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The annual salmon spawn
A lot of people think of this time of year, particularly the month of October, as the time of the salmon spawn. But here on the west coast, the salmon spawn actually goes for well over half the year - although the peak of activity is definitely through the autumn months.
There are seven species of Pacific salmon here - that is including steelhead and cutthroat trout, which used to be classified in the trout genus, but are now considered to be salmon.
Unfortunately, we also now have Atlantic salmon out here too. They have been escaping from salmon farms for years and surviving in the wild. Fishery workers have observed them ascending spawning streams, where they may disrupt the eggs of the native salmon when they spawn on top of their nests.
Although the salmon spawn in the region occurs through much of the year - starting as early as April, and continuing until early or mid-winter - the timing of the spawn is specific to each stream. Some streams host only one species of salmon, and the spawn there occurs during a specific period of a few weeks, or a month or two.
Other streams and rivers, however, host a number of salmon species. For example, Port Alberni’s Somass River (which you cross as you leave town heading to Tofino and Ucluelet) has an extended sockeye salmon run, which goes from roughly April through to September or even October. It also has numerous other species of salmon running at specific times throughout the year.
If you are not from the west coast, or have not personally witnessed the salmon spawn, it is easy to think of salmon as just “fish” that live in the ocean. They certainly are fish. But they are as much a rainforest species as an ocean species. They return to the stream of their birth to spawn. Depending upon the type of salmon, they may spend anywhere from a few weeks to a year in the stream before heading out to the ocean. The years to maturity also varies by species, but usually around their fourth year they head back to the stream where they were born, to continue the cycle.
This cycle of the salmon plays a critical part in the rainforest ecosystem, tying it to the oceans. The return of the salmon represents a wealth of nutrition flooding in from the ocean to the land: protein for animals ranging from bears and wolves, to eagles and ravens, to insects (and, through them, to songbirds, too) as well as nitrogen to feed the plants of the forest.
BC scientists, in studies conducted in Clayoquot Sound, have determined that as much as 77 percent of the nitrogen (an essential plant fertilizer) in a tree in a salmon-based ecosystem is sourced from the ocean, via the salmon! These fish are actually one reason that our rainforest is such a healthy ecosystem with the giant cedar trees for which it is famous. For more information, take a look at this article I wrote for BBC Wildlife Magazine about the relationship between salmon, bears, and cedar trees.
- Photos & text by Jacqueline Windh©
