An Unknown Condition Found on Atlantic Salmon Parr

Observation by Donna Carroll:

I have caught multiple Atlantic salmon parr with round, jelly-like matter on the fish that also appeared to have pinpoint, blood-like markings dotted in the centre of these jelly-like substances. The Atlantic salmon parr that hosted these jelly-like substances appeared to be healthy, with normal gill and eye conditions, their length-to-weight ratio was comparable to that of unaffected parr, and their behaviour appeared unchanged. To date, no variations in stages of this condition has been observed. The Shinney’s Brook habitat conditions and water properties are monitored and are comparable to other tributaries within the region. This is the only river that I have seen this condition on the fish, and on multiple occasions, throughout my annual electrofishing surveys in the last eight years in NunatuKavut, Labrador.

LEO Says:

We have shared this observation with our friends at the Alaska Department of Fish and Game, Fish Pathology Laboratory. They have a lot of experience evaluating disease in salmon, from images and observer descriptions.

Consult by Jayde Ferguson:

After consulting with Ted Meyers and colleagues in Europe, Atlantic salmon papillomatosis is the best presumptive diagnosis that we could come up with. Arni (Kristmundson) attached a few photos to show the similarity. Hopefully the folks in Labrador can test a sample to confirm. Regarding diagnostic work on this disease, one recommendation would be to work with a diagnostic lab that could run the histopathology and sequence the herpesvirus for confirmation. There is a veterinary diagnostic lab in eastern Canada at UPEI in Charlottetown PEI https://diagnosticservices.avc.upei.ca/. There is also a good one on the west coast of the USA in Pullman, WA called WADDL: https://waddl.vetmed.wsu.edu/

LEO Says:

Thank you to Jayde, Ted and Arni Kristmundson, Head of Fish Pathology at the University of Iceland. LEO Network appreciates your help on this consultation. Please note: according to the State of Maine guide on Fish Health (attached, p.38), fish with Atlantic Salmon Papillomatosis are safe to eat.

Follow up from Donna Carroll:

This is a great thread! I was speaking with my DFO (Fisheries and Oceans Canada) contact again on Tuesday about this and we believe that because our electrofishing permit only runs until September 15th, we're not able to find other stages of the disease on the Atlantic salmon parr. We think that the disease progresses and causes fatalities, which is why we've not seen any other stage than the jelly-like substance with pin-point blood marks. I'm planning to go back this coming summer and collect some samples. We're currently challenged with finding someone that can guide us in the appropriate sampling protocol for this and also providing analysis for us, but we're putting out feelers and are reaching out to folks.Thank you for following up on this - it is very much appreciated!