A mass migration of wild sockeye salmon is expected to pass by Steveston over the next two months.
About 14 million sockeye are expected to enter the Fraser River, according to early estimates from the Pacific Salmon Commission. But hot weather and a warm river could imperil the fish and hamper what could otherwise be a large fisheries opening, said the commission’s chief biologist Mike Lapointe.
“This is the dominant run. And this is expected to be a relatively large run,” said Lapointe, noting the 2018 sockeye run is part of the strongest of four life cycles for Fraser sockeye, on account of the large Adams River (Shuswap Lake) population.
Over the past three years sockeye salmon runs have been poor and the 2016 run was the lowest in recorded history (a reported 853,000).
“The other years weren’t anything to write home about,” said Lapointe.
This year could see as many as 22.9 million sockeye come up the Fraser (a 25 per cent chance) or as few as 5.2 million (a 10 per cent chance), said Lapointe.
These are the babies of the 19.8 million sockeye that arrived in 2014.
This year’s dominant sockeye population heading to the Adams is part of the “late summer” run and as such the fish have yet to arrive in the Salish Sea, from the ocean.
The Early Stuart sockeye run had a better showing than expected, according to the commission’s July 27 run status report: while the commission’s pre-season forecast was 84,000, the in-season run was counted at 122,500.
Lapointe said about 755,000 sockeye from all populations have been counted at the Mission checkpoint, to date.
Lapointe expressed worry, however, about the river’s warm temperatures and low flow of water – two factors that increase mortality rates.
Thursday’s water temperature near the Fraser Canyon was 20.3 degrees Celsius whereas for sockeye to thrive it should be closer to 18 degrees.
And water discharge is 14 per cent lower than average, according to the commission.
Lapointe said a cooling off period across the province could spell better fortune for the fish, but at the moment he pegs the mortality rate (fish passing Mission but not getting to spawning grounds) at 20 per cent.
The commission is an intergovernmental agency that works with U.S. officials as well to assess salmon populations. Data it collects from test fisheries is presented to the Fraser River Panel and Department of Fisheries to determine fisheries openings.
Managing fish is a delicate balance between facilitating a commercial fishery and protecting the environment and fish stocks.
In 2015 environmental group Watershed Watch Salmon Society claimed the 2014 run was overfished by 1.4 million and fewer fish spawned than expected.
