In 2023, Massachusetts made national history. Gov. Maura Healey signed Executive Order 618, committing Massachusetts to set biodiversity conservation goals to protect land and water, restore critical habitats, and halt the accelerating loss of native species by sustaining biodiversity and connecting people to the natural world.
But one longstanding state practice directly undermines these ambitious goals.
Under Executive Order 618, all state agencies are required to support biodiversity conservation goals. The mandate is explicit: every state department and agency must align its actions with the protection of native species and healthy ecosystems. That includes the Department of Fish and Game (DFG) and its Division of Fisheries and Wildlife, also known as MassWildlife, which is responsible for the conservation of freshwater fish and wildlife in the commonwealth, including endangered plants and animals.
Each year, MassWildlife operates five hatcheries that collectively release nearly half a million trout into Massachusetts rivers, lakes, streams, and ponds. Nearly all these fish are non-native species bred solely to support recreational fishing — not to restore native ecosystems. This routine stocking of non-native fish stands in direct conflict with the state’s biodiversity mandate.
To understand why this practice persists, it helps to understand what fish stocking actually is. Stocked fish are raised in hatcheries, indoor facilities where fish eggs are gathered, bred and raised in artificial conditions and fed pellets in a controlled environment before being released into wild waterways. Hatcheries are notorious greenhouse gas polluters and discharge waste into waterways. While the practice is often framed as harmless — or even helpful — decades of research show that stocking non-native fish disrupts freshwater ecosystems and causes native species to decline. Stocked fish compete with native species for food and habitat, alter aquatic food webs, and increase stress on ecosystems already strained by climate change.
This is evident in the case of the Eastern Brook Trout (Salvelinus fontinalis), the only trout species native to New England. Brook trout depend on cold, clean, flowing water and are highly sensitive to warming temperatures. Across their native range, populations are estimated to have declined by roughly 50% over the past 25 years due to habitat loss, invasive species, and climate change.
Ironically, MassWildlife routinely stocks brown trout — an aggressive non-native species that tolerates warmer water — into streams that still support brook trout. As climate change shrinks cold-water habitat, this added competition further stacks the odds against native fish.
Department of Fish and Game Commissioner Tom O’Shea has acknowledged the severity of the crisis. In a 2025 interview with Mass Audubon, he warned that more than 450 species in Massachusetts are threatened, with hundreds more at risk. He noted that habitat loss, invasive species, and pollution — all of which are amplified by climate change — threaten our collective future. Brook trout are among those 450 species at risk. Continuing to introduce non-native fish into brook trout’s remaining, shrinking habitat contradicts both science and the department’s own stated concerns.
However, the problem of fish stocking goes beyond competition. Studies consistently show that stocked fish experience extremely high mortality rates, often exceeding 70 to over 90 percent within weeks to months of release. MassWildlife has acknowledged that most stocked trout die shortly after being released into the wild. That means hundreds of thousands of fish are raised, transported, and released knowing most will not survive. The resulting influx of decaying biomass raises concerns about nutrient pollution, as research indicates such events contribute excess nutrients to waterways and less oxygen, leading to poor water quality and harming aquatic life.
Despite the scale and cost of MassWildlife’s fish stocking program, Massachusetts lacks comprehensive monitoring of the ecological impacts of stocking. There are no statewide studies demonstrating that routine non-native stocking does not harm native fish, aquatic insects, or primary producers — organisms like phytoplankton and aquatic plants — that form the foundation of freshwater ecosystems. In conservation, the absence of evidence is not evidence of well-being, especially when research elsewhere overwhelmingly documents harm.
If the goal is protecting biodiversity, the path is clear. Habitat restoration works. Removing dams, reconnecting streams, protecting riparian forests, and restoring cold-water habitat support native fish and biodiversity. These approaches are widely endorsed by conservation scientists and angling organizations alike. They also align directly with the goals of Executive Order 618.
Public input matters, too. Massachusetts residents can learn more about the impact of fish stocking in their local waterways and find contact information for MassWildlife and the Department of Fish and Game at www.thebeatnews.org/BeatTeam/stop-stocking. Berkshire Environmental Action Team will host a webinar on Tuesday, March 3 at 6 p.m. about fish stocking and the actions residents can take to initiate change. Public pressure has already led to meaningful changes — after more than 60 residents and conservationists emailed and wrote to the MassWildlife Board, stocking in the upper Deerfield River ended in early 2025.
Massachusetts has set ambitious biodiversity conservation goals; now it must ensure its actions live up to that promise. Ending routine non-native fish stocking and redirecting resources toward strategies proven to support biodiversity and long-term ecosystem health would be a significant step toward protecting native species. If the state is serious about biodiversity leadership, it’s time to stop stocking fish destined to die and start restoring ecosystems designed to thrive.
Chelsey Simmons is the Stewardship Director of the Berkshire Environmental Action Team (BEAT), a nonprofit organization based in Pittsfield that serves all of western Massachusetts and beyond.