Research Product

At the present time the Bureau of Commercial Fisheries is conducting a research program to determine the effects of pesticides on commercial fishery resources. I should like to discuss certain phases of this research and their relation to field applications of pesticidal chemicals. The value of the estuarine environment to commercial fishery resources can not be over emphasized. Our most important commercial species of finfish and shellfish spend all or part of their life span in estuarine waters. Sessile or slightly motile forms as oysters and clams are necessarily restricted to these inshore waters. Motile species such as crabs, shrimp, menhaden and mullet spend much of their early life in lower salinity waters near sources of natural land drainage. Heavy spraying of certain chemicals to control larvae in or near estuarine waters can be very destructive to these marine forms both through direct kills and destruction of their food supply. However, the amount of insecticides used in such coastal operations is far outweighed by that used on forest and farmlands. It seems inevitable that some of these chemicals or their metabolites will reach estuarine waters. One of the major objectives of our research program has been the determination of acute toxicity of the commonly used pesticides to representative marine species. These bioassays are conducted under controlled laboratory conditions. The development of uniform testing methods has been an important part of this research. Since several phyla of marine organisms are used as bioassay animals, different criteria of toxicity must be used. Each chemical is tested on oysters, shrimp, phytoplankton and at least one species of marine fish.