Tag Archives: PRV

“Yellow fish” issue in farmed Chinook salmon not linked to PRV, new study shows

Three heavy hitters in BC’s fisheries and aquaculture science community have published a new study after a laboratory challenge of several different species of salmon.

The study investigated the phenomenon of yellow (jaundiced) fish from a Chinook farming operation in Clayoquot Sound; the level of Piscene Reovirus (PRV) in these fish compared to other species; and any disease associated with jaundiced fish and PRV infection.

 

Activists have made much of finding yellow salmon but research shows there's no connection with PRV or a disease only observed in Europe.
Activists have made much of finding yellow salmon but research shows there’s no connection with PRV or a disease only observed in Europe.

In our controlled laboratory exposure study, we demonstrated that PRV persisted in each of the Chinook Salmon, Sockeye Salmon and Atlantic Salmon for 5 months after ip challenge without resulting in microscopic evidence of HSMI or any other disease.

Our study supports the hypothesis that exposure to PRV is not solely responsible for the development of Jaundice Syndrome. It may be possible that the presence of PRV is not contributory towards jaundice in Chinook but rather that its association is merely a reflection of the ubiquitous presence of PRV in wild and farmed salmon species of BC.

The research supports the conclusion that in Pacific waters, PRV is not connected to the Heart and Skeletal Muscular Inflammation (HSMI) disease, and that there is no connection between PRV and the jaundice phenomenon in farmed Chinook salmon.

 

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What’s better than debunking Morton myths? Seeing a real salmon scientist get international recognition!

We were going to write about the contradictions, lies and half-truths which characterized activist Alexandra Morton’s hour-long radio love-in with Ian Jessop on CFAX yesterday.

But we didn’t really want to.

The official seal of the Pseudoscience Labelling Initiative, which may soon be required by law to preface any publication by Alexandra Morton.
The official seal of the Pseudoscience Labelling Initiative, which may soon be required by law to preface any publication by Alexandra Morton.

It’s just too painful to debunk the same points over and over again. We’ve already addressed them many times on this blog, particularly her claim that the ISA virus is in BC (even though she contradicted herself on the show by admitting her results were not confirmed).

We’ve also talked about another point she raised about Piscine Reovirus, which recent research shows has been in wild fish since at least the late 1970s. This physical evidence, of course, makes her claims based on computer modelling that it must have been introduced by salmon farms in the mid-2000s moot.

A great scientist’s career recognized

So we were thrilled to read today that one BC scientist, who has been a cornerstone of fisheries science and who has published hundreds of papers crucial to understanding wild salmon, was recognized by the prestigious International Council for Exploration of the Seas.

Carl Walters
Dr. Carl Walters

Yesterday, UBC’s Dr. Carl Walters was awarded ICES’ Prix D’Excellence, an award recognizing scientists who “have contributed to the sustained use and conservation of marine ecosystems through their research, scientific leadership and/or leadership in the objective application of science to policy. Innovation, teamwork, mentoring, and objective communication with the public exemplify the career of the recipient of this award.”

Congratulations to Carl on this well-deserved award! His work over the past decade has been crucial in helping us better understand wild salmon dynamics, as well as interactions between wild and farmed salmon.

As the press release from ICES states:

“Over his career, Dr. Walters has been the most innovative scientist working in marine ecosystems and fisheries management,” remarked ICES Awards Committee Chair Pierre Petitgas at the awards ceremony during the ASC opening session. “He has also been a well-known advocate for co-operation between scientists and fishermen and has promoted cooperative arrangements between governments and fishing industries to provide improved information for stock assessment and management via methods such as industry-based surveys.”

Here is the full press release from ICES.

 

‘Novel’ virus not so novel, after presence found in steelhead samples from 1977

A “new” virus found in BC farmed and wild salmon isn’t so new after all.

Piscine Reovirus (PRV) has been around since at least 1977, according to a new peer-reviewed paper soon to be published in the Journal of Fish Diseases, with Dr. Gary Marty as lead author.

The study tested 363 preserved samples of fish from 1974-2008, and 916 fresh-frozen samples from 2013.

None of the fish showed signs of Heart and Skeletal Muscle Inflammation (HSMI), which some research done in Europe suggests may be linked to PRV.

In the past several years, PRV has been found in wild and farmed BC salmon. Last year, activist Alexandra Morton used this to launch a lawsuit against Marine Harvest Canada, alleging that the company put “diseased fish” into the ocean.

She quickly followed up the lawsuit by co-authoring a study on PRV and HSMI which suggests the version of the virus in BC diverged from the Norwegian strain in 2007, implying, of course, that somehow salmon farms in BC introduced the virus from Norway.

The study was unfortunately rather poor. Its biggest weakness is the small sample size.

  1. It relies on only 14 samples of fish taken in BC.
  2. It relies on only 10 samples of Atlantic salmon.
  3. All of the samples were taken in 2012.
  4. All of the conclusions about virus divergence are based on computer modelling.

In this study’s conclusion, it states that “Our work suggests PRV entered both Chile and western Canada recently.”

This year’s Marty study shows last year’s PRV study is wrong.

KeplerIn science, if you make a prediction about how something should work, and that prediction fails, your hypothesis was wrong and you start over.

The predictions made by the study co-authored by Morton are wrong, in light of the new Marty study.

Salmon farms did not introduce PRV to BC; it’s been here for decades and since before the first salmon farm was built, and maybe even longer.

One more tidbit: Marty’s study also showed that archived samples of Alaskan salmon carried PRV, too.