Praise then darkness, and creation unfinished

Japanese researchers have coaxed salmon to lay fertile trout eggs. They injected sperm-producing cells from trout into newly hatched, sterilized male salmon, and 1/3 of the fish grew up to produce trout sperm. Furthermore, when they injected the same male cells into sterilized female salmon, some of them laid trout eggs.

The researchers used the resulting trans-species [my term] trout sperm to fertilize both wild trout eggs and trout eggs laid by the female salmon. All the resulting fish were pure trout.

The next step is to try the process in reverse: inject stem cells from threatened species of salmon into rainbow trout, which are plentiful.

At home in Japan, the goal is to produce bluefin tuna: the lead researcher, Goro Yoshizaki, "has begun experiments on how to produce baby tuna from mackerel,which are nearly a thousand times smaller than adult tuna. If it works,'we can save space, cost and labor.'"