Introduced Fish in Maine
David B. Halliwell (Spring 2005)
What is an introduced species?
What is an introduced species?
By these definitions, introduced fishes in Maine (n = 20+) include a large number of established nonnative and native sport (game) and forage (bait) fish species comprising: (1) illegal transplants2 (e.g., black crappie, bluegill, central mudminnow, green sunfish, northern pike, and walleye); and (2) historic legal stockings2 - but also, in many cases, illegally transplanted (e.g., landlocked rainbow smelt, alewife, and white perch; chain pickerel, smallmouth and largemouth bass, and yellow perch). According to an article in the Bangor Daily News (May 13, 2002), Maine Department of Inland Fish and Wildlife fishery biologists have (recently) estimated that "more than 500 illegal fish (introductions) have been made into Maine (inland) waters since 1980, and about half of these species were not native to Maine" (hence, the other one-half are Maine native fishes!).
A third group of 'introduced' fishes comprise highly managed, hatchery-reared, and widely stocked salmonids (i.e., landlocked Atlantic salmon, brook, brown, and rainbow trout, lake trout, and splake - hybrid between lake and brook trout), in addition to introduced landlocked forage populations of rainbow smelt and alewife. Landlocked Atlantic salmon and rainbow smelt (Warner 2001) are truly indigenous to individual lakes in only four separate Maine river drainages: Presumpscot - Sebago Lake; St. Croix - East and West Grand Lake; Penobscot - Sebec Lake; and the Union - Green Lake (Warner and Harvey 1985).
Following is a listing of species within representative groups of introduced fishes occupying Maine waters (see Appendix A for scientific nomenclature). This listing is also applicable to freshwaters throughout New England, with the exception of the Lake Champlain drainage system in western Vermont - which is characterized by a more diverse indigenous fish fauna, as influenced by the richer species pool from the Great Lakes fish fauna (Halliwell et al. 1999).
Currently, there are 63 fish species established or populating Maine freshwaters (= 60 reported by Halliwell et al. 1999 + central mudminnow, bluegill and green sunfish), not including walleye, and gizzard shad - which are represented in Maine by only adult fish at this time, with no known natural reproduction occurring. Nearly one-third of Maine’s existing resident fish fauna were introduced from out-of-state, both legally by State/Federal fishery agencies (e.g., smallmouth and largemouth bass, brown and rainbow trout) and illegally by unauthorized introductions (e.g., green sunfish, bluegill, northern pike, muskellunge, and central mudminnow). There are also hundreds of records of both authorized and illegally introduced land-locked populations of native coastal and inland fish species (e.g., primarily white perch, rainbow smelt and golden shiner, but also several records of landlocked alewife, as well as numerous historical transplant records for chain pickerel and yellow perch. Illegal fish introductions to Moosehead Lake include yellow perch (mid-1950's), smallmouth bass (mid-1970's), and white perch (1984) - all of which have become established to the detriment of the wild brook trout fishery (Maine DIFW Lake Report, 2003 update). Introduced fish species inhabit a multitude of inland Maine water bodies statewide as a result of both historical and current legal sport/forage fish stockings and illegal sport/bait fish transplants. The indiscriminate and unauthorized distribution of any fish species, whether they be Maine natives or exotics, must be prevented, at all costs, in order to protect and sustain the biological integrity and future of Maine's valuable aquatic natural resources.
The introduction (intentional release) of any fish species (from any source), without a permit from the Maine Department of Inland Fisheries and Wildlife, is a Class E crime, punishable by fines up to $10,000, including jail time and loss of license to fish. A new Maine law took effect on June 23, 2003, which prohibits the transport of all live fish from their natural place of origin - with the exception of legally permitted baitfish species, inclusive of rainbow smelt. A $2,000 reward is offered for information leading to the apprehension of the person or persons responsible for the illegal introduction of fish into any inland water in Maine. This would include releases of unwanted aquarium fish species and the dumping of live baitfish into a foreign waterbody at the end of a day's fishing! The environmentally responsible and acceptable action is to dispose of unwanted bait by leaving on the land or ice to provide food for mammalian and avian scavengers. To report violations of Maine's Fish and Wildlife laws, call Operation Game Thief at 1-800-ALERT-US (1-800-253-7887).
Thanks to Peter Vaux (University of Maine, Senator George J. Mitchell Center), Dave Courtemanch and Barry Mower (Maine DEP) and the following fish and wildlife professionals, for their critical review of this paper and as primary sources for Maine freshwater fish status and occurrence information - including Maine DIFW retired (Owen Fenderson and Robert Foye - deceased, Matt Scott, Ken Warner, Fred Kircheis) and active biologists: Forrest Bonney, Dave Boucher, Francis Brautigam, Scott Davis, Phillip deMaynadier, Merry Gallagher, Paul Johnson, Jim Lucas, and Bill Woodward; Maine DMF: Nate Gray and Jim Stahlnecker (past); Brandon Kulik (Kleinschmidt Associates) and Chris Yoder (Midwest Biodiversity Institute). Thanks also to a host of newspaper writers for their active interest and timely reporting of introduced fish related happenings, including: Dwayne Rioux (past), Ken Allen, Joe Rankin, and Jonathan Humphrey (Morning Sentinel and Kennebec Journal); Deirdre Fleming (past), Misty Edgecomb, John Holyoke and Terry Farren (Bangor Daily News), and contributors from the Associated Press, as commonly published in the Portland Press Herald.