Freshwater Fish Community Data

Data about fish species and fish communities are routinely collected by CT DEEP in rivers/streams and lakes/ponds for a variety of reasons. The data presented in this application are either the number of each species counted during whole community sampling (quantitative) or being present (qualitative). The sample “type” is noted within the dataset. Please note, species numbers may not be directly comparable from one sample or location to another as sampling effort and/or gear type varies. 

For more information about CT’s freshwater fish species, visit freshwater fishes of CT. Questions about the data should be directed to deep.inland.fisheries@ct.gov or 860-424-FISH.

Historic Data in this Application:

1930s and 1950S Fishery Survey of the Lakes and Ponds of CT – Data were collected using seine and gill nets during the summers of 1953-1955. The surveys were intended to collect fish species, water chemistry, aquatic habitat, and macroinvertebrates during both 1937-1939 (A Fishery Survey of Important CT Lakes, CT Geological and Natural History Survey Bulletin 63, 1942) and 1953-1955 (A Fishery Survey of Lakes and Ponds of Connecticut, 1959). During these surveys, fish were collected at 10 to 15 stations along the shoreline with minnow seines of various lengths. To obtain larger fish, gill nets of various mesh were deployed at depths of 4 to 10 feet throughout the waterbody.

About the App

Fish Community Sample Locations (dots): Only one dot is visible on the map regardless of the total number of samples collected at the location over time. Each dot represents a unique “station id”. To see additional samples at the location, toggle the arrows located at the top left of the pop-up window.

Features of the Application

Widgets (right side of the header bar)

Filters – opens a dialog box with option to filter the data set. Filters are not nested or additive, meaning the application will only filter on one option and not filter on a filter (e.g., filter a fish species within a municipality).

To clear all filters – select the counterclockwise arrow at the lower right corner of the filter dialog box.

Fish Species – selecting the name of a fish returns the locations and samples where the selected fish species has been observed.

Town Name – selecting a town returns fish community data for samples within the selected town (municipality).

County –selecting a county returns fish community data for samples within the selected county.

Sample Year – selecting a year returns fish community data collected during that year.

Waterbody – selecting a waterbody returns fish community data for all waterbodies with that name. Note: as there are multiple waterbodies with the same name (e.g., Beaver Brook), additional data refinement may be required after exporting the results.

Subregional Basin Code – selecting a subregional basin code returns fish community samples collected within that subregional basin as found in this dataset. To identify the four-digit subregional basin code of interest, please refer to the Subregional Basin Layer.

Station ID –is a number unique to a sample location (latitude and longitude). Selecting a station id returns fish community data collected at this one specific location.

Table – use the table icon to open the attribute table for the fish community data.

Refresh – updates data based on the current view.

Show/Hide Columns –allows you to customize the columns that are visible by toggling on or off.

Exporting data – to export the selected data into one of several formats, select the “actions” widget (four circles in a square) on the right side of the table view and choose the file type you prefer.

Data Layers – the user can select from the following layers to display on the map by toggling the desired data layer on/off.

• DEEP Properties –properties owned/managed by CT DEEP.
• Subregional Drainage Basins – Watershed Boundaries and Subregional Basin Code Number (four digits).
• Connecticut Towns – Boundaries and attributes for the 169 towns.

Legend – displays symbology based on the current layers being displayed.

Basemap – changes the background of the map to one of several options.

• Topographic
• Imagery with labels
• Open street map

Print – allows the user to print or save as a PDF for the view on the screen. Customize the title and select the output format.

Please contact the Fisheries Division with any questions. 

Phone: 860-424-FISH (3474)
E-mail: deep.inland.fisheries@ct.gov

Content last updated in January 2025.