ECOLOGICAL OBSERVATIONS ON JUVENILE FLATFISH IN A TROPICAL ESTUARY - ARQUIPELAGO DOS BIJAGOS, GUINEA-BISSAU

Juvenile flatfish were studied in a tropical estuary, Arquipelago dos Bijagos in Guinea-Bissau from October 1992 until April 1993. A total o f eight flatfish species, belonging to the families Bothidae, Cynoglos sidae, Psettodidae and Soleidae, were found. In comparison with other fish groups, flatfishes abundance was low with densities of less than 13 ind . 100 m(-2). One species, Citharichthys stampflii, occurred in densities high enough to permit an analysis of distribution, growth an d mortality. During the period of study, settlement of C. stampflii wa s observed in the estuary Its distribution suggested a preference for offshore areas, densities decreasing towards the river systems. Repeat ed sampling in the intertidal area of Ilheu de Flamingos permitted a p reliminary estimate of mortality and growth. Instantaneous mortality r ates were about 0.03 . d(-1), which is similar to estimates in tempera te estuaries. Growth rates were slightly above 1 mm . d(-1), about the same as those measured in subtropical estuaries.