Estimating the harvest of Pacific walrus, Odobenus rosmarus divergens, in Alaska
ABSTRACT for J. L. Garlich-Miller): Joel_GarlichMiller@mail.fws.gov Manuscript accepted 13 January 1999 Fish. Bull. 97(4):1043–1046 (1999). For thousands of years, walrus hunting has been an important component of the economy and cul-ture of Native communities along the Bering and Chukchi Sea coasts (Ray, 1975). Today, the Pacific wal-rus (Odobenus rosmarus divergens) remains a valuable resource to coastal natives in Alaska (United States) and Chukotka (Russia) as a source of food and raw materials for traditional equipment and handicrafts. Accurate information regarding the number of animals removed annually from the population is fundamental for the conservation and management of any species. As the agency responsible for manag-ing Pacific walrus in U.S. waters, the U.S. Fish and Wildlife Service (FWS) gathers data on the size and composition of the subsistence wal-rus harvest in Alaska. The FWS presently administers two separate harvest monitoring programs: the Walrus Harvest Monitoring Project (WHMP) and the Marking Tagging and Reporting Program (MTRP). The WHMP is an observer pro-gram carried out at select walrus hunting villages in Alaska. Each spring, as the pack ice recedes northward, hunters from coastal communities in the Bering Strait region have access to herds of wal-rus as they migrate to their sum-mer range. Historical harvest infor-mation indicates that approxi-mately 80% of the annual reported walrus harvest in Alaska occurs in this region (Fay and Bowlby 1). WHMP monitors stationed at the primary walrus hunting villages in the Bering Strait region (Gambell, Savoonga, Little Diomede and Wales; Fig. 1) collect information on the size and composition of the wal-rus harvest. Harvest monitors meet boats as they return from walrus hunting trips in order to collect bio-logical samples and harvest infor-mation at the boat landing site (Garlich-Miller 2). The goal of the WHMP is to identify and record the gender and age class of every wal-rus retrieved by hunters from these villages during the monitoring pe-riod. Although there is no way of evaluating the degree to which this goal is achieved, WHMP monitors meet most of the returning boats, and the number of retrieved ani-mals not recorded during the har-vest monitoring period is believed to be small (Dickerson 3). The MTRP is a Federally man-dated year-round, statewide pro-gram (Fig. 1). The marking and tag-ging rule requires that all hunters certify (tag) walrus ivory (tusks) and report all walruses that are taken. The objectives of the MTRP are to collect harvest information and to certify specified marine mammal parts to help control ille-gal harvests and trade. Hunters are required to bring walrus tusks to a MTRP tagger within 30 days of the kill. The tagger attaches individu-ally numbered wire tags to the tusks and records the numbers on a tagging certificate. MTRP tags are not attached to calf walruses (or other walruses that may be miss-ing tusks); however, hunters are required to report all animals taken. The age class, gender, kill date, and kill location of each wal-rus are recorded on the certificate (Stephensen et al. 4). These two programs indepen-dently provide information on the size and composition of the harvest. Except in the case of the village of Wales, WHMP and MTRP staff are different people. Each of the two monitoring programs has its strengths and weaknesses. The WHMP benefits from the presence of on-site staff to collect accurate biological information from every walrus retrieved in a community during the monitoring period. Un-fortunately, the monitoring period is seasonal (restricted to the spring hunt) and operates only in four coastal villages. The MTRP is a statewide, year-round program; however hunter compliance with the MTRP rule is variable and ani-mals lacking tusks (e.g. calves, yearlings, and animals with broken tusks) often go unreported (Burn, 1998).
Full-textDOI: · Available from: Joel L. Garlich-Miller, Dec 18, 2013
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ABSTRACT: This paper presents and evaluates two perspectives on changing climate–walrus–human relationships in the Beringian region, from the viewpoints of marine biology and ecology, and from that of indigenous hunters. Bridging these types of knowledge is vital in order to grasp the complexity of the processes involved and for advancing understanding of subarctic marine ecosystems that are currently experiencing rapid ecological and social change. We argue that despite substantial gaps and distinctions, information generated by scientists and indigenous hunters have many similarities. Differences in interpretation are primarily due to scaling and temporal rates of change of knowledge, which could be rectified through more active sharing of expertise and records, enhanced documentation of indigenous observations, more collaborative research, and increased insight from the social sciences.Deep Sea Research Part II Topical Studies in Oceanography 11/2007; 54(23):2946-2957. DOI:10.1016/j.dsr2.2007.08.011 · 2.76 Impact Factor
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ABSTRACT: We conducted tests of airborne thermal imagery of Pacific walrus to determine if this technology can be used to detect walrus groups on sea ice and estimate the number of walruses present in each group. In April 2002 we collected thermal imagery of 37 walrus groups in the Bering Sea at spatial resolutions ranging from 1-4 m. We also collected high-resolution digital aerial photographs of the same groups. Walruses were considerably warmer than the background environment of ice, snow, and seawater and were easily detected in thermal imagery. We found a significant linear relation between walrus group size and the amount of heat measured by the thermal sensor at all 4 spatial resolutions tested. This relation can be used in a double-sampling framework to estimate total walrus numbers from a thermal survey of a sample of units within an area and photographs from a subsample of the thermally detected groups. Previous methods used in visual aerial surveys of Pacific walrus have sampled only a small percentage of available habitat, resulting in population estimates with low precision. Results of this study indicate that an aerial survey using a thermal sensor can cover as much as 4 times the area per hour of flight time with greater reliability than visual observation. (WILDLIFE SOCIETY BULLETIN 34(1):51-58; 2006) The last population survey of Pacific walrus (Odobenus rosmarus divergens) was jointly conducted by the United States and the Soviet Union in 1990 (Gilbert et al. 1992) and, after nearly 15 years, the current population size is unknown. The technique used at that time, a visual aerial survey, is now considered to be inadequate for measuring the size of the population with acceptable levels of accuracy and precision (Hills and Gilbert 1994, Gilbert 1999). Drawbacks to a visual aerial survey include narrow survey swath width, observer bias and fatigue, lack of a permanent data record, and safety concerns associated with low- level flight in remote areas. Of these, narrow survey swath width is considered to have the greatest impact on the precision of the resulting population estimate due to the large geographic area that must be surveyed in a short time period (Estes and Gilbert 1978, Gilbert 1999). At an international workshop of walrus biologists held by the United States Fish and Wildlife Service (USFWS) and the United States Geological Survey (USGS), the consensus opinion was that remote sensing techniques capable of collecting data over large areas should be investigated and developed as an alternative to visual surveys (Garlich-Miller and Jay 2000). The history of aerial surveys of Pacific walrus has been reviewed by Hills and Gilbert (1994), Gilbert (1999), and Udevitz et al. (2001). In the autumn season when most of the previous surveys were conducted, the walrus population is segregated, with some animals associated with the ice edge in the Chukchi Sea, while others make use of terrestrial haulouts along the coast of Bristol Bay, Alaska in the United States, and the Chukotka and Kamchatka peninsulas in Russia. Fewer surveys have been conducted in winter and early spring, when the entire walrus population occurs almost exclusively on the pack ice of the Bering Sea with concentrations in the Gulf of Anadyr, south and west of St. Lawrence Island, and south of Nunivak Island (Fay 1982).
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ABSTRACT: Changes in sea-ice conditions have direct bearing on ice-associated species such as Pacific walrus (Odobenus rosmarus divergens), an important species for coastal Alaska Native subsistence. We explore the dynamic relationships among sea ice, walrus, and subsistence hunting between 1952 and 2004 at three northern Bering Sea villages � Diomede, Gambell, and Savoonga. We integrate changes in timing, size, and gender distribution of walrus catches under four environmental regimes that alter the extent, duration, and persistence of sea ice. Our results suggest that the physical ice conditions proximal to the three villages affect timing and migration of walrus herds and thus hunting, but village-specific factors, such as the number and demographics of hunters, impart strong inter-community variability in the magnitude of catches. Decadal-scale climatic regimes are correlated with consistent patterns of timing and magnitude for the walrus hunts at Gambell and Savoonga, and at Diomede until 1989. However, a marked reduction in walrus catches at Diomede since 1989 is attributable to several social changes that compound more difficult hunting conditions. Our study highlights the important linkages between geographic location and the sociocultural capacity to hunt (e.g. number of hunters and local rules) when considering the resilience or vulnerability of village subsistence activities in a changing climate.Polar Geography 03/2013; 36(1-2):65-85. DOI:10.1080/1088937X.2013.765519