JOHN LYONS: There we go.
A little trout.
My name is John Lyons.
I'm a fisheries research biologist
for the Wisconsin Department of Natural Resources.
There we go.
We're doing a survey of the fish in the stream,
so we're interested in what kind of fish are here,
how big they are, what kind of shape they're in,
what kind of condition.
We do this with a device called an electroshocker.
(device sending out high-pitched tone)
And it puts electric current into the water
and stuns the fish briefly so that we can pick them up
and then examine them...
Brown trout, four-ten.
...measure them, weigh them...
Four-45.
In some cases, we tag them, check for how healthy they are,
and then we release them back into the water alive.
A lot of the work we do is basic fisheries management--
trying to understand the fish population and how we can
maintain it, make it better.
We look at trout and we study streams like this
because they're good indicators of the overall health
of our environment.
Trout are particularly important for climate change research
because they require very cold water.
This is open and sunny, so there probably aren't too many trout
hiding out here this time of day.
So they're sensitive to any sort of an increase
in water temperature, and one of the main things
that's going to happen as climate change occurs
is that the air temperature's going to get warmer
and that means that the water temperature's
going to get warmer, because the air temperature
largely determines how warm the water gets.
There's a very good chance that our trout populations
will suffer, particularly in those streams that are already
close to the temperatures that trout can tolerate.
They're already reasonably warm
and just barely cold enough for trout.
So those streams are going to be particularly sensitive
to climate change, and they'll be kind of sentinels,
important indicators of how trout are responding,
and in general, then how our stream and aquatic environments
are responding to climate change throughout the state.
So there's a lot of uncertainty
in exactly how the climate's going to change--
how warm it's going to get,
whether it's going to get warmer in the summer or the winter,
at night or during the day, and in some cases,
it may take only, you know, half a degree change in temperature
between the difference between a very healthy trout population
and a trout population that's really in trouble.
Certainly, if the temperature goes up three degrees,
that will have a very different effect on the trout
than if the temperature goes up six degrees.
We fish biologists are trying to understand all of it
and how it plays into whether or not the trout population
in this stream and other streams is going to be able to survive,
say, 30 or 40 or 50 years from now.