Empty nets signal trouble for Columbia River salmon – “This is really different than anything we have ever seen”

Desdemona Despair

By Lynda V. Mapes
9 October 2017

(The Seattle Times) – Scientists have been hauling survey nets through the ocean off the coasts of Washington and Oregon for 20 years. But this is the first time some have come up empty.

“We were really worrying if there was something wrong with our equipment,” said David Huff, estuarine and ocean ecology program manager in the fish ecology division at NOAA Fisheries. “We have never hauled that net through the water looking for salmon or forage fish and not gotten a single salmon. Three times we pulled that net up, and there was not a thing in it. We looked at each other, like, ‘this is really different than anything we have ever seen.’

“It was alarming.”

Moving from Newport, Oregon, to the northern tip of Washington, anywhere from 25 to 40 nautical miles offshore last spring and summer, the survey team began catching fish — but not the ones usually in those waters. Instead, warm-water fish, such as mackerel — a predator of young salmon — and Pacific pompano and pyrozomes — normally associated with tropical seas — turned up in droves. Both deplete the plankton that salmon need to survive.

In a report on their trawl survey, the scientists logged some of the lowest numbers of yearling Snake River spring chinook recorded since the survey began in 1998. Coho numbers were just as depressed.

“Every year is different. But this year popped out as being really different,” said Brian Burke, a research fisheries biologist based at the NW Fisheries Science Center in Montlake. “Not just a bunch of normal metrics that point to a bad ocean year, but the presence of these things we have never seen before, really big changes in the ecosystem. Something really big has shifted here.”

It’s not a short-term problem.

Low survival of juvenile salmon also portends a paltry return of adult salmon in two years and longer into the future — bad news for animals that depend on salmon for their own sustenance. Especially southern-resident killer whales, already at a 30-year low in their population, following the recent death of an emaciated calf.

While its body was not recovered, so the cause of the calf’s death cannot be certain, starvation makes the orcas’ other challenges, from vessel noise to toxic pollution to disease, harder to fight off.

This year’s bizarre survey results all started with The Blob, as it came to be known: an enormous mass of unusually warm water off most of the West Coast that beginning in 2013 wreaked havoc with species survival and food abundance in the ocean.

Now the blob is gone, but some of the animals that came north with it, vastly expanding their range, are still here. [more]

Empty nets signal trouble for Columbia River salmon