planted and now occur in about 20 lakes. Lake 

 Shikotsu. a large natural lake on Hokkaido, contains 

 a population of kokanee salmon and is the site of a 

 hatchery devoted to the propagation of the species. 

 Because of the low mineral content and consequent 

 low productivity, it is difficult to maintain a satisfac- 

 tory commercial harvest of kokanee salmon in Lake 

 Shikotsu without depleting the spawning population. 

 Officials of the Hokkaido Salmon Hatchery are 

 searching for sources of kokanee salmon eggs with 

 which to supplement their own supply. They have 

 requested eggs from the State of Montana, but to 

 date have not been able to get any. 



1 concluded my visit to Hokkaido by touring the 

 Chitose Hatchery where an extensive expansion 

 project is underway. 1 believe this is the oldest 

 hatchery in Hokkaido. It rears chum salmon and 

 rainbow trout iSalmo iiuinJneri). The capacity of the 

 expanded hatchery will be about 13 million eggs. 



In summary. I was impressed by the sheer volume 

 of salmon released from the hatcheries in Hokkaido. 

 These hatcheries incubate over 500 million eggs per 

 year. The breakdown by species is approximately 

 S59c chum, 10% pink iOncorhynchus gorbuscha), 

 and about 5% masu^O. mason). The chum salmon 

 are fed for 70-90 days and released in early spring. 

 The return after 2 or 3 yr at sea is consistently be- 

 tween 1 and 2%. an excellent return figure by stan- 

 dards achieved at Pacific salmon hatcheries in 

 America. 



On Sunday afternoon of October 24, I visited the 

 Tansui Fish Research Laboratory in Tokyo. 

 Yamakawa and his staff showed me the laboratory 

 and explained their research projects. 



This is a national laboratory devoted to the prob- 

 lems of freshwater fish culture. Their principal work 

 is on the diseases and nutritional problems of eels, 

 ayu. carp, and trout. The principal investigators pres- 

 ent during my visit were: Takeshi Nose who was 

 working on the nutritional requirements of eels, 

 Hiroshi Kawatsu on disease and microbiology of 

 freshwater fishes, Shimadju on ayu culture, and Inui 

 on hepatic diseases of eels. 



I visited the Nikko Branch of the Freshwater Fish 

 Research Laboratory, which is located on Lake 

 Chiizenji in Nikko National Park. The Chief of this 

 laboratory was Yoshikazu Shiraishi, who passed 

 away during his official travel to South America in 

 1972. 



Lake Chuzenji is one of the feu publicly owned 

 bodies of fresh water in Japan where public spoil 

 fishing is permitted. This cold-water lake contains 



populations of the native Japanese salmon, On- 

 c(>rli\)uliii.s mason, or cherry salmon, and various 

 exotic salmonids such as rainbow and brook trout. 

 Scientists at the Nikko Branch of the Freshwater 

 Fish Research Laboratory, are investigating the 

 population dynamics, the fish movements within the 

 lake, the characteristics of various species of sal- 

 monids, including hybrids, and the management of 

 trout in populations in streams. The interests of 

 Yoshikazu Shiraishi and his staff parallel those of 

 management biologists everywhere who are 

 charged with maximizing sport fishing yield in 

 fresh waters. 



COMMERCIAL TROUT FARMS 



Accompanied by Soichiro Shirahata, biologist 

 with the Nikko Branch of the Freshwater Fisheries 

 Research Laboratory, I visited trout farms and fish 

 processing plants in and around Fujinoyama City, 

 Shizuoka Prefecture, on October 25. 



The Shizuoka Prefectural hatchery and laboratory 

 produces 30 million rainbow trout eggs annually. 

 They make extensive use of light to control time of 

 spawning. This management technique makes it 

 possible to provide eggs for their customers over a 

 period of several months. The manager, Matsuura, 

 reported that in one instance they were able to get 

 three spawns in 2 yr from a pond of fish by regulating 

 the photoperiods. 



Matsuura and his staff are faced with a formidable 

 labor problem of removing dead and infertile eggs by 

 manual means. They were quite interested in slides 1 

 showed them of a mechanical egg picker in use at the 

 Dworshak National Fish Hatchery in Idaho. 



A thriving sport fishing business is operated by the 

 Shizuoka Prefectural Hatchery. Some 10.000 fisher- 

 men per year participate in fee fishing in a stream 

 running through the hatchery grounds. As I under- 

 stand it, the provision of sport fishing facilities is a 

 condition of granting a commercial hatchery license 

 in some, if not all, prefectures in Japan. 



Trout farms in Shizuoka Prefecture, and 1 assume 

 they are typical of Japanese trout farms in general, 

 are as modern and efficient as any I have seen. The 

 fish are reared in raceway-type ponds with a high 

 rate of water exchange. The food is pelleted dry 

 food, commercially manufactured. Ihe chemical 

 analysis is very close to that used in the United 

 States and a 1.4 conversion ratio of food into fish 

 tlesh also approximates that achieved at successful 

 hatcheries in the United States. 



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