the western region. The whole coastline of the 

 Pacific region, except in the area of Tsugaru Strait, 

 where wide, rocky shores are found, is made up of 

 simple, sandy beaches. The fundamental water sys- 

 tem of this region consists of two warm currents, the 

 Kuroshio and the Tsugaru, and one cold current, the 

 Oyashio. In the western region, the warm Tsugaru 

 Current and the cold Oyashio Current interchange 

 alternatively by seasons; therefore, the oceano- 

 graphic conditions of this region are quite variable. 

 On the other hand, in the eastern region, the coastal 

 area is affected entirely by the cold Oyashio Current 

 throughout the entire year. Dense sea fogs often 

 occur during the summer (June to August), espe- 

 cially in the eastern part. There are. on the average, 

 58 foggy days per year. 



between Hokkaido and Kunashiri Island is called 

 the Nemuro Strait. This region is characterized by 

 many large and small brackish lakes along the coast. 

 The warm Soya Current (a branch of the Tsushima 

 Current) flows southward along the Okhotsk Sea 

 coast and a cold East Sakhalin Current runs along 

 the outside and parallel with the Soya Current. Con- 

 siderable freezing of seawater, especially in lakes 

 and inlets, and drifting ice occur from December to 

 April in this region. Because of these icy conditions, 

 fishing activities as well as maintaining artificial 

 equipment for marine cultivation are greatly re- 

 stricted during this period. 



PRESENT STATUS OF THE PRODUCTIVITY 

 OF IMPORTANT MARINE ORGANISMS 



Okhotsk Sea Region 



The Okhotsk Sea coast can be divided into two 

 regions by the Shiretoko Peninsula: The northern 

 region is characterized by a flat sandy beach; in the 

 southern region, a big embayment is formed between 

 the Shiretoko Peninsula and the Nemuro Peninsula. 

 In addition, some of the Kurile Islands are located in 

 the entrance of this embayment. The channel lying 



The major species which are artificially cultivated 

 and propagated in Hokkaido are restricted in num- 

 bers because of environmental conditions of this 

 region. Almost all are northern forms which have 

 their major distributional range in Hokkaido (Table 

 1). Recently, the cultivation of fishes and other 

 marine organisms has become of major interest in 

 Hokkaido, and it has become necessary to establish 

 seed production systems for some of the most impor- 



Table 1. — Catch statistics for main fishing species as the subject of the cultivation and propagation in 

 Hokkaido in 1969, and show it related percent to the total Japanese landings. 



