Goro Yoshizaki wants to breed bluefin tuna from mackerel, a technological challenge that Olivia Judson recently blogged about at the New York Times. She writes:
At first, I thought he was joking. After all, it's a bit like saying you want to breed elephants from hamsters. It's not just that tuna are much bigger than mackerel (a fully grown tuna can weigh more than 1,300 pounds (600 kg) and reach more than 13 feet (4 meters) in length, whereas the typical mackerel is a mere snackerel). It's that part of what makes a mackerel a mackerel is that when they mate and reproduce, you get more mackerel -- not sharks, or minnows, or tuna, or anything else. But after hearing him out, he had me persuaded that his plan might just work.
And continues:
Why, why would anyone want to do all this? Yoshizaki's hope is that his work will help relieve fishing pressure on species, like bluefin tuna (Thunnus thynnus), that grow relatively slowly and cannot presently be bred in captivity. One solution -- the obvious one -- would be to stop eating tuna. But this seems unlikely to happen. And since mackerel (Scomber japonicus) are small -- you can keep them in fish tanks -- and fecund -- one female can produce 500,000 eggs in one spawning -- transplanting bluefin tuna spermatogonia into mackerel embryos could be a way to breed lots of bluefin tuna quickly.
All of this is a remarkable testament to modern technology. But should we be messing with the fabric of life (something that, let's face it, we're just beginning to understand) or considering sacrifice? Is the absence of the precautionary principle a baseline that hasn't shifted?