Using the adults of 3 or 4 years of age of black porgy which were cultured extensively in the brackish-water fishponds, some trials were made in the artificial inducement of spawning of the fish. Female fish were mated with males in small concrete tanks after intramuscular injections of saline solution of "Synahorin" (mammalian gonadotropin preparation), and the results obtained were as follows.
1) Development of the ovaries of every semimature female recipient fish was evidently hastened by injections prior to the spawning season or early in that.
2) Then, two out of three females of 4 years of age successfully spawned after 62 RU in total dosage was respectively given by means of injecting in four doses during about one month, while partial spawning occurred in only one out of four females of 3 years with the above and additional injections.
3) In the spawning season, as the results of injections of respective dosage of 20 RU (once) or 40 RU (twice) into many females which were ripening but had not yet spawned, some of them mostly in females of 4 years of age could be induced to spawn.