Preliminary estimates of the population parameters of major fish species in Lake Ayamé I (Bia basin; Côte d’Ivoire)


Author’s address: Leonard Tah, Laboratoire d’Hydrobiologie, UFR Biosciences, Université de Cocody, 22 BP 582, Abidjan 22, Côte d’Ivoire (Afrique de l’Ouest).


Length frequency data collected from artisanal fisheries in Lake Ayamé I (Côte d’Ivoire) from August 2004 to 2005 were analysed with Fisat software using the Elefan package to estimate the population parameters of 11 fish species. Asymptotic values for total length (L∞) ranged from 20.5 cm for Brycinus imberi to 78 cm for Mormyrops anguilloides. Growth rates (k) varied from 0.24 year−1 for Chrysichthys nigrodigitatus to 0.57 year−1 for Hemichromis fasciatus. The growth performance estimates were close to the values found by others authors and reported in FishBase 2008. Fishing mortality (F) and exploitation rate (E) were found to be below optimum levels of exploitation for most fish species. Recruitment was noted as year–round and bimodal for most studied populations. The data sets were limited in most cases, thus this study provides preliminary population parameters only, but for species for which information is scarce. For application in stock assessment, the growth parameters and especially the natural mortality data require further confirmation.