Moosehead Lake fishing report — Thissell Pond update

Last year, I wrote about the project to restore the wild brook trout population at Thissell Pond after an illegal introduction of smelt. We chemically reclaimed the pond in August of 2013 to permanently remove the smelt. We had documented a serious decline in brook trout abundance after the introduction, and the only way to restore the pond was to hit the reset button.

We let the pond recover over the winter and following summer. We constructed and installed a fish spawning box to encourage future reproduction. Meanwhile, fisheries and hatchery staff from the Enfield office were busy collecting fertilized eggs from wild brook trout in nearby Sourdnahunk Lake. The eggs hatched in the spring and the small, wild strain fish were stocked in Thissell Pond and other trout ponds in Baxter State Park. We were a little concerned at the smaller than normal size of these fish, but we were pleasantly surprised with the results. These fish grew … and quickly. The subsequent stockings also did very well.

Our plan was to stock this pond until we documented sufficient natural reproduction to sustain the fishery. We were using a baseline figure of around 10 fish per acre ( about 1,400 fish) as an objective. We can estimate the number of fish in a pond by conducting a mark and recapture study with trapnets. Essentially, we set four or five trapnets around the pond to live trap brook trout. We take some basic measurements then clip a piece of the tail. The fish are released and we can generate a population estimate based on the number of recaptures we collect.

So, this October we packed our gear and headed to Thissell Pond for a week of netting. The weather was not very kind. Nets were set on Monday, and Tuesday we woke to a 40-plus mph wind. While we love to work with the fishes, we didn’t want to sleep with the fishes. The nets and the fish would have to wait. The rest of the week was cold and still breezy but the work resumed.

We handled 700 brook trout during the week and roughly 50 percent were wild. That’s a good haul of fish. The population estimate was very rough because of the large number of fish we handled and the fact that we missed a day of tending. But, I would ballpark the population estimate somewhere north of 3,000 fish and south of 5,000 fish. If we figure half of those are wild, then we have already reached or exceeded our goal. Success!

We plan to curtail the stocking next year and reevaluate in another five years to make sure we are still on track. This pond has the capacity to grow some very high-quality brook trout and we want to develop a management plan that will take advantage of its unique characteristics.