I got my Ph. D degree at the School of Fisheries at the University of Washington and was working for the Department in Willapa Bay before I actually finished my degree in 1994. It is a nervous system toxin that is toxic primarily to shrimp and other arthropods although it does kill some mollusks. Since they spray it in the estuary, it is a big issue. They've been doing that since the 1960's to control ghost shrimp and that is what I've focused a great deal of my work on.
Ghost shrimp cause the oysters to sink in the mud and die.
The oysters get covered up by sand and mud and suffocate and die so the growers spray to kill the shrimp. The department was primarily interested in the effects of the spray on Dungeness crab because it kills juvenile crabs that are on the beds. My doctoral research dealt with the life history of the shrimp, looking at how we might get around spraying the pesticide or do it more effectively. The shrimp recruit to the estuaries on an annual basis. So we studied the life history of the shrimp and the effects of the carbaryl on non- target organisms.