Alaska Salmon Program - FRI

Even though the watersheds we work in are dominated by sockeye salmon, we occasionally focus our efforts on other species. Since ~2008 we’ve sampled multiple streams for juvenile coho, recording their length, the temperatures of their habitat, and collecting diet samples. In many streams, juvenile coho are found in slow, warm backwater habitat with few other species. In other streams, particularly warmer one, the coho are found in the main channel, sharing space with rainbow trout and arctic char. Coho grow faster when sockeye eggs are available to them, and those in warmer streams grow faster than those in colder habitats. Previous research by showed that these small fish, 80-120mm, will swim multiple kilometers round trip within a single stream to eat sockeye eggs available in the cold main channel, then move back upstream to a warmer tributary to rapidly digest their meal, only to turn back around and do it again!