A research study published June 2022 examined 40 years of data to compare Chinook salmon abundance with the daily calorie needs of the Southern Resident killer whales. The study showed that these whales don’t always find enough food, especially in spring—a longstanding concern, as indicated by their stress hormones.
Of great concern is the study’s estimation that from 2018 to 2020, there were insufficient salmon to meet the whales’ daily prey needs over a more prolonged period—from spring to fall. “Premature deaths, and few births—in a population that ought to have six or seven calves a year—are likely due to these ongoing seasonal prey shortages,” said Dr Giles, Wild Orca’s Science & Research Director.
The ‘whales of concern’ list—issued to promote more whale wise boating behavior—usually flags pregnant females; however these aerial studies also identify poor body condition. “If food has been in short supply since 2018, as this new study suggests,” said Giles, “then sadly we can expect this year’s list to identify whales in poor health.”
According to the study, Canadian fisheries likely caught as many Chinook as did the Southern Resident killer whales between 2000 and 2020. Affirming the importance of policy first implemented in 2021—closing fishing once these whales are confirmed present in BC’s inland waters. The unexpected, but welcome return of J pod in May triggered earlier closures this year. Yet a similar mandate does not occur on the U.S. side of the Salish Sea. Given that salmon and killer whales travel huge distances to feed, it is not logical, nor scientific to manage these species differently by country.
Fecal Samples from Southern Resident killer whales are prepared for laboratory analysis.
Wild Orca’s team is on the water collecting fecal samples for analysis. Our Southern Resident Killer Whale Health Monitoring Program is a direct window into the effects of seasonal and more long-term food shortages on these whales’ health, including pregnancy. We aim to provide near real-time information to management agencies so that swift and meaningful action can be taken, beyond asking vessels to give the whales space.
When the Southern Resident killer whales were listed as endangered in 2005, lack of prey was NOAA’s hypothesis. Despite 16 years of research, this hypothesis remains, not yet considered settled science. This is the scientific method, but it’s also a shield that NOAA Fisheries uses to authorize Chinook fisheries each season. We shouldn’t need another study to confirm that fishing an endangered species puts the survival of their predator at risk of extinction. This isn’t a hypothesis, this is reality.