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2. Adulls mated: 



Prevent founder effects by ensuring that hatchery founders represent a 

 statistically significant sample of the donor stock's gene pool. 



In every breeding season, maintain the largest effective population size possible 

 under the operating constraints of a particular hatchery by: breeding as many 

 parents as is feasible; mating at least one male per female in daily matings; 

 whenever possible in daily matings. splitting gametes of the least numerous sex 

 into subsets and crossing each subset with gametes from a different individual of 

 the more numerous sex; and minimizing variation in family size at the time of 

 mating. 



Avoid intentional and unintentional artificial selection in collection of parents 

 from donor stock and from adults returning to the hatchery. 



3. Fertilization protocol: 



Maintain high effective population size and minimize hatchery-induced variation 

 in family size by using the milt from an individual male to fertilize the eggs of an 

 individual female (Withler 1988). In cases where effective population size can be 

 increased by breeding more than one male per female, use the milt of a different 

 male to fertilize each separate subset of eggs from an individual female. In 

 situations where egg supply is severely limited or male fertility is highly 

 variable, pool tlie milt from overlapping pairs of males (A and B, B and C, C and D, 

 etc.) and immediately fertilize eggs of individual females (Gharrett and Shirley 

 1985). 



4. Rearing practices: 



Reduce artificial selection during incubation, rearing, and in fish releases. 



If artificial selection programs are planned or practiced, evaluate if they are 

 consistent with genetic conservation goals. 



5. Size of donor stock remaining to reproduce naturally: 



Ensure that numbers of individuals remaining to reproduce naturally are 

 sufficiently large to prevent loss of genetic variation in the donor stock. 



Prevent selective removal of adults to ensure existing life history patterns of the 

 donor stock are conserved in individuals remaining to breed naturally. 



Indirect Genetic Impacts of Hatchery Fish 



A. Institute policies and guidelines on indirect genetic impacts of hatchery 

 stocks on wild and natural stocks. Consider impacts due to: ecological 

 interactions, such as competition for limited resources in natural 

 habitats; and reproductive overfishing in mixed-stock fisheries. 



B. Develop guidelines for case-by-case determination of allowable numbers 

 of hatchery fish released in order to minimize indirect genetic impacts. 



