Pollock Conservation Cooperative Research Center
2007 Awarded Research Projects
Walleye pollock stock distribution, growth, and condition in the Bering Sea
Brenda Norcross, Nate Bickford and Michael Castellini
Abstract:
Climate change is expected to alter the distribution and growth of fishes, though exactly what the effects will be is unknown. We will analyze otoliths and develop condition indices from Pollock that were collected in the Bering Sea (NOAA/BASIS) in summers 2002-2005. We will establish a baseline of geographic distribution (statistical and GIS maps) in relation to their associated water masses using otolith chemistry. Age, growth estimates, trace elements in otoliths, condition indices, and morphometric relationships will all be used to assess the health of these fishes. These values will be compared to the distribution of pollock, especially in relation to water masses. Water masses are expected to retain their distinctive characteristics, but be distributed northward with climate change. Therefore assessing parameters that indicate movement and quality of fish should have broad implications for effects of climate change.
Analyzing trace element signatures in fish otoliths is a chemical method to determine the distribution of a fish across time and space. The core of the otolith is the signature of the water mass where the fish were spawned and the edge is the signature of the water mass where the fish were collected. By analyzing pollock across large areas, we will enable future studies to track distribution changes, especially those associated with climate change. The results of this component will be available to managers to develop appropriate management strategies and risk vulnerability models to assess reaction fisheries to projected ecosystem changes in Arctic waters.
Developing condition indices for different fishes in the Bering Sea will allow us to better understand how 'fit' these fishes are within and among water masses. Monitoring the condition of fishes will provide evidence of fish movement into different water masses as their fitness changes in relation to changes in climate and water temperature. A decrease in overall fitness, determined by condition indices and morphometric measurements, may indicate that Arctic fishes are being displaced by sub-Arctic fishes moving to more northern habitats.
Back to 2007 PCCRC Funded Projects
2007 PCCRC awards press release
Research projects
Contact PCCRC
Denis Wiesenburg, PCCRC Director
School of Fisheries and Ocean Sciences
University of Alaska Fairbanks
P.O. Box 757220
Fairbanks, AK 99775-7220
Phone: (907) 474-7210
Fax: (907) 474-7204
Email: wiesenburg@sfos.uaf.edu