VALIDATION OF A FISH HABITAT MODEL FOR LAKES

Water temperatures and dissolved oxygen concentrations in 27 classes o f lakes have been hindcast by simulation models and related to presenc e of coldwater, coolwater, and warmwater fishes in 3002 Minnesota lake s. A one-dimensional, dynamic water quality model driven by 25 years o f daily weather data was used to model water temperature and dissolved oxygen profiles of these lakes. Fish presence data were available for these lakes from the Minnesota Lake Fisheries Data Base. Water temper ature and dissolved oxygen criteria derived from a very large United S tates Environmental Protection Agency fish-temperature database and di ssolved oxygen observations were used to define and link simulated wat er temperatures and dissolved oxygen conditions to suitability of habi tats for coldwater, coolwater, and warmwater fish assemblages. Good ag reement was found between fish presence and numerical simulations of f ish habitat defined by water temperatures and dissolved oxygen concent rations. Generally water temperature and DO are good indicators of sui table fish habitat.