Sushi Surrogates!

Save the Sushi was my original title for this blog post but I didn’t want to mislead anyone into thinking it was about how to store left overs. Sushi’s source is actually the rosy, fatty "chu-toro" from the upper part of the bluefin tuna’s belly. The bluefin tuna is a fish that in the Pacific appears on the red list, meaning threatened with extinction. In the Atlantic the number of bluefin has been recovering rather than declining but still has quotas attached to prevent overfishing. Researchers in Japan, where 60 to 80% of all bluefin tuna are consumed largely in sushi, are attempting to use mackerel as surrogates for bluefin that could be farmed or even released since these bluefin would not be genetically modified. They are stressing that this is not genetic modification and have already succeeded in using surrogate technology to produce tiger puffer fish, the poisonous "fugu" used in sashimi and hotpot, using smaller grass puffer fish. They've also produced trout spawned by salmon, and companies that import rare and tropical fish also are interested in their technology. They do this by extracting reproductive stem cells from the discarded guts of tuna shipped by cold delivery from fish farms and inserting them into mackerel fry so tiny they are barely visible. Under the right conditions, the tuna stem cells migrate into the ovaries and testes of the mackerel, and the mackerel, the researchers hope, when mature, will spawn tuna. So sushi lovers, commercial fishermen, and conservationists take heart. Maybe we can all find common ground with this new technology.