We really hate writing about Alexandra Morton, but the things she says about salmon farming are just plain wrong and need to be corrected. We’re sure she is a nice person, and seems very pleasant, but her scientific claims are nonsense. In her latest scaremongering post she makes an error which can only be interpreted as either deliberate — and therefore dishonest — or ignorance — and therefore showing she really knows nothing about what she is talking about.
This post includes a disgusting picture of salmon steaks which she says are infected with kudoa, a parasite which can turn salmon flesh to mush after the salmon dies.
Morton does not say if this fish is farmed or wild. However, her disciples at Salmon are Sacred are quick to make this assumption without checking any facts, and launch yet another shame and guilt campaign aimed at salmon farmers and their customers, at least judging by their “tough” talk on Facebook.
We can see by the upper right corner of this picture that it is a screenshot of a Google Image Search result; the white box with the X appears around an image when you search for it in this way.
So we know she found this picture on the Internet somewhere.
But surprise! It’s not kudoa. It’s labelled Henneguya zschokkei and is a picture of something completely different. Here is the page where it appears in context. It’s all about fish diseases and parasites.
And this page includes an interesting description of Henneguya, a common parasite of wild salmon in B.C.
According to Canadian biologist Dorothy Kieser, protozoan parasite Henneguya salminicola is commonly found in the flesh of salmonids. It has been recorded in the field samples of salmon returning to the Queen Charlotte Islands. The fish responds by walling off the parasitic infection into a number of cysts that contain milky fluid. This fluid is an accumulation of a large number of parasites.
Henneguya and other parasites in the myxosporean group have a complex lifecycle where the salmon is one of two hosts. The fish releases the spores after spawning. In the Henneguya case, the spores enter a second host, most likely an invertebrate, in the spawning stream. When juvenile salmon out-migrate to the Pacific Ocean, the second host releases a stage infective to salmon. The parasite is then carried in the salmon until the next spawning cycle. The myxosporean parasite that causes whirling disease in trout, has a similar lifecycle. However, as opposed to whirling disease, the Henneguya infestation does not appear to cause disease in the host salmon — even heavily infected fish tend to return to spawn successfully.
According to Dr. Kieser, a lot of work on Henneguya salminicola was done by scientists at the Pacific Biological Station in Nanaimo in the mid-1980s, in particular, an overview report which states that “the fish that have the longest fresh water residence time as juveniles have the most noticeable infections. Hence in order of prevalence coho are most infected followed by sockeye, chinook, chum and pink.” As well, the report says that, at the time the studies were conducted, stocks from the middle and upper reaches of large river systems in British Columbia such as Fraser, Skeena, Nass and from mainland coastal streams in the southern half of B.C. “are more likely to have a low prevalence of infection.” The report also states “It should be stressed that Henneguya, economically deleterious though it is, is harmless from the view of public health. It is strictly a fish parasite that cannot live in or affect warm blooded animals, including man”.
Sample of pink salmon infected with Henneguya salminicola, caught off the Queen Charlotte Islands, Western Canada in 2009
According to Klaus Schallie, Molluscan Shellfish Program Specialist with the Canadian Food Inspection Agency, “Henneguya salminicola is found in southern B.C. also and in all species of salmon. I have previously examined smoked chum salmon sides that were riddled with cysts and some sockeye runs in Barkley Sound (southern B.C., west coast of Vancouver Island) are noted for their high incidence of infestation.”
Here’s another picture of Henneguya in wild fish.
And this is a picture of what kudoa actually looks like. This is an affected Atlantic salmon fillet.
There you have it.
So what are we to make of this? Morton writes a long post about how salmon farming is not viable, using kudoa as an example, and posts a picture from Wikipedia which isn’t even kudoa.
It’s either dishonest or ignorant. Either way, people need to fact-check and ground-truth everything Ms. Morton says about salmon farming before they choose to believe her, because clearly she isn’t making enough of an effort to be accurate or factual.
UPDATE 2012-06-27 10:04 a.m.
It appears Ms. Morton has “corrected” the incorrect information on her blog posting, sort of. But the correction itself seems dishonest. There is no simple “oops, I was wrong, here’s the right photo” from her; instead she swapped out the picture with no explanation or corrective text, and had this to say in the comments section.
So let’s get this straight. She posts a link to images from a science paper about kudoa in Japanese sea bream, sea perch, jack mackerel and albacore to justify the error. What does this have to do with farmed salmon? Nothing. She also posts a link to food poisoning in Japan of people who ate raw olive flounder. Again, what does this have to do with farmed salmon? Absolutely nothing.
Finally, the icing on this mushy cake, she swapped out her original picture of a completely different, natural parasite of wild salmon for a picture of kudoa in fish from Australia’s Great Barrier Reef:
What is this? A clownfish? A tang? A parrotfish? A coral trout, perhaps? We have no idea. But this image comes from the Australian Queensland Museum’s page about parasites in fish of the Great Barrier Reef.
Why would she use this?
Because it appears she is fixated on the idea that kudoa causes these visible cysts in fish flesh. Which it can do. In a huge host of wild fish all around the world.
But it DOES NOT DO THIS IN FARMED SALMON. See the picture above. And it does not appear to do this in wild salmon either.
Scientists have been studying kudoa in wild B.C. fish since it was first discovered in hake in Georgia Strait in 1981. In 1989 scientists also studied the heart tissues from more than 1,800 salmon, all wild species, and found kudoa prevalent in their populations.
There is plenty of literature out there about kudoa and how it affects Pacific fish. People have been studying it for decades. All the literature we’ve seen shows that it causes spores in salmon, not cysts, spores that have to be coloured and viewed under a microscope to see them properly.
This doesn’t make for the gross shock value photo Ms. Morton apparently seems to be trying to find.
Ms. Morton’s “bug hunt” is silly, bad science and she continues to make error after error, and tenuous connection after tenuous connection in her crusade against salmon farms. There is no science here; she is using cherry-picked pieces of data and information to attack salmon farming, working backwards from her conclusion which she apparently formed long ago.
We would suggest readers that actually want to learn about fish diseases and parasites go back to the Wikipedia page from where Ms. Morton originally took her image and misidentified it. The page includes some excellent information, and points out that we only know as much as we do about fish diseases and parasites thanks to aquaculture, which allows scientists to observe fish during their entire life cycle:
All fish carry pathogens and parasites. Usually this is at some cost to the fish. If the cost is sufficiently high, then the impacts can be characterised as a disease. However disease in fish is not understood well. What is known about fish disease often relates to aquaria fish, and more recently, to farmed fish.
Parasites in fish are a natural occurrence and common.
Clearly, ignoring the facts, and refusing to admit mistakes and correct them, is part of Ms. Morton’s agenda to scare people about farmed salmon. We recommend people re-read our post about how to recognize a crank as a supplement to this post. By refusing to admit she was wrong, and dogmatically pursuing a single-minded agenda well on the outskirts of science, she certainly seems to fit this definition well.