PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1923. 5 



and if they find ascent to their natural spawning grounds in the 

 headwaters cut otf by a barrier, the parent fish die, their eggs are 

 wasted, and the supply of salmon is reduced to that extent. 



It is part of the work of the bureau's hatcheries to seine these 

 fish from below the barriers and to remove their eggs and incubate 

 them. The vitality and fertility of the salmon egg is wonderful. 

 If carefully handled and cared for, approximately 95 per cent of 

 them will hatch. The young fish resulting from the eggs are held 

 in ponds and troughs in such numbers as is practicable and are fed 

 artificially until they have attained a length of 2 or 3 inches, when 

 they are liberated. Shortly after liberation they descend to the 

 sea and, with the exception of one sipecies, which returns in two 

 years, they remain in salt water for four or five years. At the ex- 

 piration of that time they seek the headwaters of various coastal 

 streams, where they reproduce and then die, completing the life cycle. 

 It can readily be seen that hatchery work of this character is of the 

 greatest importance if this valuable and extensive industry is to 

 be maintained. 



A somewhat dift'erent problem is presented by the fishes of the 

 Great Lakes and Atlantic coast. Eggs from these valuable com- 

 mercial species are taken only from fish caught for the market by 

 men employed to go out with the fishing boats and salvage the eggs 

 as the fish are removed from the nets. Were it not for this work, 

 some three or four billion eggs would be wasted annually, being 

 sent to market with the fish and discarded in the process of cleaning. 

 This also applies to the shad, herring, and yellow iperch. 



In addition to the work of salvaging eggs for propagation in the 

 hatcheries, experienced spawn takers are detailed to accompany the 

 otfshore fishing fleet operating from Gloucester, Mass., going out 

 on the boats for trips of a week or two weeks' duration. As the 

 eggs from such fish as the cod. pollock, and haddock can not be 

 held until the return of the vessel, they are carefully removed from 

 the fish, fertilized, and planted on the spaAvning grounds. As in 

 the case of the other sipecies, these eggs would be a total loss were 

 it not for the bureau's intervention. Being exposed to the attacks 

 of natural enemies, the percentage of eggs hatched of those thus 

 treated must be far smaller than that attained in the hatcheries, but 

 as they can not be handled in hatcheries, because of the inaccessibility 

 of tlie latter, it is believed even the smaller percentage hatched fully 

 justifies the time and money expended in the work of fertilizing 

 and returning them to the spawning grounds. 



COOPERATION WITH STATES, OTHER FEDERAL AGEN- 

 CIES, AND FOREIGN GOVERNMENTS. 



The division of fish culture has pursued its usual policy of working 

 in conjunction with the States so far as possible. This cooperation 

 consists in the interchange of fish and eggs, distribution of fish, joint 

 production of fish, and joint operation of field stations for the collec- 

 tion of eggs. Sometimes State authorities are supplied with eggs 

 of certain species and in return they fill applications for fish sub- 



