A recent report in Science examines the trans-Atlantic breeding cycles of tuna. According to the article, industrial fishing has reduced the biomass of the population by 90% (which is absolutely insane), and current regulation haven’t helped much. Part of the problem may be a misunderstanding about the breeding cycles of the fish, leading to ineffective policies. Admittedly, another part of the problem is general overfishing to supply an ever-growing number of people, both of which would be easily solved by cannibalism. But, for now, we’ll focus on the migration patterns.
To determine where varieties of blue tuna are going to spawn, they examined the isotopic content of ear stones called otoliths. The level of carbon and oxygen isotopes in the otoliths can indicate where the fish were spawned, and where they end up. There are two main groups of bluefin tuna which co-mingle in water outside of the US, and it looks like both groups are pretty heavy travelers. The suggestion is that both groups have to be maintained for the tuna population to survive and flourish. It is not unlikley that similar conclusions could be drawn about many other aquatic species.
So think about this during your next tunafish sandwich. That sucker had a radio-active stone in it’s ear that it carried around underwater across the entire Atlantic Ocean, and now it’s in an itty-bitty aluminum can. You’re welcome.
Aren’t you glad that livestock is so much simpler? Can you imagine if we had to throw out nets to catch flocks of chicken when they were passing through? Then we’d have to take out all the robins and squirrels that accidentally got caught and throw them back. It would be no fun to be a chickenfisher.