Researchers recently made a somber discovery off the coast of Vancouver Island that is part of a troubling pattern for a critically endangered species. An adult female southern resident orca whale was observed carrying a dead newborn calf in the Strait of Juan de Fuca near Sombrio Point on Oct. 3, according to the U.S.-based Center for Whale Research. The organization says it is unclear if the calf was carried to full term before birth, nor whether it died after it was born or was a stillbirth. Researchers also couldn’t determine the calf’s sex. Researchers say J31, the mother born in 1995, has experienced reproductive loss and failed pregnancies in the past. She was seen carrying a dead calf once before in 2016. J31 has one surviving daughter, J56, who was born in 2019. “Although the cause of this calf’s death is not known, it occurs against a backdrop of longstanding reproductive difficulties within the population. For a population as small as the southern residents, the successful birth and survival of every calf matters,” the CWR wrote in a social media post Wednesday. Researchers say many factors are limiting the population’s ability to recover, but one of the most significant is the availability of Chinook salmon—southern resident orcas’ main food source. The CWR says 69 per cent of southern resident killer whale pregnancies end in miscarriage, which is “highly correlated” with salmon availability. According to the CWR, Chinook salmon make up at least 80 per cent of the killer whales’ diet and an adult needs to eat between 18 and 25 adult salmon daily to meet its energy requirements. There are fewer than 80 southern resident killer whales off the cost of B.C. and in the Pacific Northwest. “The southern resident killer whales remain critically endangered, and their recovery depends not simply on increasing the number of pregnancies, but on creating the conditions in which mothers and calves can survive and thrive,” the post concludes.
