The southern resident orcas have a diet of just one dish, chinook salmon. With recent reports from the Committee on the Status of Endangered Wildlife In Canada stating that nearly half of southern British Columbia’s chinook salmon populations are in decline, it has put a stress on the killer whale’s main source of food.
What has caused this shortage of salmon? The emergence of commercial fishing alongside the development of the surrounding areas around the Fraser River that have led to drastic climate change is what Jason Colby, Environmental professor and author of Orca: How We Came to Know and Love the Ocean’s Greatest Predator believes to be the culprits.
“Ultimately this is a story of starvation, this is a story about this shrinking population [where] even its current numbers can’t manage to feed itself on the prey that was once super abundant,” said Colby.
With climate change altering the temperature in the water, it has only added to the number of problems the chinook salmon are facing. The growing number of sea lions hunting the salmon, as well as the increased toxicity and acidity in the ocean is what some experts believe to be the reasons for the decline.
But Colby still points to one of the big reasons he believes the numbers are down; fishing.
“How much are people willing to restrict fishing because despite the fact that [the orcas are] starving, there’s still commercial fishing continuing on the US and Canadian side – there’s still sport fishing that takes out thousands of chinook salmon a year,” asks Colby.
With the southern resident killer whale’s being a bi-national population – crossing borders, travelling along Vancouver Island all the way down to Washington State, Colby says it is hard to regulate due to the need for cross-border regulations, but is necessary for the survival and growth of the chinook salmon.