Description
The U. S. Fish & Wildlife Service, Region Seven (7), Alaska, intends to award a sole source, firm-fixed price purchase to Washingtion State University. The U.S. Fish & Wildlife Service, Region Seven (7), Alaska requires the services of captive feeding trials to improve the use of fatty acids and stable isotopes for diet determinatoin in polar bears. Dr. Charlie Robbins with Washington State University has over 20 years of experience conducting feeding experiments and studies the nutritional ecology in ursids. His work has been published in over 20 scientific journals and he currently houses 10 captive brown bears. Dr. Charlie Robbins has the setup ready to conduct the requested services. Work description: Polar bears comprise a clearly-defined fifth trophic level in the Arctic marine food web. Because of their long life spans and vast home ranges (Amstrup et al. 2000), polar bears are affected by ecosystem processes operating over multiple temporal and spatial scales. For instance, long-term changes in sea ice conditions in Hudson Bay have had significant negative effects on polar bear body condition, reproduction and population size (Stirling et al. 1999, Regehr et al. 2007). However, short-term, year-to-year changes in the sea ice habitat can also significantly affect polar bear body condition, reproduction, and behaviour (Stirling and Derocher 1993, Stirling et al. 1999). Although the broad-scale foraging success of polar bears will be closely related to the productivity and availability of their main prey, ringed seals (Phoca hispida; Stirling and ritsland 1995), polar bears will prey substantively on locally-abundant prey such as beluga whale (Delphinapterus leucas; Lowry et al. 1987), bowhead whale (Balaena mysticetus; Bentzen et al. 2007), walrus (Odobenus rosmarus; Thiemann et al. 2008a), and harp seal (Phoca groenlandica; Derocher et al. 2002, Iverson et al. 2006, Thiemann et al. 2008a). As the climate and sea ice regime of the circumpolar Arctic continues to change, further short- and long-term shifts in polar bear diets should be expected. Two relatively new biochemical approaches have provided important insights into the diets of free-ranging predators, including polar bears. Stable isotope analysis is based on the predictable incorporation of naturally-occurring isotopes of carbon and nitrogen present in different food sources. Fatty acid signature analysis is based on the knowledge that ingested fatty acids are predictably incorporated into the adipose tissue of consumers. Both approaches can be integrated into statistical models that generate quantitative estimates of predator diets. However, both techniques also have limitations that are largely a consequence of an incomplete understanding of predator metabolism and nutritional physiology. This study aims to address these conceptual shortcomings and provide new insights into polar bear ecophysiology. The results of this work will improve our ability to accurately estimate the diets of free-ranging polar bears. This study will estimate fractionation values of N and C and fatty acid coefficients and the potential effects of variation in dietary fat to protein ratios and fasting behavior required to more accurately determine prey composition. Goals: The goals of this project are to: 1. Estimate isotopic fractionation values and fatty acid coefficients that are representative of tissue deposition occurring from typical diets consumed by wild polar bears. 2. Determine the potential effects of variation in fat intake on isotopic fractionation values, fatty acid coefficients, and energy requirements. This notice is not a request for competitive proposals and the Government does not intend to accept proposals received.