Computing expected reproductive success of female Atlantic salmon as a function of salmon size


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A method is described for determining the expected reproductive success (gonadal mass of a returning fish times the probability of surviving to return) and expected fecundity of salmonids as a function of smolt size. Application of the method requires data relating (i) return weight and smolt size; (ii) probability of survival and smolt size; (iii) probability of return after one or two sea winters and smolt size; and (iv) gonads and return weight. Although there exists no published data set that contains all of this information, it is possible to piece together enough information from published sources on female Atlantic salmon to demonstrate the feasibility of the method, with the goal of encouraging the publication of datasets that will allow meaningful calculations for a single river. Thus, one should not expect general predictions about Atlantic salmon, but once local conditions are taken into account, it will be possible to predict the relationships between smolt size and expected fecundity or expected reproductive success.