U.S. GLOBEC: Retrospective Analysis of Growth Rate and Recruitment for Sablefish, Anoplopoma fimbria, from the Gulf of Alaska and California Current System (Berkeley, S. A. [Oregon State Univ. (OSU)]; Chelton, D. B. [OSU]). The PI's will use the otoliths of the long-lived sablefish, which may live up to 70 years, to examine variability in growth from year to year. Sablefish are one of the most valuable groundfish species in the region. They have a widespread distribution in the Northeast Pacific, occurring in two discrete stocks in the two major oceanographic regimes (Gulf of Alaska and the California Current). During their first 6-9 months they reside in pelagic waters over the shelf and slope, broadly overlapping the temporal and spatial distribution of juvenile salmon. This proposal hypothesizes that growth of sablefish during their first year is modified by variability in the pelagic environment, that early juvenile growth influences subsequent recruitment success, and that a common juvenile environment results in correlative relationships between year class strength in salmon and sablefish. Previously collected and archived sablefish otoliths have the potential to establish a 50-60 year time series of juvenile growth, thus allowing extensive retrospective comparison of the influence of climatic factors on a key ecological parameter of fish populations.

The specific objectives of this study are 1) to establish a time series of juvenile sablefish growth beginning in the 1940s, using otoliths that have been collected from sablefish in the Gulf of Alaska and off the west coast since the early 1980s. 2) To evaluate the correspondence between juvenile growth and subsequent recruitment to the adult stocks of sablefish, and the relation of these factors to year class strength in west coast and Gulf of Alaska salmon stocks. 3) To compare and contrast growth rates and recruitment indices between the Gulf of Alaska and west coast stocks of sablefish. 4) To develop preliminary models of the interannual and interdecadal response in growth and recruitment to past environmental conditions. 5) To provide these data to other researchers to allow development of more comprehensive models and help refine subsequent process and monitoring studies. 6) To provide training for graduate students.

The otoliths of more than 35,000 sablefish previously collected from both the Gulf of Alaska and California Current stocks are available for analysis. Representative samples from as complete a time series as possible will be analyzed for both stocks. The distance from the central core of the otolith to the first annulus will be measured and used as an estimate of the first year's growth. Recruitment indices have been developed for both stocks that extend back at least 20 years. A variety of comparative techniques will be applied to the growth and recruitment time series developed in this study and archived physical data to identify statistically significant links between the biological and environmental variability. Available data on salmon year class strength and results of similar studies likely to be undertaken on salmonid stocks will be contrasted with sablefish to determine whether growth and mortality of juvenile salmon and sablefish covary (in or out of phase).

This page was last updated on March 15, 2007.

Maintained by:
Hal Batchelder
College of Oceanic and Atmospheric Sciences
Oregon State University
Corvallis, OR 97331-5503
phone: 541-737-4500; FAX 541-737-2064