No abstract

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 reproductive biology of Heterotis niloticus has been studied from monthly samples taken from artisanal fishing on the Agneby river during the period june 2013 to May 2015. The whole sample consisted of 498 specimens of which 269 females and 229 males were examined. Sex-ratio observed was in favour of females (1: 1.17; X2 = 3.21; p > 0.05). The monthly evolution of the gonado-somatic index (GSI), the liver-somatic index (LSI), the condition factor (K) and maturation stages suggests that this fish has two periods of reproduction. The two periods were respectively from june to august and from november to december. The standard length at first sexual maturity was 490.6 mm for females and 436.3 mm for males. The absolute fecundity was ranged from 5424 to 25591 oocytes in females of 595 mm to 780 mm standard length. The relative fecundity was 3752± 1491 oocytes/kg of female.

No abstract

Les taux de capture standardisés sont souvent utilisés comme indices d'abondance relative dans l'analyse des données de capture. La pêcherie artisanale maritime en Côte d'Ivoire a été très active entre 1988 et 2007 en débarquant aussi bien des grands thonidés, les thonidés mineurs que les poissons porte-épées à l'aide de filets maillants. Dans le présent document, il a été utilisé le delta GLM pour standardiser la capture par unité d'effort (CPUE) du Voilier Atlantique (Istiophorus albicans Latreille, 1804) durant cette période allant de 1988 à 2007 dans l'optique de voir son niveau d'exploitation. Pour ce faire, trois facteurs explicatifs (année, trimestre et mois), avec interactions entre eux, on été employés. Tout au long de cette observation, la CPUE standardisée du voilier Atlantique suggère une très forte tendance à la baisse ; dans l'année, les quantités débarquées semblent être liées aux saisons marines.