A press release from the Living Oceans Society offers video and photographic evidence of three species of marine mammals killed in anti-predator nets at a salmon farm in British Columbia. The salmon farm apparently is only required to report dead marine mammals that they shoot themselves, and they further disputed that there ever was a Steller’s sea lion that died in their nets. Living Oceans notes that the video evidence demonstrates that even self-report would be unreliable from these sources.
This is a problem. Management of protected marine species depends upon good information concerning losses in populations, so having unreliable data or incomplete data is in some ways worse than no data at all. At least with no data there is no temptation to rely upon a non-existent number as if it had some meaning for your analysis. Famously, the International Whaling Commission (IWC) accepted as true the log books from Soviet whaling factory ships, when after the Soviet government collapsed it was revealed that the ships kept two sets of log books, one for the IWC showing them taking whales in approved waters and numbers of the correct gender, and the actual log books that reported that the ships were really whaling in waters where whales calved and taking whatever animals came in range.
We know what worked for the US tuna industry, which was the addition of a NMFS observer to crews on tuna ships as an independent check on the veracity of reports concerning bycatch. It also resulted in a chunk of the US tuna industry moving its registration to foreign countries to evade that requirement. (Although the primary reason for the registry shift wasn’t the fact of observers being placed on ships per se, but rather that the NMFS observer pool included females, and the tuna ship crews weren’t having any of that.)
Pretty much any change that really makes a difference to the reporting of marine mammal bycatch in aquaculture — and its reduction — is going to make aquaculture more expensive. The Living Oceans Society is pushing for self-contained aquaculture facilities that will eliminate any interaction with marine mammals. It is obviously easier and cheaper to produce aquaculture when you simply net off an existing chunk of ocean and don’t have any sort of water system of your own to deal with. But at a minimum, government bodies charged with the oversight of marine mammal populations need to take action to assure that they are getting good information about interactions with aquaculture.