Composición, distribución y abundancia del plancton en el estuario de San Lorenzo, Esmeraldas - Ecuador

Abstract

El presente trabajo es una contribución al estudio del plancton estuarino presente en el área comprendida del Canal de San Lorenzo, provincia de Esmeraldas, para lo cual existe poca información sobre este tema.

The present work comprehends the study of the qualitative and quantitative distribution of the phytoplankton, zooplankton and ichthyoplankton at San Lorenzo in Esmeraldas Province. For the effect 12 stations were established located at the Estero Chimbusal, Estero Nadadero, Canal de San Lorenzo. The sample was taken in the phases flow and refflux the days ist and 2nd of september 2001. There were identified 63 species in water samples and 77 species in samples with net of 50u in the community of the phytoplankton. The diatoms prevailed dominant and in smaller concentration the dinoflagellates, tintinnoids, cianobacters and flagellates. The cell biomass was represented by Messodinium rubrum and Chaetoceros compressus, they were the most abundant species in all the area. In net samples of 50u the dominant species were: Biddulphia sinensis, B.mobiliensis, Chaetoceros compressus, Pleurosigma angulatum and Skeletonema costatum, tytical of a high fertility in the area. The regimen refflux registered 17 taxas of zooplankton an the dominants were Copepods (35%), Chaetognaths (34%) and the Crustacean Larvae such as Zoeas of Brachyuran (11%). The regimen flow showed 14 taxas and were evident the Copepods (60%), Fish Larvae (21%) these groups of zooplankton were considered dominant and frequent. With regard to Ichthyoplankton registered in the regimen flow 3462 fish eggs/10m², the dominant families were Engraulidae (62%), Clupeidae (33%), however it was observed a high abundance of fish larvae with a total 11495/ 10m² and registered the dominant families Clupeidae (40%), Engraulidae (37%) and Scianidae (16%). The regimen refflux presented the biggest abundance on eggs of fish with 19649 eggs/ 10m². The dominant families were Clupeidae 68% and Engraulidae 31%, the fish larvae were low on abundance with 826 larvas/10m² being the dominant families Clupeidae (57%), Scianidae (24%) and Engraulidae (14%).