THE COLLAPSE OF THE STRIPED MOJARRA EUGERRES PLUMIERI (PISCES: GERREIDAE) FISHERY IN THE CIÉNAGA GRANDE DE SANTA MARTA: FISHING, ENVIRONMENTAL OR BIOLOGICAL CAUSES?

Abstract

The collapse of the striped mojarra (Eugerres plumieri) fishery, a traditional resource in Ciénaga Grande de Santa Marta, from 1994-1996 to 2000-2007, is analyzed. The BACI (Before and After Control Impact) approach used relates fishery, biological and ecological aspects with striped mojarra abundance. The outcome point out that fishing was not determinant of E. plumieri abundance diminution, but a series of different related and cascading events. Seemingly, mojarras were deprived in short time of their preferred food (Mytilopsis sallei), a small sessile bivalve very abundant at one time on oyster banks (Crassostrea rhizophorae). These were buried by sediments delivered initially by tributaries from Sierra Nevada de Santa Marta, and then, since 1996, by works connecting lagoon to Magdalena River. Models are proposed, explaining abundance variation confronted with catch and effort, as well as reduction of carrying capacity for mojarras and their prey, due to impact of sediments proceeding from neighboring ecosystems. The need and usefulness of an ecosystem approach when considering fish resource management is emphasized.