New research says gray whales in Oregon are in trouble

The Oregon coast is experiencing a dramatic rise in the population of purple sea urchins, a phenomenon with serious ecological consequences. This increase in sea urchins has led to the devastation of kelp forests, which play a crucial role in the marine ecosystem. According to a new study, this ecological shift has negatively impacted local gray whales, a beloved species of the Pacific Northwest. 

Gray whales are massive, they can grow to about 49 feet long and weigh approximately 90,000 pounds. They embark on one of the longest migrations of any mammal,  traveling about 10,000 miles round-trip between their breeding grounds in Mexico and feeding grounds in the Arctic. They even have a unique feeding technique that involves turning on their side and scooping up sediment from the ocean floor to filter out small organisms. It turns out some gray whales also love Oregon’s kelp forests.

Urchins everywhere

Unfortunately, kelp is a purple sea urchin’s favorite food and they have a huge appetite. When their numbers increase uncontrollably, they can decimate kelp forests, which are essential habitats for zooplankton. These tiny aquatic organisms are a primary food source for many marine animals, including gray whales. With the kelp forests disappearing, the population of zooplankton also declines, leading to a significant reduction in the foraging grounds for gray whales.

The explosion of sea urchins off the Oregon coast began following the sea star wasting syndrome pandemic that started in 2013. This pandemic caused a catastrophic decline in sunflower sea stars, reducing their population by an estimated 90 percent. The sunflower sea star, a natural predator of the sea urchin, is now critically endangered. But another urchin predator is also absent from Oregon’s shores, and bringing them back could be the solution our kelp forests desperately need.

The otter way out

Historically, sea otters also played a vital role in controlling sea urchin populations, but they were wiped out over a century ago because of the Fur Trade – they have the densest fur on any animal on Earth. It’s clear the absence of both sea otters and sunflower sea stars has left no effective predators to keep the sea urchin population in check and it’s having downstream effects on other critters that rely on kelp forests, like gray whales.

The recent research, conducted over several years as part of a 10-year study on the foraging ecology of gray whales, found that as kelp forests deteriorated, so did the availability of zooplankton, particularly tiny shrimp, which are a significant part of the gray whales’ diet. As a result, gray whales have less food to eat in our coastal areas. The researchers noted that they have seen fewer and fewer whales and the ones they did see were in poorer health.

This study makes it clear that we need to restore balance to our coastal ecosystems. We think bringing sea otters back could be the solution. Reestablishing sea otters to their historical habitat could have far-reaching positive effects on the marine ecosystem. By controlling sea urchin populations, sea otters would allow kelp forests to recover, providing a habitat for zooplankton and, consequently, restoring the foraging grounds for gray whales.

Restoring balance

Right now, the U.S. Fish and Wildlife Service is considering whether or not to bring these marine mammals back to Oregon’s coast. In 2022, they released a feasibility study which found that bringing them back would likely have a positive environmental impact on Oregon’s ocean. It could improve ocean resiliency, revive our kelp forests, and ensure a healthier, more biodiverse future for Oregon’s coastal waters. Our federal officials should move forward swiftly with the next steps to bring them back and you can join us in calling on them to do so.