When people think of invasive species in the Adirondack Park, they think of Eurasian watermilfoil, zebra mussels, Asian clams, or any number of other exotic plants and animals that have made the headlines.

People don’t usually think of brown trout and rainbow trout, but neither fish, though abundant now, is native to the region.

Brown trout are native to Germany and were introduced to New York State in the late 1800s. Rainbow trout, native to the West Coast, were introduced around the same time. In both cases, the goal was to enhance fishing opportunities.

Today, the state Department of Environmental Conservation continues to stock, and allow stocking, of tens of thousands of brown and rainbow trout in the Adirondacks, and for the same reason—to improve fishing.

Stocking has long been part of the fishing culture, but some scientists and anglers have begun to question aspects of the practice, particularly its large scale and use of non-native species.

Curt Stager, a biology professor at Paul Smith’s College, argues that DEC should reassess its stocking program and look beyond fishing to consider the ecosystems of waters being stocked. “There are species that have value of their own, in addition to put-and-take fish,” he said. “There’s genetic diversity, biodiversity here that could well be threatened that we’re totally overlooking in our rush to only make more fish to catch.”

Perhaps the biggest concern is stocking’s effect on native brook trout. Intact brook-trout populations exist in only 5 percent of the rivers and streams in the state that once contained them, according to the Eastern Brook Trout Joint Venture, a coalition of organizations and state and federal agencies working to restore brookie populations. Most of the remaining brookie waters are in the Adirondacks and the Tug Hill Plateau, west of the Park.

The coalition – to which DEC belongs – lists higher water temperatures as the top reason for the decline of wild brook trout in streams and rivers. Temperatures have risen for a number of reasons, including the removal of streamside vegetation and the resurgence of beavers, which dam rivers and streams.

The coalition regards the introduction of non-native fish, especially brown trout, as the second-biggest threat to native brook trout in rivers and streams because they compete with the native fish for food and territory.

In lakes and ponds, the biggest threat is warm-water non-native fish, such as bass. In addition, acid rain has rendered some ponds, especially in the western Adirondacks, unfit for brook trout.

Jon Fieroh, an aquatic biologist with DEC, said the department stocks or allows stocking of browns and rainbows only in waters where brook-trout populations wouldn’t survive, including rivers that get too warm for brookies in the summer.

“You really have to take a case-by-case basis to see if brook trout are going to make it,” he said.

Fieroh said DEC leaves intact brook-trout populations alone and works hard to restore native brook trout to ponds throughout the Adirondacks, a fact that many anglers acknowledge.

However, some observers question whether DEC does enough to protect brook trout from non-native species of trout and from non-native strains of brookies that are raised in hatcheries and released in rivers and streams.

Vince Wilcox, president of the Tri-Lakes chapter of Trout Unlimited, said he’d like DEC to put an end to stocking brown and rainbow trout in a stretch of the West Branch of the Ausable River—namely, upstream of an iron bridge off River Road outside Lake Placid. He also wants non-native stocking stopped in the lower Chubb River, which enters the West Branch not far from the bridge. In addition, he proposes that anglers be allowed to take two twelve-inch fish. Presumably, these would be browns and rainbows as brook trout rarely grow that large in streams. Thus, the brook trout would be protected while the nonnative populations would be reduced.

The West Branch is celebrated for its trout fishing, but most of the fish are stocked browns and rainbows. Wilcox feels his proposal would give brook trout a chance to re-establish themselves in part of the river. He submitted the proposal to DEC in December and is waiting to hear back. (DEC says it is reviewing the proposal.)

“I’m shocked nobody will move forward from a state level and say this is what’s right,” said Wilcox, who owns Wiley’s Flies in Ray Brook.

He noted that state and local governments have spent millions of dollars to combat aquatic invasive species such as milfoil and spiny water fleas. “We’re going to put boat-washing stations in what sounds like every lake eventually. You’re going to have all this stuff about that, yet we continue to stock invasive species in our rivers year after year. It’s weird. It’s really odd to me,” he said.

Wilcox said other states, such as Montana, Colorado, and Wyoming, have taken more aggressive steps promote wild trout populations in rivers and streams. In some cases, authorities not only stop stocking fish, but they also require anglers to kill non-natives after catching them. “These people out there, they fight tooth and nail for their wild native populations,” said Wilcox, who once lived in Colorado.

Often, he said, restoration programs require stocking of native species at the start until the population becomes self-sustaining – in a word, wild.

DEC has identified eleven heritage strains of Adirondack brook trout, fish that evolved in the region over thousands of years. The department monitors these fish and stocks certain strains in backcountry lakes and ponds in the hope that they will become self-sustaining.

Scientists say that protecting genetic diversity is key for the long-term survival of native fish species.

Generally, heritage strains in the Adirondacks are associated with lakes and ponds. For example, they include the Horn Lake strain, the Windfall Pond strain, and the Little Tupper Lake strain. Tim Mihuc, a scientist with the Lake Champlain Research Institute, says more research is needed to identify heritage trout in the headwaters of streams and rivers.

“There are probably many, many more genetic heritage strains of brook trout in the Adirondacks that we just haven’t discovered yet,” he said.

Smaller tributaries are often better able than rivers to support brook-trout populations because they flow through shady, forested areas and have been less impacted by humans.

The Ausable River Association, which supports Wilcox’s proposal, is starting to take a harder look at brook-trout populations in the tributaries of the East Branch of the Ausable River. Brown trout are stocked in at least two of those tributaries—Norton and Otis brooks—that may contain wild brook trout.

Kelley Tucker, the association’s president, said the habitat in the main stem of the river has been degraded to the point that it is too warm in summer to support wild brook trout. Nevertheless, some people say it’s possible that wild trout do move in and out of the main river from the tributaries.

Tucker said her dream is to see the habitat of the East Branch restored so wild trout can live there again.

John Mills, former president of Paul Smith’s College and a member of Trout Unlimited, is a big supporter of Wilcox’s proposal and thinks the Adirondacks would greatly benefit from having more wild brook-trout populations in rivers and streams, not just ponds.

“If you build heritage and unique fisheries it becomes an economic engine because the rabid fly fisherman and trout fisherman will spend a lot of money to catch even a small brook trout as long as it’s a native,” Mills said.

DEC stocks streams and rivers with brook trout, but they are hybrid or mongrel strains raised in hatcheries. Some anglers say these fish are not as colorful or as rewarding to catch as native brookies. Moreover, hatchery fish stocked in streams and rivers tend to survive for only a year or two—meaning the department must restock them year after year to accommodate anglers.

If DEC were to stop stocking brook-trout waters, however, the native fish might get fished out, which likely would create an outcry among anglers. Wilcox’s solution is to impose stricter regulations to protect the wild trout from overfishing.

“There’s thousands of river miles that exist within the Adirondack Park, but there’s less than fifty miles of catch-and-release trout water, and to my knowledge there’s zero catch- and-release brook-trout water in a stream,” he said. “That just shocks me.”

Jack Williams, a senior scientist with Trout Unlimited’s national organization, said state agencies often feel a lot of pressure from the public to stock fish for anglers instead of looking at why waterways aren’t supporting fish.

“The hatcheries become too easy an answer to the problem of not having enough fish in the streams from an angler’s perspective,” Williams said, “when really we should be taking a harder look at those stream conditions and the factors that are really influencing degradation of those streams as the way to improve our trout fishing.”

Williams, who lives in Oregon, says stocking is beneficial in some waters, but it shouldn’t be done where populations of native fish exist. He said putting hatchery fish into waters with native fish can wipe out the genetic heritage of a population that evolved over hundreds or thousands of years.

“That’s one of the big issues with fish stocking is that by stocking the non-native fish into those habitats, we really tend to swamp out some of those native genes in the native trout,” he said. “Ironically, stocking non-native trout is one of the big threats to native fish.”

Stocked Fish

The state Department of Environmental Conservation uses the Catch-Rate-Oriented- Trout-Stocking model to determine the species and numbers of trout to stock in water bodies, according to DEC spokesman David Winchell. The model takes into account a number of factors, including water temperature, habitat, presence or absence of native trout species, and fishing pressure.

DEC does not stock any species of trout (brown, rainbow or brook) where there is a viable population (75 percent of the water’s carrying capacity) of wild brook trout. In addition, Winchell said DEC does stock brown trout in waters with brook trout if the habitat is unfavorable to brook trout and the brown trout will not have a negative impact on the brook-trout population.

Below are trout and salmon species stocked in Adirondack waters.

Adirondack heritage brook trout
Windfall strain. Stocked in lakes and ponds.
Little Tupper strain. Stocked in lakes and ponds.
Horn Lake strain. Stocked in lakes and ponds.

Domestic-strain trout*
Brook trout. Stocked as yearlings in rivers and streams in spring.
Rainbow trout. Stocked in rivers, streams, lakes, and ponds.
Brown trout. Stocked in rivers, streams, lakes, and ponds.

Hybrid brook trout
Domestic crossed with Temiscamie strain (originally from Quebec). Stocked in lakes and ponds in fall.

Domestic crossed with Windfall strain. Stocked in lakes and ponds in fall.

Landlocked salmon
Sebago strain (originally from Maine).

*Domestic trout are hatchery trout whose origin is unknown.

Photos, from above: an angler with a rainbow trout (photo by Nancie Battaglia); an angler on the West Branch of the Ausable (Nancie Battaglia photo); Gay Barton casts for trout in the West Branch of the Ausable (Nancie Battaglia); Flies used to catch trout (Nancie Battaglia); Brook Trout (photo by Larry Master).

This story originally appeared in the Adirondack Explorer, a nonprofit newsmagazine devoted to the protection and enjoyment of the Adirondack Park. Get a full print or digital subscription here.