Fish assemblage structure in the Tropical Coastal Lagoon of Grand Lahou (Cte DIvoire, West Africa)

Abstract

Fish assemblages and their relationship with hydrological variables were investigated in the coastal lagoon of Grand-Lahou (Cote-d’Ivoire) from November 2013 to October 2014. Samplings were carried out by means of artisanal fisheries, once a month, in three sites. A total of 8571 fish belonging to 47 fish species from 25 families were recorded. The most represented families were Cichlidae and Mugilidae with six species. Each environmental variable, notably, dissolved oxygen (DO), temperature and salinity according to the canonical correspondence analysis (CCA) allowed the distinction of two main sectors in the lagoon, associated with three fish assemblages. Sector 1 including sampling sites 2 and 3, characterized by high salinity fluctuations, functioned as a typical estuary. Two fish assemblages identified in this sector were Lutjanus dentatus, Mugil cephalus, Mugil bananensis, Tilapia guineensis and Tylochromis jentenki in station 2 and Sarotherodon melanotheron, Liza falcipinnis and Pomadasys jubelini in station 3. Sector 2 comprising the sampling site 1, characterized by low salinity fluctuation is associated with 11 fish species, notably, Ethmalosa fimbriata and Elops lacerta. The fish assemblage in this sector depends on season, temperature and DO. Key words: Ichthyofauna distribution, environmental variables, Grand-Lahou lagoon, Cote d’Ivoire.