EFFECTS OF RAINFALL PATTERN ON DISTRIBUTION OF Callinectes amnicola AND Macrobrachium vollenhovenii FROM INTERCONNECTING LAGOONS LAGOS, NIGERIA

Abstract

Crustaceans form a very popular food items in the diet of coastal communities in West Africa. In Nigeria, there is paucity of information on the effect of rainfall pattern on shellfishes found in these aquatic environments. C. amnicola and M. vollenhovenii were collected monthly from four interconnecting lagoons between 19992000 and 2013-2015. The rainfall data for the periods were collected from Nigerian Meteorological Agency, Oshodi Lagos.  The sizes of crabs/prawns ranged from 3.5-8.4 cm/4.5-10.4 cm (small-sized), 8.5-13.4 cm/10.5-16.4 cm (medium-sized) and 13.5-18.4 cm/16.5-22.4 cm (large-sized) respectively. The relationship between the sizes of the species and the rainfall pattern were assessed based on onset and offset of rainfalls. The results showed that during high rainfall, the small-sized crabs dominated Badagry and Lagos Lagoons, medium-sizes were more in Badagry and Lekki Lagoons while the large ones were more in Lekki Lagoon. Small sized prawns were noted to be in abundance during the rainy seasons from Badagry, Lagos and Epe Lagoons while the large-sized prawns were dominant in Epe Lagoon. The changes in rainfall pattern could be said to have significant effect on the size variations and distribution of these shellfishes. Hence, effective conservation should be adequately enhanced by prohibiting the fishing of these organisms especially during the rainy season. This information would assist Biologist on the population dynamics of these aquatic species and its implication for the management of the fisheries and culturability of their uses as a commercially important species.