It occurs primarily in the SLE and seasonally in the Gulf of St. [...] The significant reduction in abundance in the 20th century was also accompanied by an approximate 65% contraction in the summer range from the 1930s to today. [...] The number of carcasses found “endangered” because of troubling signs of recent declines and cases is recorded and the carcasses are sampled on site or transported to of unexplained mortality in young belugas. [...] Photographic surveys also provide an estimate of the percentage of calves in the population aged 0 Figure 2 Total (open circle) annual reports of dead beluga in the Estuary to 1 year. [...] The as the cause of death for any of the newborns examined, factors that beluga population model did not predict high numbers of newborns can contribute to separation from the mother may be a major cause of that year, and the unusually high number of carcasses found could be calf mortality.