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LANDLOCKED FALL CHINOOK SALMON EGG SIZE IS POSITIVELY RELATED TO HATCHING TIME

Wyatt Krebs, Eric Krebs, Nathan Huysman and Michael E. Barnes

Within fish species, there can be considerable variation in the sizes of eggs produced by individual females. Specifically within the family Salmonidae, the relationship between egg size and hatching time is uncertain. This study examined eggs obtained during the spawning of landlocked fall Chinook salmon from Lake Oahe, South Dakota, USA. Diameters were obtained from the eggs of 24 randomly-selected females spawned in October, 2017, and the number of days to hatch was recorded after incubation at 11°C. Mean egg diameter was 7.22 mm and ranged from 6.36 to 8.36 mm. Over 90% of the eggs survived, with mean hatching occurring from 46 to 49 days of incubation. Significant correlations were observed between egg diameter and time-to-initial-hatch (r=0.581; p=0.003), as well as between egg diameter and mean hatching time (r=0.450; p=0.027). There was no correlation between egg diameter and survival to hatch (r=-0.363; p=0.081). These results are the first reported relationship between egg size and time-to-hatch in landlocked fall landlocked fall Chinook salmon.