Wall Dive, Bering Sea Style

by John Hocevar

July 21, 2012

If youre a SCUBA diver, youve probably got a favorite wall dive. Its hard to beat the feeling of moving slowly up a steep reef, with dense marine life above and below. Ill always remember my first deep wall dive, on a visit to Curacao as a teenager in the 80s.

My new favorite, though, involves a submarine rather than SCUBA. After a few dozen dives in Pribilof and Zhemchug Canyons, on the Bering Sea shelf break, I thought I had some idea of what to expect: gradual slope, soft sediment bottom, with coral and sponge density somewhere around 1 per square meter. So when we dropped onto a near vertical wall with nearly 100% invertebrate cover at 270 meters, I was giggling like a fourteen year old.

Zhemchug, named pearl by the Russians who discovered the canyon the 1960s, was carved out of what is now the Bering Sea shelf by the Yukon River during past Ice Ages. Today, it sits on one of the most productive and lucrative stretches of ocean in the world. Known as the Green Belt, the Bering Sea shelf break is home to several of the largest fisheries in the US. Rather than embracing the idea of protecting a portion of this economically and ecologically vital region as a buffer against uncertainty or an insurance policy, most of the catch sector has opposed the idea of putting any of the shelf break off limits to fishing.

Video of this spectacular wall may help convince fishermen and their representatives on the North Pacific Fishery Management Council that the canyons are worth protecting if not for their beauty or biodiversity, at least for their role as nursery areas and habitat for fish and crab. Frequently, we saw juvenile fish especially rockfish hiding out in sponges, or nestled up against corals. Clouds of what appear to be tiny fish larvae swarm around gorgonians. Many of the sponges we collect turn out to be holding globs of fish eggs.

Juvenile rockfish in a sponge

Some people are uncomfortable with the idea that scientists can also be advocates for conservation, but Ive always felt a responsibility to press for the solutions that seem necessary based on the best available science. It may not always be popular at the time in fact, it rarely is but science based advocacy often seems to me to be our best hope for a future with coral habitats at any latitude. For more info and to get involved, visit

John Hocevar

By John Hocevar

An accomplished campaigner, explorer, and marine biologist, John has helped win several major victories for marine conservation since becoming the director of Greenpeace's oceans campaign in 2004.

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