Movements of Beluga Tagged at the Nastapoka River PDF Download

Author: D. W. Doidge
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Languages : en
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"Beluga whales (Delphinapterus leucas) occupy Hudson Bay in summer where they are an important source of country-food for the Inuit. Two stocks have been identified; the western stock is estimated to contain at least 23,000 animals, approximately 15 times larger than the eastern stock (Richard et al 1990). The two stocks are genetically distinct (Brown et al 1997). The eastern stock has been designated by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threatened and a quota system has been applied to the Inuit subsistence harvest on the northern Quebec coast. The western stock has no quota since harvest levels are lower than the estimated sustainable yield. Aerial surveys in 1985 (Smith and Hammill 1986) and 1993 (DFO unpublished) indicate the summer distribution of beluga whales extends between the Quebec coast (Nunavik) and Sanikiluaq (Belcher Islands). Also, satellite tags, which transmitted for a short time in 1993, showed one whale, tagged at the Little Whale River on the Quebec coast, frequented areas offshore as far as the Belchers. These data would indicate a common stock between Nunavik and Sanikiluaq. However, genetic analysis indicates whales harvested in Sanikiluaq are more similar genetically to western Hudson beluga than those caught along the eastern Hudson Bay coast, just 100 km distant. The conflicting scientific information (genetic make-up vs distribution data) has led some Nunavik Inuit to question the scientific validity of the existing co-management regime and quota system. The number of satellite tags deployed in 1993 (DFO unpublished data) has not been sufficient to clearly resolve the movements of whales that frequent the Quebec coast. The hunters' association of the Nunavik Inuit (HFTA) requested that the issue of stock identity be resolved. A resolution supporting the satellite tagging project was passed at the HFTA's annual general meeting in 1998. With support from World Wildlife Fund Canada, Fisheries and Oceans and Makivik Corporation, three satellite tags were deployed on belugas at the Nastapoka River in 1999. ... In August, the tagged animals frequented the offshore between the mainland coast and the Belcher Islands, an area indicated to be the summer distribution of belugas previously by aerial surveys. While the single, gray animal ventured to the Belcher Islands, the time spent in that vicinity accounted for a small proportion of the time it was tracked (ca. 8%). The two adults with calves did not venture as far to the west. The sample size of tagged animals is too small to estimate the probability of animals that occupy the Nastapoka being caught at the Belchers. However, analysis of the DNA of belugas harvested at the Belchers indicates that the number having the eastern Hudson Bay haplotype is low. The degree of site-tenacity and estuarine use appears to be variable. Other studies demonstrate that belugas will return to the locality of tagging (Orr et al 1998, DFO unpublished data). However, the three whales tagged by us, did not appear to re-enter Nastapoka Estuary. Radio transmitters are becoming more dependable enabling data to be gathered over a longer period of time. Two tags transmitted long enough to indicate that whales remain in the Hudson Bay Area until early October. The start of a northward migration, presumably to over-wintering grounds in Hudson Strait, was documented for one whale until its transmitter sopped signaling near Puvirnituq in late October. A large quantity of data has been received from these satellite tags. The inshore areas of beluga habitat, such as estuaries, are well documented from traditional knowledge and scientific studies. The data from satellite tagged whales show areas, offshore of the Nastapoka Islands, where the whales have remained for several days. The bathymetry of these locations will be examined in relation to the whales' diving activities to better understand habitat-use of beluga whales in eastern Hudson Bay. This analysis is scheduled for Winter 2000-01. The method of using surgical pins to attach the transmitter to the whale's back remains invasive, but no alternative has yet been found. The number of whales tagged has been kept to a minimum. A thorough review of the dive data will determine if a realistic correction factor to account for submerged whales, not counted during aerial surveys can be estimated, or whether further tagging is needed"--ASTIS [online] database.