Sebago Lake has long been one of the premier landlocked salmon fisheries in Maine. It is one of only four waters in the state to which the fish are native.
But there is concern among anglers and biologists alike that Sebago Lake’s native salmon, and the rainbow smelt population that feeds them, are in trouble.
The state’s stocking of lake trout, natural fluctuations in bait fish abundance, changes in angler behavior and the illegal introduction of freshwater alewives and Northern pike have conspired to create a rapidly changing fishery in the state’s second largest lake.
As a result, the number of smelts, the primary forage of salmon and lake trout, are again approaching historic low levels. That has left salmon and lake trout fighting for survival.
Jim Pellerin, regional fisheries biologist for the Maine Department of Inland Fisheries and Wildlife, said Sebago’s smelt population is not at its lowest level ever, but his observations of salmon condition indicate it has only been worse two or three times in the last half-century.
Sebago built its reputation on producing trophy salmon during the late 1800s and early 1900s, before the population was decimated by overfishing. Stocking efforts by DIF&W eventually restored numbers, including those of native fish.
Then, it was a man-made situation that took a huge toll on Sebago’s fisheries.
“We almost lost the salmon and smelt back in the ’60s during the DDT era,” Pellerin said of the pesticides. “So we’ve recovered some from some pretty bad situations before and hopefully we can do it again.”
The next threat to native salmon came when, under public pressure, the state finally agreed to stock lake trout, also known as togue, in Sebago.
The late Stu DeRoche, the regional fisheries biologist in southern Maine waters at the time, was reluctant to do so, Pellerin said. The department eventually relented in 1972, hoping that a strain of deep-dwelling lake trout from New York would create a two-story fishery — one in which the salmon would live higher in the water column, above 40 feet, while the lake trout would stay at lower depths, and the two could co-exist.
Instead, the lake trout adapted quickly by imposing themselves on salmon habitat, where they began feasting on smelts — and the salmon themselves. By the early 1990s, the lake trout were everywhere.
“Once those big lake trout over 23 inches showed up, the salmon became prey,” Pellerin said, conceding that the stocking, in hindsight, had been a mistake.
However, Pellerin pointed out that lake trout fishing became popular among anglers and has provided an economic boost for the area over the years.
To combat the lake trout problem, the state enacted rules allowing anglers to take more fish. It worked, and the salmon again flourished.
“In 2013 we saw the best salmon fishing we’d ever seen historically, based on the records that we had all the way back to the late ’60s,” Pellerin said. “Catch rates were the highest we’d ever seen.”
The salmon fishing peaked over the next two years. Approximately 80 percent of salmon caught in the lake in 2013 were native fish, compared to 25 percent during the late 1980s.
At the same time, biologists were aware that anglers were not removing enough lake trout to maintain the balance of species. In 2012, the state created a new slot limit for lake trout that would protect the largest and smallest fish.
The idea, based on research done in Idaho, was that the large lake trout would cannibalize their young and help control the population.
“That regulation basically overprotected the lake trout,” Pellerin said.
Freshwater alewives were illegally introduced into Raymond Pond around 2007, and found their way into Sebago. Their numbers shot up simultaneously with the salmon resurgence.
Lake trout ate the alewives, which are larger than smelts. The alewives were mostly too large for salmon to eat, and salmon that consumed them had difficulty reproducing.
By 2016, biologists were seeing salmon decline, while lake trout fishing remained robust. It was a matter of too many predators and not enough prey, and in order to not lose the smelt population, the number of lake trout needed to be decreased, Pellerin said.
Many anglers and fishing guides continued to employ catch-and-release tactics with lake trout and were keeping only a small number of the fish. Lake trout fishing was particularly productive during the winter in years when there was sufficient ice on Sebago to permit anglers to access large areas of the lake.
Pellerin said a group of five friends once caught 90 lake trout in a span of only five hours.
“I kept telling people, that is not sustainable for this lake,” he said. “It was very alarming.”
The department tried to encourage anglers to harvest the smaller fish and keep as many as they could. Instead, most of them were returned to the lake, even after the lake trout population began to collapse.
That hampered the state’s efforts to reduce the predators and help restore the dwindling smelt population on which the lake’s two primary species depend so heavily for survival.
In 2019, the landlocked alewives, which also had been competing hard with smelts for food, suddenly left Sebago in droves for other waters. It’s a dynamic that occurs periodically with alewives.
The result was a large drop in the number of smelts, which fell prey to lake trout that had lost alewives as a food source, and a corresponding decline in the landlocked salmon that rely on smelts for food.
Now, the alewives have begun to come back, but it isn’t clear how the lake trout and salmon will respond to that change.
The salmon population is down 57 percent since 2013, and lake trout is down between 29 and 33 percent in the last five years, Pellerin said.
Anglers may legally harvest an unlimited number of lake trout, of any size up to 26 inches, but only one per day may exceed that length.
“The lake trout are essentially starving, so they’re not producing as many young,” Pellerin said, noting the large number of long lake trout with huge heads and skinny bodies anglers are catching.
Northern pike are another threat to Sebago’s native salmon. The voracious predators, which can grow to more than 20 pounds, were illegally introduced in 2002.
While it is believed the pike have remained primarily in shallow, weedy areas, which is not good salmon habitat, they may be targeting salmon smolts as food.
Pellerin said pike spawn around ice-out in shallow, flooded grasses. Large pike have been seen in the Songo River, a key tributary, and they may remain in those waters long enough to pick off wild salmon smolts dropping into the lake.
Anglers also target pike and, as with lake trout, routinely release them in the hope they will get larger. The state is working with ice fishing derby sponsors to include prizes for the most pike or the heaviest combined total weight.
One positive for smelts is that fewer salmon and lake trout mean more smelts should be surviving and hopefully reproducing. The state also puts about 3 million smelt eggs in Sebago every year. That combination could boost salmon and trout.
“We don’t know if we’ve hit rock bottom yet and when that’s going to start to turn around,” Pellerin said of the smelts. “They can turn around pretty quickly. We’ve seen it happen before.”
The long-term prognosis for salmon and lake trout in Sebago Lake will be dependent not only on what’s happening in the ecosystem, but also on whether anglers commit to harvesting more lake trout.
Pellerin said during the 1970s, virtually all legal-size lake trout were harvested. Today, there is a 70 percent release rate on those fish.
“My feeling is, either anglers are going to have to change their attitudes or we’re going to have to look at new methods to try and manage these wild, self-producing populations,” Pellerin said.
While unpopular, measures such as mandating that all lake trout caught must be killed at once, paying a bounty for every fish caught by anglers, or even commercial netting to remove large numbers of the fish, which occurs in other states, might be some of the only ways to tip the balance back in favor of Sebago Lake’s native salmon.
“Lake trout are very difficult because they live forever, they don’t have a lot of predators and they consume a lot of food,” Pellerin said.
Salmon, by contrast, have a much shorter life span, usually less than 10 years for wild fish. And they can’t survive extended periods without food like lake trout can.
Despite all of the changes and illegal introductions that have adversely affected the Sebago Lake fishery, Pellerin remains hopeful the state can avert the potentially catastrophic loss of smelts and native salmon.
“If we’ve got that predator population down enough, we may start to see a shift,” Pellerin said. “The real challenge moving forward is finding a way to harvest and keep those wild populations in balance.”