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The Baffled Biologist

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“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.

 

Salmon aquaculture virus study leaves one big unanswered question

A study by Norwegian researchers published late last month is apparently ” the first study confirming the presence of virus-infected escaped farmed Atlantic salmon in a nearby river shortly after escaping.”

The study makes some interesting speculations:

The recapture of the infected escaped salmon in nearby marine sites highlights the potential contribution of escapees in virus transmission to other salmon farms in the area.

…little is known about the effect of viral disease outbreaks in aquaculture on the wild salmonid populations. Disease outbreaks in salmon farms may lead to a substantial increase in infection pressure on wild fish in the surrounding area.

…escaped salmon may disperse over long distances, may enter rivers and may interact with wild conspecifics in their habitats. Therefore, an infected escapee may spread pathogens from the sea to wild fish populations in both sea and rivers distant from a disease outbreak.

That’s interesting, but there’s one big problem, which the researchers acknowledge.

…baseline data from the river regarding these viral infections in salmonids are lacking.

They cannot answer the question: how do the levels of viral loading on farmed salmon escapees compare to the natural viral loads in wild salmon?

As Yoda once said:

ControlToo bad this flaw doesn’t stop their speculation.

This could have been an excellent study if the researchers had taken some time to get data on wild fish in the rivers where escapees were found and sampled. Of course, wild fish sampled from these rivers post-escape would not provide any valuable baseline data, but they could at least provide information about viral loading in wild fish.

And the researchers could have also gotten some control data from other similar rivers where no escapees are found.

But it seems that in the rush to be able to declare this paper the “first” at something, or because it was outside the scope of the finding grant, they decided to sacrifice context in favour of speculation.

At least it does provide some good information about viral loading in escaped farmed salmon in Norway. It will undoubtedly be valuable to the researchers that decide to investigate natural viral loading in wild fish in Norwegian rivers.

More complaining about salmon aquaculture compensation is unmerited

Yet again Blacklocks Reporter resurrected their story about compensation paid out to salmon farmers in Canada last week.

But there isn’t anything new here. They’ve reported this story several times already, but it must have been a slow news day.

Predictably, it again raised the ire of the anti-salmon farming crowd on social media, giving them something to Tweet about on a slow news Monday.

Yes, it’s true salmon farmers in Canada received around $93 million over three years in compensation for being ordered to destroy salmon infected by, or in close proximity to fish infected by, ISA virus and IHN virus.

The market value of those fish, however, would have been at least triple that amount. Nobody made money off compensation; at best, it meant people didn’t have to be laid off because of a massive gap in production. After all, farmed salmon grow for up to two years in the ocean. A chicken takes only eight weeks to grow to harvest, so it’s not nearly as big of a hit if a chicken farmer has to cull a herd.

All farmers get compensation

Compensating farmers for having to destroy their stock is nothing new.

2014-09-30 10_41_06-Livestock Diseases Prevention, Control and Compensation Schemes_ Prevention ...

In 2004, BC chicken farmers received $71 million in compensation for destroying nearly 14 million birds.

From 2002-2010, cattle, sheep and chicken farmers received $115 million in compensation for disease outbreaks, costs covered by the Canadian taxpayer.

Range cattle at risk from BSE? Why not just put them all in bags, then, how dare you expect taxpayers to bail you out.
Range cattle at risk from airborne diseases? Why not just put them all in bags and helmets, then, how dare you expect taxpayers to bail you out.

Yet there’s no moral outrage over that. No calls for chicken farmers to hermetically seal their barns to prevent airborne diseases from entering. No calls for sheep farmers to create massive domes over their pastures with airlocks to keep airborne diseases out. No calls for cattle ranchers to equip each cow with hazmat suits to keep viruses out.

Yet when it involves salmon farms, people think it makes perfect sense to conclude that the solution MUST be moving farms out of the ocean.

It isn’t.

The ocean is the best environment to farm fish. And although farmed fish are more susceptible to viruses because they live in closer proximity to each other than wild fish, they still are generally very healthy. More than 90% of the fish entered into the ocean live up to two years to harvest, and that’s with a minimal use of antibiotics, a pittance to what chicken farmers use to keep their herds alive for just eight weeks.

Missing the point of compensation

Farming is hard work. Farmers do not want the hassle — and costs — that come along with a disease outbreak.

Many farmers are tempted to follow the terrible advice of Canada’s biggest-ever boob of a premier Ralph Klein, who said during the mad cow disease crisis in Alberta that any “self-respecting rancher would have shot, shovelled and shut up.”

Can you imagine what would happen if salmon farmers, faced with a reportable disease diagnosis, just sat on the fish, quickly harvesting them in the hopes that the disease wouldn’t spread too fast? The outrage there would be!

Oh wait, that’s EXACTLY what happened more than a decade ago, before salmon farmers were eligible for compensation, when IHN virus spread all around the BC coast because farmers didn’t immediately cull their fish.

Dozens of companies went out of business. Hundreds of workers lost their jobs.

And although no one’s quantified what potential risk the outbreaks posed to passing wild fish (which carry IHN naturally, that’s where it comes from) it’s certainly never been higher than it was in those three years.

Compensation is intended to encourage farmers of all kinds to act quickly and co-operate with authorities.

“It reduces the time lag between an outbreak and containment actions, and hence diminishes the overall cost of control. “

Disease and disease control is just a part of farming. It’s the price farmers of all animals — and even vegetables — have to pay for grouping creatures and plants close together.

Nature has always been a battlefield of creatures and viruses trying to find their niche. Within the last 10,000 years we have radically altered that balance by developing agriculture.

It’s the price we pay for civilization.

The key is that we do it properly, with as few environmental impacts as possible. Salmon farming has made great strides since it began just 40 years ago towards being one of the most sustainable forms of livestock production on the planet.

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.

 

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.