PARENT SESSION
Oral Session #26: Aquatic Ecology: Fish - Populations, life history, autecology. Presiding: M. Fox.
Tuesday, August 7, 2001. 8:00 AM to 12:00 PM. Hall of Ideas H.
Effects of habitat alteration on Great Lakes steelhead parr: an individual-based modeling analysis.
Tyler, Jeffrey1, Goller, Carlos1, Rutherford, Edward2, 1 2
ABSTRACT- Land-use change and habitat fragmentation by hydropower dams have reduced and degraded Great Lakes fish habitat by altering the natural temperature and flow regimes of Great Lakes tributaries. We developed a spatially-explicit, individual-based simulation model to study effects of habitat changes on the growth and survivorship of steelhead parr. The model focuses on parr because survivorship through this stage may have important effects on recruitment to the adult population. The model characterizes the environment as a linear series of cells with dimensions, substrate, water velocity and temperature designed to represent the Manistee River, MI. We simulate growth of parr with standard bioenergetics and foraging equations, give parr of larger sizes priority access to foraging stations, and link foraging rate to water velocity. Model individuals move about the environment with fitness-based habitat selection and movement distance rules. Parr mortality is based on length, condition and water temperature. Simulation experiments examine how changes in stream discharge, water temperature, and nursery area affect parr growth and survivorship. Our results suggest that steelhead parr growth and survivorship may be affected by initial parr density and interactions between parr density, water temperature and water velocity.
KEY WORDS: salmonid, individual based model, parr, habitat alteration