Pseudotolithus elongatus of the family of Sciaenidae lives in Ebrie lagoon, where it is regularly met in the unloadings of artisanal fishing. The diet was studied according to the seasons and of the size of the various specimens (immature and mature). About 437 individuals of measuring between 14,5 and 42,7 cm total length were examined during July 2013 to February 2015. On the 437 examined stomachs, 182 were empty, which gives a rate of vacuity of 41,64%. A feeding index (IRI: index of relative importance of food item) by combining three methods (frequency occurrence, numerical method and weight method) was used. The identification of the items found the stomach contents revealed that the principals food items were the Crustacean (%IRI = 89,26) and the fish (%IRI = 10,54). Annelids (%IRI = 0,1) and the vegetable detritus (%IRI = 0,1) are accidental food. This feed does not varied seasonally and among the size of fish.
The diet of 233 specimens of Heterotis niloticus (Cuvier, 1829) coming from artisanal fishing on the Agneby river was studied during one year according to the hydrological seasons and the size of fish. The stomach contents were analysed by using the methods of frequency of occurrence, numerical frequency and specific abundance. The results obtained reveal that this fish is omnivorous because its diet contains insects, microcrustacea, rotifer, nematodes, Arachnida, molluscs, seeds, phytoplankton, detritus and sand. It mainly fed on microcrustacea in particularly ostracoda. However, there is not variation in the diet according to the hydrological seasons and size of the individuals.
The study of diet examined 272 specimens of Sphyrna zygeana (162 males and 110 females) and 215 specimens of Isurus oxyrinchus (120 males and 95 females) from artisanal fisheries. They were collected between October 2009 and September 2010. The analysis of stomach contents revealed that 87estomacs Sphyrna zygeana were empty (31.98%) and 185 stomachs contained food (262 prey). 154 stomachs of Isurus oxyrinchus contained food (224 prey) and 61 stomachs were empty (28.37%). According to the index of relative importance (IRI) calculated both diets consisted mainly of fish. Levin's Index obtained from S. zygeana (Bi = 0.446) and I. oxyrinchus (Bi = 0.432) indicates that trophic niche is relatively narrow. These two species are specialist predators that use fewer resources with a preference for fish. The community index of Jaccard (Sj = 0.265 <0.5) indicates a similarity between the diet of both species. There is also a dietary overlap (? = 0.7644) between these two species and gender (I. oxyrinchus, C? = 0.897 and S. zygeana, C? = 0.868).
The dynamics of the exploited population of Istiophorus albicans (Atlantic sailfish) from artisanal gillnet fishery was investigated based on length frequency data, using FiSAT software. Specimens were sampled from the artisanal fishery captures in the coastal waters near Abidjan (C
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