https://bio.nikkeibp.co.jp/atcl/news/p1/24/10/02/12442/
Professor Goro Yoshizaki of the Department of Marine Bioresources, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, and his colleagues announced that they have succeeded in making bluefin tuna sperm in spotted mackerel, a fish that matures in a shorter time than bluefin tuna, by using the “surrogate parent fish technique” to transplant reproductive stem cells between different species. If they are successful in producing eggs in the future, it may be possible to use spotted mackerel to produce bluefin tuna seedlings (juvenile fish) in a short period of time.
The surrogate parent fish technique is a fish seedling production technique developed by Professor Yoshizaki and his colleagues. When a cell group containing germline stem cells is extracted from a live fish or a fish that has just died (donor fish) and placed in the abdominal cavity of a host fish, the germline stem cells are not rejected by the immune system and migrate to the gonads, where they take root and mature. This makes it possible to mature the germline stem cells of fish that take a long time to reach sexual maturity or fish that are technically difficult to cultivate in aquaculture in the gonads of fish for which farming techniques have been established, and then cultivate them through surrogate birth.