breams in Japan was nearly constant from 1965 to 

 1967, butduring 1968 and 1969 decreased slightly to a 

 level of about 30,000 tons (Japan Fisheries Associa- 

 tion. 1971). 



Research on the farming and artificial propagation 

 of red porgy began in Japan over 70 yr ago but was 

 generally unsuccessful until recent years. In 1958 

 research on artificial propagation was intensified 

 with more modern facilities are equipment and suc- 

 cessful results were obtained on an experimental 

 scale in 1962. By 1965 an experiment in the propaga- 

 tion of red porgy using artificially produced seed- 

 lings succeeded at the Propagation Center in the Se- 

 to Inland Sea. It now appears that a basis has been 

 established for expansion of red porgy farming, but 

 this knowledge has not yet been commercially ap- 

 plied (Fujiya. 1969). 



The Association of Marine Stock FarmoftheSeto 

 Inland Sea was incorporated in 196.'^ to increase the 

 fisheries resources of the Inland Sea of Japan by 

 releasing young marine fishes. In 1958, this Associa- 

 tion produced 166,686 red porgy in a hatchery and 

 released them into the Inland Sea. The effectiveness 

 of these plantings in supplementing natural stocks is 

 now being investigated. The success of this hatchery 

 also portends the expansion of commercial farming 

 of the red porgy. 



According to Fujiya (1969). larvae of the red 

 porgy, 2 to 3 cm in length, are usable as seedlings. 

 They have been grown successfully in floating net 

 cages using fresh fish meat or pellets as food and 

 reach market size in 12 to 18 mo. 



CULTURE OF OTHER MARINE FISHES 



Several other species of marine fishes are being 

 cultured in Japan on an experimental or limited 

 commercial basis. These include amberjack, Seriola 

 purpurescens, and the striped jack, Longirostniin 

 ch'licdtissiniiis. Both of these species can be cultured 

 by using the methods which are so successful with 

 the yellowtail. Teruo Harada of Kinki University is 

 conducting large-scale experiments in the culture of 

 these species at the University facility at Shirahama 

 in Wakayama Prefecture. Commercial culture of 

 these species is especialK attractive because there is 

 a demand at prices considerably higher than those 

 for yellowtail. 



Al the same research facilit\ Harada is studying 

 the artificial culture of many other species of fish 

 including the Japanese parrotfish, Oplciiiuithiis fas- 

 iititiis. and the spotted parrotfish. O. piincidtiis. and 



the flatfish. Paralkhlhys olivuceus. Ptiralichthys is 

 in high demand at a price 4 times as great as for 

 yellowtail, so artificial propagation of this species 

 should be profitable. Harada et al. (1966) described 

 growth and rearing methods for the fry of the floun- 

 der, Paralichthys olivaceus, obtained by artificial 

 fertilization. 



The silver sea bream. Spurns xarbci, is also being 

 studied at the Shirahama field station of Kinki Uni- 

 versity. 



Another marine fish Sehci.sticiis inarniorcitus. 

 known as the scorpionfish is artificially produced in 

 the hatchery of the Association of Marine Stock 

 Farm of the Seto Inland Sea, and 125,536 juveniles 

 were released into the Inland Sea in 1968. Similar 

 releases of sea breams are being made by the Nansei 

 Regional Fisheries Laboratory, many of which are 

 tagged to evaluate the success of these plantings. 



TROUT CULTURE 



Trout have been raised in Japan in fresh water for 

 domestic and export markets for many years and 

 standard rearing methods have been developed. 



Recently, methods have been developed for cul- 

 ture of rainbow trout, Salino iiuirdneri irricleiis. in 

 the marine environment. Three Fishermen's 

 Cooperative Associations in Japan are now rearing 

 trout commercially in the protected waters of coastal 

 bays and estuaries; the most recent a new venture at 

 Ogatsu Bay in Miyagi Prefecture. 



Procedures for marine culture of rainbow trout 

 described by Akimitsu Koganezawa, Chief of Shell- 

 fish and Fish Research for the Miyagi Prefectural 

 Station, are as follows: 



Rainbow trout spawn in December in this part of 

 Japan and are raised in fresh water until the following 

 September or October. At that time they are accli- 

 mated to salt water over a period of 12-20 days by 

 gradually increasing the salinity to that of the marine 

 environment which is about 34"/(iii. Koganezawa has 

 determined that mortality during acclimation can be 

 minimized by increasing the salinity lO'r each day 

 except at the levels of 409^ and SOCf of the salinity of 

 seawater which appear to be more critical. The fish 

 are therefore held at least one extra day at these 

 salinities. 



At the time of transfer to the sea the trout weigh 

 100-150gand are about lK-23cm in length. The trout 

 are harvested the following August at 1 .5-2.0 kg, but 

 some may reach a size of 3.4 kg. 



Maximum survival during the marine phase of this 



118 



