Illegal Fish Stockings Threaten Maine Lakes and Rivers

illegal fish stocking

Maine's lakes and rivers have been plagued with an epidemic of illegal fish introductions that pose real and immediate threats to our native fish fauna. Some recent examples:

Northern Pike, illegally introduced into the Belgrade Chain of Lakes in the 1970's, are now present in at least 16 lakes in the Kennebec, Androscoggin, and coastal river drainages. They are suspected to occur in several additional waters. These newest populations have been derived from illegal transport or by out-migration from lakes were they have become established. Pike are voracious predators on other fishes, and their presence in one lake is suspected of destroying one of the state's premier landlocked salmon populations. Know the difference between Northern Pike and Chain Pickerel.

Smallmouth and largemouth bass are both non-natives but widely established in southern, central, and parts of eastern Maine. Since 1986, Maine fishery biologists have determined that illegal introductions have established new populations in 57 additional lakes! One of these illegal stockings occurred at Umbagog Lake in the upper Androscoggin River drainage, where they now threaten one of our nation's premier wild brook trout populations. Largemouth bass are being illegally introduced into many Downeast waters at an alarming rate with unpredictable consequences to long established, economically important smallmouth populations.

The Black Crappie is an exotic species that until recently was restricted to about a dozen lakes in the Presumpscot and Sebasticook River drainages. Since 1985, illegal stockings have expanded their range to 65 lakes in the Penobscot, Kennebec, and Androscoggin River drainages. Larger crappies are fish predators and may compete with native species.

Bluegill and Green Sunfish, both exotics, have only recently been discovered in several Maine lakes and streams. In 2002, both species were discovered in a small pond in central Maine - they have out-migrated to a stream that supports a fine native brook trout population, and they will soon colonize a large headwater lake in the Sebasticook River drainage. Their effects on native fish species are unknown.

Unauthorized introductions of invasive, exotic fish species are particularly destructive to Maine's native brook trout populations, but they may also cause irreversible changes to entire aquatic ecosystems by restructuring plankton and forage fish communities that have evolved since the last glacial retreat. Moreover, strategies to eliminate or control invasive fish are difficult to design and implement, costly, and almost entirely ineffective.

The illegal introduction of any fish into any Maine water is a Class E crime, punishable by fines up to $10,000! The Maine Department of Inland Fisheries and Wildlife is offering a minimum reward of $2,000 for information leading to the apprehension of persons responsible for the illegal introduction of fish. Call Operation Game Thief at 1-800-253-7887.

Submitted by:
David Boucher, Fishery Biologist, Maine Department of Inland Fisheries and Wildlife