THE HALIBUT FISHERIES 125 



water can easily be provided aboard fishing trawlers. Tests in which sea 

 water with 50 to 60 ppm free chlorine was used aboard a trawler showed 

 that slime and blood were easily removed, pen boards were easier to 

 wash than with plain sea water, and fewer bilgy and spoiled fish were 

 landed. 



Freezing Halibut at Sea. An obvious solution to the limited storage 

 life of the chilled fish is to freeze it at sea. Such frozen fish are most apt 

 to be frozen whole for later processing. If thawed ashore for filleting and 

 packaging, the fish may have to be refrozen. Studies on bottom fish^-^-^ 

 indicate that fish frozen at sea within a few hours of their capture show 

 little adverse quality defects from freezing, thawing for processing, and 

 finally refreezing. Any changes caused by refreezing were far outweighed 

 by the obvious gain in over-all quality. 



In considering the freezing of halibut within a few hours of capture, 

 pretreatment to allow the fish to pass through rigor mortis may be 

 desirable, since the halibut would probably be cut into steaks while 

 frozen. Studies in freezing cod at sea aboard the trawler Northern Wave 

 by the Torry Research Station^ suggested that ''No fish be frozen sooner 

 than 6 hours after catching, preferably not until 12 hours." Later research 

 on cod at Torry^-^ indicate, for example, that undesirable texture can 

 result, such as loss of juiciness, if fish are frozen prior to rigor. It was 

 concluded, however, that under practical conditions the freezing of pre- 

 rigor fish would not produce an unacceptable product. With halibut the 

 enzymatic action in the skin leading to substantial slime formation is 

 normally completed during the icing stage; subsequently, the slime is 

 easily washed off prior to freezing. If frozen within a few hours after 

 capture, such halibut may show an undesirable formation of slime during 

 later thawing for use. Further research undoubtedly will clarify these 

 problems. 



Processing Fresh and Frozen Halibut 



Most Pacific halibut vessels arrive at the landing port after a 3 to 

 4-week trip with a total catch from 50,000 to 80,000 pounds. A few larger 

 boats have landed over 100,000-pound trips, and the recent developments 

 in Canadian boat construction suggest that the larger capacity boats will 

 become more common in halibut fishing. As a rule, the entire trip of 

 halibut is posted on the board of the exchange and sold to the highest 

 bidder. 



Unloading and Grading the Fresh Halibut. Halibut are landed dressed 

 (head on) and traditionally are sold on a heads off basis. The fishermen 

 do the unloading and heading (Figure 9.3); a fish grader employed by 

 the buyer grades the halibut for size and condition in accordance with 



