LIGHT' 



(from U.S. Bur. Comm. Fisheries) 



Figure 29. Diagram of halibut gear as set. Instead of wooden kegs, buoys now consist of round, 



coloured plastic buoys. 



Dressing and Icing Down 



According to the size of the vessel, from 5 to 40 tons of crushed or flaked ice 

 are taken each trip. Many vessels have recently installed refrigeration to slow the 

 melting process and thus sharply reduce the amount of ice needed. This refriger- 

 ation also holds the temperature of the fish close to the freezing point of fish but 

 not below that point. 



Halibut are dressed or cleaned soon after they are brought aboard and the 

 body cavity, or "poke" is scraped and washed. Then the halibut are filled with 

 ice and stored in layers, dark side down in pens in the hold. Each layer of fish is 

 insulated from the other with crushed ice. 



In the fishery off British Columbia or Southeastern Alaska, the average length 

 of trip (from port to port) is about 13 days; in the Gulf of Alaska, the average trip 

 is between 20 and 25 days, depending on the grounds fished and port of landing. 



Fishing Records or Logs 



The vessels keep a day-to-day log of fishing operations giving the location, the 

 amount of gear fished, the estimated catch of halibut, as well as other information. 

 These records are copied by the Halibut Commission at the landing ports and the 

 data are analyzed by computers (Figure 30). 



The catch per unit of gear fished is a statistic used by the Commission as a 

 measure of the relative abundance of halibut on the grounds. There is both theoretical 

 and empirical evidence that the catch per standard unit of gear varies proportionately 

 with the abundance of halibut. In determining the catch per unit of gear, variations 

 in the construction of the gear and in the baits used require the calculation and use 

 of standardized factors so that the statistics of stock size are as comparable as possible 

 from one period of time to another. 



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