CONSERVATION OF THE HALIBUT — THOMPSON 379 



These great numbers are produced because of the perils which 

 the young meet during their drift in the sea. Depending as they 

 do upon the currents, vast numbers of them must be swept to sea 

 and lost simply because they do not reach the banks upon which 

 they can develop. These losses would, of course, be additional to 

 those caused by enemies. 



Something like this must happen to the halibut at the southern 

 extreme of the range, oif the coasts of Washington and Oregon. 

 There at one time a very large stock of halibut had accumulated, 

 but the fleet, having discovered them, concentrated upon them and 

 in 2 years had so reduced them in numbers that only a small fishery 

 could be carried on. The fishery has never recuperated and has sup- 

 ported but few vessels annually since that time. Apparently the 

 powers of recuperation there are small, and it is noteworthy that 

 in that district the winds are offshore. The currents may be either 

 south or offshore so that the young may indeed be lost in very great 

 numbers. 



The life history of the halibut in the light of what has been dis- 

 covered may be summarized as follows : 



The halibut along the Pacific coast may be divided into several 

 different stocks, that inhabiting the Gulf of Alaska and westward 

 being fairly distinct from those to the south. In this stock the adult 

 fish migrate freely between the entrance to Bering Sea and Cape 

 Spencer on the east. Spawned after an eastward movement the eggs 

 and larvae drift slowly in the deeper water for a period of 4 or 5 

 months. Then, they rise into the upper layers of water to be de- 

 posited inshore and along the coast where they undergo their meta- 

 morphosis to small halibut. As such they remain on the bottom 

 until they reach maturity. This is reached on the average in their 

 twelfth year when they resume the migrating habits of the adult. 



This stock of halibut in the Gulf of Alaska and westward, there- 

 fore, has its being in the giant water eddy which is characteristic 

 of that region. It does not inhabit the coast of Alaska as much as it 

 does the Alaska Stream, or eddy. 



To the south mature fish are so lacking that neither the eggs 

 and young nor the adults can be studied with any exactness. Al- 

 though it is known that several distinct stocks of adult fish exist 

 there on grounds known to the fishermen as spawning banks, yet 

 the extent to which the young drift has not yet been demonstrated. 

 In the last year, under the regulations of the Commission, the stock 

 of adults has shown a distinct increase, and it has been possible to 

 begin a study of the eggs and larvae in one of these stocks, that 

 off Cape St. James at the southern end of the Queen Charlottes. 



