Managing fish as a moving target in a liquid environment
Earth’s oceans are vast. Consider just the narrow strip of Pacific Ocean that forms the Oregon Coast. At any given time, there may be 50 salmon stocks found there and at least 60 stocks of groundfish, according to Gil Sylvia, COMES director. “All these stocks are sharing a shifting, three-dimensional environment for spawning, feeding, or sheltering. Fishery managers must accommodate life histories of hundreds of stocks and species through space and time. Without good science, it’s not possible.”
David Sampson, a fisheries scientist at COMES, provides some of the science necessary to ensure that Oregon’s fisheries remain sustainable and productive. Sampson develops and evaluates methods for fish stock assessment; and he conducts groundfish stock assessments for the Oregon Department of Fisheries and Wildlife.
Stock assessments provide information on the status of fish populations through time and space, whether the stocks are increasing or decreasing, and why. Fish are hard to count; they are hard to see, and they move around. And the natural variability of their ocean environment makes it difficult to measure or predict changes in their health or status.
“If a stock assessment underestimates the productivity of a fishery, managers might needlessly limit the number of fish that can be caught. This reduces the available supply of seafood and the economic opportunity for fishermen,” Sampson said.
“However, if a stock assessment overestimates the productivity of a fishery, too many fish might be harvested, leaving too few to reproduce and replace the harvested number,” he said.
So Sampson is working to ensure that the methods of assessing a moving target in a complex environment use the best science available to assure fisheries for now and the future.