WYOMING— Ever wonder how fish survive the freezing Wyoming winters? According to The Wyoming Game and Fish Department, a fish’s survival is almost entirely based on how, when and where ice forms.
Ice usually forms across an entire stream in late fall and gets covered with snow. This is an ideal situation for fish to survive the winter because they’re safe from predators and harsh weather conditions.
Fish move to areas where the stream is flowing slow and deep – like pools or underneath stream banks. Because there’s snow on the ice blocking sunlight, fish do not move around or eat much during the winter. According to Game and Fish, they can live on their energy reserves for up to five months.
While ice can be good for fish if it’s a solid cap on streams “slush ice” caused by warm spells, or suddenly cold weather in the spring can create problems for fish. As slush ice floats downstream, the ice can clog the gills of fish. Some fish move to shallow areas along the bank where slush ice may not flow. Others go toward deep pools where the slush ice usually floats over top. But all too often, the fish that move to the shore get caught and eaten by mink that hunt for food along stream margins all winter. On the other hand, small fish that move into deep pools can be eaten by bigger fish that live there.
Game and Fish biologists work with water managers and dam operators around the state to keep the flow in rivers stable during the winter which helps streams and rivers to ice over.
