Bull Trout Activities in Idaho’s Boise River Basin

Bull Trout Activities in Idaho’s Boise River Basin


[music] Dmitri Vidergar: Reclamation is monitoring the Bull Trout population in the Boise River Basin as part of an obligation for the Endangered Species Act. [underwater sounds] Mary Faurot: So Bull Trout, throughout their range in the northwest, have been diminishing. We need to understand their biology and their
life history so that we can make conditions optimal for them to live out their life history and for their populations to increase, one day hoping they can get off of the Endangered Species List. [water flowing] Dmitri: Bull Trout demonstrate an adfluvial life history. Adfluvial fish are fish that live in a reservoir during a portion of their life and then they migrate far up into the headwater tributaries in order to spawn. [water flowing] We’ve used this migratory weir to sample the fish as they’re moving from the head water areas down to the reservoir. So instead of us chasing after the fish, we’re letting the fish come to us. [music] Mary: Every fish that’s either coming upstream or downstream can be counted and determine the species, the age and size and weight, and samples can be taken for DNA determination. Dmitri: Another important behavior of these fish is to hang out in the reservoir. So to capture that part of the population, that will give us an idea of all the different ages that are present in the reservoir. [net scoops up fish] [water dripping] We have four different types of tags that we’ll use on these fish. We have radio tags, we have acoustic tags, we have temperature archival tags and we have pit tags. [beep] Woman: Nope, he’s a newbie. Dmitri: Each of those four types of tags allow us to collect data on the type of habitat that these fish prefer to use. It’ll be a three year effort. So at the end of these three years we’ll have a bunch of data that we can compare to previous years. The preliminary numbers are the trend is up from last few times that we sampled. So that’s good. That’s a good sign. This is a very extensive project and it wouldn’t be possible without the cooperation from our partners. The important thing is that Bull Trout aren’t just in the reservoir. There’s far more work than one agency can do by themselves. We’re working with our partners to sample the whole gamut of habitats from the Sawtooth Wilderness to Arrowrock Reservoir. [music]

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