Spawning salmon: A wonder of nature
By Richard Bussanich/contributor
For us who get our hands wet and handle this amazing fish, sockeye salmon, take a moment and understand that perhaps there’s more to this fish, than realized.
We often use the term Master fisher, a title deserving of those who study, respect and understand how to “lure” and handle fish.
Then pause. This fish has a lifetime of stories and has made a choice to offer itself to you.
A gift to nourish you with a memory of on-the-water with a companion, a morsel of value-added protein and good fats, dollars traded for gas, and the list goes on.
Some would argue that the fish is instinctive and just hit my lure, end of story. Yet, maybe, just maybe, the flip side of that is the fish allowed itself to be caught for you.
When you are holding this beautiful creature, give thanks and be mindful that what you are embracing is unique, and if it could speak would share its life story.
As a baby aelvin, near its Oliver spawning beds, it made first contact with the water surface in May, and by the flow of current, made its way to Osoyoos evading predatory bass, trout, perch, and northern pike minnow.
Once in Osoyoos, these toddlers stay near the shoreline for about one to two months before they realize more food and fewer predators are present in the deeper parts of the lake, and transition to what is called the “limnetic zone” (deeper area, greater than 20 metres).
From July through to the following May, the juveniles roam the lake, feeding and avoiding predators. By this time, up to half have survived to make it to the next phase in their life.
As teenage “smolts,” they have a cue (a magnetic pull) to go to sea, in June, traveling down the Okanagan to the Columbia River, passing through nine Dams, an entourage of Caspian Terns, and the like.
Travel time from Osoyoos to the mouth of the Okanagan, about five to seven days depending on flow rates, and another 28 days or so to the estuary of the Columbia.
Initial studies using miniature tags reveals how these fish travel down the Columbia River, and survive.
Over the last three years, we see that our Okanagan Sockeye can travel to the estuary over 21 to 30 days, and observe survival ranges from 20 to 35 per cent.
Of the one to four million smolts that have left Osoyoos Lake each year, about 0.2 to 1.5 million make it to the estuary.
The sockeye meet up with other sockeye from other rivers, and begin moving into larger groups, becoming a ‘Superorganism,’
By now, it’s July and our heroic Okanagan sockeye spend another one to two months in the estuary, getting used to an all-new environment, of salt water, a whole host of new food, and new predators.
By September, schools upon schools of fish begin the trek via the California current to the open sea.
The “Big Black Hole” is another term fisheries biologists call the ocean. Where’s Captain Kirk when you need him?
For our next generation of biologists, this is your quest.
From observational data, our Okanagan sockeye travel up to 150 km off the US coast, parallel to west Vancouver Island, then between it and the central coast of B.C., then they peel off and venture out, for one to two years, circling the Pacific gyre, three times a year.
Their travels take them somewhere between Hawaii and Alaska—what an adventure!
Then about February or March, cohorts (groups of same salmon from the same spawning time and area) are “cued” by their biological clock that life is near ended, and survival depends on making their way home.
It’s estimated that there is not much harvest by Canada, US, Japan, Norway, China, Russia, Korea or Poland. We don’t know, but we estimate a low catch number at one per cent or the total population.
That figure shows areas of concentrated harvest by US fisheries along the Washington Coast, Columbia River before trekking back into a man-made feature called the US-Canadian boundary.
Via a gauntlet of fisheries (and seals and sea lions), back through nine dams, and warming water temperatures, these fish prefer and seek 10C water, will tolerate 20 C for a period of time, but need to find that refugia where the temperature is right.
From May through August, the Okanagan sockeye travel from the Columbia’s mouth to Osoyoos Lake, where they hunker down between 20m and 35m of water depth, relying on body fat to sustain them.
They are off feed, putting all energy onto their gametes (eggs and sperm development).
Avoiding low oxygen and high water temperatures is essential, otherwise energy destined for gamete development may be short-circuited to “survival mode” or just in keeping cells alive.
Short term response is eggs may get “resorbed” and instead of the average 2,600 eggs per female, we may see an unknown percentage not available due to environmental stress, like repeat handling from fishers at the warmer surface.
All these factor into how productive the stock is.
Under favourable conditions, Okanagan sockeye return between seven and 20 adults from every one female spawner (during El Nina events, versus unfavourable El Nino events), which puts our Okanagan return between 0.5 to two adults for every one female spawner.
Last but not least, these fish make their way into the river and commit between the third week in September and mid-October, to go back to the very spot their parents spawned. How amazing is that?
Genetic analysis and tagging studies are revealing the “families” sired structure and processes that go into the conservation of this stock. What could this mean for biologists?
Rather than manage a population to the “river,” we could be managing to the “family.” Certain families carry a unique set of genes which may be the “key” to survival when facing “environmental changes.”
If only the salmon could speak to us, and tell us its story. When holding this beautiful creature, please be fish wise, sensible and respectful –and give thanks.
Richard Bussanich is a fisheries biologist with the Okanagan Nation Alliance.