Chapter 4: Affected Environment - Aitkin County Government

4.4.10 FishThe lakes and rivers of the Headwaters generally have healthy fisheries. Walleye,northern pike, muskellunge, yellow perch, largemouth bass, smallmouth bass, bluegill,and crappie are the most common species sought after by anglers. Walleye tend to bethe most important game fish for most anglers. Some lakes are stocked with game fishspecies by the MDNR, but many are supported strictly by natural reproduction. Ingeneral, game fish populations are stable; however, increased fishing pressure has ledto decreased individual fishing success. In some cases, this has led to the perceptionthat the fishery is in decline. While in general fish populations are stable, the potentialfor future problems is increasing due to increasing human impacts.Other common fish species that can be found in some or all areas of the Headwatersinclude rock bass, pumpkinseed sunfish, sauger, whitefish, tullibee (cicso), shortheadredhorse, bullheads, white sucker, burbot (eelpout), bowfin (dogfish), common carp,common shiner, and rainbow smelt.A number of fish species are less common in the Headwaters and some are listed asspecies of special concern by the MDNR. The lake sturgeon, least darter, and pugnoseshiner are three species found in the study area that are listed as species of specialconcern by the MDNR. The American eel, longear sunfish, greater redhorse, and weedshiner are four species being considered for listing by the MDNR. Impacts to these andother non-game fish species have been considered during the ROPE study. Nofederally listed threatened or endangered fish species are known to occur in theHeadwaters.4.4.11 Aquatic MacroinvertebratesBenthic macroinvertebrates are small animals that live in lakes and streams. They forman important link in the food chain as they provide food for fish while feeding on algaeand microscopic animals as well as contributing to the breakdown of plant and animaldebris. They primarily consist of insects that live part or all of their lives in the water suchas dragon flies, mayflies, black flies, whirligig beetles and various bugs likebackswimmers and water boatmen. Benthic macroinvertebrates also include smallcrustaceans such as scuds and crayfish, leeches and other worms, snails and clams(discussed elsewhere).Most benthic macroinvertebrates are mobile and can adjust to changing water levels byrelocating. During the winter some may be frozen if the lake bottom is exposed tofreezing.4.4.12 MusselsHistorically, as many as 39 mussel species including three federally listed species –Higgins eye mussel (Lampsilis higginsii), winged mapleleaf (Quadrula fragosa), and fatpocketbook (Potamilus capax) – and most state listed species in Minnesota have beenfound within the Headwaters basin. The mussel fauna below the Falls of St. Anthonywas historically and presently is far more diverse than the fauna above the Falls, a resultof the Falls itself, which historically served as a faunal barrier to the post-glacialHeadwaters ROPE Study 75