EFFECTS OF FISHING ON THE REPRODUCTIVE BIOLOGY OF THE MULLET MUGIL INCILIS (PISCES: MUGILIDAE) IN THE CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIAN CARIBBEAN

Abstract

The mullet Mugil incilis is one of the most important fish resources in the Ciénaga Grande de Santa Marta. Based on monitoring of fishery statistics collected in the periods 1994-1996 and 2000-2007 and biological aspects of the species between 2006 and 2007, we evaluated fishing effects on the reproductive biology of M. incilis. Fishery statistics revealed that catch and fish size declined with time. Peak spawning was observed to occur between November - December, when the gonadosomatic index and condition factor showed their maximum values, contrasting with water salinity that plunged in the rainy period. Male: female ratio was estimated as 1:3 after a sample of 1954 individuals, and mean maturity size (MMS) calculated as 23.8 cm total length (TL), lower than that previously reported. Mullet represented 30 % of the whole fish catch in the period 1994-2007, and 65 % of the individuals were found below their MMS, mainly caught with cast-nets at spawning time. Lower occurrence of larger fish in the catch seems to be a reasonable explanation for the reduction of MMS. No evidence was found to attribute this decrease to a species strategy. Management measures for this fishery are discussed and suggested.