Vectorial transport of toxins from the dinoflagellate Gymnodinium breve through copepods to fish

Abstract

Toxins from the dinoflagellate Gymnodinium breve were traced through experimental food chains from dinoflagellates, through copepod grazers, to juvenile fish. The generality of this food web transfer was demonstrated using three different combinations of copepods and juvenile fish during different seasons. Fish were not exposed directly to the toxic dinoflagellates but were fed toxin-laden copepods in order to examine sublethal vectorial intoxication. Toxins were shown to move from fish viscera to muscle tissue within periods of 2-6 h to 25 h. A new toxin detection method was used in this first stepwise demonstration of multi-trophic-level intoxication of a planktonic food chain by G. breve. Micellar electrokinetic capillary electrophoresis with laser-induced fluorescence allowed measurements of toxins at trace levels and nanoliter-sized volumes critical for planktonic food web transfer studies.