https://www.science.org/doi/10.1126/sciadv.adm8713

https://bio.nikkeibp.co.jp/atcl/news/p1/24/05/22/11937/

A research team led by Professor Goro Yoshizaki at the Tokyo University of Marine Science and Technology has  succeeded in laying salmon eggs in rainbow trout using a surrogate broodstock technique that involves transplanting reproductive stem cells between different species. It is based on the observation that when a cell population containing germline stem cells is extracted from a live fish or a recently deceased fish (donor fish) and placed into the abdominal cavity of a host fish, the germline stem cells are not rejected by the immune system and migrate to the gonads, engraft, and mature.

Professor Yoshizaki is aiming for applied research using this technology, such as making mackerel lay bluefin tuna eggs and increasing the number of seedlings. So far, he has succeeded in making rainbow trout give birth to yamame trout and char, and in making Kusafugu give birth to tiger puffer fish.

King salmon are in high demand for food, but the problem with aquaculture is that it takes three to seven years for the parent fish to reach sexual maturity, and they only spawn once. This research might make it possible to repeatedly produce king salmon eggs and sperm using rainbow trout host fish, and to produce seedlings while reducing the cost of raising king salmon broodstock.