Complete Scientific Manuscript on Long-term Trends in
Water Column Stratification in the California Current

Current Status of Accomplishment or Milestone: Results presented at the 2003 Eastern Pacific Ocean Conference (EPOC). Draft manuscript completed and in internal review

Background: Environmental influences on fish populations are partly realized through water column control on lower trophic levels. In particular, stratification is an important determinant for primary and secondary production in coastal upwelling ecosystems. State-space methodologies are used to characterize long-term trends and to identify important climate shifts in temperature-derived stratification parameters in the California Current System. The implications of these trends for fluctuations in important fish stocks are considered.

Purpose of Activity/Goal of Project: Characterizing regime shifts in stratification 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 stratification 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 over 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)