Reproductive biology ofChromidotilapia guntheri(Sauvage, 1882) (Cichlidae, Perciformes) in four coastal rivers (Ehania, Noé, Soumié and Eholié) of Côte d’Ivoire in West Africa

Abstract

Key-words:spawning activities, Chromidotilapia guntheri, Ivorian coastal streamsThe reproductive activities of a small Cichlid Chromidotilapia guntheri were investigated from July 2003 to March 2005 in four coastal rivers (Ehania, Eholié, Noé and Soumié), in the southeast of Côte d'Ivoire. Trends in gonadosomatic indices and reproductive stages of development suggested that C. guntheri is a multiple (fractional) spawner and breeds all year round with little fluctuation in spawning intensity. However, spawning activities were more intensive in August and September. The estimated mean standard length at first maturity did not differ significantly between rivers. It was, in the overall population, 85.53 mm SL for males and 100.13 mm SL for females. In general, the sex ratio differed from 1:1 with the predominance of the males in rivers, standard length classes, seasons and the entire population. Absolute fecundity (F) varied from a minimum of 70 to a maximum of 470 eggs. The range of variation in the relative fecundity was from 3066 to 9135 eggs per kilogram of fish in the total population. Fecundity did not differ extensively between rivers. The absolute fecundity relations to fish standard length (SL) and eviscerated weight (We) were best described in the whole population by the following equations: F = 0.00069 × SL 2.72 and F = 2.54 × We 1.15 , respectively. Moreover, there was no relationship between absolute fecundity and oocyte diameter. a varié de 70 à 470 ovocytes dans toute la population et n'a présenté aucune différence significative entre les rivières. Les relations fécondité absolue (F)-longueur standard (LS) et fécondité absolue-poids éviscéré (We) ont été mieux décrites respectivement par les équations suivantes : F = 0,00069 × LS 2,72 et F = 2,54 × We 1,15 . En outre, il n'est apparu aucune relation entre la fécondité absolue et les diamètres ovocytaires.

Stock structure analysis ofLabeo rohita(Hamilton, 1822) across the Ganga basin (India) using a truss network system

“…These results are similar to the findings of Boussou et al. () in the Chromidotilapia guntheri from three coastal rivers of Africa where environmentally‐induced morphological differences were found among the tributaries of the Tanoe River, which were geographically close to each other. Quilang et al.…”

Morphological differentiation among species of the genus Mugil Linnaeus, 1758 (Mugilidae) from Côte d’Ivoire

“…Linear measurements were always taken by the same person with digital Vernier calipers and recorded to the nearest 0.05 mm. Measurements follow those of Gourène and Teugels (1993), Thomson (1997), and Boussou et al (2010). A total of 53 characters-40 metrics (Figure 2), 2 morphologics (based on the body color and appearance of the fins), and 11 meristics-were measured on each specimen.…”

Temporal Dynamics of Reproduction of the Neotropical Fish,Crenicichla menezesi(Perciformes: Cichlidae)

“…menezesi attain sexual maturity earlier than the males, mobilizing their energy reserves for reproductive process well before the males. In the West African cichlid Chromidotilapia guntheri , both sexes attain sexual maturity with equal size, reflecting equal energy allocation to reproduction [ 33 ]. However, the time of sexual maturation is closely associated with body size of fish when the optimal size is reached [ 34 ].…”