Key fish species trends in Puget Sound
Researchers integrate multiple datasets to assess long-term trends in key Puget Sound fish stocks and possible causes of decline, such as fishing, coastal growth, climate change, and proliferating seals and sea lions.
Timothy Essington, UW School of Aquatic and Fishery Sciences
Tessa Francis, University of Washington, Tacoma
Correigh Greene, NOAA Northwest Fisheries Science Center
Dayv Lowry, Washington Department of Fish & Wildlife
Eric Ward, NOAA Northwest Fisheries Science Center
Between 1948 and 1972, the captain of the University of Washington’s School of Fisheries’ research vessel took meticulous notes on all of the fish tows conducted under his watch. With funding from Washington Sea Grant, researchers combed through over 1,000 of these logbook entries to analyze the information regarding the species caught in each tow, including when and where the fish were caught. The researchers then fit Bayesian statistical models to both this historical logbook and the contemporary monitoring data to reveal longer-term trends in local fish populations.
Due to challenges including pollution, habitat impairment and commercial fishing, many fish species in Puget Sound are threatened. State and federal efforts to rehabilitate these at-risk populations are impaired by a lack of historical data on species and community trends: unlike most major U.S. estuaries, Puget Sound did not have long-term monitoring until the late 1980s. This missing baseline information is essential to provide context for the current status of the marine ecosystem, and to understand the relative roles of the challenges that face it.
The trends that the researchers discovered suggest the concept of “baseline” data may be a fallible one. Even species that are commonly thought of as widespread or stable, such as English sole, undergo large fluctuations at long timescales. However, it is clear that other species, including Pacific cod, lingcod and spiny dogfish, are far less common now than they were from 1948 to 1972. This historical context could help resource managers make important restoration decisions.