Tag Archives: goodscience

“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.

 

Why does farmed salmon flesh sometimes go soft? Study offers new insights

Kudoa in Atlantic salmon fillet
Soft and separated flesh in a salmon fillet caused by Kudoa

When customers open a box of fresh, farmed salmon only to find the flesh has gone soft after being in storage for a few days, that’s a huge problem for both the customer and the seller.  No one wants that to happen.

Most of the fish produced in BC is premium quality.  But sometimes soft flesh problems arise.

BC salmon farmers have worked for years to prevent this from happening — after all, premium quality fish command premium quality prices.

Years of research have pinpointed one common culprit behind soft flesh: a fish parasite known as kudoa, which sometimes affects BC farmed salmon but has also affected wild-caught BC fish used in fish sticks and surimi for 40 years.

But sometimes soft flesh in farmed salmon happens without the presence of kudoa, and a 2014 study brings us closer to understanding why.

The study’s findings suggest that soft flesh is linked to how much glycogen (stored sugar) the fish has in its cells:

“We report for the first time an association between soft flesh of Atlantic salmon and massive intracellular glycogen accumulation coinciding with swollen and degenerated mitochondria, myocyte detachment and altered extracellular matrix protein distribution. The results are important for further understanding the etiology of soft salmon.”

The study authors caution that they are not sure if the accumulation of glycogen is a symptom or cause of soft flesh, but the new findings will definitely help researchers better understand what is happening with soft salmon flesh and get closer to finding a solution.

Risk assessment of Norwegian salmon farming offers some surprising points

Every year since 2011, the Norwegian Institute of Marine Research has published a risk assessment for ocean salmon farming in Norway.

The results, most recently published in July 2014, offer up some points that might surprise die-hard salmon farming critics.

The most concerning risks in Norway, according to the research, are:

  • Wild Atlantic salmon face a moderate to high risk for “genetic introgression” (cross-breeding) from escaped farmed Atlantic salmon.
  • About 27 of 109 farms investigated for sea lice infection indicate moderate to high risk of likelihood for passing wild salmon smolts, and 67 farms indicated moderate to high risk of mortality from sea lice for wild sea trout.

The interesting results are in what doesn’t appear to be a concern:

Despite “extensive release of virus in many areas,” screening of wild salmonids showed low to very low presence of the same viruses.

  • Only 2% of all farms displayed unacceptable levels of “organic loading” (fish poop and feed) below the farms; therefore the “risk of eutrophication and organic load beyond the production area of the farm is considered low.
  • It’s interesting that, in Norway at least, the two points that salmon farm critics seize on the most — viruses and fish poop — are of least concern.

It’s debatable how meaningful it would be to extrapolate these findings to BC, but they raise some interesting points. Here in BC, where we have strong populations of wild salmon, which are unable to interbreed with farmed Atlantic salmon, the issue of “genetic introgression” is moot.

More than a decade of sea lice research has also shown that sea lice from salmon farms are unlikely to have any measurable impact on wild salmon, as experts at the Cohen Commission agreed.

Also, as BC experts said, the risk to wild salmon from farm diseases might be possible, but is also probably low.

‘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.

Yes, the CFIA CAN detect ISA virus HPR0

One of the favourite claims in Alexandra Morton and friends’ narrative about the ISA virus in farmed salmon is that the CFIA can’t detect it.

Another one of their favourite claims is that the strain of ISA virus that doesn’t cause disease, HPR0, is elusive and hard to detect and so therefore it must be in the Pacific somewhere.

Neither are true.

The CFIA has no trouble detecting all known variants of ISA virus, and just recently confirmed (this word is important) HPR0 in New Brunswick.

 

 

They test wild and farmed fish in BC too, so if it was actually here, you’d certainly be hearing about it.

 

 

Consortium plans to turn carbon dioxide emissions into aquaculture feed

Carbon dioxide emissions from oil refineries in Mongstad will be used to grow algae for fish feed
Carbon dioxide emissions from oil refineries in Mongstad will be used to grow algae for fish feed

By next year, a prototype facility should be operating in Norway which will use carbon dioxide from oil refineries to grow algae for fish feed.

The facility will be built by the CO2BIO consortium of companies, which includes feed manufacturers, salmon farmers, universities and investors.

The Norwegian government has also committed funds to the project.

Algae is a growing source of protein for fish feed manufacturers, who have drastically reduced the amount of protein from wild fisheries in their feed diets during the past decade.

Algae growing in pipes fed by carbon dioxide.
Algae growing in pipes fed by carbon dioxide.

NEWS SOURCE: Undercurrent News