In this study, the seasonal variation in sex ratio, macroscopic stages of sexual maturity, gonado-somatic ratio, hepatostatic ratio, condition factor, and size-weight relationship in Auxis thazard from Gulf of Guinea were studied from January to December 2016. Sex ratio observed was in favor of males (1: 0,78; X² observed = 20,16 ˃ theoretical X² = 3,84 ; p ˂ 0,05). The variation of maturity stages associated with GSI, HSI, and K during different seasons of the year showed that this specie spawns throughout the year. Length-weight relationship was W = 0,0039 L 3, 4108 (R 2 = 0,93 ; N = 291) for males, W = 0,0036 L 3, 4376 (R 2 = 0,91 ; N = 227) for females, and W = 0,004 L 3, 4118 (R 2 = 0,92 ; N = 519) for the combined sexes. The b value was significantly higher than the theoretical value of 3 for males (t-test, t = 233,218, p ˂ 0,05), for females (t-test, t = 227,776, p ˂ 0,05), and for all individuals (t-test, t = 315,821, p ˂ 0,05). This situation however indicates a faster increase of the fish in weight rather than in length. ResumeDans cette étude, la variation saisonnière de la sex-ratio, des stades macroscopiques de maturité sexuelle, du rapport gonado-somatique, du rapport hépato-somatique, du facteur de condition et la détermination de la relation taille-poids chez Auxis thazard provenant du golfe de Guinée ont été étudiées de janvier à décembre 2016. La sex-ratio déterminée a montré une prédominance des mâles (

A study of Synodontis punctifer (family: Mochokidae) of Taabo Lake was conducted from October 2015 to September 2016. This was carried out so as to evaluate its quantity (biomass) caught by fishing and also its morphological characteristics. The fish were caught using gillnets at 4 sites of the lake and different measurements were made. The fishing effort was 23 to 11 fishermen / day in Taabo city, 17 to 11 fishermen / day in Courandjourou, 13 to 5 fishermen / day in Ahondo, and 8 to 3 fishermen / day in Taabo village. The catch per unit effort (CPUE) ranged from 17.7 to 3.7 g / fisherman / day, 9.2 to 1.2 g / fisherman / day, 8.3 to 0.7 g / fisherman /day, 8 to 1g / fisherman / day at Ahondo, Courandjourou, Taabo city and Taabo village, respectively. The overall annual production was estimated at 2199.3 kg, i.e. 817 kg (40%) at Ahondo, 788.3 kg (35%) at Courandjourou, 462.5 kg (20%) at Taabo, and 131.5 kg (5%) in Taabo village. The overall sex ratio (1: 1.33) was in favor of females. Individuals have negative allometric growth at all sites with values ranging from 1.72 to 2.89. The condition factor does not vary significantly between different categories of individuals (ANOVA, F = 2.79, p ˃ 0.05). A significant difference was observed between the average sizes of the individuals of the different sites (test, p˂0,05). The large size specimens were captured at Ahondo, mean (avg = 15.38 ± 1.68 cm FL). In Courandjourou, the sizes were intermediate (avg = 13.63 ± 1.64 cm LF). Smalls sizes have been observed in Taabo city (mean= 12.37 ± 1.24 cm FL) and Taabo village (mean= 15.58 ± 1.58 cm FL).

The shape of sagitta otoliths was used to compare individuals of little tunny (Euthynnus alleteratus) harvested on board commercial fishing vessels from the coastal areas along the Eastern Atlantic, including the Mediterranean Sea. Fish sampling and selection was designed to cover possible seasonal changes and tuna size. The research encompassed both morphometric and shape analyses of left sagittal otoliths extracted of 504 fish specimens. Four shape indices (Circularity, Roundness, Rectangularity, and Form-Factor) were significantly different between two groups, showing a statistical differentiation between two clear spatial units. The degree of divergence was even more pronounced along the rostrum, postrostrum, and excisura of the generated otolith outlines between these two groups. One group corresponds to the samples from the coastal areas in the Northeast Temperate Atlantic and Mediterranean Sea (NETAM Area) and a second group from the coastal areas off the Eastern Tropical Atlantic coast of Africa (ETA Area). This study is the first to use otolith shape to differentiate tunas from separate spatial units. These results could be used to re-classify previously collected samples and to correct time series of data collected.

The rainbow runner, Elagatis bipinnulata, which belongs to the Carangidae family, is regularly encountered in the landing of artisanal fishing in Abobo-Doumé (Republic of Côte d'Ivoire). The object of this work is to study the diet of Elagatis bipinnulata according to the marine seasons and the size of the various specimens (immature and mature). About 900 fish measuring between 43 and 93 cm (fork length -FL) were examined from September 2015 to August 2017. On the 900 examined stomachs, 541 were empty, which is giving a vacuity coefficient of 60.11%. A feeding index (IRI: index of relative importance of food item) combining three methods percentage occurrence, numerical method and weight method) was used. The identification of the items found in the stomach contents revealed that the principals food items were fish (%IRI=48.85) and crustaceans (%IRI=45.78). Cephalopods (%IRI=4.17), fish detritus (%IRI=1.2) and crustaceans (Portunus puber) (%IRI=0.55) are accidental food. The diet of the species does not change according to the seasons and the size of fish.