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Author Topic: Lethal virus from European salmon found in wild BC salmon  (Read 244132 times)

alwaysfishn

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #660 on: January 18, 2012, 11:58:21 AM »

Interesting e-mail response that a BC fishing guide recently received from Gary Marty, to an e-mail expressing concern over ISAV. Almost looks like a veiled threat, suggesting if we pursue finding out the truth about ISAV, then they will shut down all sport fishing in BC??



Brian Silversides Fishing McKinlay

Dear Brian,

Thanks for sharing your thoughts. I admire your passion for wild fish.

When the Pacific herring population in Prince William Sound, Alaska, crashed in 1993 and did not recover, I was called to conduct a comprehensive study to determine the role of disease in limiting recovery. I concluded that a parasite (Ichthyophonus hoferi) and a OIE-reportable virus (VHSV) were limiting recovery (Marty et al. 2010).

The commercial herring fishery there has been closed since 1998.

Consider this scenario:

    1) ISAV is confirmed in BC

    2) Therefore, to protect our stocks all first nations, sport, and commercial salmon fishing must be prohibited indefinitely.

QUESTION: Given this potential result, are you still convinced that ISAV has been confirmed in BC?

Sincerely,
Gary
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absolon

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #661 on: January 18, 2012, 03:41:00 PM »

Could you also post the email the guide sent? I'm curious what question would get that answer.
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Bassonator

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #662 on: January 18, 2012, 03:49:34 PM »

Must be grasping at straws now.... ;D
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alwaysfishn

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #664 on: January 18, 2012, 05:33:11 PM »

That wasn't research or science you posted, and I not only disagree with it, I've proved it to be the BS that it is.

Could you also post the email the guide sent? I'm curious what question would get that answer.

.....  yah, I'll get right on that.....   ???  ::)

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absolon

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #665 on: January 18, 2012, 06:01:30 PM »

Thanks
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Sandman

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #666 on: January 18, 2012, 06:03:32 PM »

Yours is an interesting variation on the scientific method where a hypothesis that explains an observed phenomena is developed and then tested. You start with a hypothetical phenomena, construct a hypothetical set of facts, massage them into a semi-plausible scenario that might allow the phenomena to occur and declare your conclusion proved. You'll forgive me if I see little point in arguing the validity of your conclusion.

I am not using the scientific method at all.  I was not positing an experiment nor was I stating a conclusion. I simply asked if the "semi-plausible" scenario was not possible?  If it is possible, it seems like a pretty serious risk to the fish swimming past the pens.  I would love a biologist to test that hypothesis to see if it can happen.  I am sure they would use the scientific method in doing so.
 
You still haven't explained why you felt it necessary to add that incomplete citation in a venue where you specifically state it isn't necessary.

You had asked me to cite my sources, but you had also stated it was the reader's responsibility to find the information themselves.  I was trying to make you happy.  My mistake.

The farmers have never suggested the commercial fishery be shut down, so obviously don't have any arguments on the subject. That was my suggestion and your response . . . is a pointless personal comment addressed to me, indicative of the personal animosity you bring to the discussion.

My comment WAS directed at you.  My comment about the farmers you support was that your suggestion would play into their arguments for why they are a necessity in meeting today's demands for salmon.  Furthermore, please re-read my comments towards you and your comments toward me and another member of the discussion and tell me who brings "personal animosity" to the discussion.  I have been nothing, if not polite and respectful toward you, personally, while I may disagree vehemently with your arguments.
« Last Edit: January 20, 2012, 04:10:16 PM by Sandman »
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absolon

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #667 on: January 18, 2012, 06:33:09 PM »

.....  yah, I'll get right on that.....   ???  ::)



Actually, no need to bother now.

Apparently there was a second email from Dr.Marty in response to someone questioning his first; I found it at the same place you found the first, posted by the same person. It does give some indication of what prompted the answer. Apparently it was a response to the suggestion that the farm industry should be shut down because they might spread a virus. Here is the body of the email as posted:

Thanks for sharing my thoughts with “tens of thousands of sportfishermen” in their exact context. Informed dialogue is very helpful. If aquaculture facilities are being asked to shut down their operations because they might spread a virus, then it is only prudent that any other activities that might spread the virus must also be shut down. To be clear, I was only offering a scenario, not a recommendation. Because of these potential implications, however, I hope that you will agree with me that we need to be very sure that ISAV positive PCR tests are confirmed, and we need to be very sure about whether what is being found is minor or major.



My next question to consider:



“On what basis are you concerned about ISAV in Pacific salmon?”



Here is the information that I use:



1. The first word of the title of Molly Kibenge’s draft manuscript regarding her ISAV PCR findings in BC Pacific salmon is “Asymptomatic” (= no disease). [Cohen Exhibit #]. It is quite common for fish (and people) to have virus but not have a disease.

2. When Dr. Kristi Miller reported ISAV positive PCR results in farmed Chinook salmon, she made it very clear that “There's no indication that it's causing disease” [December 15 Cohen transcripts, p. 53, lines 9 - 16]. I am the histopathologist that examined samples from the fish tested by Dr. Miller on the Creative salmon case, and I agree with Dr. Miller [see Cohen Exhibit # 2078]

3. Dr. Fred Kibenge isolated an eastern Canadian strain of ISAV from farmed coho salmon in Chile in 1999 (Kibenge et al. 2001), but the fish did not have clinical signs characteristic of ISA, and ISAV was not confirmed in the affected tissues; instead, the fish had a disease characterized by jaundice that continues to occur in Chile without any evidence of ISAV (Smith et al. 2006), supporting Dr. Kibenge’s conclusion that his ISAV findings in 1999 “might have been coincidental” (Cohen Exhibit #2086). The eastern Canadian strain of ISAV was never again found in Chile.

4. When Pacific salmon species were exposed to one of two strains of ISAV during controlled laboratory experiments, “No signs typical of ISA and no ISAV-related mortality occurred among any of the groups of Oncorhynchus spp. in either experiment (Rolland & Winton 2003).”

5. In 2008, the European strain of ISAV was widespread among farmed Atlantic salmon in Chile. Annual production of farmed coho salmon in Chile is greater than annual production of all species of farm salmon in BC. None of the Chilean coho salmon contracted ISA [December 19 Cohen transcripts, p. 53, lines 30 - 41].



The evidence in the peer-reviewed scientific literature and the Cohen Commission proceedings supports the conclusion that known and suspect strains of ISAV are not a major threat to wild Pacific salmon.



ISA is an Atlantic salmon disease, not a Pacific salmon disease. I remain confident that we do not have imported strains of ISAV in either our farmed Atlantic salmon or farmed/wild Pacific salmon. I am awaiting confirmatory evidence regarding some preliminary evidence that a native ISAV-like virus occurs in BC.



When VHSV (it causes a different OIE-reportable disease) was first isolated from hatcheries in the State of Washington in 1989, people were very concerned that it might be an imported strain. Today, however, we know that the 1989 finding was actually a native strain that is not a great concern to Pacific salmon species.



Sincerely,



Gary

-------------------------------------------------------------
Gary D. Marty, Fish Pathologist
Animal Health Centre
Ministry of Agriculture
1767 Angus Campbell Rd.
Abbotsford, BC, V3G 2M3
604-556-3123



Literature cited:

Kibenge FSB, Garate ON, Johnson G, Arriagada R, Kibenge MJT, Wadowska D (2001) Isolation and identification of infectious salmon anaemia virus (ISAV) from Coho salmon in Chile. Dis. Aquat. Org. 45:9-18



Rolland JB, Winton JR (2003) Relative resistance of Pacific salmon to infectious salmon anaemia virus. J. Fish Dis. 26:511-520



Smith PA, Larenas J, Contreras J, Cassigoli J, Venegas C, Rojas ME, Guajardo A, Perez S, Diaz S (2006) Infectious haemolytic anaemia causes jaundice outbreaks in seawater-cultured coho salmon, Oncorhynchus kisutch (Walbaum), in Chile. J. Fish Dis. 29:709-715
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alwaysfishn

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #668 on: January 18, 2012, 07:11:00 PM »

Thanks

Now that is the most respectful, understandable and well written contribution you've made to this thread!  ;D

Didn't know you had it in you...  :o
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absolon

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #670 on: January 18, 2012, 11:41:56 PM »

Now that is the most respectful, understandable and well written contribution you've made to this thread!  ;D

Didn't know you had it in you...  :o

Probably the first one you completely understood too  ;)
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chris gadsden

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #671 on: January 19, 2012, 08:21:32 AM »

absolon

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #673 on: January 20, 2012, 01:40:29 PM »

With thanks to Ironnoggin who posted this elsewhere............

Here are some further responses from Dr. Gary Marty with respect to that email conversation that AF posted but a small piece of. It makes for some interesting reading and certainly refutes some of the ideas that have been proposed by a few here in this thread:

"Here are some thoughts on the questions in your e-mail:

Are you trying to say that ISAv cannot mutate and affect our wild salmon?

Nearly all viruses can mutate, and some of those mutations are more pathogenic than others, but I am not aware of any scientific research that demonstrates the number or type of mutations that would be required for ISAV (an Atlantic salmon disease) to kill Pacific salmon. If you are aware of such scientific research, please send me the citation.

More important than the basic potential for mutation is the risk that such a mutation of sufficient magnitude to affect wild salmon might actually occur. Based on 25 years of empirical evidence, I rate the risk negligible. Infectious salmon anaemia has been known as a disease of farmed Atlantic salmon in Norway since the mid-1980s, but despite ongoing outbreaks among the farmed salmon ISAV has never been associated with a die-off of wild Atlantic salmon. In 2011 farm salmon production in Norway for the first time exceeded 1 million tonnes (about 12 times BC farm salmon production), and ISAV does not seem to be significantly limiting their production under much greater concentration of fish than we have in BC. If under these conditions ISAV does not affect wild Atlantic salmon, the risk is significantly less to wild Pacific salmon.

To get an better understanding of the potential risk of ISAV to wild salmon, we can look even broader at a related virus, avian influenza virus. Whenever we sample wild ducks in Canada, it is quite common to find 10 - 20% PCR positive for avian influenza virus (see p. 14 of “CCWHC Annual Report 2010 - 2011 (EN)”at http://www.ccwhc.ca/annual_reports.php). Occasionally one of these strains gets into our farmed chicken population, mutates, and causes devastating losses for the industry (e.g., 2004 in the Fraser Valley). Because avian influenza has the potential to mutate and infect people, the CFIA response to specific strains of avian influenza in poultry is rapid and vigorous (i.e., kill all potentially exposed birds).

Despite avian influenza (the virus) being common in wild ducks, outbreaks of avian influenza (the disease) in wild birds are rare. Indeed, most PCR positive test results in wild bird surveys come from healthy birds. I asked our poultry extension veterinarian (Dr. Bill Cox) ,our avian pathologist (Dr. Vicki Bose), and our veterinary virologist (Dr. John Robinson) if they knew of any populations of wild birds that had gone extinct as a result of an avian influenza outbreak; they could not think of any cases. A probable reason for this is that wild birds are more widely dispersed than farmed birds, thereby decreasing the chances for disease transfer. The same can be said for wild salmon compared with farmed salmon.

Chickens are not native to BC (they are native to Asia), their farms displace habitat that once was used by other wildlife, and yet we do not call on poultry farmers to remove them from land (e.g., to rear them in sealed underwater marine pens where they will have no contact with surface freshwater ducks).

The relevance of all this to wild salmon is that even a mutated form of a virus is unlikely to affect wild salmon populations because wild salmon spend most of their lives dispersed more widely than farmed salmon. This makes transmission of any virus difficult. In contrast, a mutated virus is more likely to affect farmed salmon. We have more than 30 million farmed salmon in BC marine waters at any given time--all monitored daily by farm staff--yet we have no evidence of a massive disease outbreak since the IHNV outbreaks of 2002/2003. As with poultry, I am confident that the biosecurity measures used by farms to protect their fish against an outbreak of IHNV will also serve to protect farm fish and wild fish from spreading outbreaks of other diseases like ISAV.

What benefit besides purely financial there is to raising these fish in waters that are normally only inhabited by pacific salmon?

In many ways, BC is an ideal place for rearing Atlantic salmon on farms. Atlantic salmon are not able to compete with Pacific salmon populations. Therefore, fish that escape from farms are easily identified, they do not interbreed with wild Pacific salmon, and despite years of concerted stocking efforts by DFO in the 1900s, Atlantic salmon have not established populations in BC rivers. Also, none of our common domestic livestock are native to BC: cattle (Europe), sheep (Europe and Asia), pigs (Middle East), turkeys (NE U.S.A, and Mexico), or goats (Iran, Scandinavia). I do not see the risk of farm fish to wild fish any differently than the risk of terrestrial livestock to wild life: a negligible risk that can be reasonably managed.

Moving farm animals around the world is nothing new or unusual. We have protocols in place to minimize the risk of disease transfer with these movements, to the point that now the OIE considers the movement of animal goods as a significant risk: “People and goods now travel long distances in a very short time, thus creating enormous challenges that demand efficiency and speed of response on the part of both public health and veterinary authorities.” [see OIE, http://www.oie.int/current-issues/ “Notification of animal and human diseases: Global legal basis”]

My “thought question” for the day: If fish farms need to be removed because of the risk of ISAV, should we also prohibit people coming to BC from around the world, catching fish infected with ISAV, then traveling back home with those infected tissues?

[background: Dr. Kristi Miller reported to the Cohen Commission (Dec. 15, 2011 transcript, pages 35, 36, and 52) that she has found ISAV in most salmon populations that she has tested, including sockeye salmon dating back as far as 1986. In most groups she has tested 13 - 20% are positive for ISAV.]

Sincerely,
Gary"


and:

"Thank you. You might not know that I have more scientific publications about the health of wild Pacific salmon than I do on farmed Atlantic salmon (my cv is Cohen Exhibit #1659). I have proposed a study plan that would help us understand the role of health and disease in Fraser River Sockeye salmon (Cohen public submission 818). And, I recently signed on as the histopathologist for the project with similar goals designed by David Welch; this study focuses specifically on the impact of salmon farms (Cohen Public submission #1127); Dr. Kristi Miller is a co-investigator on that proposal. Dr. Miller and I scrutinize each others’ work, as good scientists should, but in my view good scrutiny serves to improve our science. Dr. Miller’s research so far suggests the presence of an ISAV-like virus that is different enough from European strains of ISAV that we can be confident that it was not imported (with either farm fish since the 1980s or stocking attempts before that). However, Dr. Miller still has lots of work to do to confirm her findings."

I admire your wiliness to learn more. I am currently examining wild juvenile salmon captured as part of the BAMP program in the Broughton Archipelago (see http://bamp.ca/pages/home.html). The Animal Health Centre is interested in ensuring healthy animals in BC, including wild salmon. I need to spend most of my time in the laboratory, so I depend on observations by people like you who are out in the field. Sampling tissues for histopathology is probably the best way to get an idea of what is going on in the fish you described. If you are in Campbell River, I recommend that you contact Dr. Sonja Saksida at the Centre for Aquatic Health Sciences (http://www.cahs-bc.ca/) for assistance in tissue preservation and shipping. Your cost is the same as what we charge the fish farms: $30/fish for diagnostic histopathology.

Dr. Saksida and I are coauthors on a paper that came out last week that identifies liver cell abnormalities as a possible cause of the lowest pink salmon runs on record in the Broughton Archipelago (in 2008).

I am working with DFO to get a second fish pathologist in BC. I keep too busy assisting the fish farms with diagnosing disease and certifying fish as disease-free (with ~40 million fish, a few a bound to be sick; but, surprisingly to many people, most of the farm fish are very healthy), so I do not have the time I need to work on wild fish projects. Any assistance you can provide would help.




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Dave

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Re: Lethal virus from European salmon found in wild BC salmon
« Reply #674 on: January 20, 2012, 03:26:36 PM »

 ;)
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