Efforts to save endangered killer whales in B.C. urgently needed, scientists warn
Time is running out for the critically endangered population of southern resident killer whales as they face increased threats to their habitat, warns a new study by B.C. conservation group Raincoast and an international team of scientists.
The study, published this week in Communications Earth and Environment, finds there are warning signs of an accelerating decline for these orcas.
This study updates research from eight years ago, which estimates the population has a 24 per cent chance of extinction within 100 years. Now the situation is dire, with a worst-case scenario of extinction in 40 years.
Habitat degradation through underwater noise, high concentrations of industrial chemicals, and declining quality and quantity of chinook salmon inhibit population recovery, the authors conclude.
Southern resident killer whales live in the Pacific Ocean off the coasts of B.C., Washington, Oregon and California. They are considered to be nearing extinction, with only 75 left.
In January, the Center for Whale Research said the newest member, a calf born in December, was presumed dead. Researchers say the mortality rate for calves is very high among the southern residents.
This study found lower recovery potential than previously estimated in 2017 due to fewer breeding females, the loss of individuals to ship strikes, inbreeding, and a reduced ability of chinook salmon abundance to affect birth rates. To recover the population, more effort is “urgently needed” to address three primary threats, including a recovery in salmon, reduction of noise, and significantly reducing harmful contaminants in salmon or whale habitat.
Co-author Peter Ross, the healthy waters director at Raincoast, said the problem is orcas now must find food in increasingly busy, noisy and polluted waters.
“Without food, we all perish and food for residential whales is largely chinook salmon and chinook salmon is under pressure for a number of other reasons,” he said Wednesday.
“We really need governments to look at salmon in a more ecosystem-like fashion, whereby we're looking at watersheds, we're looking at riparian zone protections, we're looking at the discharge of pollutants along a lengthy course of water that they've got to navigate.”
In all scenarios outlined in the study, the best path to a fully recovered population is ambitious salmon management.
Ross also said these cetaceans need to use their echolocation to find food and each other, but there has been an increase in noisy vessels, a problem he doesn't think is going away any time soon.
“We can't keep adding more and more noisy vessels to the Salish Sea without implications for southern resident killer whales,” he said.
Orcas are also facing increased mortality from pollution from toxic chemicals and microplastics.
While the government banned harmful PCBs in the 1970s, they persist in the water, and now marine animals are under threat from a chemical called PFAS — perand poly-fluoroalkyl substances — used in items that range from waterproof clothing to nonstick cookware. The chemicals don't break down and have been linked to serious illness, including cancer.
“We need the federal government to do a better job of evaluating and managing chemicals. We need regional authorities and municipalities to do a better job managing waste through the liquid waste ... but also road run-off, storm sewers and we need industry to adopt best practices and to look at what it releases in light of salmon and whales,” said Ross.
The scientists are calling the decline of the whales a bright extinction, which means they are watching the decline of a well-studied and understood species. It is the opposite of the term dark extinction, which has been used to describe the loss of species for which there is limited data.