Introduction to Fisheries Management Habitat Management December 7, 2004 Chapters 10 and 11 Introduction to Fisheries Management

Lake and Reservoir Habitat Management Stream Habitat Management

Lake and Reservoir Mgt. 200 ha or larger (~500 acres) Lakes – natural bodies of water Reservoirs – artificial controlled lake

Common Habitat Problems in Lakes Nutrient Loads and Eutrophication (Oligotrophic, Mesotrophic, and Eutrophic) Dissolved Oxygen Acidification Nuisance Vegetation Deterioration of Shoreline Habitat Lack of Structural Complexity

Eutrophication and DO Stratification acts as habitat; temperature and DO; epilimnion often too hot, but hypolimnion often has no DO. Destratification, Aeration, Control of Nutrient Inputs, Biomanipulation

Acidification Acid precipitation a large problem in part of Europe and North America Treatment with lime; retention time >6 months.

Nuisance Vegetation Chemical, mechanical, and biological controls Mechanical controls can be implemented to improve fish habitat (increases edge for ambush predators) Reduce amount of nutrients coming in to the lake/reservoir

Lake Shore Erosion Control Grading Slopes Construction of retaining walls Revegetation Reducing energy of incoming waves Wake limits

Fluctuations in Water Levels Reservoirs, particularly hydropower peaking facilities, can fluctuate greatly and dewater fish nests and reduce habitat availability Reduces aquatic vegetation

Management with Water Fluctuations Many fishes use flooded riparian zone (northern pike, perch, largemouth bass) Control of aquatic vegetation (both to improve populations and reduce nuisance species) Devils Lake, WI Lake Powell, AZ

Shoreline Management Riparian zone is the area of the greatest direct influence on lakes Many lakes require landowners to maintain riparian conditions

Artificial Structures Generally best in habitat limited systems Attraction vs. Production Debate Provide a good opportunity to interact with the public.

Stonewall Jackson Lake, West Virginia