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In this paper the Vacuity Index (VI), Fullness Index (FI) and Food Preference Index (FPI) for the stomach contents of Pomadasys kaakan were evaluated to assess the quantity and kind of food which this fish consumes in the Persian Gulf. A total of 227 specimens were collected from fishing trawlers or landings from November 2005 to September 2006. 24...
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... The results from Puri on the other hand were in conformity with earlier studies on the diet of P. kaakan. From the Persian Gulf, the main diet contents of P. kaakan was reported as crustaceans particularly crabs and shrimp, followed by fish and molluscs (Valinassab et al., 2011). Small shrimps were reported as the dominant diet item in P. kaakan from eastern Johor Strait, Singapore (Hajisamae et al., 2003). ...
This study provides the first report on the length-weight relationship, reproductive biology and diet of Pomadasys kaakan (Cuvier, 1830) from western Bay of Bengal. Specimens for the study were collected from two locations, Visakhapatnam and Puri, with 301 fishes collected from the former and 153 from the latter. The mean size of P. kaakan at Visakhapatnam was 38.7 cm total length (TL) and 32.07 cm TL at Puri. The length-weight relationship indicated negative allometric growth in the species from both locations. The length at first maturity for female fish was estimated to be 31.5 cm TL at both locations. Our study indicated spawning throughout the year with peaks in February-April and July-August for P. kaakan in the study area. Analysis of diet indicated that in the study region the species had divergent feeding habits. At Visakhapatnam, teleosts (unidentified finfish, eels and silverbellies) were dominant diet items whereas crustaceans (crabs and shrimps) were the dominant diet components of P. kaakan at Puri. The close similarity in size distribution and reproductive biological parameters from the two regions points towards the possibility of a single stock of the species in the study region. Coastal fisheries, Fish stock, Javelin grunter, Life history, Tropical fisheries
... The percentage of the gastric emptying index in the studied samples was much higher than that reported in the Red Sea coasts near Al-Hodeidah, where only three empty stomachs were found at a rate of 2.1% [29], may be due to the lack of samples that were studied in the coasts near Al-Hodeidah, as they amounted to 140 samples, in addition to the absence of samples in the summer. In the northern Arabian Gulf, the index of stomach emptying for the type P. kaakan was 63.45% [34], and this value is greater than the value in the study samples in the coasts of the Gulf of Aden. The percentage of empty stomach varies according to habitat, season, time of day, and size [22]. ...
The feeding habits of two species fish, D. pictum and P. argenteus (Family: Haemulidae), were studied monthly from July 2021 to June 2022. Contents of 214 stomachs of D. pictum and 223 stomachs of P. argenteus were analyzed using Fullness index and percentage of occurrence, According to vacuity index for to species, the percentage were 45.3% and 44.4% respectively. The contents of the stomach were examined; it was found that the food of D. pictum consisted of crustaceans, fish, molluscs and sea grasses. The food to P. argenteus consists of crustaceans, molluscs and fish, where crustaceans constituted the main food for two species D. pictum and P. argenteus by 42.1% and 45.7% respectively. It was observed that the increased of longitudinal group followed increased percentage of fish increased as food and disappeared of the percentage of molluscs and sea grasses in D. pictum. In P. argenteus crustaceans dominated in the various longitudinal groups, while molluscs appeared from length of 25 cm and varied in their proportions in long group, likewise, fish appeared in a group of 32 cm in length and differed in their proportions in the large groups.
... Each stomach was weighed separately from the intestines, then the entire stomach content and empty stomachs were weighed. A vacuity index was used to express the number of empty stomachs found as a percentage of all stomachs examined (Bacha and Amara 2009) to estimate the fraction of the population that had prey remains in the stomach (Valinassab et al. 2011). Vacuity index values <20% are deemed characteristic of 'edacious species', whereas values >60% characterise 'moderate feeders', and values of 81-100% indicate 'abstemious' predators (Valinassab et al. 2011). ...
... A vacuity index was used to express the number of empty stomachs found as a percentage of all stomachs examined (Bacha and Amara 2009) to estimate the fraction of the population that had prey remains in the stomach (Valinassab et al. 2011). Vacuity index values <20% are deemed characteristic of 'edacious species', whereas values >60% characterise 'moderate feeders', and values of 81-100% indicate 'abstemious' predators (Valinassab et al. 2011). The various prey items were separated by taxonomic group (phylum) and identified to the lowest taxonomic level possible by using specialised literature and considering the degree of digestion. ...
Context: Establishing the roles that different species play within ecosystems is key to understanding how ecosystems function and determining the feeding relationships among species.
Aims: This study analysed the stomach contents of finescale triggerfish, Balistes polylepis, at two sites in the southern Gulf of California, in order to describe its diet.
Methods: The prey-specific index of relative importance (%PSIRIi) was determined, diet width was calculated with Levins’ index and the Costello method, and the trophic position was estimated using the R package dietr.
Key results: B. polylepis is an omnivorous species with a preference for animal material (TL = 3.1) that feeds on a wide range of prey. It is categorised as a generalist predator (Levins’ index, Bi = 0.99). The most important items in the diet were the colonial ascidian Lissoclinum fragile (%PSIRIi = 13.52) at Las Ánimas, and the Xanthidae family (%PSIRIi = 13.24) at San Juan de la Costa.
Implications: B. polylepis plays an important role. Because it can exploit a broad variety of resources, it participates in trophic interactions with several other species. It is essential to determine the trophic habits of this species in other areas of its distribution.
... Values of Gastro-Somatic-Index (GSI) showed variations in each sampling station, depicting the medium feeding activity of the fish species during this time, which may be in correspondence with the breeding period (Țiganov et al. 2016). During spawning season, the ovaries are substantially larger, filling the body cavity and transferring the energy content of the body to gonads, displacing and limiting the size of the digestive tract, thus limiting fish feeding (Valinassab et al. 2011). There is a clear variation in the feeding intensity, pattern of feeding intensity depending on the seasonality of prey abundance and the qualitative species composition (Garrido et al. 2008). ...
Mesozooplankton organisms, due to their very important role in the nutrition of fish larvae and juvenile fish, influence the state of fish stocks and have long-term effects on the demographics as well as composition and productivity of fish populations. In the autumn season, an expedition was carried out to collect data about the mesozooplankton community and Alosa tanaica fish population. The mesozooplankton component was represented by 19 taxa, with the fodder component being dominant. The group of Copepoda was best represented and had the highest density, followed by the meroplanktonic component. Totally, 120 Black Sea shad individuals were analysed in order to identify the mesozooplanktonic organisms that this species consumes. Seventeen taxa belonging to the mesozooplanktonic community were identified in the stomachs of A. tanai-ca. The identified items were species of Copepoda, Cladocera and meroplankton, the last being the one that had the major contribution to the fish diet. The stomach content analysis of A. tanaica revealed that the most frequently consumed mesozooplanktonic items were Decapoda larvae, especially those at the mysis stage.
... Further, the total length and wet weight of the gut was measured to the nearest 0.1 mm and 0.01 g respectively. Feeding periodicity was explored by analysing the stomach fullness index (SFI) and vacuity index (VI) following the methods given by Chiou et al. (2006) and Valinassab et al. (2011) respectively and using the given equations: ...
The feeding habits and reproductive biology of red-toothed triggerfish Odonus niger (Ruppell, 1836) was analysed from 449 specimens collected from the Karnataka coast of the south-eastern Arabian Sea. Of the total stomachs examined, only 54 (12%) were empty and 395 contained food remains. The diet comprised crustacean remains (48.0%), zooplankton (21.4%), algae (16.5%), fish remains (6.1%) and cephalopod remains (5.3%) along with partially digested matter (2.3%) and detritus (0.4%). The species was found to be a generalist feeder and an omnivore. The overall sex ratio between males and females (1: 0.44) was significantly (P<0.05) different. Histological examination of the ovaries indicated asynchronous ovarian development in females, with males maturing earlier than females. The gonadosomatic index (GSI) patterns of males and females, and the presence of ripe ovaries and spermatozoids suggested that April–May is the peak spawning period. The absolute and relative fecundity estimates ranged from 16,464–312,420 eggs and 251–2812 eggs g−1 respectively. Fecundity was positively correlated with total length and body weight. The biological information on diet composition and reproductive traits provided for the first time in this study can facilitate conservation, management and sustainable exploitation of this species in the study area.
... The feeding intensity was classified as empty, trace, ¼ full, ½ full, ¾ full, and full based on the eye estimation. The stomach fullness index (SFI) and vacuity index (VI) were estimated following the methods given by Chiou et al. (Chiou et al., 2006) and Valinassab et al. (Valinassab et al., 2011) respectively using the formula: ...
The feeding dynamics and nutritional value of obtuse barracuda, Sphyraena obtusata collected from the coastal waters of Karnataka, southeastern Arabian Sea, India, were investigated between August 2019 to March 2020. Three hundred and fifty five specimens of obtuse barracuda having 16.5–30.1 cm total length and 23.63–175.27 g total weight were analyzed. Of the analyzed stomachs, 119 stomachs (vacuity index = 33.52%) were empty. The high feeding intensity was observed during March with 32.43% fishes having full stomachs. Stomach fullness index values were significantly (p < 0.05) higher during November (2.46 ± 0.44) and March (2.46 ± 0.41). The most dominant prey item in terms of frequency (87.80%), number (57.63%), volume (91.82%), and % IRI (93.76%) was teleosts. Crustaceans and cephalopods were encountered less frequently and were represented by Acetes sp. and Uroteuthis duvauceli respectively. The high protein (21.39 ± 0.52%) and fat (1.21 ± 0.33%) content recorded during March resulted in high-energy value (102.11 ± 5.20). The information on dietary composition and nutritional value of obtuse barracuda provided in this study can be useful for sustainable management of the fish stock in the Karnataka coast. The high protein and energy content indicated that this fish may be considered as highly nutritive food for a healthy diet.
... Iran is surrounded by the Persian Gulf and Oman Sea in the south [11] and fishery is the second most important natural resource in the region [12]. The waters of the Persian Gulf and Oman Sea are also unique because of the special environmental conditions (high temperature and salinity) and the existence of many important commercial species. ...
... The waters of the Persian Gulf and Oman Sea are also unique because of the special environmental conditions (high temperature and salinity) and the existence of many important commercial species. Different types of fish and aquatic resources have provided nutrients, job opportunities and potential export earnings in the south of Iran [11][12][13]. In 2014, Iran was in the 28th place in world fishery production, the 20th place in world aquaculture production and 27th place in overall production. ...
... Groupers species (particularly Epinephelus spp.), one of the most important commercial fish in the Persian Gulf and the Oman Sea [15], and also Asian Sea bass (Lates calcarifer) are found highly susceptible to VNN [16,17]. Since more than 60% of the marine fish production in Iran is in the south of Iran [11] and the Persian Gulf is a semi-closed water body, connected to the Oman Sea [12], there is no significant difference in the abundance of fish species in these two seas [11]. Therefore, the spread of this emerging disease between wild and farmed fish and especially its vertical and horizontal transmission as well as the significant economic damage it causes to the aquaculture industry makes it necessary to carry out VNN detection [9]. ...
The emergence of diseases has caused much health and economic damage. Viral Nervous Necrosis (VNN) is considered as one of the most important threats to aquatic ecosystems. VNN can cause severe mortality and economic loss in fish farms. The high water temperatures in southern Iran and the observed incidences of fish mortality in the Persian Gulf led to the hypothesis of the possible emergence of VNN. Therefore, this study aimed to monitor two species of fish susceptible to VNN using PCR, and Nested PCR methods and comparing the sensitivity of these methods to the identification of Betano-davirus infection in apparently healthy and symptomatic fish. About 850 Grouper (Epinephelus spp.) and Asian Sea bass (Lates calcarifer) fish of the Persian Gulf were collected randomly and examined. Molecular methods were used to identify NNV in visibly healthy and symptomatic fish of the Persian Gulf of Iran. The results of the PCR showed no positive cases, but the Nested PCR revealed some positive results. Then, the phylogenetic analysis of the virus sequence was performed. The nucleotide sequence of Nested PCR products revealed a 98-100% homology with Red Spotted Grouper Viral Nervous Necrosis (RGNNV). This is the first report on VNN tracing and detection as well as phylogenetic analysis of the virus from the Persian Gulf of Iran. Therefore, considering the importance of emerging viral diseases and the irreparable damage they cause, continuous monitoring and epidemiological studies of VNN were recommended by authorized organizations.
... Even though scanty details are available in literature, the present work tried to bring a combination of different indices for describing feeding biology of E. jonesi from the south-east coast and can be considered as a first of its kind. The seasonal patterns in this study were consistent with observations by Valinassab et al. (2011) ...
The relative condition factor (Kn) based on length-weight relationship and food and feeding habits of Jones’ pony fish Eubleekeria jonesi (James, 1971) off Mandapam waters was studied during December 2016 - April 2018. The Kn values showed variations on a monthly basis with maximum value during September (1.23) for male and March (1.53) for female. Analysis of fullness of stomach of 961 samples within the size range of 51-130 mm revealed 40.87% fishes as actively fed, 36.19% as moderately fed and remaining 22.94% as poorly fed. The monthly mean fullness index (FI) was highest during September for both sexes. Highest gonadosomatic index (GSI), vacuity index (VI) and Kn value were observed during March-April in females, probably indicating a spawning peak and hence meagre feeding, which resulted in lowest fullness index (FI). Fishes of smallest length group (51-70 mm) had highest FI and minimum VI and vice versa. The values of index of relative importance (IRI) indicated that the species was planktivorous as well as detritivorous, with top priority towards crustaceans (27.6%) followed by bivalves (23.6%), foraminifera (15.4%), phytoplankton (12.5%), gastropods (9.1%) and nematodes (8.3%) in the gut contents. Diet did not show significant variation either sex-wise or size-wise.
... Food remains from the stomach contents (not including the spiral valve) were separated, counted and weighed, and each prey item was identified to the lowest possible taxonomic level. In order to reflect the frequency of feeding, which has been used previously to estimate the fraction of the population presenting prey remains in the stomach, the vacuity index was calculated using the equation proposed by Euzen (1987) in Valinassab et al. (2011). ...
... Previously recorded vacuity values for R. steindachneri and R. bonasus oscillated between 18.1% and 52.9% (Orth, 1975;Díaz-Carballido, 2011;Fisher et al., 2011;Simental-Anguiano, 2011;Ajemian & Powers, 2012;Navarro-González et al., 2012;Bornatowski et al., 2014;Ramírez-Rodríguez, 2014) which are high values compared with those recorded in studies of the diet of other batoid species (Bornatowski et al., 2010(Bornatowski et al., , 2014Viana et al., 2017). According to Euzen (1987, in Valinassab et al., 2011, vacuity values <20% are considered characteristic of 'edacious species', whereas values >60% are characteristic of 'moderate feeders'; and vacuity values between 81-100%, such as those found in this study, are characteristic of 'abstemious' predators. However, vacuity values from the latter category are reported only rarely. ...
Rhinoptera steindachneri is a commercially important, medium-sized, pelagic migratory
batoid fish with benthic feeding habits. It has been considered a specialized predator that
feeds on molluscs as well as benthic ophiurids and arthropods off the Mexican Pacific
coast. Most biological aspects of this species in La Paz Bay are unknown, despite its being a commercially important species of conservation interest. Therefore, the aim of this study was to characterize the feeding habits of R. steindachneri based on specimens caught in artisanal fisheries. The stomach contents of 310 specimens (146 females and 164 males) were analysed, all captured from 2013 to 2015. The vacuity index was 97.1%, and the most important prey species were Mysidium spp. and Cylichna spp. Because of the high frequency of empty stomachs recorded, it was not possible to describe with precision the general diet of the species. Three hypotheses were developed to try to explain why this characteristic occurred in this species, ranging from eating habits to physiology and prey digestion and geographic location of the study. However, considering the mechanical process of prey handling of R. steindachneri, several hypotheses were formulated, with the hour of capture, chemical processes and physiology and prey digestion being the most probable to explain this high vacuity index reported in this study
... After spawning, a large amount of energy and nutrients is need to recruit resources for growth and preparation for next reproduction cycle (Dadzie et al., 2000). Similar feeding characteristic has been reported for P. kaakan, where lowest feeding intensity and highest value for VI found during spawning season i.e. spring (Valinassab et al., 2011). Whereas Safi et al. (2013) found highest feeding intensity rate of P. stridens in October and March, concluding that feeding intensity is higher in colder seasons, followed by a decline in warm seasons. ...
Feeding habits of Pomadasys stridens were studied in northern part of the Persian Gulf. A total of 591 specimens were collected from the coastal water of Bushehr Province using trawl boats from May 2012 to April 2013 and diet composition, feeding intensity and season changes in diet composition were investigated. Vacuity Index was 81% during the study. RGL was 0.98±0.03 classifying this species as carnivorous to omnivorous fish. Pomadasys stridens had consumed 48 different food categories in 7 taxonomic classes. Crustacean, Mollusca, foraminifera, nematodes, Echinodermata, Annelida and miscellaneous were the main observed food items. There was no significant difference between males and females regarding diet composition in different months.
