Recently published research funded by the UC Davis SeaDoc Society suggests that growth in gray whale populations may have unexpected benefits for other marine animals in trouble, such as diving sea ducks.

SeaDoc Society Director Joe Gaydos, based on Orcas Island, said the finding was made in 2006 by Eric Anderson and Jim Lovvorn of the University of Wyoming as they studied the feeding ecology of ducks called scoters. Theirs was one of $250,000 in research projects that SeaDoc supported that year.

The researchers were observing a gray whale near Sandy Point on Whidbey Island, about 30 miles north of Seattle. Gray whales suction-feed, sieving out ghost shrimp and other small sea animals from the sea floor. As they eat, the whales create giant pits and stir up clouds of invertebrates, which settle back to the bottom and flourish in the altered landscape left after the whales have passed.

In a paper published in the May 2008 Issue of Marine Ecology Progress Series, Lovvorn and Anderson said they watched as 125 sea ducks (surf scoters and white-winged scoters) flew to the gray whale and began diving in its tracks, about 300 feet behind, with a few ducks diving as a group barely 15 feet from the whale.

It was the first documented observation of an association between cetaceans and birds that feed on the sea bottom.

Anderson and Lovvorn suggest that such increases could enhance feeding opportunities for scoters and other bottom-feeding animals during the critical spring period, when typical food is less abundant and nutritional requirements needed to prepare for migration and reproduction are high.

More than 60 other fish and wildlife species in the Puget Sound region are listed as threatened or endangered, or are candidates for listing, Gaydos said. “Usually we are trying to deal with endangered species eating other endangered species, so this evidence that the recovery of one species could benefit the recovery of other is a welcome breath of fresh air.”

The SeaDoc Society (www.seadocsociety.org) works to ensure the health of marine wildlife and their ecosystems through science and education. A program of the Wildlife Health Center at the University of California, Davis (UC Davis), the SeaDoc Society has a regional focus on improving the health of the Salish Sea.