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

Toxins from the dinoflagellate Gymnodinium breve were traced through experi mental food chains from dinoflagellates, through copepod grazers, to juveni le fish. The generality of this food web transfer was demonstrated using th ree different combinations of copepods and juvenile fish during different s easons. Fish were not exposed directly to the toxic dinoflagellates but wer e fed toxin-laden copepods in order to examine sublethal vectorial intoxica tion. Toxins were shown to move from fish viscera to muscle tissue within p eriods of 2-6 h to 25 h. A new toxin detection method was used in this firs t stepwise demonstration of multi-trophic-level intoxication of a planktoni c food chain by G. breve. Micellar electrokinetic capillary electrophoresis with laser-induced fluorescence allowed measurements of toxins at trace le vels and nanoliter-sized volumes critical for planktonic food web transfer studies.