• Sayce, Clyde S.
  Fisheries Biologist
  
• Chambers, John S.
  Fisheries Biologist
  

The Washington State Department of Fisheries has developed procedures and techniques for controlling ghost shrimp, Callianassa californiensis, and the mud shrimp, Upogebia pugettensis, on oyster beds using the insecticide Sevin (1-naphthyl N-methylcarbamate). Under an experimental-use permit and rigid supervision, the insecticide is applied to infested beds between the time of oyster harvesting and reseeding. Application and results of each treatment are monitored by the Department of Fisheries to obtain additional information on the use of Sevin.

Although several experiments have been carried out to assess the presence of Sevin in oyster meats at varying times after treatment with different concentrations of the insecticide, additional information was desired. On August 9, 1967, an experiment was carried out in cooperation with commercial oyster grower, Mr. Lee J. Wiegardt, to obtain this information.