Good news and bad news in endangered Southern Resident orca population
27 September 2018 - 8:16pm
After a heartbreaking summer for the critically endangered Southern Resident orca population, new information from the ongoing aerial photogrammetry program, a joint effort between the National Oceanic and Atmospheric Administration (NOAA), Vancouver Aquarium, and SR3 (Sealife Response, Rehabilitation, and Research), has raised new concerns for the community.
Photographs taken with drones can show the body condition of individual orcas, an important sign of their health, and can track changes between seasons and over time. Understanding when and where the orcas may not be getting enough to eat can help managers focus on specific salmon runs and targeted actions to help orcas at times they may be struggling.
New photographs show that K25 (Scoter) a 27-year-old adult male, looks thinner than he has in previous years. Scoter lost his mother, K13 (Skagit) last year, and research has shown just how much male Resident orcas depend on their mothers – young males are three times more likely to die in the year following the death of their mother, and older males (over 30) are eight times more likely to die. Mothers often share food with their families, especially sons, who have higher energetic demands. Researchers are concerned that Scoter is declining due to the loss of his mother, and NOAA is currently monitoring his condition.
In better news, recent aerial images have also shown that Scoter’s sister, K27 (Deadhead) is pregnant, along with at least two other females (one each in J and L pods). New babies are a sign of hope in any struggling population, but with no successful births in almost three years, the recent loss of J35’s (Tahlequah) calf, and historically low abundance of Fraser River Chinook salmon – the orcas’ primary summer food source – in this case the pregnancies are also nerve-wracking. Two of the orcas appear to be in the late stages of their pregnancies, and miscarriages at this stage have been documented in the population in recent years.
NOAA and the Pacific Whale Watching Association (PWWA) are asking boaters to give the Southern Resident orcas extra space to reduce noise and harassment, giving them their best chance at foraging and finding salmon currently available. In the fall, the Southern Residents have a more diverse diet, with increasing amounts of Coho and chum salmon that are returning to rivers in Puget Sound. The orcas have already made two brief trips South into Puget Sound this month, but have not stayed in the area, suggesting there is not enough salmon to feed the population. With frighteningly low returns of salmon coastwide this summer, there are significant concerns that the trend will continue into the fall, and this struggling orca community will continue to suffer from a shortage of prey.