The Blob as it appeared off Alaska in 2014. The warmest water is in red/NOAA graphic

News analysis

Alaska is going to end the 2018 salmon season with a catch a little over half that of last year despite another phenomenal return of Bristol Bay sockeye salmon.

But anyone who tries to tell you this is the result of “The Blob” – a shape-shifting pool of warm water first detected in the Gulf of Alaska in 2013 constantly on the move until its ultimate death near the end of last year  – is so over simplifying the story that the only term for that conclusion is fake news.

The simple reality is this: The five-year average Alaska salmon harvest for “The Blob” years – 2013 to 2018 – is close to 205 million fish.

The largest salmon harvest in state history, an astounding 272 million fish, came in 2013 as The Blob was just forming.

The second highest harvest in state history, 263.5 million salmon, came in 2015 as The Blob was nearing its peak.

By September of the next year, National Geographic magazine would be reporting about “The Blob That Cooked the Pacific” with writer Craig Welch ominously warning of dead whales and sea otters, and the projections of scientists that “toxic (algae) blooms will be more frequent, more widespread, and more toxic.”

There is no doubt The Blob was causing havoc in the food chain in the way a hurricane causes havoc when it comes ashore. As The Blob moved around the North Pacific Ocean like giant amoeba, it brought chaos.

It might have played some role in the drop in Alaska’s salmon harvest in 2016. The catch that year fell to just over 110 million fish, but the salmon bounced back strong the next year.

The 2017 catch was 224.6 million salmon, the third largest on record, the summer after Welch described the North Pacific as cooked.

Alaska brags

“Tremendous harvests occurred across Alaska from Kotzebue to Southeast, highlighted by an all-time record statewide chum salmon harvest,” Forrest Bowers, the deputy director of the state’s Division of Commercial Fisheries raved in an official media statement from the Alaska Department of Fish and Game. “In addition, 2017 is the third year in a row statewide sockeye salmon harvest exceeded 50 million fish. Record wild salmon harvests like these are a testament to Alaska’s sound, science-based management, the professionalism of ADF&G’s staff, and thoughtful stakeholder engagement.”

Bowers, the press release said, “characterized the 2017 Alaska salmon season as a banner year for the industry and state of Alaska.”

There was no mention whatsoever of The Blob. And no media picked up on the phenomenon of Alaska’s third-best salmon return in history a year after The Blob supposedly “cooked the Pacific.”

This is largely how environmental reporting works in the U.S. in modern times. Disasters are highlighted; confounding successes are ignored.

One would think that if The Blob gets the blame for the bad returns, it would also get the credit for the good returns. But it doesn’t work that way.

“People like simple stories,” noted fisheries scientist Greg Ruggerone, and journalists even more so.

The fisheries of the North Pacific are the opposite of simple. They are a web of complex with big fish of every species eating little fish of every species, and there are dozens of species involved in this food fight.

Still, the simplest parts of the complexity deserve some honest reporting:

The years 2013, 2015 and 2017 – from the start of The Blob through its demise – produced  the three biggest salmon returns in Alaska history. The situation is way too complicated to conclude the weak 2018 return, or at least weak compared to 2013, 2015 and 2017, is because The Blob “may have decimated the food web in the Gulf of Alaska” as Alaska Public Media reported.

Blobs within blobs

The problem with this sort of thinking is that the food web is itself a blob. It is constantly shifting and changing in response to changes in water temperatures and the foraging capabilities of all the little fish at the bottom of what is a giant pyramid of life.

Human attention focuses near the top of that pyramid where the big fish live. The salmon, halibut, cod, pollock and more that survive to reach harvestable size are what interest humans, who have a bad tendency to celebrate record returns and then fret when those record numbers aren’t met year after year.

Context is important when looking at the big picture. Here’s the context:

“While most people familiar today with the Alaska salmon fishery would consider annual commercial salmon harvests of less than 100 million as a disaster,” state scientists wrote in a lengthy, 2006 review of “The Commercial Fishery in Alaska,” “from the inception of the salmon fishery in the late 1800s through the 1970s, such harvest levels were considered a Godsend. Prior to the (state salmon) plan being written, annual commercial harvest levels in excess of 100 million salmon had only happened in six years (1918, 1934, 1936 to 1938, and 1941; only 6 percent of the years prior to 1980). Since 1980, the Alaska commercial salmon fishery has only once (4 percent of the years) harvested less than 100 million salmon—in 1987, the harvest was 96.6 million fish.”

Prior to 1980, the “weak” harvest of this year would have been one for the record books. That it is viewed as weak now is because Alaska salmon runs are oscillating in a big way: Down in 2012, up in 2013, down in 2014, up in 2015, down in 2016, up in 2017, and down in 2018.

Why? That’s a multi-million dollar question.

The strong-weak phenomenon used to be largely limited to pink salmon, which have long shown an odd-year dominance in the 49th state. But scientists Alan M. Springer and Gus B. van Vliet in 2013 hypothesized that as the North Pacific warmed in the 1980s and salmon numbers increased greatly, the natural even-year, odd-year variation in pinks began to influence other salmon populations.

“One species in particular, pink salmon, became so numerous by the 1990s that they began to dominate other species of salmon for prey resources and to exert top-down
control in the open ocean ecosystem,” they wrote in a peer-review study published in Proceedings of the National Academy of Sciences of the United States of America. “Information from long-term monitoring of seabirds in the Aleutian Islands and Bering Sea reveals that the sphere of influence of pink salmon is much larger than previously known.”

The odd-year, even-year cycle of pink salmon, which has now been shown to be influenced by genetically distinct populations of odd-year and even-year fish, continues, and there are hints that in areas with naturally large pink populations, the fastest growing salmon in the ocean might be depressing numbers of their slower growing relatives, especially Chinook, coho and sockeye salmon.

Scientists studying Prince William Sound in a continuing search for long-term damage from the 1989 Exxon Valdez oil spill last year found evidence Prince William Sound pinks were suppressing returns of Copper River sockeye salmon.

The Sound is home to a moderate-size, natural run of pinks that has been hugely boosted by commercial hatcheries that operate as private, non-profit companies in the state of Alaska.

“All sockeye salmon stocks examined exhibited a downward trend in productivity with increasing PWS hatchery pink salmon returns,” the scientists wrote in their peer-reviewed study. “While there was considerable variation in sockeye salmon productivity across the low- and mid-range of hatchery returns (0–30 million), productivity was particularly impacted at higher levels of hatchery returns.

“Pink salmon have been found to negatively affect sockeye salmon productivity and growth from British Columbia and Southeast Alaska, Bristol Bay, Kodiak, and Russia. Pink and sockeye salmon compete in the marine environment due to a high degree of similarity in diets, including similarities in diets of adult pink salmon and juvenile sockeye salmon.”

Kodiak, Southeast, British Columbia and Russia are the areas with the largest naturally returning runs of pinks. The Sound has the largest returns of  hatchery pinks. The 2017 pink harvest in the Sound numbered near 50 million with 87 percent of the harvest hatchery fish. 

The 2018 Copper River sockeye return was a disaster for commercial fishermen, although enough salmon returned to meet spawning and subsistence fishing goals after the commercial fisheries closed after three brief openings with a catch of only 26,000 sockeye. 

The mayor of Cordova, the fishing port nearest the mouth of the river, has blamed The Blob. Cordova is the home base for the Prince William Sound Aquaculture Association.

“The inconsistency of the Cook Inlet salmon runs (to the north of the Sound) over the past few years have now arbitrarily pointed to hatchery releases as the culprit,” Mayor Clay Kolpin wrote in the Anchorage Daily News. 

“It is understandable that as demand for Cook Inlet salmon expands and catch rates go down, fishermen from all user groups are looking for answers. Unfortunately, we have little control over the likely cause cited by scientists: the recent ocean conditions wreaking havoc on the Gulf of Alaska’s ecosystem. Referred to as ‘the blob,’ the mass of warm water that formed in 2013 and lingered through 2016 stripped the typically bountiful Gulf of Alaska of vital nutrients, creating cascading effects throughout the food chain. Scientists believe it to be responsible for mass die-offs of juvenile cod and salmon — impacts that are clearly visible in this year’s salmon runs.”

Scientists have published on the issue of cascading effects, but they didn’t link that to The Blob. A number of scientists have now linked large numbers of pink salmon to so-called “trophic cascades.”

Scientists Sonia Batten and Ruggerone were but the latest to do so. In a peer-reviewed study published in Fisheries Oceanography, they reported even-year, odd-year declines in salmon prey in the Bering Seas and eastern Aleutian Islands “likely caused by the predation pressure on copepods from biennially abundant eastern Kamchatka Pink Salmon that results in a trophic cascade.”

Ruggerone, in an interview, said this situation would likely be compounded by The Blob, but it exists with or without The Blob.