THE RESOURCES 15 



the following season. After 1965 the stocks collapsed dra- 

 matically, and the reduction fishery was closed 

 indefinitely in 1968. 



A minor fishery for local food and bait herring contin- 

 ued after the 1968 closure, but in the early 1970s, as the 

 stocks began to recover and a market for herring roe 

 opened up in Japan, heavy industrial exploitation of her- 

 ring resumed. 



The roe-herring fishery has since been a major but 

 unstable industry, with landings in excess of 80 thousand 

 short tons in 1976 and 1977. Catches have been much 

 lower since then; landings amounted to 34 thousand 

 short tons in 1981, and some 28 thousand tons in 1982. 

 Lesser fisheries for food and bait herring continue, with 

 landings of food fish around 10 thousand tons in recent 

 years and landings of bait around 1 to 2 thousand tons. 



Trends in Stocks 



Data on herring have been gathered since the 1930s, 

 and it has been possible to observe the response of the 

 stocks to a wide range of exploitation rates. As a result, 

 the west coast herring fishery is well documented for pur- 

 poses of biological assessment. 



Analysis of the historical evidence indicates that the 

 peak catches of the early 1960s followed recruitment of 

 several unusually strong year-classes; then in subsequent 

 years exceptionally weak recruitment coincided with very 

 heavy fishing pressure until the stocks collapsed. Stronger 

 year-classes began to appear by 1971 and within four 

 years most stocks recovered to the level of the 1950s. 

 Subsequently, except for a strong recruitment in 1977-78, 

 recruitment has apparently been weak, especially in 

 northern areas. 



The rise and subsequent sharp decline in production 

 follows a classical pattern observed in many exploited 

 fisheries. But the recent recovery in these stocks is 

 remarkable. 



Potential Yields 



Estimates indicate that by 1975 the herring stocks in 

 the Strait of Georgia had recovered to nearly the opti- 

 mum level for long-term yields, and the spawning stocks 

 on the west coast of Vancouver Island and the Queen 

 Charlotte Islands may even exceed this level. Recent 

 recruitment to the stocks off the west coast of Vancouver 

 Island has been weak, apparently the result of normal 

 fluctuations. Experience suggests that refraining from 

 heavy fishing on these weaker year-classes will be neces- 

 sary if the kind of collapse that occurred in the reduction 

 fishery is to be avoided. On the north coast, stocks are 

 well below the optimum size, and there are some indica- 

 tions that ecological changes may have reduced produc- 

 tivity in that region in recent years. 



Biologists now believe that the optimum rate of herring 

 exploitation is in the range of 30 to 50 percent of the 

 stock per year, and suggest that the stocks should be 

 managed and exploited conservatively with harvests not 

 exceeding 30 percent. On this basis, the average annual 

 catch of herring could be as high as 160 thousand metric 

 tons for the whole coast, though with significant year-to- 

 year variations. However, in order to achieve this poten- 

 tial, resource data and regulation of the fishery will have 

 to improve substantially, as I explain in Chapter 4. 



HALIBUT 



The halibut fishery is among the oldest on the Pacific 

 coast; and, until it was recently overtaken by the roe- 

 herring fishery, it was second in importance to salmon. 

 The fishery began in the last century off the coast of the 

 State of Washington, and significant Canadian participa- 

 tion began during the first World War. 



Native Indians and early commercial fishermen 

 enjoyed a rich harvest from extensive stocks that con- 

 tained a high proportion of large, mature fish. The land- 

 ings of Canadian and U.S. fishermen peaked in the 1920s 

 at some 70 million pounds, then dechned to about 30 

 million in the early 1930s. 



Recognizing the need for joint action to preserve and 

 develop the fishery, Canada and the United States cre- 

 ated an mternational commission for this purpose in 

 1923. The commission's conservation program was suc- 

 cessful in rehabilitating the stocks so that landings rose to 

 75 million pounds m 1962. Since then, the stocks have 

 again declined, and the landings of the two countries 

 combined have ranged between 20 and 30 million 

 pounds. 



The International Pacific Halibut Commission has 

 accumulated a great deal of scientific information on this 

 species and unusually complete statistical data on the 

 fishery. We now know that by the 1960s U.S. and Cana- 

 dian trawl fleets, fishing for lower-valued bottom fish 

 such as pollock, hake, sole and rockfish, caused high mor- 

 tality in immature halibut caught incidentally and 

 returned to the sea. Even more serious was the trawling 

 of distant-water fleets from the Soviet Union and Japan 

 directed mainly to other groundfish. Heavy by-catches of 

 halibut were almost certainly the main cause of the sharp 

 decline in halibut stocks. Other contributing factors were 

 incidental catches in the Alaskan king crab fishery and, 

 possibly, changes in the oceanic environment. 



Hahbut are a long-lived species and take many years to 

 mature; so rebuilding the stocks to the level of the early 

 1960s may well take more than a decade. Thus the Cana- 

 dian catch may need to be held below 6 million pounds 

 for some time, and improved control of by-catches in 

 other fisheries will be necessary as well. 



