GENETIC-VARIATION OF THE ST-LAWRENCE BELUGA WHALE POPULATION ASSESSEDBY DNA-FINGERPRINTING

Recent surveys suggest that the endangered St, Lawrence beluga (Delphi napterus leucas) population is not recovering significantly despite 20 years of protection. Dead individuals that have been autopsied show h igh levels of tumours and infections. This situation could be a result of pollution, loss of genetic variation, inbreeding depression or a c ombination of these factors. Analyses of DNA fingerprints from St. Law rence belugas with three minisatellite probes (Jeffreys 33.6, 33.15 an d M13) indicate a reduced level of genetic variation compared to Beauf ort Sea animals, The average band-sharing between individuals of the S t. Lawrence beluga population for the three probes (0.534, 0.573 and 0 .478, respectively) was significantly higher than that of the Beaufort Sea beluga population (0.343, 0.424, 0.314, respectively). Higher lev els of mean allele frequency in the St. Lawrence belugas (0.33 vs. 0.2 1) suggest that this population is composed of individuals which are r elated. Inbreeding depression could therefore be a factor in the lack of recovery of the St. Lawrence beluga population.