Abstract
The Cook Inlet beluga (CIB) whale population, a genetically and geographically isolated stock which resides in Cook Inlet Alaska, has been declining in numbers since at least 1994 when the National Marine Fisheries Service (NMFS) began conducting annual aerial surveys of the population. A subsistence hunt in the 1990's ended in 1999, yet the beluga population has failed to increase for unknown reasons and in 2008 CIBs were listed as endangered. The most recent aerial survey estimates that there are only 340 whales in this population. Because physically handling live CIBs is currently not allowed, researchers need to make the most of information gained from photographs and observational studies. The LGL CIB Photo-Identification Catalog, initiated in 2005, contains photographs of about 250 individual whales, some with marks indicative of disease and injury.1 Other cetacean photo-id studies have used assessment of marks in photographs to provide valuable information about the relative amounts of predation pressure, the incidence of disease,2,3 progression of disease,4 and human-caused mortality.5 Further analysis of CIB photographs offers the opportunity to learn more about the incidence of risk factors that may be preventing their recovery by documenting the general source of different marks, their occurrence, frequency, and association with particular demographic groups. General categories of marks include those from predators or conspecifics, disease, net damage, ship strikes, struck and loss lesions from hunting, propeller impacts, and other natural or anthropogenic causes. Images of belugas from other populations including captive animals, paired with diagnostic findings confirming the cause of skin marks, are being sought to create a reference catalog and improve interpretation of images of CIBs. Similar to other cetacean photo-identification studies,6 we hope to help identify the sources of marks found on CIBs as a foundation to pursue additional research related to conservation of CIBW and of cetaceans in general.
Acknowledgements
The authors greatly appreciate support from the National Fish and Wildlife Foundation, Chevron, ConocoPhillips Alaska, the North Pacific Research Board, National Oceanic and Atmospheric Administration, and the United States Fish and Wildlife Service.
References
1. McGuire TL, Kaplan CC. 2009. Photo-identification of beluga whales in Upper Cook Inlet, Alaska. Final Report of Field Activities in 2008. Anchorage: LGL Alaska Research Associates for National Fish & Wildlife Foundation, Chevron, and ConocoPhillips Alaska. 28 p.
2. Bearzi M, Rapaport S, Chau J, Saylan C. Skin lesions and physical deformities of coastal and offshore common bottlenose dolphins (Tursiops truncatus) in Santa Monica Bay and adjacent areas, California. Ambio 2009; 38(2):66–71.
3. Van Bressem MF, Van Waerebeek K, Reyes JC, Felix F, Echegaray M, Siciliano S, Di Beneditto AP, Flach L, Viddi F, Avila IC, Herrera JC, Tobon IC, Bolanos-Jimenez J, Moreno IB, Ott PH, Sanio GP, Castereira E, Montes D, Crespo E, Flores PAC, Haase B, Mendonca de Souze SMF, Laeta M, Fragoso AB. A preliminary overview of skin and skeletal diseases and traumata in small cetaceans from South American waters. Latin American Journal of Aquatic Mammals 2007; 6:7–42.
4. Burdett Hart L, Wells RS, Adams JD, Rotstein DS, Schwacke LH. Modeling lacaziosis lesion progression in common bottlenose dolphins Tursiops truncates using long-term photographic records. Dis Aquat Org 2010; 90:105–112.
5. Read AJ, Murray KT. 2000. Gross Evidence of Human-Induced Mortality in small cetaceans. US Department of Commerce, NOAA Tech. Memo. NMFS-OPR-15. 21 p.
6. Bradford A, Weller D, Ivaschenko Y, Burdin A, Browell R. Anthropogenic scarring of western gray whales (Eschrichtius robustus). Marine Mammal Science 2009; 25(1):161–175.