Response of two zooptankton grazers to an ichthyotoxic estuarine dinoflagellate

• Published in: Journal of Plankton Research
• Main Authors: Mallin, Michael A., Burkholder, JoAnn M., Larsen, L.Michael, Glasgow, Howard B.
• Format: Text
• Language: English
• Published: Oxford University Press 1995
• Subjects: ORIGINAL ARTICLES; Copepods; Rotifer
• Online Access: http://plankt.oxfordjournals.org/cgi/content/short/17/2/351; https://doi.org/10.1093/plankt/17.2.351

The dinoflagellate Pfiesteria piscicida (gen. et sp. nov.). a toxic ‘ambush predator’, has been implicated as a causative agent of major fish kills in estuanne ecosystems of the southeastern USA. Here we report the first experimental tests of interactions between P.piscicida and estuarine zooplankton predators. specifically the rotifer Brachionus plicatilis and the calanoid copepod Acartia tonsa . Short-term (10 day) exposure of adult B.plicatilis to P.piscicida as a food resource, alone or in combination with the non-toxic green algae Nannochloris and Tetraselmis . did not increase rotifer mortality relative to animals that were given only non-toxic greens Similarly, short-term (3 day) feeding trials using adult A.tonsa indicated that the copepods survived equally well on either P.piscicida or the non-toxic diatom Thalassiosira pseudonana . Copepods given toxic dinoflagellates exhibited erratic behavior, however, relative to animals given diatom prey. The fecundity of B.plicatilis when fed the toxic dinoflagellate was comparable to or higher than that of rotifers fed only non-toxic greens We conclude that, on a short-term basis, toxic stages of P.piscicida can be readily utilized as a nutritional resource by these common estuarine zooplankters. More long-term effects of P.piscicida on zooplankton, the potential for toxin bioaccumulation across trophic levels, and the utility of zooplankton as biological control agents for this toxic dinoflagellate. remain important unanswered questions.