77 



CENTIMETERS 



Figure 16. Size composition of trawl and setline-caught halibut. 



The high percentage of small sizes in the unregulated European fishery creates 

 a demand for imports of the larger sizes of North American setline-caught halibut. 

 This has resulted in the export of several million pounds of halibut annually from 

 the Pacific Coast to Great Britain. 



Food 



Halibut are strong swimmers and their food consists primarily of a large variety 



of fishes and, to a lesser extent, of the larger invertebrates such as crab and shrimp. 

 The species most frequently observed in halibut stomachs include grey cod, sable- 

 fish, pollock, turbot, hake and, to a lesser extent, assorted rockfish, bullhead and other 

 bottom fish. Halibut also leave the bottom to actively feed on midwater and pelagic 

 fish such as sandlance and herring. The juvenile or young halibut (one to three 

 years of age) subsist chiefly on small Crustacea including shrimp. 



Migration of Halibut 



Each year thousands of halibut are caught by the Halibut Commission's chartered 

 fishing vessels and are marked with numbered tags (Figure 17). Rewards are paid to 

 persons recovering such marked halibut. Between 1925 and 1969 about 179,000 hali- 

 but were marked and released of which about 27,000 have been recovered to 1969. 



Marking has shown that, in some areas and at some seasons, most of the fish 

 migrate little (Figure 18). In other instances there is. considerable dispersion or migra- 

 tion (Figure 19). The record migration observed to date by a tagged halibut was from 

 the Aleutian Islands in western Alaska to northern California, a distance of 2,300 

 miles along the coast. 



