Statewide Lake and Large River Electrofishing Survey

Warmwater Fish Monitoring Program 

Connecticut anglers spend over three million trips per year fishing for largemouth and smallmouth bass and other warmwater fish species (U.S. Fish and Wildlife Service, 2011). Prior to the 1980s, it had been 25 years since a major statewide lake and pond fisheries survey had been conducted. Therefore, the Connecticut DEEP Fisheries Division (FD) implemented a statewide night boat electrofishing survey of nearly 200 lakes, ponds and large rivers between 1988 and 1995. This survey provided fisheries management staff with invaluable information on fish populations throughout Connecticut. However, lakes are dynamic systems and information on parameters such as fish population structure, growth and mortality must be current to make informed management decisions.

In 1996, the FD began an ongoing statewide Warmwater Fisheries Monitoring Program that involves sampling approximately 100 sites by night boat electrofishing every 3 or 4 years. This monitoring program includes all of the state’s more important public lakes and ponds, plus large river sites in the Connecticut, Housatonic and Thames River drainages.  FD staff also sample a handful of large private lakes as well as some water supply reservoirs that are closed to angling. Sampling unfished and lightly fished water bodies gives us valuable insight into the fisheries potential of, and the effects of fishing on, our more heavily fished public waters.

Routine monitoring of lakes and ponds statewide allows us to have a “thumb on the pulse” of Connecticut’s warmwater fish populations. Beyond that, this program serves a number of directed objectives, which include:  determining the success of warmwater fish stocking programs (catfish, walleye and pike); assessing any effects that these stockings may have on other fish populations; assessing the effects of human-caused environmental disturbances such as lake drawdowns, herbicide treatments, dredging and introductions of invasive species (for example, zebra mussels and alewives); and monitoring the effects of climate change on Connecticut  fisheries.

The link below will bring you to a PDF file that contains fish catch data for every night boat electrofishing sample conducted by the IFD from the 1980s to 2018. This file will be updated as new data becomes available.

Statewide Lake and Large River Electrofishing Survey

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Content last updated October 2019