Complete Scientific Manuscript on Long-term Variability in the Seasonal Cycle of Subsurface Temperature off the West Coast of North America and its Relation to Fish Population Dynamics

Current Status of Accomplishment or Milestone: Draft manuscript completed and in internal review.

Background: Recent research has suggested that subsurface ocean conditions are important influences in the dynamics of fish populations off the west coast of North America, including listed salmon stocks. Furthermore, the life histories of many marine species are tuned to seasonal variations in the ocean environment. This paper follows up on an earlier manuscript by PFEL researchers describing long-term climate trends in the subsurface ocean temperatures of the California Current System.

Purpose of Activity/Goal of Project: Characterizing regime shifts in the subsurface structure of the California Current System and relating these changes to changes in marine resources.

Description of Accomplishment and Significant Results: In this paper, we characterize the changes in the seasonality of subsurface temperatures in the California Current region since 1950, and relate these changes to fluctuations in important fish stocks.

Significance of Accomplishment (e.g., to the Center, to Management, and to NMFS Strategic plan Goals): NOAA/Fisheries is increasingly concerned with climatic regime shifts and predicting when these shifts will occur, and which stocks, if any will be affected by these regime changes. The emphasis on all the coasts will be changes in subsurface structure, particularly stratification. This paper is one in a series examining regime shifts in the subsurface structure of the California Current System and the implications for marine resources.

Problems: None.

Key Contact: Roy Mendelssohn (831-648-9029, rmendels@pfeg.noaa.gov)