Of course just like a lots of studies that come out they sure get numbers mixed up. The article says an orca need 670 fish a day.
Then they say there is 87 orcas in 3 pods. So if each whale needs 670 a day that is 241,200 a year or over 20 million for the pod. Something wong here when they say 300,000 chinook head to the Fraser each year. With figures like this no one wonder our stocks are in decline. Bad reporting of a story or maybe I cannot multiply.
VICTORIA — A large share of chinook salmon heading to the B.C.'s Fraser River each summer may have to be earmarked for endangered resident killer whales if the whale population is to recover, a new paper says.
"If the aim on both sides of the border is to not only stop the decline of killer whale populations, but also help increase their numbers, then we have to ensure the salmon they require are there when they need them," said lead author Rob Williams of the University of Washington and University of B.C.
That could mean adjusting fishing plans to include an allocation of chinook for the whales and underlines the need to increase chinook salmon runs, according to the paper, published this week in the online scientific journal PLoS ONE.
"Temporary reductions in fishing quotas may buy some time while salmon spawning habitat is improved to increase salmon returns," Williams wrote.
"An intriguing policy solution would be to give killer whales a salmon catch allocation under the (Pacific Salmon) Treaty. This would be consistent with the spirit of Canada's wild salmon policy, which places conservation needs ahead of fishery allocations."
The study estimates that 87 whales in the three resident pods consume between 12 and 23 per cent of the average 300,000 chinook that head for the Fraser River each summer. Each whale needs about 670 fish a day and 42 per cent more if it is a nursing female.
"Our research indicates that southern resident killer whales easily consume 100,000 chinook each year and, depending on their winter diet, their requirements could easily be double that," said co-author Erin Ashe.
In comparison, the average total catch in fisheries is 18,000.
If the population recovers to 155 animals over the next 28 years — the goal of a U.S. recovery strategy — the whales' need for food would increase by up to 75 per cent, the paper estimates.
Resident killer whales specialize in feeding on chinook, often ignoring other species of salmon. The newly-released Canadian recovery strategy, under the Species At Risk Act, says adequate supplies of prey must be available to the whales.
But one problem facing researchers and fisheries managers is that both resident orcas and chinook are at risk, which means the needs of one species has to be balanced against another.
"When one protected species relies almost exclusively on another protected species, it can be difficult to develop management frameworks that meet the needs of both species," the paper says.
The fear is that the more charismatic species will unfairly trump the prey species, it says.
In 1908, an estimated 690,000 chinook returned and an ecosystem-based approach to fisheries stock assessments and management is needed for the runs to recover, it says.
John Ford, senior research scientist with the federal Fisheries Pacific Biological Station in Nanaimo, B.C., said the efforts to estimate how many chinook are needed by killer whales falls in parallel with work at joint workshops involving the Department of Fisheries and Oceans and the National Oceanic and Atmospheric Administration .
An independent scientific panel is looking at how to balance the needs of whales and chinook salmon, Ford said.
"There is a strong link between chinook abundance and resident killer whale survival," he said.
One of the unanswered questions is what the whales eat in winter, Ford said.
"Is it chinook? We know so little about their whereabouts," he said.
"All these questions are getting a lot of attention now as we look at whether there's a need to modify the human-based harvest."
Victoria Times Colonist
jlavoie@timescolonist.comRead more:
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Topic: Cutting salmon catch could save voracious, endangered orcas: study (Read 3558 times)