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.