Native brook trout can be found in waterways throughout Maine. This particular trout, caught in Winterport, was released after the photo was taken. Credit: Courtesy of Matthew Denbow

The Rapid River is special. It is to Maine what the Batten Kill is to Vermont, Beaverkill River is to New York, South Platte is to Colorado, Henry’s Fork is to Idaho, Madison is to Montana, and Snake River is to Wyoming: the state’s most famous trout river.

Along with the upper Yellowstone River in Yellowstone National Park and Snake River near Jackson, Wyoming, the Rapid River is also one of the finest wild native trout rivers in the nation. Unfortunately, wild native trout fisheries in large rivers sadly are rare today, most having succumbed to invasive fish introductions, including state-sponsored, non-native trout.

Five or so years ago, Terry Gunn, owner of Lee’s Ferry Anglers in Arizona, approached me to write about the Rapid River for his book, “50 Best Tailwaters to Fly Fish.” A few years later, well-known Colorado fly fishing guide and author Landon Mayer asked me to write about the Rapid in his book, “The Hunt for Giant Trout: 25 Best Places in the United States to Catch a Trophy.” In both cases, the Rapid was the only Maine water featured.

The Rapid River is featured in all three of my books: “50 Best Places Fly Fishing the Northeast,” “25 Best Towns Fly Fishing for Trout,” and “Squaretail: The Definitive Guide to Brook Trout and Where to Find Them.” My current book project also will feature the Rapid River.

Unfortunately, the Rapid River is now infected with highly invasive non-native smallmouth bass. They entered the river in the mid 1990s via Umbagog Lake on the Maine-New Hampshire border and are now self-sustaining. They got into the lake in the 1980s as the result of an illegal introduction.

To be clear, no wild native brook trout river has escaped a non-native bass introduction unscathed, and the Rapid is no different. The bass compete with native species for food and habitat, and also prey on brook trout. I recently saw a picture of a bass from Down East that had two, four-inch brook trout in its stomach.

Bass are now found throughout the Rapid River, including Pond in the River. They are pushing up against Middle Dam, putting them mere feet away from Lower Richardson Lake. If they get into the lake, the only thing stopping them from getting into Mooselookmeguntic and Cupsuptic lakes, as well as the Kennebago River, is Upper Dam. Sadly, that is likely to happen, based on what we have seen elsewhere.

As may already be happening in the Rapid River, non-native fish populations tend to go up and down. They tend to boom and then flatline, and even experience drop-offs, but they rarely go away. This is especially noticeable in the early stages of an infestation when the population sees notable increases from one year to the next. Then things settle down and the population stabilizes.

“Smallmouth bass numbers, as indicated by clerk catch rate statistics, increased dramatically in the Rapid River from 2002 (0.011 fish per hour) to 2007 (0.192 fish/hour), but declined slightly in 2010 (0.137 fish/hour),” the Department of Inland Fisheries and Wildlife reported.

When non-native bass were first detected in the Rapid River, DIF&W imposed a S-13 regulation (no bag or length limit on bass) and posted signs that encouraged harvest. A subsequent general law change removed all regulations on bass in the North Zone, eliminating the S-13 regulation and supporting informational signage. DIF&W countered this with some general invasive species signs that emphasized avoiding introductions, rather than removal.

DIF&W, along with several fishing and conservation organizations, organized a tournament to bring awareness to the problem and remove some bass from the river. The event, which included a controversial temporary moratorium on the “fly fishing only” regulation, drew anglers from all across the state. Unfortunately, it was never repeated.

Feeling that non-native bass messaging was dangerously lacking, the Maine chapter of Native Fish Coalition in 2020 approached Rangeley Region Guides’ and Sportsman’s Association and DIF&W to develop an informational sign for the Rapid River. The lack of signage gave the impression that we had given up, the worst possible message we could send out.

NFC also reached out to DIF&W in regard to increasing formal bass removal efforts. While DIF&W was supporting similar initiatives on Sebago Lake (non-native lake trout) and nearby Mooselookmeguntic Lake (non-native landlocked salmon), they were not interested in doing the same on the Rapid, citing “effectiveness” as the reason. I struggle with the idea that we can make a difference on sprawling lakes with deep-water fish, but not on a river with an easily targeted fish.


It is highly unlikely that the non-native bass found in the Rapid River can ever be totally eradicated. It is part of a large, interconnected system that includes 7,850-acre Umbagog Lake, as well as the Magalloway River and Dead Diamond River systems. But the bass can, and should be, controlled and reduced to the lowest number possible in order to help maintain the wild native brook trout fishery.

The current strategy is primarily to manipulate flows to make the Rapid River less hospitable to bass. Water is released from Middle Dam in the spring to disrupt spawning and reduce the recruitment of bass. While it appears to be helping, based on the high number of bass now found in the river, especially in the late spring into early fall, it isn’t enough to get the job done.

Mechanical removal using electro-fishing equipment would help remove large predatory spawning-age bass from the river. It would also help address the bass in Pond in the River that are unaffected by spring flow manipulation. This has worked well in Yellowstone Lake, where the ongoing targeted removal of non-native lake trout has helped rebuild the native cutthroat population.

As the National Park Service has done in Yellowstone National Park in regard to non-native lake trout in Yellowstone Lake, and rainbow trout and brook trout in the Lamar River drainage, as well as in Shenandoah National Park with non-native brown trout and rainbow trout, DIF&W should make the destruction of non-native bass mandatory in the Rapid River.

“All lake trout caught from Yellowstone Lake must be killed — it is illegal to release them alive.” — National Park Service

“Releasing any captured brown or rainbow trout back into any park stream [is prohibited].” – National Park Service

Without a comprehensive and sustained control plan, the Rapid River’s non-native bass population will level off and likely stay there with only minor seasonal bumps and drops. The wild native brook trout fishery will likewise stabilize, but not at the level it once was. This new equilibrium will favor the bass at the expense of the finest wild native brook trout population in the nation. And the fishing experience, and economic and ecological value of the fishery, will suffer.

It’s time to think out of the box, try some new ideas and embrace a much broader approach to managing the Rapid River bass problem than we are doing today. Sustained pressure in the form of mechanical removal of non-native bass would help the native brook trout. So would more targeted removal by anglers, including appropriately timed and well-managed formal events. I believe some of this could be done with volunteers if they were allowed to do so.

To be clear, while bass numbers on the Rapid River appear to be stabilizing, and the population is responding to manmade flow manipulations, it’s not enough. The river and the fishery have been seriously compromised. We are not doing everything we should be doing to save this nationally known and ecologically, economically, and socially important wild native brook trout fishery. Standing by watching the river flow will not change that.

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Bob Mallard, Outdoors contributor

Bob Mallard has fly fished for 40 years. He is a former owner of Kennebec River Outfitters, a Registered Maine Fishing Guide and a commercial fly designer. Bob is a blogger, writer and author. He is also...