Fish bioassay and toxin induction experiments for research on Pfiesteria piscicida and other toxic dinoflagellates: workshop summary.

In late January 2000, the Centers for Disease Control and Prevention sponsored a workshop to discuss standardizing the laboratory materials and methods used for in vivo fish bioassays and toxin induction experiments. Representatives from six laboratories using these assays to conduct research on Pfiesteria piscicida Steidinger & Burkholder, similar organisms (i.e., members of the toxic Pfiesteria complex) or their toxins were invited to attend. The workshop objectives were a) to discuss the need for uniform quality assurance for fish bioassays and toxin induction, b) to encourage publishing the relevant materials and methods in the literature, c) to foster communication among the laboratories conducting this work, and d) to respond to requests from state health and environmental protection agencies for guidance in interpreting the results from fish bioassays conducted in different laboratories. To facilitate discussion at the workshop, researchers conducting Pfiesteria research completed a detailed questionnaire in advance about fish bioassays and toxin production assays. Workshop participants discussed experimental factors that might influence the reproducibility or interpretation of fish bioassays and toxin-induction experiments. The experimental factors were categorized into physical, chemical, and biological parameters. In addition, participants ranked experimental factors by their relative importance in conducting these assays as a) factors that are critically important and should be maintained within a recommended range, b) factors that are important in conducting the assays but that may be variable among laboratories or within experiments and whose values should be recorded and reported by investigators, and c) factors of unknown importance that should be considered important research questions. This article summarizes results obtained from the questionnaire and workshop discussions.