Mortandad de caballa Scomber japonicus en la plataforma bonaerense (Mar Argentino)asociada a un florecimiento del dinoflagelado tóxico Alexandrium tamarense.

Abstract

Spring blooms of the toxic dinoflagellate Alexandrium tamarense in the Argentine sea produce shellfish toxicity through the parallytic shellfish poison (PSP)accumulation. The trace PSP content in the mackerel Scomber japonicus liver was previously demonstrated in the Buenos Aires province coastal region (Carreto et al, 1993a),and a certain capability to accumulate the toxins was suggested.However, it was up to spring 1993 when a great number of PSP intoxicated mackerels where detected for the first time in a wideshelf area off the Buenos Aires province. This area, known as 'El Rincón' (39°00'-40°30'S), has become a growing importance mackerel fishing ground during the last few years. A high PSP concentration was determined in those mackerels, being the maximum located in the stomach content (2800 ugSTXeq/100g). It was predominantly composed of gelatinous zooplankton and a high concentration of A. tamarence cells indicating a probable way for the toxins transference. The mackerels mortality area corresponded with the A. tamarense maximum concentration in the Buenos Aires province coastal region, where a widespread water discoloration was produced.