Paradox Project (2010 – 2012)

Paradigm or Paradox:  Can we attribute species changes to global climate change in central California?

Authors: Launer AL1,2, Wadsworth T, Breaker LC1, and Starr RM1

1Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039

2contact information: alauner@mlml.calstate.edu, 831.771.4479

Basin wide changes in temperature and productivity have occurred over the past 100 years in the Pacific with many more predicted in the future.  On the central California coast, we have noticed a cooling trend over the past 10 years despite increased observations of warm water fishes such as Humboldt squid (Dosidicus gigas) and Swordfish (Xiphias gladius).  The goals of this study were to (1) determine the relationship between environmental variation and changes in demersal fish assemblages in central CA (2) and quantify changes in the distance of warm isotherms off the central California coast to determine potential relationships with abundance of pelagic species.  We compared fish abundance estimates from fishery dependent surveys, commercial landings, and stock assessments with in situ and satellite sea surface temperature and basin-scale climate indices, to determine if there are relationships among these variables.  Time series analyzed were 1916-2003 and 1980-2003. Results of cross correlation and logistic regression analyses of temperature and abundance provided inconclusive results. Despite this, temperature data from Pacific Grove and Farallon Islands were highly correlated with one another. However, basin-scale climate indices include salinity and chlorophyll-a as well as sea surface temperature.  Results of cross correlation analyses using these indices provided strong correlations with fish abundances.  We conclude changes in temperature alone are not driving changes in fish populations, and other environmental factors are additionally important.

Paradigm or Paradox? (2012 Western Groundfish Conference Poster Presentation)