The fishes of the Connecticut River include members of three evolutionary lines

At the close of the last ice age and the draining of Lake Hitchcock about l2,000 ybp, the Connecticut River came into being. This essentially fishless waterway was populated by species from southern and coastal freshwater encironments. According to Whitworth (1996), perhaps 22 freshwater species immigrated into the Connecticut River basin. Interestingly, some of the freshwater fish species that dominate the river did not get here "naturally" but were introduced by humans. These fishes include: carp, northern pike, bowfin, rainbow trout, brown trout, channel catfish, rock bass, bluegill, smallmouth bass, largemouth bass, white crappie, black crappie and walleye.

Some fishes must spend part of their lives in both fresh and salt water (diadromous species); these species had less of a problem colonizing the Connecticut River after the last Ice Age. Examples of diadromous fishes include shad, American eels, sea lampreys and salmon.


Hartel, K.E. 1992. Non-native fishes known from Massachusetts freshwaters. Occasional Reports of the MCZ Fish Department (Harvard University), Number 2.

Whitworth, W.R. 1996. Freshwater Fishes of Connecticut. State Geological and Natural History Survey of Connecticut. Second edition, Bulletin 114.

Visit the Conte Website for more information on fish and fish research in the Connecticut River.