New research suggests wild salmon exposed to fish farms have 'much higher' rate of viral infection

Discussion in 'Conservation, Fishery Politics and Management.' started by Whole in the Water, Dec 14, 2017.

  1. Whole in the Water

    Whole in the Water Well-Known Member

    More nails in the net pen fish farming industry coffin. the faster we get these net pens out of the ocean and on to land the better!

    Wild salmon exposed to open-net fish farms are much more likely to be infected with piscine reovirus (PRV) than those that don't have that contact, a new study has concluded.

    The data also show that the virus makes it more difficult for wild salmon to swim upstream to their spawning grounds, which has major implications for the sustainability of the populations.

    "The government has to remove this industry from the key salmon migration routes or we risk the complete loss of wild salmon in this province," said Alexandra Morton, lead author on the report and an outspoken advocate for wild salmon.

    Major implications for Fraser sockeye, chinook
    According to the research, PRV was found to be much more prevalent in the lower Fraser River than the upper Fraser River.

    "This suggests that salmon infected with PRV are less capable of swimming up through strong rapids in places like Hell's Gate and therefore unable to reach their spawning grounds," said co-author Rick Routledge, a professor of statistics at Simon Fraser University.

    The study showed a 37-per-cent rate of infection of wild salmon in the Discovery Islands and 45 per cent in wild salmon in the Broughton Archipelago.

    Both areas have a high density of farming activity.

    Important commercial fish populations run through the area, including Fraser River sockeye and chinook, which are an essential part of the diet of southern resident killer whales.

    The Discovery Islands were the focus of the 2012 Cohen Commission, which concluded that fish farms were likely having a serious impact on Fraser River sockeye, which pass through the area on their journey back to the Fraser.

    "Nobody has looked at this and these fish are collapsing," said Morton who worries that because the disease is believed to have originated in Norway, native species do not have a natural defence against the infection.

    Detected in wild trout
    The disease was found in both wild salmon and trout, such as steelhead, which have also featured dramatic decreases in annual returns in recent years.

    The study examined fish in the Broughton Archipelago, where First Nations have recently occupied fish farms in protest of the practice of open-net farming.

    "The difference between the infection level in wild fish in the north and south was absolutely startling," said Morton.

    Salmon stocks in the Fraser, Skeena and Nass have all seen record low returns in 2017 though scientists point to a number of factors including warming oceans, increasing river temperatures, predation and loss of habitat as contributing factors.

    The research is the first of its kind to conclude that large numbers of B.C's wild salmon are becoming infected with PRV through exposure to fish farms.

    PRV is a disease that causes an acute infection in the red blood cells of the fish, which reduces oxygen levels.

    Industry disputes suggestions of harm
    In Norway, the local strain of the virus has been linked to a deadly salmon disease called Heart and Skeletal Muscle Inflammation, or HSMI.

    HSMI has been documented on a fish farm in this province, but any connection to PRV has yet to be established, and Fisheries and Oceans Canada says the evidence in this country suggests the B.C. version of the virus has a "low ability to cause disease."

    Researchers here have tried exposing Pacific and Atlantic salmon to the B.C. strain of PRV in controlled experiments, but none of the fish have fallen sick or died, according to the federal ministry.

    Those in the fish farming industry say they're not convinced the virus causes any illness in salmon.

    "Our members aren't considering any direction actions on their farms," said Jeremy Dunn, executive director of the B.C. Salmon Farmers Association.

    "This virus is well known to be common amongst farm fish for many years. It is not associated with any sickness with the fish on our farms, and this paper in particular ... hasn't provided any direct evidence that there's any harm being caused."

    Still, the scientists behind the new report worry that long before a fish develops HSMI, the effects of the virus weaken fish to the point they cannot make it back to their spawning grounds, which require swimming long distances upstream

    bigdogeh likes this.
  2. Whole in the Water

    Whole in the Water Well-Known Member

    Here is a link to the actual study:

    Be interesting to see how the pro net pen fish farm industry posters on the forum try to discredit, disprove and deflect yet another piece of peer reviewed research that links net pen fish farms to harming wild salmon and the environment.

    The effect of exposure to farmed salmon on piscine orthoreovirus infection and fitness in wild Pacific salmon in British Columbia, Canada

    Alexandra Morton1*, Richard Routledge2, Stacey Hrushowy3, Molly Kibenge4, Frederick Kibenge4

    1 Raincoast Research Society, Sointula, British Columbia, Canada, 2 Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, British Columbia, Canada, 3 Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada, 4 Department of Pathology and Microbiology,Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island, Canada

    ☯ These authors contributed equally to this work.
    The disease Heart and Skeletal Muscle Inflammation (HSMI) is causing substantial economic losses to the Norwegian salmon farming industry where the causative agent, piscine orthoreovirus (PRV), is reportedly spreading from farmed to wild Atlantic salmon (Salmo salar) with as yet undetermined impacts. To assess if PRV infection is epidemiologically linked between wild and farmed salmon in the eastern Pacific, wild Pacific salmon (Oncorhynchus sp.) from regions designated as high or low exposure to salmon farms and farmed Atlantic salmon reared in British Columbia (BC) were tested for PRV. The proportion of PRV infection in wild fish was related to exposure to salmon farms (p = 0.0097). PRV was detected in: 95% of farmed Atlantic salmon, 37–45% of wild salmon from regions highly exposed to salmon farms and 5% of wild salmon from the regions furthest from salmon farms. The proportion of PRV infection was also significantly lower (p = 0.0008) where wild salmon had been challenged by an arduous return migration into high-elevation spawning habitat. Inter-annual PRV infection declined in both wild and farmed salmon from 2012–2013 (p ≤ 0.002). These results suggest that PRV transfer is occurring from farmed Atlantic salmon to wild Pacific salmon, that infection in farmed salmon may be influencing infection rates in wild salmon, and that this may pose a risk of reduced fitness in wild salmon impacting their survival and reproduction.
    Last edited: Dec 14, 2017
    tincan and bigdogeh like this.
  3. bigdogeh

    bigdogeh Well-Known Member

    Not looking too bright for the open net pen Fish Farming community.
  4. OldBlackDog

    OldBlackDog Well-Known Member


    Eric Taylor is a zoology professor at UBC and chairman of the Committee on the Status of Endangered Wildlife in Canada. Ian Lindsay / Vancouver Sun

    The eight Fraser River sockeye spawning populations now assessed as endangered may never be officially protected by the federal government.

    The Cultus Lake sockeye run was deemed endangered in 2003 by a committee of independent scientists, but has still not been officially added to the list of endangered species under the federal Species at Risk Act (SARA).

    “In practice, most marine fishes that are (commercially) exploited are never listed under SARA, even though many of them are highly endangered,” said Eric Taylor, chairman of the Committee on the Status of Endangered Wildlife in Canada, which advises the federal government.

    That is bad news for the Fraser River sockeye.

    Eight of the 24 distinct sockeye populations that spawn in the Fraser and its tributaries are now regarded as “endangered” by the committee. Two others are “threatened” and five more are of “special concern”.

    But the federal environment minister is under no obligation to protect them.

    If the Fraser sockeye — even just the endangered populations — are officially protected under SARA, it becomes illegal to “kill, harm, harass, capture or take an individual” of the species, which would effectively close all Fraser sockeye fisheries until the populations recover, said Taylor, who is a professor of zoology at the University of B.C.

    The problem is that the spawning populations deemed endangered enter the river mixed with other commercially sustainable runs.

    Federal governments have long exploited a “loophole” in the law that allows the environment minister to avoid officially recognizing species as endangered, by entering an open-ended period of consultation, he said.

    In response to a private member’s bill tabled by South Okanagan-West Kootenay MP Dick Cannings, Environment Minister Catherine McKenna has promised to decide whether or not to list species under SARA within nine months of receiving the committee’s recommendations. They will be officially delivered next October.

    However, in the case of the Fraser sockeye, the answer could well be no, said Taylor.

    “However, just because a species isn’t listed in SARA doesn’t mean good things can’t happen,” he said. “DFO can get involved well before the minister’s decision, and as we saw last year, there was no sockeye fishery at all.”

    According to the committee, Fraser sockeye are being harmed by a combination of rising water temperatures — which exhaust the fish as they swim upstream — the pressure of commercial, recreational and First Nations fisheries, and other environmental factors.

    The eight populations identified by the committee have experienced significant declines in numbers over three or more generations, said Taylor.

    Meanwhile, a local study published this week in the online journal PLOS One found that 95 per cent of farmed salmon purchased in B.C. supermarkets tested positive for the piscine reovirus (PRV).

    According to the authors, PRV was also detected in “37 to 45 per cent of wild salmon from regions highly exposed to salmon farms and five per cent of wild salmon from the regions furthest from salmon farms.”

    The study — co-authored by fish farm opponent and independent biologist Alexandra Morton — concludes “that PRV transfer is occurring from farmed Atlantic salmon to wild Pacific salmon, that infection in farmed salmon may be influencing infection rates in wild salmon, and that this may pose a risk of reduced fitness in wild salmon impacting their survival and reproduction.”

    The committee doesn’t consider the effect of net-pen fish farms a “smoking gun” in the decline of the sockeye.

    “The evidence that fish farms are a major driver is not clear,” said Taylor. “There is something going on in the ocean, but the greatest decline in survival comes after the fish get … past Vancouver Island.”

    Fisheries and Oceans Canada was not able to respond to questions on Thursday.

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