25 million sockeye salmon expected to be swimming into the Strait of Juan de Fuca near Seattle are nowhere to be found!
It has been a record-breaking year again this year for salmon up and down the Pacific Coast. But amid the story of the historic bounty of salmon returning from their restored and revived ocean pasture an even bigger ocean mystery is building with respect to the salmon lost on their way home to the Fraser River.
Since the 1950’s the International Pacific Salmon Commission has tracked salmon on the Pacific coast and the biggest run of salmon, the Sockeye salmon that spawn in the Fraser River of British Columbia, have normally swum home to that river by two routes. Half take the northern route through the inside passage and the Johnston Strait and half take the southern route through the Strait of Juan de Fuca.
Each year when the school of Sockeye that have been grazing in vast North Pacific ocean pastures are on their way home but still perhaps a 500-1000 miles out in the Pacific they split into the two schools. This 50/50 split of Sockeye has rarely been seen to vary in all of history.
But this year is unusual in two ways. First the Fraser Sockeye this year have been predicted to return in the largest numbers ever, perhaps even double the largest number in all of history this year reaching 72 million. A huge restored abundance is certain. Given the historic behaviour of the sockeye this also means that half of this historic number of Sockeye or 25-30 million should be swimming home via each of the two routes they almost always follow.
But now as the return of the Sockeye to the Fraser River is just about complete only a few percent of the Sockeye, some hundreds of thousands instead of tens of millions, are finding their way through the Southern route that goes through the Strait of Juan de Fuca. At the same time the other half of the Sockeye, just as expected, are being counted as usual swimming down the inside passage with some 25-30 million having made it to the river. What if that’s just half the salmon expected.
The Juan de Fuca school are salmon lost?
They have gone largely missing and it is believed by many they may be holding in the open ocean to the west of the Juan de Fuca. Since about 5% of that school has made it into and through the Juan de Fuca it is clear that the entire southern school was not simply diverted and is swimming home with the northern inside passage school. It’s just as likely 20-25 million Sockeye have become stuck off shore for some mysterious reason.
Whether they are alive or dead is unknown, they are like Schrödinger’s Salmon in an offshore box both alive and dead at the same time we just don’t know which.
The reason for this mystery is now the hot topic of an emerging debate among salmon pundits and “authorities.” A prominent explanation that is gaining in media popularity is that a “warm blob of surface ocean waters to the west of the state of Washington is blocking the fish.” That idea seems to track back to University of Washington weatherman Nick Bond. There are also some few reports from ~50 years ago of a similar diversion correllated with warm sea surface water.
That unusual warm blob of ocean is several degrees warmer at the surface than normal ocean waters for this time of year and it extends across the mouth of the Strait of Juan de Fuca. Did it form a thermal barrier that is confusing the returning salmon?
It is surmised that the Juan de Fuca school of sockeye, encountering this unusually warm water are confused by it into thinking that it is still high summer and not yet the start of the fall which is their cue to return in haste to the river where they hatched to spawn and complete their lives. Meanwhile every cell in their bodies is telling them to change them from silver to scarlet preparing them for spawning. The internal conflict must be incredible.
Or perhaps this is a not so uncommon Sockeye characteristic that might explain the mystery of why some sockeye come back in their 5th year instead of 4th year. Have a large school of sockeye been turned back to their ocean pasture? Will they come back next year as 5 year olds? Good stuff for salmon mystery buffs.
Curiously the “warm blob of ocean water” didn’t seem to affect the salmon returning to the Columbia River this year which has experienced its all time record count of salmon since accurate records were started in 1938, including a return of Sockeye of double the number expected. All along the coast of Washington and Oregon fishermen have been enjoying the best salmon catch ever so those salmon too made it through the warm water just fine. Surely more ideas and explanations for the lost sockeye will emerge, so the deductions of all the would be Holmes, Pirots, and Marpoles must await more clues. Tragically no special ocean science is being undertaken to search for clues of the lost salmon.
We can hope that the unseasonably warm weather in the Pacific Northwest comes to and end and cools the ocean sending the lost fish home to the river weeks late. Better late than never.
Meanwhile the northern inside passage school of sockeye is behaving perfectly normally and is flooding down the inside passage in record numbers. Experts agree that at least 25 million of the inside passage fish have arrived close to the mouth of the Fraser River in numbers that are close to the largest counted in all of history.
That record to break is held by the 2010 volcano miracle return of Sockeye where 35-40 million fish made it home from ocean pastures made lush and healthy by the Kasatochi volcanic ash fall of 2008. In 2010 half of those fish came from the Juan de Fuca school and half from the inside passage school.
International Salmon Commission experts this year had forecast the largest number of Sockeye ever predicted to be up to 72 million fish to arrive. Now with about half that record forecast accounted for and seen to have swum down through the inside passage the forecast looks to have been right on target.
Tragically though with an equal number of millions of salmon lost or stuck in offshore waters to the west of the Strait of Juan de Fuca the official return will likely be somewhere in the range of 25-30 million fish with 25-30 million additional being in the lost school.
The next few weeks may solve the mystery of the lost school of salmon.
In the last few days the hot summer has finally broken in the Pacific Northwest and temperatures have cooled to near normal. The rains are beginning and if the cool air and cooling rains signal to the lost school that all is well with their world then perhaps they will rush in and join their school mates in the greatest return of spawning salmon in all of history to the Fraser River, said to be the greatest salmon river in the world.
If not the mystery will deepen as the fate of lost school of salmon remains a mystery like that of Schrödinger’s Cat, the answer to whether the lost salmon are alive or dead may never be revealed.