Brook Trout Beat the Heat

During the hot summer months, brook trout and other fish will search for cooler spots in a river or pond, seeking “thermal refuge” from the heat. These thermal refuges will often congregate fish in high numbers, and often you can find them huddled near spring holes or tributaries. While these thermal refuges do provide some relief from the heat, fish grouped in large numbers often attract predators, such as birds, turtles, animals and even humans. IFW Fisheries Biologist Wes Ashe placed an underwater camera at the confluence of a smaller stream and larger river as part of a stream survey in central Maine. When reviewing the footage, he discovered a large snapping turtle that came into the picture looking for an easy meal. As you can see from the video, the trout cleared out when the turtle arrived, stayed away while the turtle remained there, and then returned once the turtle left the scene. Ashe and the Region B crew were in the stream and river electrofishing. For years, a poorly designed road culvert upriver of this spot pooled water on the upstream side, and created a small waterfall on the downstream side. This both warmed the water and prevented fish passage upstream. IFW worked with the town, and the town removed the smaller, poorly-placed, circular culvert and replaced it with an arched culvert that provided a more natural flow to the stream. It allows brook trout access up river, and does not restrict stream flow, keeping the stream cooler. The fish in the picture are wild brook trout, which likely spawned upriver in an area that was inaccessible just a few years ago. [embed]https://www.youtube.com/watch?v=PYQlOqSVg64[/embed]