Jellyfish Boom As Little Fish Disappear In Puget Sound

Little fish are disappearing from much of Puget Sound, according to a new study.

These are the fish that orcas and salmon depend on, and they’re being replaced by ballooning populations of jellyfish, which most fish and seabirds don't eat.

That’s why Gov. Jay Inslee signed a bill last week to authorize a major study of these "forage fish" in Puget Sound. The study could help provide answers to why herring and other "forage fish" have become so rare and what to do about it.

On a recent afternoon, Correigh Greene, a biologist at NOAA’s Northwest Fisheries in Seattle, stood near the end of a fishing dock in West Seattle. He said that if threw a net in the water, he could expect to catch a few young salmon pumped out by hatcheries from up the Duwamish River.

“And that’s mostly it, aside from a bunch of jellyfish that we routinely catch in these urban areas,” he said.

He recalled one of the biggest jellyfish hauls: "The net was so filled with jellyfish we couldn't bring it on board. It was too heavy for our winch. It's fairly disturbing when all you pull up are these huge masses of jellyfish."

Jellyfish are native to Puget Sound. They belong here. But almost nothing in Puget Sound eats jellyfish, except bacteria. So they’re a bit of a dead end for the food chain. And jellies seem to be replacing the tastier parts of the food chain, like herring.

Greene and other federal biologists can't explain why "forage fish" like herring and surf smelt have declined by 98 percent or more in much of Puget Sound.

It could be because so many shoreline habitats where fish lay their eggs are now buried under concrete walls and rock piles. Greene calls them the little fish that matter.

"People might not care about jellyfish and forage fish so much, but they might care about seabirds,” he said. “They might care about orcas, and they might care about salmon. All those species feed on forage fish, but they do not feed on jellyfish."

The study approved by Governor Inslee could cost up to $2 million. State legislators still must decide how much the little fish matter and how much to spend on studying them.