Moosehead Lake region fishing report

By Tim Obrey, Moosehead Lake region fisheries resource supervisor

It’s exciting when we get a chance to really move the needle to improve our understanding of the fisheries in the region. The development of our fish weir in 2008 and associated radio telemetry/tagging studies gave us an opportunity to gather post-spawning survival, homing, movement, relative abundance, and frequency of spawning information on our wild brook trout and salmon in places like Socatean Stream and the Roach River.

It has been an incredibly useful tool. In 2008, when we liberalized the lake trout regulations on Moosehead Lake, we had no idea how long it would take to see a change in the population. We weren’t even sure if it would work. But within three years we had successfully removed many of the surplus fish and we witnessed a vast improvement in all of our coldwater gamefish species. The creel survey data collected pre and post purge has given us better insights into the abundance of lake trout and their impacts on the forage base.

The discovery of the shore-spawning brook trout in 2017 led to some important studies and conservation measures that have helped to protect these behemoth trout that are roaming Maine’s largest lake.

Smelts are the primary source of food for our lake trout and salmon, and it has become abundantly clear that lake trout drive this bus. Time after time, lake trout have demonstrated the ability to greatly reduce the forage base when they are over-abundant. Our goal is not to eliminate lake trout. No, far from it. They are native to Moosehead Lake, and we want the best fishery we can produce. Sometimes that necessitates thinning the herd to maintain good growth for all our coldwater game species.

It would be most beneficial if we could estimate the population of lake trout in the lake from time to time. Estimating population size is possible in smaller waters using mark and recapture techniques with trapnets, but it’s a whole different ballgame in a 75,000-acre lake with a deep-dwelling species like lake trout.

This past fall we embarked on a new pilot study on lake trout that has the potential to be another landmark study for our lake. With financial assistance from the Natural Resource Education Center at Moosehead, we designed and purchased special trapnets that can fish in deeper water and are not attached to the shoreline. Two of these nets are tied off on either end of a large lead net that resembles an eight-foot-tall tennis net. This arrangement is set adjacent to a lake trout spawning shoal in six to eight feet of water. We made a test run on Sebec Lake in the fall of 2023 with some good success. This past fall we took our nets out to a known lake trout spawning shoal on Moosehead Lake. This was a small shoal, and the substrate was smaller rocks which was very good for netting and for lake trout spawning.

We caught 201 mature lake trout in just 16 days of netting. It was impressive with fish up to 31 inches. We implanted passive integrated transmitter tags, small internal tags coded with individual numbers, into these lake trout. We can read the tag numbers in live or dead fish with a handheld tag reader.

We hope to see some of these fish on the ice this coming winter. More importantly, we see the possibility of expanding this work to multiple shoals next fall and vastly increasing our sample size.

The Moosehead Lake Fisheries Coalition and NREC are teaming up to provide match funding for a potential grant this winter that will allow us to purchase four more nets and hire staff for this study. That will give us the ability to sample three different shoals in the fall and vastly increase the sample size of marked fish in the lake. We hope to see enough tagged fish during the following winter creel survey to estimate the population of mature lake trout in the lake. Understanding population density will help us evaluate exploitation and carrying capacity of the lake trout population which is so important to the successful management of all our gamefish species in the lake.