Outside of ice fishing, there's not a lot of angling this time of the year on Montana's icy rivers and lakes.
But this is when state fisheries biologists work as hard as ever, processing all the samples and data they collected over the past year.
During the winter you will find most fish crews, not on a lake or river, but holed up in a dark room over a microscope.
"For all those anglers out there these are kind of the behind the scenes surveys and studies that we do, that don’t get a lot of attention, but help us draw a lot of conclusions about how to make the fishery the best possible fishery for the angler," said Adam Strainer with Montana Fish, Wildlife and Parks.
Fish crews across the state conduct a variety of wintertime surveys; from diet analysis to aging fish, in order to better understand a fishery’s overall picture
"By now we have some idea of what went on this past summer, but now we are truly getting a great cross section as to everything that is happening whether it be starting on the bottom of the food chain with zooplankton all the way to the top of the food chain with predator, growth rates and aging," Strainer added.
Biologists can tell the age of a fish by their scales and spines but the go-to aging structure is an ear bone called the otolith.
"The rings will tell us just like on a tree how old that particular fish is. We are also going to see what’s out there in our population, is it comprised of older fish, younger fish or a bunch of fish in between," explained FWP's Heath Headley.
While the work can seem monotonous it is really a culmination of all the time spent on the water that makes this winter work important in managing Montana’s fisheries.
"It’s nice to get summarized and make heads or tails of what’s really going on out there, that’s the cool thing about it," Headley concluded.