to 1 yrold), they are sold to the fishermen for 10 yen 

 each. The growth rates in the area of the Kanagawa 

 Station are as follows: 



The hatchery-reared abalone acquire a green shell 

 coloration which natural populations do not have. 

 This green ""tag" helps to evaluate the government's 

 success in this seed planting program since the color 

 persists throughout the abalone's life. It has been 

 estimated, on preliminary results, that there is a 10% 

 recovery on planted seed (Ryther, 1968). 



In addition to the Prefecture laboratories which 

 are producing seed abalone, there are Regional 

 laboratories (equivalent to Federal laboratories in 

 the United States) which are studying the biology of 

 abalone. One such laboratory is the Tohoku Re- 

 gional Fisheries Research Laboratory located in 

 Shiogama, about 10 miles northeast of Sendai. Sev- 

 eral studies on the growth of abalone are now un- 

 derway. These include studies on the growth of 

 juveniles using different varieties of diatoms and the 

 growth of older forms on different varieties of sea- 

 weeds. 



Shogo Kikuchi. biologists at the Tohoku Labora- 

 tory, is initiating a large-scale study where he will 

 establish an artificial kelp bed in one of the Japanese 

 bays. It is planned to plant the area with 10 million 

 seed abalone. There are many areas in Japan where 

 abalone set but do not grow or survive due to the lack 

 of macroscopic algae. The development of artificial 

 kelp beds may help to solve this problem. Kikuchi 

 plans also to keep a close watch on invading pred- 

 ators and develop control methods if such invasion 

 does take place. 



The only commercial company producing seed 

 abalone in Japan is the Oyster Research Institute. 

 The Institute is located on Mohne Bay near the City 

 of Kesenuma. Under the initial leadership of Takeo 

 Imai, the Institute has become famous throughout 

 the world for some of the basic studies in molluscan 

 aquaculture. Since the untimeK death of Takeo Imai 

 in 1971, Hisashi Kan-no of the Tohoku Laboratory 

 has been .Acting Director. 



The tank farm at the Institute has been described 

 in a number of papers (Imai, 1967: Ryther, 1968: 

 Costlow, 1969). .M the time of my visit, 80^ of the 

 tanks (there are 180 in all) were devoted to abalone 



culture. The remainder contained oyster and scallop 

 seeds. 



At the Institute, abalone are spawned in early 

 September and the larvae are caught on plastic plates 

 (coated with Platymonas and Navicula) similar to 

 those used at the Kanagawa Station. As the juveniles 

 grow, they are removed from the plates, placed in 

 plastic containers wrapped in netting, and resus- 

 pended from the floating tank farm. Twice a week 

 the abalone are fed seaweed such as Ulvci and 

 Laminciria. When they are 20 mm or larger, the 

 Institute sells them to the fishermen for 1 yen/ 

 mm. 



The Institute has a cooperative program with the 

 Sendai Thermal Power Station located near Shio- 

 gama on Matsushima Bay. Young abalone (1 to 

 2 mm in size) are transferred in the fall from the 

 Institute's installation at Mohne Bay to tanks at the 

 Power Station. Using the heated water from the 

 Power Station, the young abalone grow four to five 

 times faster than in the natural environment. When 

 the abalone are 1 cm in size, they are transferred 

 back to the tank farm at Mohne Bay. Lack of sea- 

 weed around the Power Station and costs for collect- 

 ing or buying seaweed are the main reasons for 

 moving them back to Mohne Bay at the 1-cm size. 



Because the preliminary results were so promis- 

 ing, the Power Station had built five new canvas- 

 lined, steel-frame tanks. Each tank, 20 x 1 x Vi m 

 deep, can hold 60,000 seed abalone. Plans are to 

 build up to 50 of these tanks in the next few years 

 with a goal of producing 10 million seed abalone 

 annually. All the equipment, including installation, 

 is being paid for by the power company. 



SCALLOPS 



The sea scallop fishery reached its peak of produc- 

 tion in 1934when80,000metric tons (in shell weight) 

 were harvested. Since then, production has declined 

 and only 6,000 metric tons were produced in 1968 

 (Sanders, 1971). With the increased expansion of 

 off-bottom culture, scallop production has been in- 

 creasing in the past few years. The Japanese esti- 

 mate that 40,000 metric tons would he produced in 

 1972 and possibly 100,000 tons in 1974. 



In Mutsu Bay, the longline method of culturing 

 scallops has been expanding in recent years. Here 

 longlines are used not only for collecting seed but 

 also for growing the scallops to market size. A scal- 

 lop longline differs from those used in oyster culture 

 in that there is a second buoyed line 3 to 8 m below 



109 



