Chinook salmon fecundity in the Unalakleet River, 2008–2010

Alaska Department of Fish and Game, Fishery Data Series No. 12-86, Anchorage

Unalakleet River Chinook salmon are one of the northernmost Chinook salmon stocks and to understand the production of the stock, reproductive potential should be examined.  Over a three-year period, 2008–2010, Unalakleet River Chinook salmon were harvested from the gillnet test and subsistence fisheries to evaluate relationships between age, length, and fecundity.

A total of 110 Chinook salmon were harvested and 84 salmon were aged.  Average fecundity for all Chinook salmon was 9,223 eggs per fish while aged salmon had an average fecundity of 9,289 eggs per fish.  There were two dominant age classes: age-1.3 and age-1.4.  Fecundity was positively correlated with length and there were distinct length-fecundity relationships for age-1.3 and age-1.4 Chinook salmon.  Fecundity-at-length was generally larger for age-1.3 salmon than age-1.4 fish; however there was no difference in egg size.

While most results are similar to other studies, the relationship between length and fecundity by age is unclear; it may vary by region and system.  Future work should explore other aspects of the reproductive potential of Unalakleet River Chinook salmon such as competitive interactions, egg deposition, and survival on the spawning grounds.