"Cetacean Assessment and Ecology Program"

The Cetacean Assessment and Ecology Program has a continuing project to study predation on marine mammals in the Aleutian Islands.

Through an Inter-Agency agreement (IA) between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), NMML is conducting a dedicated multi-year study to determine relationships between dominant currents passing from the Bering Sea into and through the Chukchi Sea and prey resources delivered to the Barrow Arch area (an area of high bowhead whale and prey concentrations between Wainwright and Smith Bay), and to provide information about the dynamic nature of those relationships relative to whale distribution and habitat utilization in the eastern Chukchi and extreme western Beaufort Seas. This study will also provide important baseline data on the occurrence, distribution and habitat use of large whales in an area that is subject to rapid change in climate and human industrial development. This quarterly report covers the first period of this study between 25 July and 30 September 2012. The major activity during this period consisted of purchasing equipment, deploying the first set of longterm moorings, and opportunistically tagging a gray whale during the Chukchi Sea Acoustics, Oceanography, and Zooplankton (CHAOZ) cruise on 25 August, 2012. The CHAOZ cruise took place from 8 August through 7 September on the chartered research vessel R/V Aquila. Seventeen scientists, technicians, and observers from eight different laboratories and institutions participated on the CHAOZ cruise.

Through an Inter-Agency agreement (IA) between the National Marine Mammal Laboratory (NMML) and the Bureau of Ocean Energy Management (BOEM), NMML is conducting a dedicated multi-year study to determine relationships between dominant currents passing from the Bering Sea into and through the Chukchi Sea and prey resources delivered to the Barrow Arch area (an area of high bowhead whale and prey concentrations between Wainwright and Smith Bay), and to provide information about the dynamic nature of those relationships relative to whale distribution and habitat utilization in the eastern Chukchi and extreme western Beaufort Seas. This study will also provide important baseline data on the occurrence, distribution and habitat use of large whales in an area that is subject to rapid change in climate and human industrial development. This annual report covers the first year of this study between March and December 2012. The major activity during this period consisted of planning for the 2013 vessel survey.

Alaska Fisheries Science Center Quarterly Report

Beluga whales (Delphinapterus leucas) in Cook Inlet are the most geographically and genetically isolated of the five stocks recognized around Alaska (OCorry-Crowe et al. 1997, Laidre et al. 2000). Their isolation, in combination with high site fidelity in summer (Rugh et al. 2000, 2005, 2010), makes them particularly vulnerable to both environmental (Moore et al. 2000) and anthropogenic impacts (Hill 1996). The population of Cook Inlet belugas declined by nearly 50% between 1994 and 1998 to an estimated 347 whales (Hobbs et al. 2000). Despite cessation of the Alaska Native subsistence hunt in 1999 of approximately 70 animals per year (Mahoney and Shelden 2000), the abundance estimates of belugas in Cook Inlet have remained low (321 and 340 animals in 2009 and 2010 compared to 653 in 1994) with no notable signs of recovery (Hobbs and Shelden 2008). In recognition of the low numbers of belugas remaining in Cook Inlet, the U.S. government listed this isolated population as endangered under the U.S. Endangered Species Act in October 2008.

Beluga whales, Delphinapterus leucas, live year-round in arctic and subarctic seas of the Northern Hemisphere (Hazard 1988). In Alaska waters, belugas spend summer in different regions of Alaska (Frost and Lowry 1990) to the extent that genetic differentiation has occurred within the species (O’Corry-Crow et al. 1997). These summering populations are found in Cook Inlet, Bristol Bay, the eastern Bering Sea, the eastern Chukchi Sea, and the eastern Beaufort Sea (Fig. 1). For Cook Inlet, both geographic and genetic isolation from the other beluga populations in Alaska has resulted in evident genetic drift (O’Corry-Crowe et al. 1997, 2010). While some of these Alaska populations are migratory, covering 1,000s of kilometers between summering and wintering regions, most Cook Inlet belugas remain year-round within the boundaries of the inlet.