EO Media Group
CANNON BEACH — The humpback whale stranded in Seaside in January may have become entangled or struck by a boat, according to Debbie Duffield, a Portland State University biology professor.
More than 30 people gathered for a lecture, “Marine Mammals, the Marine Mammal Stranding Network and Marine Reserves,” last week at the Cannon Beach Library.
The topic was particularly timely. In the past few weeks, a humpback whale washed ashore in Seaside, and a harbor porpoise and two striped dolphins were found on the North Coast. Experts are still waiting on necropsy results for the whale to see whether it was infected or if it had an accident.
The humpback has bruising that could have been from entanglement or a boat strike, Duffield said. It also carried a fairly heavy parasite load for a whale not more than 2 years old.
The presentation — a partnership between Duffield and Keith Chandler, the Seaside Aquarium general manager — was part of Haystack Rock Awareness Program’s lecture series.
The Oregon Marine Mammal Stranding Network, which Duffield and Chandler belong to, responds to mammal strandings from Tillamook to Long Beach, Washington. They see 149 stranded animals a year on average. The most common animals include California sea lions, harbor seals and Steller sea lions.
Strandings allow researchers to evaluate otherwise inaccessible animals, and necropsies tell scientists vital physiological and biological information. Marine mammals’ tissues are sampled and used for studies on ocean pollution, biotoxins and other environmental changes.
Once they evaluate a stranded animal, researchers take samples back to the university to study it in a controlled area and test for infections. After they finish the necropsies, they might prepare the bones for students to piece together.
“Every once in awhile we have species that, because of their charismatic value, are of great interest to everybody,” Duffield said.
For example, a killer whale was stranded in Long Beach several years ago, drawing veterinaries, researchers and onlookers alike. Duffield also recalls when a Baird’s beaked whale came in live in Seaside during a volleyball tournament. “Luckily, people weren’t around it when it started to die and thrash, because it could have killed somebody,” she said.
Why do these animals appear on shores? Seals, sea lions, whales, dolphins and porpoises are primarily stranded due to human interaction, such as gunshots, fisheries interaction and net entanglement. Bacterial disease, cancer and infections also cause strandings.
Sometimes the human-related interactions are extreme. Duffield displayed a jarring photo of a California sea lion that had part of its face destroyed by an explosive device.
She also showed a picture of plastics and debris on the Seaside beach. Sea lions get entangled in plastic bands, but since they bite, it’s difficult for humans to help them remove bands and recover from wounds. In 2010, a dead whale stranded in Washington’s Puget Sound beach had 50 gallons of material in its stomach that was mostly algae, but also human debris, such as sweatpants, plastic bags, duct tape and towels.
The Oregon Marine Mammal Stranding Network works to improve treatment and disentangle marine mammals from debris and fishery gear.
Duffield said that the animals are resilient. Seals and sea lions often carry worms in their stomach that can form ulcers. “They just live with that,” she said. “Their parasite loads are tremendous.”
The strandings may also point to larger forces at work. The El Niño climate pattern that’s increasing coastal temperatures, along with the warm “blob” of water in the north Pacific Ocean, affect the animals’ prey.
“We’re at the apex of these changes that we can actually follow annually,” Duffield said. “It’s a fascinating change that we’re living through.”