THE SALMON FISHERIES 115 



excess of ice be maintained in the tanks at all times to insure proper 

 cooling. This type of preservation is also limited by loading capacities 

 and storage time as is the mechanically refrigerated system, and the 

 chilled brine installation must have mechanical circulation systems to 

 be fully effective. Attention must also be given to maintaining the proper 

 salt level in this system as the melting ice dilutes the brine. 



The third refrigeration method in general use aboard the vessel is a 

 combination of the mechanical refrigeration method and the chilled 

 brine method using mechanically refrigerated sea water or brine with 

 the addition of ice, especially at the time of heavy loading of the tank 

 with fish. 



Fish taken in traps are usually moved aboard tenders to the processing 

 plants without ice as they are kept alive in the traps until needed at 

 the plants and arrive in good condition because the trap locations are 

 near the processing plants. 



The second important period in the handling and preservation of the 

 salmon is aboard the tender or scow which will take the fish to the plant. 

 A number of the plants are a considerable distance from the fishing 

 grounds and, as the fishing boats would lose too much time from the 

 grounds if they made this run, all of the processors operate tenders to 

 bring the salmon into the plants. These tenders are large boats, power 

 scows, or towed scows which are equipped to handle salmon from a 

 number of fishing boats and deliver them to the processing plants. These 

 tenders either use ice or, more generally, one of the three systems of pre- 

 cooled sea water. 



The third important period in handling salmon to the processing plant 

 is at the plant itself. The fish which is received at the plant is processed 

 as soon as possible after being received from the tenders and day boats. 

 If there is going to be a delay in processing, the fish are iced in bins at 

 the cannery or held in shore tanks with refrigerated brine or chilled sea 

 water. 



The refrigerated sea water or chilled brine systems are a recent inno- 

 vation in the salmon industry and have contributed a great deal to the 

 success of the industry. In past years with fewer canneries and processing 

 plants operating, use of such systems has made it possible to transport 

 salmon in good condition over greater distances. Their use has also made 

 it possible for tenders to stay on the grounds longer so that the runs to 

 the plants could be made with full loads. These systems allow for the 

 transportation of the fish to the plants w^ithout the weight of fish in iced 

 or dry loads causing a loss in yield through pressure drip. At the plant 

 these systems have allowed the operator to even out the operating day 

 to bring about the most effective and economical production. 



