Nowadays, the successful management of small scale fisheries requires the use of biometric data collected in the field, in order to transform them into suitable indicators. The present study describes the lengthweight relationships for 36 freshwater fish species from two tropical reservoirs Ayame I and Buyo, in Côte d'Ivoire. The main objective of the study was to provide a length weight key for a wide range of freshwater fish species from these tropical reservoirs exploited by the inland fisheries. The samplings were carried out at Buyo from July 1997 to August 1998, and from August 2004 to July 2005 in Ayame I. Fish specimens were collected from catches of artisanal fisheries using gill-nets, cast-nets, beach seines and bamboo traps. After landings, samples were identified, total weight for each specimen was recorded to the nearest gram and standard length was measured to the nearest millimetre. A total of 12 724 individuals belonging to 15 families and 24 genera were obtained in this study. The results indicated that the family with the highest number of species was Cichlidae with eight species. Six families were recorded with only one species per family. The value of the exponent b in the length weight relationships (W=aL b) ranged from 2.173 for Marcusenius furcidens to 3.472 for Polypterus endlicheri and the median of b was 2.756. The modal value of the exponent b equal to 2.70 indicates that most of the fish species in Ayame I and Buyo Reservoirs have negative allometric growth. The length weight parameters of the three species, Lates niloticus, Synodontis koensis and S. punctifer are described for the first time in these regions. The present length-weight key for 36 freshwater fish species could be used as a valuable tool for fishery managers, in order to improve the inland fisheries statistics largely based on hydropower reservoirs in Côte d'Ivoire.

Length frequency data collected from artisanal fisheries in Lake Ayame´I (Coˆte dÕIvoire) from August 2004 to 2005 were analysed with FISAT ISAT software using the ELEFAN LEFAN 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.

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The Ecopath software with Ecosim and Ecospace was used to describe structure and trophic relationships in Lake Ayamé. The total biomass of fish is 8 t.

The new dam of Soubre in Cote dIvoire resulted in the creation of a 17.3 km2 lake in April 2017. After an 18-month ban, the exploitation of fishery resources started and is mainly carried out by foreignBozofishermen. The present study, whose main objective was to conduct the ichthyological inventory of this lake, was executed between August 2019 and July 2021. The artisanal catches of fishermen were examined monthly in the three main landing sites of the lake. The species richness of the lake was estimated at 42 species. The specific weight composition of the catches indicates the predominance of the catfish Chrysichthys nigrodigitatus with 16% of catches.For numerical abundance, the Mormyridae Marcusenius senegalensis leads the catches with a17% rate. It should be noted that this study allowed the observation of specimens of the freshwater shrimp of the genus Macrobrachium upstream of the lake, in the river-lake transition zone, while no individual of this species was captured in the lake.