In terms of fisheries management, sustainability, and health, salmon is superior. It's time to give it a chance.
It is a rare occurrence that a black-and-white choice presents itself in the complicated world of ethical seafood buying. The conscientious diner striving to save depleted cod stocks might choose a farmed tilapia for his fish and chips only to learn that his tilapia may have been grown in China and high doses of antibiotics and toxic antifoulants could have been administered on the farm. A shrimp lover might eschew farmed shrimp because of the damage shrimp farming can do to mangrove forests, only to learn that shrimp caught in the wild often result in significant bycatch of unmarketable fish and sea turtles.
But in spite of all of this noise in the marketplace, there are actually a few very clear choices. One of them presents itself each time we step into a large supermarket. It is a choice made not at the fresh seafood counter or even in the frozen section. It is made in that humdrum aisle where the cans are kept. The choice is there before us: canned salmon or canned tuna? Which is better?
The answer is salmon, hands down, with three quick and easy explanations.
1. We know how many salmon there are and how many we can catch.
Salmon do something that makes managing them relatively easy—they return to spawn in the place where they were born. This means that fisheries managers can, year in and year out, determine how many salmon there are and how many we can take without damaging the long term viability of a given population. True, there are places like far eastern Russia where not-so-careful salmon census-taking occurs, but the majority of canned salmon comes to our supermarkets from Alaska, where careful monitoring is in place and to which the Marine Stewardship Council has issued sustainability certification.
Tuna range far and wide across the oceans. Estimates of tuna population sizes are therefore considerably less exact than those for salmon. In addition, tuna stocks are fished by multiple nations simultaneously, with a significant amount of tuna coming from the no man's land of the High Seas. The management that does exist is centered around politically charged bodies called Regional Fisheries Management Organizations (RFMOs). Catch data provided to these RFMOs from the dozens of nations that fish tuna can be imprecise and hard to obtain. All of this begs the question—if we can't really estimate how many tuna there are and how many tuna are being caught, how can we really know if we are managing them correctly?
2. We know how to catch salmon without significantly hurting the marine environment.
It has taken a while, but we have figured out how to catch salmon in a responsible way that does not do too much harm to other creatures. In the bad old days, canneries would sometimes string nets across the entire width of a river, killing everything that migrated inland. But now salmon fishing is much more selective. Salmon used for canning is generally caught with gear that obstructs only a small portion of salmons' natal rivers. Mesh sizes of nets can be altered on a daily basis to select the particular fish that is coming into the river, allowing other fish to pass through unharmed. Marine mammals do occasionally get ensnared in salmon nets, but the bycatch is nowhere near as bad as it is for tuna fishing, in which longlines hundreds of miles long can catch threatened sea turtles and sharks.