Changes in Stock Productivity: a Tale of Two Coasts

Climate induced changes in stock productivity can have substantial impacts on abundance. Changes in oceanographic conditions modify vital rates altering the quantity and quality of available habitat and impacting survival. Species with different life histories are likely to respond in different ways to environmental changes, however, exploitation status may also impact the environmental response of species. Stocks at low population size may be more vulnerable to climate impacts. We examined changes in stock productivity with a time-varying stock recruitment model fit within a Kalman Filter framework. The Kalman Filter parses variability in recruitment into measurement variability and longer-term process variability interpreted as climate induced shifts. We modeled the changes in productivity for twenty-five stocks on the West Coast of the United States and compared the results to a similar study on the East Coast. The results suggested patterns in productivity by life history, though potentially stronger patterns based on exploitation status.