Feast or Famine

Gray whales have roamed the world’s oceans for some 30 million years. The species hasn’t survived that long without adapting to changes, such as those in the California Current over the past decade.

2006 was a banner year for the whales and whale watching on the central Oregon coast. In kelp beds a mere quarter-mile out from Depoe Bay, 45-foot-long gray whales frolicked away the summer, feeding head-down, their tail flukes extended high above water. It was in stark contrast to the previous year, when the tell-tale spouts were rarely seen from lookouts along Oregon’s Highway 101.

OSU graduate student Carrie Newell has discovered that the difference may stem from the relative abundance of tiny shrimp-like zooplankton called mysids, a gray whale delicacy. In 2006, the mysids took advantage of the super-charged upwelling to feast on phytoplankton blooms. These half-inch, opaque crustaceans, which look like small shrimp, form clusters or “swarms” up to 20 feet thick in shallow waters.

Find a handful of gray whales in the neighborhood, and chances are that a mysid swarm is down below.

A biological oceanographer, Newell began investigating the connection between whale abundance and the mysids in 1999. The scientific literature suggests that whales in the Northwest feed on mud-dwelling amphipods, yet the kelp beds that attracted the whales were anchored in rock.

So Newell donned her scuba gear and dropped into the chilly waters of the Pacific Ocean to take a look.

“I couldn’t believe it,” she said. “There were mysids everywhere. It seemed obvious the whales were feeding on them, but I had to be sure.”

Her solution? Take samples of whale excrement and search for remnants of mysids, a process nearly as disgusting, though not as simple, as it sounds.

“Well, you don’t want to get too close,” she says with a laugh, “and it dissipates quickly. But I did get a number of samples that proved my hypothesis, that whales were eating mysids, and lots of them. It’s probably their favorite food.”

So during the delayed upwelling season of 2005, mysid swarms were scarce. She could tell something was amiss by the behavior of some of her well-known whale friends.

“Rambo came into the area three different times in 2005 to check things out,” Newell says, “but there wasn’t any food and he cruised on out. Cutter stayed five days; Stretch hung around for a couple of days, then left. And that was about it. There just weren’t many whales that year.”

But in 2006, when the biological productivity off Oregon exploded, the gray whales returned for the mysid buffet and brought new whales with them. Most stayed for several weeks, and one named Eagle Eye spent more than 120 days in the same vicinity.

Newell is expanding her research to look at mysid densities and whether their movements are related to tidal changes. She is continuing to determine the relationship between physical factors, mysid biomass and gray whale residency.

To help pay for her studies, Newell began her own whale-watching business in Depoe Bay, Whale Research Excursions. She has spent the last several years studying Oregon’s summer resident gray whales, which she can identify individually by their unique markings.

She passes along her findings to the classes she teaches at Lane Community College, and to clients aboard her whale-watching cruises, who sometimes help her with the research.

“I love sharing what I do with others,” Newell says. “It makes people happy to see whales in their natural environment and, for some people, it is a life-changing experience. I’m translating what I’ve learned at OSU directly to the general public, and they turn around and spread that to others.”

One Response to “Feast or Famine”

  1. [...] Gray whales have roamed the world’s oceans for some 30 million years. The species hasn’t survived that long without adapting to changes, such as those in the California Current over the past decade. Read more… [...]