile cuttlefish are fed on live prey enriched with PUFA, they accept frozen prey earlier in their life and their survival is enhanced. These observations have a potential importance in the culture of juvenile cephalopods.
We report here how the sensitivity of the eye of the cuttlefish (Sepia officinalis) to light changes with the growth of the animal. Measurements of body length and eye diameter show that cuttlefish hatch with relatively large eyes but these then grow throughout the animal's lifetime at a slower rate than the body, resulting in an allometric scaling coefficient of less than one. Electroretinograms (ERG) evoked by the application of controlled flashes of light were obtained from different sized animals and demonstrated that ERG amplitude decreased with increasing animal size and this appears associated with a small decrease in retinal sensitivity. However, increasing the stimulus flash duration increased the sensitivity of the retina; this result is similar to the situation in vertebrates but not that in most other invertebrates. The cuttlefish retina was found to be 100 times more sensitive to flashes of blue light than yellow; however animals of 7 cm mantle length demonstrated an enhanced sensitivity to blue light, when compared to smaller or larger animals. The results are discussed in relation to differences in the lifestyles of the juvenile and adult animals, particularly the tendency for the young animals to live in bright, shallow waters, and the older animals to migrate to deeper, darker waters.
1. Introduction 2. Estimation 3. Hypothesis testing 4. Graphical exploration of data 5. Correlation and regression 6. Multiple regression and correlation 7. Design and power analysis 8. Comparing groups or treatments - analysis of variance 9. Multifactor analysis of variance 10. Randomized blocks and simple repeated measures: unreplicated two-factor designs 11. Split plot and repeated measures designs: partly nested anovas 12. Analysis of covariance 13. Generalized linear models and logistic regression 14. Analyzing frequencies 15. Introduction to multivariate analyses 16. Multivariate analysis of variance and discriminant analysis 17. Principal components and correspondence analysis 18. Multidimensional scaling and cluster analysis 19. Presentation of results.
We examined the foraging behaviour, growth and survival of Atlantic cod (Gadus morhua) larvae in two different colours of tank bottom; either beige (light hereafter) or black (dark hereafter) bottomed tanks with black walls. Results showed no significant differences in the growth, foraging behaviour, or survival of Atlantic cod larvae in response to tank bottom colour indicating that larvae could be reared in lighter bottom tanks without any detrimental effect to the larvae. Using a light bottom tank is also of greater benefit to the culturist as they provide better contrast to monitor the behavioural and morphological development of the larvae.
Cultured species of aquatic animals span more than five phyla. Animal welfare attention is directed towards the vertebrates because of the their neural complexity, and is currently focused on the finfish because of the size and visibility of that segment of the aquaculture industry. The characteristics of the aquatic environment and their impact on the animal have forced growers to develop cultural practices designed to control and minimize animal stress. This was not done as a result of social awareness, but out of necessity to keep fish alive and healthy; and managing stress is a principal key in ensuring animal welfare. Aquatic farmers are aware of the consequences of fish stress, but have limited knowledge of the basic biological principles of animal stress and have little exposure to the linkages between these concepts and the issues critical to animal welfare. Although the industry has many tools available for monitoring and preventing stress, not all growers have had exposure to the information that is available or know of its value when addressing issues of animal welfare.
For many organisms vision is of fundamental importance to many aspects of their lives. Here we present the first study to examine the effects of ontogeny and light intensity on the vision of a cephalopod. We measured the visual acuity of four size classes of Sepia officinalis L., 1758 (common cuttlefish) under four light intensities. We used an optomotor testing system in which we recorded the unconditioned whole-body movements exhibited by individuals when placed inside a rotating cylinder lined with vertical black and white stripes. By varying the width of these stripes to determine the minimum width associated with a positive response, we were able to estimate the visual acuity angle or minimum separable angle (MSA). We found a significant effect of both body size and light intensity; larger animals had greater visual acuity, while individuals of all size classes discriminated more detail at higher light intensities. The minimum recorded MSA for S. officinalis was 34' of arc (0.57°) for the largest animals (80 mm) at the highest light intensity used (15 µW·cm–2). Decreasing light intensity from 15 to 4.5 µW·cm–2 affected animals of all sizes to approximately the same degree, reducing their visual acuity by approximately 55%.
The literature data on mechanisms of activation (deactivation) and regeneration of visual pigments in vertebrates (mammals) and invertebrates (cephalopod molluscs, insects, crustaceans) are summarized and analyzed. The activation pathway of the visual pigment includes a cis-trans photoisomerization of chromophore and an interaction of the activated photoproduct, metarhodopsin II (vertebrates) or metarhodopsin (invertebrates) with G-protein. The quenching of activity of metarhodopsin II in vertebrates (deactivation stage) is provided by a so far unclear interaction of metarhodopsin II with metarhodopsin kinase, arrestin, Ca2+, S-modulin, retinoid oxidoreductase (ROR), and phosphatase 2A. The activation (deactivation) pathway of rhodopsin in insects has several characteristic features: (1) metarhodopsin is relatively stable, but can change its thermostability and efficiency of the G-protein activation, (2) binding of arrestin by metarhodopsin precedes phosphorylation of the latter by metarhodopsin kinase, (3) arrestin controls both phosphorylation and dephosphorylation of metarhodopsin. The regeneration pathway of rhodopsin in vertebrates is represented by the following thermal reactions: dephosphorylation of metarhodopsin II by phosphatase 2A, reduction of all-trans retinal to all-trans retinol by ROR, transport of all-trans retinol to pigment epithelium (PE), its esterification to all-trans retinyl esters, transformation of the latter into 11-cis retinol, oxidation of 11-cis retinol to 11-cis retinal and transport of the latter from PE back to ROS. The formation of 11-cis form of the chromophore, the rhodopsin, is provided in invertebrates by the following: 1) trans-cis photoisomerization of the chromophore included in metarhodopsin (all invertebrates), 2) trans-cis photoisomerization of chromophore in an additional protein-catalyst (retinochrome in cephalopod molluscs; retinal photoisomerase in insects, king-crabs) with the subsequent exchange of chromophores between metarhodopsin and protein-catalyst, 3) thermal isomerization of all-trans retinyl esters of unsaturated fatty acids with their simultaneous transformation into 11-cis retinol (crustaceans), like it takes place in PE of vertebrates. The presented data are discussed with respect to similarities and differences in mechanisms of activation, deactivation, and regeneration of visual pigments, as well as pathways of isomerization of their chromophore in some representatives of vertebrate and invertebrate animals.
This review intends to provide a reflection regarding Directive 2010 ⁄ 63 ⁄ EU, on animal welfare, and its application concerning cephalopod breeding and experimentation in aquaculture research. To do so, we gathered different perspectives of our group members, involving two cephalopod aquaculture researchers, an aquaculture fish production technician and a veterinary professional, the latter with no background on cephalopod research. The inclusion of this class in the animal welfare legislation; the definition of live cephalopods, stress, pain and suffering are revised according to the latest scientific knowledge. Considering the 15 year background that the Centre of Marine Sciences holds on the cultivation
of the European cuttlefish, an evaluation of existing production protocols, aquaculture technology related research, ethics and cephalopod welfare are discussed. The application of anaesthesia, analgesia and euthanasia is discussed, bearing in mind the different procedures applied on a daily basis in aquaculture
breeding and experimentation and the requirements of the new Directive. Finally, an overview of the above and progress on 3Rs (replacement of animals, reduction in number of animals and refinement of procedures) application to cephalopod welfare is presented.
Individual growth rates, feeding rates (%BWd−1) and food conversions for cuttlefish (S. officinalis) hatchlings and juveniles were determined during this study. A flow-through system was used. Water temperature reached 30 °C during the hottest part of the day, gradually decreasing to 25 °C during the night; salinity varied between 37 ± 3 ppt and lights were kept on for 14 h day−1. Hatchlings were placed in separate compartments with a water volume of 1.2 L. Juvenile cuttlefish (from 0.5 to 25 g) were placed in bigger baskets, with a water volume of 5.2 L. Water flow was 120 L h−1. The biggest cuttlefish used in these experiments (> 25 g) were gathered in groups of five and placed in circular tanks (water volume of 250–300 L). Thus, results obtained in this case are means and not individual data. During the first 10, 20, 30 and 40 days, mean growth rates (of all individuals sampled by age group) decreased consistently (11.8 ± 4.1, 9.8 ± 1.8, 8.1 ± 2.2 and 7.3 ± 0.7%BW−1 respectively); in similar fashion, mean feeding rates decreased with age group (33.7 ± 13.5, 22.0 ± 7.9, 17.3 ± 3.9 and 16.7%BWd−1 respectively). Mean food conversions varied between 3.6 and 2.5 between the age groups. When grouping results by weight class, similar patterns occur, as growth and feeding rates decrease consistently as cuttlefish grow bigger. Highest mean growth and feeding rates are obtained by hatchlings (< 0.1 g) with 12.4 ± 4.5 and 35.3 ± 15.1%BWd−1, respectively, while the lowest growth and feeding rates were recorded for the largest animals, between 15 and 25 g (3.4 ± 1.1 and 10.8 ± 4.1%BWd−1 respectively). For these weight classes, mean food conversions varied between 2.7 ± 0.9 and 3.8 ± 2.8.
The role of vision in the entry of the cuttlefish Sepia esculenta into basket traps was examined in laboratory experiments and by histological examination of the retina. Both entry into the trap and feeding on shore crabs stopped when the tank was completely darkened. The eyes of cuttlefish have a high sensitivity to light. The visual field of cuttlefish was determined by the optical method, based on the assumption that incident light on the pupil from any direction reaches the retina through a refractive lens. The uniocular visual field was found to be 253° on the horizontal plane, and the anterior and posterior binocular visual fields were 86° and 60° respectively. On the retina, areas with especially high visual cell density formed a visual equator slightly above the optical equator. The distribution of the visual cell density indicates no specific visual axis. The visual acuity is 0.36 when estimated from the bait recognition distance and the size of bait during feeding, and 0.89 when determined from the visual cell density at the visual equator and the focal length of the lens. Cuttlefish have far superior visual acuity than fish.
The effects of different tank colours (white, yellow sandy and black) on the growth, mortality and biomass production were studied for hatchling and early juvenile cuttlefish. For hatchlings, the use of different colour tanks did not promote differences in growth due to the higher variability (standard deviation) found in the white- and sand-coloured tanks. Black tanks promoted the lowest and highest values for total mortality and biomass respectively. For juveniles, the use of different tank colours promoted different growth (P<0.05), but not mortality. Black tanks promoted the best results in terms of growth and biomass. The results obtained in the present study advise the use of black (or dark colour) tanks in the hatchling and early juvenile stages to reduce the standard deviations associated with growth, mortality and biomass production. This will contribute to minimize problems associated with slow and fast growers and competition.
Three feeding experiments, using live mysid shrimp, grass shrimp or fish fry as prey for 1-, 30- and 60-day-old cuttlefish were conducted to determine the efficiency of each dietary source in relation to cuttlefish size and age. Additionally, a fourth experiment using fish fry and grass shrimp, but previously frozen, was also conducted. The results showed that when 1-day-old cuttlefish were fed mysids, grass shrimp or fish for 4 weeks, mysids were the best prey, but only during the first week. From this moment until the end of the experiment, the best growth rate was when cuttlefish were fed grass shrimp. Cuttlefish fed fish fry showed the poorest growth rate throughout the experiment. Similarly, cuttlefish aged 30 or 60 days fed grass shrimp or fish fry had the best growth rates when fed grass shrimp. When cuttlefish were fed live fish, survival increased with size of cuttlefish (73.3%, 91.7% and 100% for 1, 30 and 60 days cuttlefish, respectively). In the fourth experiment, using frozen diets, overall acceptance of each diet (feeding rates) was the same for fish and shrimp. However, lower growth was obtained when cuttlefish were fed fish compared to grass shrimp. This lower growth was due to a lower food conversion (28% vs. 41%). Since cephalopod paralarvae and juvenile most likely need prey rich in polyunsaturated fatty acids (PUFA), phospholipids and cholesterol, and a moderate content in neutral lipids, we have analyzed the biochemical compositions of the different prey to evaluate the influence of this factor on growth and survival.
The combined effects of photoperiod and feeding frequency on survival and growth of juvenile cuttlefish has been studied in experimental rearing. During juvenile cuttlefish growth, survival and growth rate were low when the photoperiod was short (8 h of light and 16 h of dark). Increased frequency of diet did not stimulate the appetite of animals reared in normal or long photoperiod (16 h of light and 8 h of dark). However, by studying the combined effects of photoperiod and feeding frequency, we have demonstrated that an increase in feeding frequency can enhance survival and growth in the group receiving the shortest period of light per day. Temperature is an important factor in the regulation of the incubation period of eggs and of growth after hatching, but it also appears in this investigation that the combined effect of photoperiod and feeding frequency must be considered during growth of juvenile cuttlefish.
Studies have shown that most marine fish larvae are visual feeders and their feeding incidence increases with light intensity. Although laboratory studies on photoperiod showed variable results, evidence from the field suggest that larvae exposed to a continuous light may grow better than larvae exposed to reduced photoperiods. We set up experiments to investigate the foraging, growth and survival of Atlantic cod larvae (Gadus morhua; Grand Banks origin) at different light intensities and photoperiods. Behavioural observations were also carried out in an attempt to explain any differences in the performance of cod larvae under varying light intensities. Larval cod were reared at four light intensities (300, 600, 1200 and 2400 lx or 4.93, 10.96, 19.89 and 37.32 μE m−2, respectively) and three photoperiods (24 L:0 D, 18 L:06 D and 12 L:12 D) from hatching to metamorphosis (42 days post-hatch; dph). Cod larvae grew and survived better in higher light intensity (2400 lx) and 24 L:0 D photoperiod. Examination of the foraging indicated that cod larvae reared in higher light intensity captured prey more efficiently than larvae reared in low light. Results also showed that the mortality rates of larval cod from 2400 lx and 24 h photoperiod were significantly lower than the larvae from other light intensity and photoperiod treatments until 28 dph. This indicates that photoperiod and light levels could be reduced beyond 28 dph.
Retinal photodamage has previously been studied in teleost fish but very few have been performed on aquaculture species. To study retinal damage, Atlantic cod (Gadus morhua), Atlantic salmon (Salmo salar) and European sea bass (Dicentrarchus labrax) were previously acclimated to a control 12L:12D photoperiod with standard experimental low light intensity (0.1 W/m2, equivalent to 3.2 × 1013 photons/s/cm2) for at least 4 weeks and then kept under constant darkness (DD) for 3 days. Thereafter, fish were exposed to continuous high intensity light (51–380 W/m2, equivalent to 1.63 × 1016–1.22 × 1017 photons/s/cm2) for 3, 7, 15 or 25 days before returning to a control 12L:12D photoperiod (same intensity than during acclimation period) to study retinal regeneration over a period of 30 days. Retinal damage was exclusively assessed through the analysis of morphometric parameters. Results showed the presence of light-induced damage in the three species examined, as well as recovery once the control photocycle was restored. Cod was the most light-sensitive species as demonstrated by early signs of retinal damage (from three days of exposure) and reduced photoreceptor layer thickness (PRos/is) (43.1% relative to basal value in comparison to 51.6% and 73.3% respectively in salmon and sea bass). However, once the light–dark cycle was resumed the retina recovered in the three species studied (after 15 days in cod and 30 days in salmon and sea bass). Exposure to continuous high intensity light also resulted in significantly increased plasma cortisol levels in cod at LL15 (13.4 ± 2.0 ng/ml) and sea bass at LL3 (120.6 ± 12.2 ng/ml) and LD15 (54.2 ± 7.1 ng/ml). These results have important welfare implications with regards to the use of artificial light in culture and should be considered when designing lighting protocols in the aquaculture industry.
One of the problems encountered with intensive production of Atlantic cod (Gadus morhua L.) is inconsistent growth and survival from hatch through metamorphosis. This could be attributed in part to a poor understanding of the optimal culture conditions required for large-scale commercial production. Studies to date have indicated that cod larvae reared under high light intensities perform better than larvae reared under low light intensities. However, an earlier study from our laboratory suggested that Atlantic cod may not require high light during the later larval stages. Therefore, this study examined the foraging behavior, growth and survival of Atlantic cod larvae reared under varying light conditions during the late larval stage. In this experiment, larvae were subjected to three different light intensity regimes: treatment 1–2200 lux from 3–58 days post-hatch (dph), treatment 2–2200 lux from 3–27 dph and 600 lux from 28–58 dph and treatment 3–2200 lux from 3–39 dph and 600 lux from 40–58 dph. All tanks were kept under 24 h light. Weekly length and weight measurements were taken, and foraging behaviour was recorded twice a week. The results show that larvae reared in treatment 2 showed better growth in terms of standard lengths and dry weights than the larvae reared in treatments 1 and 3. Larvae reared in treatment 2 were also more efficient foragers than the other two treatments. However, there were no differences in the survival among the three treatments. These results indicate that a reduction in light intensity in cod larval tanks during the late larval stages would enhance the growth performances.
Experimental rearing of juvenile cuttlefish was carried out in a semi-closed system for 40 days at 19°C. Different quantities of live food were offered to isolated animals. The actual ingestion rate was enhanced by the amount of food offered, this tendency decreasing with age. Frozen food was ingested at the same rate, but was less effective than live food for growth. The quantity of food ingested during the first 20–30 days of life seems to affect further growth, especially weight increase. Aspartate transcarbamylase activity appeared to be a good indicator for the early phase of growth (first 20–30 days) which is likely due to hyperplasy, and moreover for predicting future growth.
The effects of feeding two alternative live prey (exclusively caprellids (Caprella equilibra) or several species of gammarids, mainly Ericthonius brasiliensis, Jassa marmorata and Elasmopus sp.), to cuttlefish hatchlings were compared to feeding mysids (Mesopodopsis slabberi), which are normally used during the first weeks of the life cycle. Weight (g) and growth rates (GR, % BW d− 1) were determined. Cuttlefish hatchlings fed with mysids and gammarids grew faster (6.7 ± 0.4 and 5.7 ± 0.9% BW d− 1, respectively) compared to caprellids (1.6 ± 0.2% BW d− 1). Survival was higher (96.7 ± 5.8%) for hatchlings fed mysids, compared to 83.3 ± 15.3% and 76.7 ± 5.8%, for those fed gammarids and caprellids, respectively. According to the results obtained, gammarids could be used as an alternative prey to mysids, while Caprella equilibra did not deliver appropriate growth rates and should be disregarded as alternative prey for rearing early stages (hatchlings) of Sepia officinalis. This is the first study revealing a successful use of amphipods, mainly gammarids, as alternative prey for cuttlefish hatchlings.
The photochemical cycle and the accompanying charge displacements of rhodopsin were investigated in membrane fragments and solubilized rhodopsin from the retina of Sepia officinalis. Absorption changes were measured following excitation by a short laser flash. Light excitation produces successive forms with absorption maxima at 536 nm and 474 nm assigned to lumirhodopsin and mesorhodopsin, respectively. The lifetimes of these forms were 8 ± 3 μs and 96 ± 5 μs, respectively. The absorption spectrum of the acid meta form was found to be almost identical to that of rhodopsin. Membrane fragments were also oriented by a d.c. electric field and fixed in gel. Charge displacements following light excitation were measured as a displacement current. The electrical signals from the oriented gels were separated into two exponential components with time constants identical within errors to those obtained from the absorption kinetic experiments. It is shown that the protein conformational changes indicated by the absorption changes are accompanied by intramolecular charge displacements. The transitions are assigned to the decay of the lumi and meso states.
"Developments during the past two years confirm the trends already observed at the end of the 1990s: capture fisheries production is stagnating, aquaculture output is expanding and there are growing concerns with regard to the livelihoods of fishers and the sustainability of commercial catches and the aquatic ecosystems from which they are extracted. The State of World Fisheries and Aquaculture 2004 reports on several of these issues. "It is not only fishers and fish farmers who have these concerns; they are increasingly shared by civil society at large. Moreover, the importance of international trade in fish and fish products, combined with the trend for major fishing and trading companies to operate on a multinational basis, means that such issues are becoming global in nature affecting a growing number of countries, be they large fish producers or large consumers of fish. It is heartening to note that governments and other stakeholders have begun to collaborate with their neighbours and partners in trade in an effort to find shared solutions. "Concrete examples of positive outcomes of this globalization of concerns are the establishment of new regional fishery management organizations and the strengthening of existing ones. It is probable that ongoing discussions among intergovernmental organizations on topics such as trade in endangered aquatic species, the use of subsidies in the fishing industry, and labour standards in fisheries will also result in agreements of overall benefit to world society. "Given the nature and tone of the international discussion on fishery issues and the developments observed during recent years, I believe that fishers and fish farmers, in collaboration with governments and other stakeholders, will overcome the obstacles they face currently and will succeed in ensuring sustainable fisheries and continued supplies of food fish at least at their present levels."
In two groups of newly hatched cuttlefish, from eggs incubated at different temperatures, the emergence of predatory pursuit was correlated with the development of some characteristics of the vertical lobe complex (namely, the development of the vertical and superior frontal lobes and the appearance of the vertical-subvertical lobe tracts) and with the state of resorption of the inner yolk sac. The temperature of egg incubation influences the appearance of postnatal pursuit behavior. Expression of this predatory behavioral characteristic is concomitant with the appearance of the vertical-subvertical lobe tracts. In contrast, the growth of the vertical and the superior frontal lobes relative to the growth of the supraesophageal mass and final yolk absorption are not correlated with the appearance of pursuit. To maintain a prey in the frontal visual field during predatory pursuit, short-term memory processes must be involved. Thus, the development of the vertical-subvertical lobe tracts, which is concomitant with the emergence of pursuit, appears essential in the maturation of these short-term memory processes.
J Vasc Surg 1999;29:748-51.
Cells from virtually all organisms respond to a variety of stresses by the rapid synthesis of a highly conserved set of polypeptides termed heat shock proteins (HSPs). The precise functions of HSPs are unknown, but there is considerable evidence that these stress proteins are essential for survival at both normal and elevated temperatures. HSPs also appear to play a critical role in the development of thermotolerance and protection from cellular damage associated with stresses such as ischemia, cytokines, and energy depletion. These observations suggest that HSPs play an important role in both normal cellular homeostasis and the stress response. This mini-review examines recent evidence and hypotheses suggesting that the HSPs may be important modifying factors in cellular responses to a variety of physiologically relevant conditions such as hyperthermia, exercise, oxidative stress, metabolic challenge, and aging.
Light- and dark-adaptation leads to changes in rhabdom morphology and photopigment distribution in the octopus retina. Molecular chaperones, including heat shock proteins (Hsps), may be involved in specific signaling pathways that cause changes in photoreceptor actin- and tubulin-based cytoskeletons and movement of the photopigments, rhodopsin and retinochrome. In this study, we used immunoblotting, in situ RT-PCR, immunofluorescence and confocal microscopy to localize the inducible form of Hsp70 and the larger Hsp90 in light- and dark-adapted and dorsal and ventral halves of adult octopus retinas. The Hsps showed differences in distribution between the light and dark and in dorsal vs. ventral position in the retina. Double labeling confocal microscopy co-localized Hsp70 with actin and tubulin, and Hsp90 with the photopigment, retinochrome. Our results demonstrate the presence of Hsp70 and Hsp90 in otherwise non-stressed light- and dark-adapted octopus retinas. These Hsps may help stabilize the cytoskeleton, important for rhabdom structure, and are perhaps involved in the redistribution of retinochrome in conditions of light and dark.
This paper provides the first detailed description of the time courses of light-evoked pupillary constriction for two species of cephalopods, Sepia officinalis (a cuttlefish) and Eledone cirrhosa (an octopus). The responses are much faster than hitherto reported, full contraction in Sepia taking less than 1 s, indicating it is among the most rapid pupillary responses in the animal kingdom. We also describe the dependence of the degree of pupil constriction on the level of ambient illumination and show considerable variability between animals. Furthermore, both Sepia and Eledone lack a consensual light-evoked pupil response. Pupil dilation following darkness in Sepia is shown to be very variable, often occurring within a second but at other times taking considerably longer. This may be the result of extensive light-independent variations in pupil diameter in low levels of illumination.
Practical Statistics for Field Biology Ontoge-netic changes in the visual acuity of Sepia officinalis mea-sured using the optomotor response
- Food And Agriculture Organization Of The United Nations
- Rome
- J Fowler
- L Cohen
- P Jarvis
FAO (2009) The State of World Fisheries and Aquaculture 2008. FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, Rome. Fowler J., Cohen L. & Jarvis P. (1998) Practical Statistics for Field Biology. Wiley, New York. Groeger G., Cotton P.A. & Williamson R. (2005) Ontoge-netic changes in the visual acuity of Sepia officinalis mea-sured using the optomotor response. Canadian Journal of Zoology-Revue Canadienne De Zoologie 83, 274–279.
Experimental Design and Data Analysis for Biologists Key reactions of visual cycle in vertebrates and invertebrates: activation and regenera-tion of rhodopsin
- Quinn G P Keough
Quinn G.P. & Keough M.J. (2002) Experimental Design and Data Analysis for Biologists. Cambridge University Press, Cambridge, U.K., pp. 556. Shukolyukov S.A. (1999) Key reactions of visual cycle in vertebrates and invertebrates: activation and regenera-tion of rhodopsin. Journal of Evolutionary Biochemistry and Physiology 35, 579–595.
Cephalopod Behav-iour Food intake and growth in reared early juvenile cuttlefish Sepia officinal-is L-(Mollusca Cephalopoda)
- R T Hanlon
- J B Messenger
Hanlon R.T. & Messenger J.B. (1996) Cephalopod Behav-iour. Cambridge University Press, New York. Koueta N. & Boucaud-Camou E. (1999) Food intake and growth in reared early juvenile cuttlefish Sepia officinal-is L-(Mollusca Cephalopoda). Journal of Experimental Marine Biology and Ecology 240, 93–109.
Role of vision in behavior, visual field and visual acuity of cuttlefish Sepia esculenta
- N Watanuki
- G Kawamura
- S Kaneuchi
- T Inashita
Watanuki N., Kawamura G., Kaneuchi S. & Inashita T.
(2000) Role of vision in behavior, visual field and
visual acuity of cuttlefish Sepia esculenta. Fisheries Science 66, 417-423.