Health Assessment of Beluga: Baseline Data, Novel Findings, and Disease Trends

There are 29 putative populations of beluga worldwide with 5 distinct groups in Alaska and 7 in Canada.  There are healthy robust, diminished but stable, and declining beluga populations throughout their ranges.  These animals are predominantly circumpolar, subsistence hunted in Canada, Alaska, Russia and Greenland and integral to the natural history and folklore of aboriginal peoples.  Because of these factors, beluga are excellent sentinels of ecosystem health. To establish baseline information on the health status and potential zoonotic concerns of hunter harvested whales for human consumption, long term multi-institutional and multidisciplinary studies have been undertaken on dead beach cast and hunter harvested animals.    After collection of morphometric data, harvest of muktuk and muscle, internal organs are assessed and representative samples collected for histopathology and ancillary research and diagnostic studies.  Laboratory and necropsy results vary considerable across populations and geographic regions; however, there are specific disease entities that are consistently identified in animals.  Degenerative changes within the thyroid and adrenal glands of most whales and profound interstitial pneumonia in select individuals.  Polymerase chain reaction was negative for influenza virus, West Nile virus, Brucella spp, morbillivirus and a small number of animals were positive by consensus primers for Mollicutes and typical Mycobacterium spp.   Serology for Brucella spp has consistent identified positive animals with annual variations between 4 to 18% of sampled animals.  Tissues screened for Apicomplexa detected a large proportion of infected whales.  Enzyme digestion assays conducted on skeletal musculature were negative for Trichinella spp.; however, pooled tissue samples were positive for Hemabartonella spp and Hemobartonella canis.  Contaminants such as PCB’s, PBDEs have been measured in blubber and Hg was measured in skin, muscle and liver with evidence of long term declining trends in this heavy metal. Toxin associated endocrine endpoint have also been measured in blubber and blood.  From a nutritional/conditional perspective lipid classes and fatty acids have been measured in blubber and stable isotopes were determined in liver to assess trophic feeding. These ongoing investigations provide seminal baseline information into the health status of beluga whales. Additional comprehensive studies in the future will assess possible trends and potential impact of these factors on population status.