Steelhead are at a fraction of the abundance they used to be, said fisheries stock assessment biologist Robert Bison who heads up the Ministry of Forests, Lands and Natural Resources Interior Fraser Wild Steelhead conservation program.
“A typical breeding steelhead population in the entire Chilcotin watershed is about 100 fish,” Bison said. “It’s very low now, where it used to be thousands. In the Thompson watershed we are down to a couple 100 where they used to return closer to 10,000 before fishery removal.”
Continuous funding from the Habitat Conservation Trust Fund (HCTF) has made it possible for the steelhead monitoring program to continue, including $98,677 for this year. The program has been tracking and monitoring breeding steelhead populations for more than 40 years.
Bison said the strongest evidence at this time is that most of the decline of steelhead has been the unintended consequence of restoring marine mammal populations.
“In the early 1970s, on the west coast of Canada the harvest of seals and sea lions was reduced to zero and in Puget Sound in the U.S. they enacted similar legislation.”
This move impacted salmon numbers, he noted, but especially steelhead because when they migrate out to to sea as two-or three-year-old fish, quite big in body size, they are attractive to harbour seals.
Then when they return as adults, after two years out at sea, they are attractive to not only harbour seals, but sea lions and orcas.
There is also some evidence of changes off-shore in the marine environment impacting steelhead.
He cited repetitive oceanographic patterns of change over time, the possibility that climate change is sitting on top of that cyclical phenomenon, plus some evidence there are too many salmon in the ocean right now as being contributing factors.
Large salmon population can be attributed to the development of hatcheries in the 1970s and 80s, he noted.
“The big hatchery producers in the Pacific are Japan, Alaska and Russia. Canada is kind of a minor in-putter of hatchery salmon. There is 40 per cent more biomass in the ocean than we have ever seen and almost all of that originates from hatcheries.”
There is no evidence that freshwater factors, such as stream flows, stream temperatures or freshwater habitat have been responsible for the decline of steelhead populations to date, he added.
“It doesn’t mean they won’t in the future, but at least for over the last 40 years to now almost all of our decline has happened by decline in survival from when they leave freshwater, smolt and go to sea, and when they return. The latter half of their lives is where the problem lies.”
Counting in the Chilcotin watershed is done by helicopter over the Chilko River up toward Chilko Lake and in the Thompson, electronic fish counters are used in one watershed and in another watershed they use periodic boat-based counts, supplemented with tagging.
Information gathered through the monitoring and tracking is provided to First Nations, provincial and federal fisheries to be used in their management and conservation planning.
Funding and support for projects across B.C. distributed by HCTF come from groups such as the British Columbia Wildlife Federation, the Forest Enhancement Society of BC, provincial government contributions, court fines and endowments.
A significant source of funding also comes from the conservation surcharge paid by B.C.’s anglers, hunters, trappers, and guide outfitters.