Salmon Confidential: Response from Dr. Gary Marty, British Columbia Fish Pathologist
Blog: Environment, History, Science, Stephen Bocking, Trent University, January 31, 2014
My January 27 post regarding the "Salmon Confidential" film with Alexandra Morton elicited a detailed response from Dr. Gary Marty, fish pathologist at the BC Ministry of Agriculture's AAVDL-accredited veterinary diagnostic laboratory. Dr. Marty appeared several times in the film. His comment raises some important questions regarding the presentation of scientific information in the film.
Comment from Dr. Gary Marty:
I agree that "Alexandra Morton was the star". When I attended public showings, the audience reacted to me as one of the villains. What is frustrating about that for me is that the audience was not given all the information they need to make an informed decision.
I support your idea to "use it in the classroom". I also encourage you to consider including information about how the film takes information that medical specialists use to rule out disease, but instead uses the same information to convince the viewer that the disease is present. I offer two examples:
1) The viewer is led to believe that because the industry veterinarian asked the government diagnostic laboratory to test farm salmon for ISA, the fish have ISA and this information is being hidden from the public. In contrast, when medical experts see that animals with suspicious but nonspecific clinical signs are tested for a virus of concern, and the test results are all negative, they consider this the highest standard for demonstrating that the fish do NOT have the tested virus.
2) The viewer is led to believe that mushy hearts are evidence that wild salmon are dying from a nasty heart virus. In contrast, when medical experts see that the mushy hearts in the video are dark, and scientific papers say that fish with the heart disease of concern (HSMI, or heart and skeletal muscle inflammation) have pale hearts, they consider the dark hearts good evidence that the salmon are NOT affected by HSMI. Medical experts require more information to determine the cause of the mushy heart, which might simply be decomposed more than the firm heart.
Example #1 details: 35:46 - 36:04
Ms. Morton says, "Okay, but look at this one here. Marine Harvest...two days later... specific request for test for ISA...ISA is not supposed to be here, but this company is familiar with...with ISA...is asking for a test. Signed by Gary Marty. And what do you know, Gary Marty?"
At 35:51 - Case 09-3322; not shown very clearly, but detectable using screen capture of the HD version, I know that the test results for "PCR - ISA" are "Result - Negative" (i.e., no virus).
Source: Cohen Exhibit #1549-318, page 254; available here.
Not included on the film, but in a confidential note released during the Cohen Commission hearings, Ms. Morton's veterinarian, Dr. Fred Kibenge, reported to her, "Where RT-PCR testing for ISAV was also performed and the results were negative, this would rule out ISA in those cases." Source: Cohen Exhibit #2086, page 4 of 10, lines 13 and 14; available here.
Example #2 details: 54:48 - 55:22
Ms. Morton says, "And then this really horrible one called piscine reovirus, it...it gives the salmon heart attacks. It weakens the heart muscle, and people I've talked to in Norway don't think a salmon can swim up a river that has this virus."
The image then switches to a cutting board with two salmon hearts.
Ms. Morton continues, "And look at that tissue. Piscine reovirus, one of the symptoms is a soft heart." Pointing to the heart on the left, Ms. Morton continues, "This one is a...very firm". Next, pointing to the slightly darker heart on the right she says, "And this heart is extremely soft. This is a classic symptom of piscine reovirus: the mushy hearts."
Not included in the film, scientists describe the appearance of hearts affected with the disease HSMI as, "Autopsy findings typically include a pale heart..." (Kongtorp et al. 2004); other descriptions include a soft (mushy) heart among the clinical signs of fish with HSMI. [Heart and skeletal muscle inflammation is a European disease of farmed Atlantic salmon that some scientists think is caused by piscine reovirus.] The pale heart is caused by white blood cells infiltrating the heart of fish with HSMI. Therefore, the dark heart in the film is evidence that the heart does not have infiltrating white blood cells and, therefore, the dark heart is medical evidence that the fish did NOT have HSMI.
Also not included in the film are the piscine reovirus test results from the firm heart and the mushy heart; I am not aware that this information has ever been released to the public.
Literature cited: Kongtorp, R.T., Taksdal, T, and A. Lyngøy 2004. Pathology of heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon Salmo salar. Diseases of Aquatic Organisms. 59:217-224.
It takes a remarkable talent to produce a film that uses information that rules out disease to instead convince the public that the diseases are present. However, such tactics do little to advance the conservation of salmon stocks.
Finally, based on the examples I have given, I find it ironic that Ms. Morton uses obfuscation to, as you say, attempt to target "government obfuscation".
Gary D. Marty, D.V.M., Ph.D., Diplomate, A.C.V.P.
Fish Pathologist
Animal Health Centre
BC Ministry of Agriculture
1767 Angus Campbell Rd.
Abbotsford, BC, V3G 2M3
PAA Note: Embedded links in Dr. Marty's response can be accessed on the Blog response.
