Angler Wendy Brum of Windham is all smiles handling a Sebago Lake trout on a guided trip with Tom Roth. Photo by Tom Roth

I love trolling Sebago Lake on a crisp September morning. The summer residents have pulled up stakes and the lake returns to the quiet I only know around ice-out time. Evenings are perfect for trolling the lake, and salmon and lake trout come on the bite as waters cool and oxygen levels increase with the “turning over” of the lake.

Scientifically speaking, cool nights and wind lower the surface temperature of the water. The cool water at the surface becomes denser (or heavier) and it sinks. Warmer water moves up toward the surface and is generally enriched with nutrients, drawing smelt and with the smelt, game fish. Cooler waters exist in a band, and the smart angler finds these bands and trolls at this depth.

One great tool that Sebago Lake anglers now have is the Portland Water District buoy that measures temperatures at varying depths and reports live to your cell phone via an app. Download Live Datacenter and select Sebago Lake from the menu. Salmon and lake trout prefer waters close to 50 degrees, so by finding that depth on the app and watching your fish-finder for bands of fish, you can find the optimum depth to troll.

Last September, I found salmon and lakers between 25- to 35-feet of water. A quick check on the app showed I was fishing water that was between 50- and 55-degrees. I used my downriggers and sent out a Carlson spoon in silver and copper behind a dodger on one rod. The other was baited with a pickled smelt on a bait harness behind a dodger, too. Both proved productive in September as I caught a few salmon, a bunch of togue and a few bass with both offerings. I would occasionally see clouds of baitfish (likely smelt) just above, just below or right in the middle of the thermocline. This was prime territory!

Anglers without downriggers can get in on the action, too. Many of us drag lead-core line behind the boat with good success. Lead-core line is aptly named as it has a nylon covering over a lead line. The heavy line sinks rapidly. The line is colored in 30-foot increments. You will often hear anglers say they caught salmon at four colors. This means they let four colors of line out, or 120 feet. Lead-core line comes in varying weights, with the heavier weights sinking faster. This is trial-and-error fishing, but if you use lead-core line long enough, you will know how it works and how much to let out to target a specific depth. Be sure to run a long leader of monofilament from the lead-core core line, as the lead-core is thick and not transparent. I prefer at least an 8-foot leader but sometimes use 30-feet of 8-pond monofilament line.

September returns peace and tranquility to one of the state’s busiest lakes and sets the stage for late-summer anglers to cash in on the cooling of the big water. You will find this angler out on the lake, getting one last stab at lake trout and salmon before winter covers her up with an icy shroud.

Tom Roth is a freelance outdoor writer who lives in Raymond on the shore of Sebago Lake. He has been fishing and hunting in this region for more than 30 years and is a Registered Maine Guide.