Identification of a Climate Regime Shift in 1998 and its Implications for Fisheries, Marine Mammals and Protected Resources

Current Status of Accomplishment or Milestone: Completed.

Background: For over thirty years, the Pacific Fisheries Environmental Laboratory (PFEL) has focused on relating environmental variability to fluctuations in fisheries, marine mammals and protected resources. The degree to which marine resources respond to interannual changes in ocean conditions is critical to improving assessments of populations, as prescribed by the MSPA, ESA, and MMPA, and for implementing ecosystem-based management. Our research has led to innovative ways of looking at environmental and ecological variability, and has produced a number of important scientific publications and collaborations. This work focuses on building a mechanistic-based understanding of how climate variability direct or indirectly impacts living marine resources. This has culminated in documenting important rapid changes in ocean conditions that have coincided with observed changes in the distribution and production of many important fish stocks and marine mammals.

Purpose of Activity/Goal of Project: To identify and characterize regime shifts in the ocean and its likely consequences for management of fisheries and marine mammal populations, and for the rebuilding of protected resources.

Description of Accomplishment and Significant Results: PFEL scientists and their colleagues have been following major physical and biological changes in the North Pacific. Analysis of recent atmosphere and ocean conditions in the context of long-term patterns indicates the region may have undergone a rapid and significant shift to a new climate regime in about 1998.

Following the strong 1997-98 El Niño, the climate of the North Pacific underwent a rapid and striking transition. Many large-scale indicators of climate changed. Upwelling-favorable winds strengthened over the California Current (CC), and winds weakened in the Gulf of Alaska (GOA). Coastal waters of the CC and GOA cooled by several degrees. These changes showed similar patterns to those associated with past identified climate regime shifts (e.g., 1925, 1947, 1976). These historical shifts have been identified not only from environmental changes, but also from collapses and increases of commercially important fisheries. With our other NMFS colleagues, we have linked many ecosystem changes at all trophic levels to these environmental shifts.

Several papers and scientific presentations by PFEL scientists were among the first to identify this regime shift; and a number of presentations were given at the recent Ocean Sciences Meeting in Portland and at the “International Symposium on Quantitative Ecosystem Indicators for Fisheries Management” in Paris related to this regime shift.

Significance of Accomplishment (e.g., to the Center, to Management, and to NMFS Strategic plan Goals): The identification of regime shifts in the ocean environment critical to the success of marine populations should assist in better resource and ecosystem management, thus building sustainable fisheries, and in assessing the effects of climate change on these resources.

Problems: None.

Key Contact: Franklin Schwing (831-648-9034, fschwing@pfeg.noaa.gov)