Wintertime ocean conditions synchronize rockfish growth and seabird reproduction in the central California Current ecosystem

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Black, Bryan A., Schroeder, Isaac D., Sydeman, William J., Bograd, Steven J., Lawson, Peter W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2010
• Subjects: Common Murre; Uria aalge; uria
• Online Access: http://dx.doi.org/10.1139/f10-055; http://www.nrcresearchpress.com/doi/full-xml/10.1139/F10-055; http://www.nrcresearchpress.com/doi/pdf/10.1139/F10-055

Chronologies developed from annual growth-increment widths of splitnose rockfish ( Sebastes pinniger ) and yelloweye rockfish ( Sebastes ruberrimus ) otoliths were compared with time series of lay date and fledgling success for the common murre ( Uria aalge ) and Cassin’s auklet ( Ptychoramphus aleuticus ) in the north-central California Current. All time series were exactly dated and spanned 1972 through 1994. In a principal components analysis, the leading principal component (PC1 bio ) accounted for 64% of the variance in the data set. By entering the upwelling index, the Northern Oscillation index, sea surface temperatures, and the multivariate ENSO (El Niño Southern Oscillation) index into principal components analysis, a time series of environmental variability PC1 env was developed for each month of the year. Over the interval 1972 through 1994, PC1 bio most strongly correlated with PC1 env for February and, to a lesser extent, January and March. Moreover, when each of the six biological time series was related to the 12 PC1 env through stepwise multiple regression, February was always the most significant (p < 0.01). The same was true if upwelling index was substituted for PC1 env . As upper-trophic predators, rockfish and seabirds independently corroborate that wintertime ocean conditions are critical for productivity in the California Current ecosystem.