Bradford says he can only speculate on why so many juvenile salmon use streams like Croucher Creek. The smaller streams could also provide a refuge from predators such as inconnu and pike, kingfishers and mergansers. What the fish do under the ice all winter is still a mystery. In the summer and fall, Bradford spent time snorkeling in the creeks, observing the salmon at different times of the day. Bradford says he would have been willing to brave the cold water in December to observe the fish, but there just was not enough room under the ice in the shallow stream for him to move around.
Winter is obviously a stressful time for fish.
The water is colder and has less dissolved oxygen in it, and there is less to eat. It is assumed that in winter fish conserve their energy by hiding among the cobbles and woody debris on stream bottoms for most of the day, emerging at dusk to feed on whatever insects they can find. Chinook salmon in other parts of North America do not have the challenge of surviving a northern winter. For example, on the Sacramento River in sunny California, chinook grow quickly and begin migrating to the ocean within several weeks of hatching. Chinook in the Yukon River are at the northern end of their range.