28 ARTIFICIAL PROPAGATION OF PACIFIC SALMONS. 



On shipboard, as the greater part of the journey is made, the cases of eggs 

 are kept in one of the fruit or cold-storage rooms having a temperature of about 

 38° F. To this room the attendant has access, and it is his duty daily to 

 moisten the eggs by pouring through the ice hopper water of the same tem- 

 perature as the eggs, 34° to 85°. The ice compartments are frequently re- 

 plenished, and the eggs are picked over whenever necessary. 



It will be seen that the method of caring for the eggs is not novel. The 

 chief improvements in the case are to make it easy for the caretaker to handle 

 the eggs in the crowded quarters of a ship's storage compartments and to 

 facilitate handling each individual tray. 



WATER SUPPLY FOR HATCHERY. 



One of the most important factors to be considered in connection 

 with sahnon propagation is the water supply, which should always 

 be taken from a stream that salmon are known to frequent for spawn- 

 ing. Spring water or water from a spring-fed creek is objection- 

 able, as it shortens the incubation period, bringing out the fry at 

 an earlier period than if hatched under natural conditions and at 

 a season of the j^ear when the natural food supply in the streams is 

 at its lowest ebb. 



In choosing a site for a salmon hatchery the matter of conveying 

 water thereto at a proper height for a gravity service should be 

 planned for, if possible. The supply may be conducted through a 

 substantially built flmne or by a pipe line, the dimensions of either 

 to be governed by the extent of the work contemplated, having in 

 mind the further development of the plant and the size of the pond 

 system it is desired to establish. The point for the intake should be 

 selected with the view to its protection, so far as is possible, from 

 the ravages of floods and ice. This may be accomplished by means 

 of 'piling or sheer booms. In some cases the construction of a low 

 dam will be required in order to raise the water to the proper level 

 to enter the flume or pipe line. 



Water taken from an open stream always contains more or less 

 sediment, necessitating the use of a filter for the elimination of the 

 greater part of it. A small quantity of sediment in the water supply 

 is not objectionable; in fact, it is apparently beneficial. 



Where a proper fall can be secured, with a sufficiently rapid cur- 

 rent at the point of intake, the water can be delivered by means of a 

 current wheel, provided climatic conditions are favorable to its 

 operation. A wheel for this purpose should be constructed on the 

 order of a large undershot water wheel, with buckets on the outside 

 of the rim. As the wheel revolves the buckets fill and empty into a 

 trough or tank connecting with the supply flume leading to the 

 hatchery. 



CARE OF THE FRY, 



The eggs of the chinook salmon, as do those of the other Salmonidse, 

 liatth very gradually at first, only a small percentage coming out the 

 first day. But the number increases daily until the climax is reached, 

 when large numbers of young burst their shells in a single day. 

 Great care and vigilance are required at this time. The vast numbers 

 of shells rapidly clog up the guard screens at the outlets of the 

 troughs, which should be kept as free as possible by thorough cleans- 

 ing from time to time. 



