Distribution of Fishless Habitat and Chaoborus in Northwestern Maine

Fishery Interim Summary Report Series No. 02-02

By Tim Obrey

Maine Department of Inland Fisheries and Wildlife
Fisheries and Hatcheries Division
Augusta, Maine

January 2002


There are nearly 6,000 lakes and ponds greater than 0.4 ha (1 a) in the State of Maine. To date, approximately 2000 (33%) of these waters have been inventoried by the Department of Inland Fisheries and Wildlife. Regional Fisheries Staff routinely survey a handful of the estimated 3,800 unsurveyed waters each summer. When surveyed, most of the ponds contain at least one fish species, but on occasion fishless ponds are located. As of 1998, 30 of the 2,076 waters in the Department’s lake inventory database were classified as fishless. A number of fishless ponds have been stocked with brook trout by the Department during the past 40 years. Recently, concerns over the ecological consequences of stocking fishless ponds are being raised within the Department. Specifically, these concerns include the lack of knowledge regarding the distribution and abundance of fishless ponds, the possible effects on rare or endangered species, and whether or not these types of communities are unique in Maine.

In this study potential fishless ponds in the Moosehead Lake Region were identified using the outlet slope as an indicator. A subsample of ponds was then surveyed to determine the presence or absence of fish. Macroinvertebrates, in particular Chaoborus spp., were sampled in a wide variety of waters in the region to determine distribution.

For more information or a complete report, please contact:

Tim Obrey
Maine Dept of Fisheries and Wildlife
Fisheries Division
650 State Street
Bangor, Maine 04401-5654
Tel #207-941-4719
Email tim.obrey@maine.gov