The Chinese government is locking down neighborhoods again in response to an outbreak in Beijing — 36 cases — and many Chinese seem to believe that the virus is being spread through salmon:

Salmon has been taken off the shelves in supermarkets and grocery delivery platforms across major Chinese cities, while top experts are warning people not to consume the omega-3 rich seafood. The boycott came after the chairman of a major fruit and vegetable market called Xinfadi, the site of nearly 100 newly-detected infections, said that the virus was traced to the chopping board used by a seller of imported salmon.

Zeng Guang, a senior expert with the National Health Commission, said in an interview with state media on Sunday that “we have yet to find out whether human beings transmitted the virus to salmon, or salmon contracted the virus first.” He warned Beijing residents not to eat raw salmon or purchase imported seafood for the time being.

Infrequently cleaned cutting boards are definitely a potential risk for food-borne illnesses, but with the exception of norovirus, those illnesses are more often from bacteria, not viruses — salmonella, E. Coli, listeria. Any time a knife leaves a groove in a cutting board, it creates a spot where bacteria can hide. A regularly cleaned cutting board should be safe . . . but who knows how frequently the cutting boards in Chinese wholesale markets are cleaned?

Back in April, the World Health Organization published a study that concluded that the risk of catching coronavirus from eating a fish was negligible:

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Currently, there is no evidence to suggest that SARS-CoV-2 can infect aquatic food animals (e.g. finfish, crustaceans, molluscs, amphibians) and therefore these animals do not play an epidemiological role in spreading COVID-19 to humans. Aquatic food animals and their products, like any other surface, may potentially become contaminated with SARS-CoV-2, especially when handled by people who are infected with the virus. Nevertheless, with proper food handling and sanitation, the likelihood of contamination of aquatic animals or their products with SARS-CoV-2 should be negligible…

No data are available regarding the survival of the virus on the surfaces of seafood. Nevertheless, with proper food handling and sanitation, the likelihood of contamination of aquatic animals and their products with SARS-CoV-2 should be negligible. Even if fish or fish products become contaminated with droplets from an infected handler, coronaviruses are thermolabile and do not withstand normal cooking temperatures (>70 °C). Hence, these animals and their products are safe to eat as long as they are prepared and served under standard hygiene and food safety measures.

Is it possible that whoever was cutting the salmon at that board transferred the virus to the fish, and that whoever subsequently handled the fish or ate it (perhaps raw?) contracted the virus? Sure. But that person infected with the virus also probably interacted with other people at the market, which is much more likely to spread the virus. The salmon was probably not the transmission vector.