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Climate Variability & Marine Fisheries
Alaska Sockeye Salmon Could Be Restricted In Ocean Distribution By Prolonged Warming
A recent study of salmon in the Pacific suggested that sharp thermal boundaries characterized species-specific distribution patterns. The potential implications of climate change scenarios were analyzed for one species, the sockeye salmon. The temperature that limits distribution increases from about 7°C in winter and spring to 12 to 13°C in late summer. Temperature dependent metabolic rates may explain the thermal limits. In cold-blooded animals, the basal metabolic rates increase exponentially with increased temperature. Fish can grow faster in warmer water, but only if the supply of food is great enough to overcome the increased caloric demand of higher metabolism. Sockeye can move into warmer waters as food levels seasonally increase. This study considered how predicted ocean surface temperature changes with a doubling of atmospheric CO2 will impact thermal habitat of sockeye salmon. Results suggested that the ocean area suitable for sockeye would be greatly restricted. Sockeye could be limited by temperature in summer to feeding in the Bering and Othotsk seas (red in figure), a much smaller area than what they currently occupy (red plus light blue) and perhaps restricting their migration home to their native rivers.
From A Doubling of the CO2 level
(Figure source: see text reference two below)
Click on image to enlarge
TEXT REFERENCES:
1) Welch, D.W., Chigirinsky, A.I., and Ishida, Y. 1995. Upper Thermal Limits on the Oceanic Distribution of Pacific Salmon (Oncorhynchus spp) in the Spring. Canadian Journal of Fisheries and Aquatic Sciences. 52:489-503. 2) Welch, D., Y. Ishida and K Nagasawa. 1998. Thermal Limits and Ocean Migrations of Sockeye Salmon (Oncorhynchus nerka): Long-term Consequences of Global Warming. Canadian J. of Fisheries and Aquatic Sciences. 55:937-948. [Download jounal article as pdf file (0.66K]
Read more about the effects of climate on Salmon at the following links:
Fisheries and oceans advances international research on climate and stock Abundance--paper by Ware and Beamish,
go to: http://www.pac.dfo-mpo.gc.ca/sci/osap/publ/publist_e.htm Increasing atmospheric concentrations of anthropogenically-emitted greenhouse gases, including CO2, CH4 and N2O, have changed the earth's climatic system, warming the earth's surface and producing other changes in climate, go to: http://www.cses.washington.edu/db/pubs/allpubs.shtml Global Warming and Fisheries, David Welch, Canada High Seas Salmon Research, Fisheries & Oceans Canada, go to: http://www.fisheries.org/cars/l_feat1.htm Research on the Relationship of Ocean Temperature to Oregon Coho Salmon Survival, PFEL, go to: PFEL Salmon Research
