Scheuerell, M. D. University of Washington, scheuerl@u.washington.edu
Schindler, D. D. University of Washington, deschind@u.washington.edu

 
THE EXTENT OF SPATIAL AGGREGATION OF PREDATORS AND PREY IN LAKES
 
Due to the heterogeneous nature of aquatic habitats and the high mobility of some aquatic organisms, assumptions of homogeneously distributed predators and prey are likely to be seriously violated. For example, fish and zooplankton are often highly aggregated in patches that comprise a small proportion of total lake volume. We analyzed the spatial distributions of fish during the day and night in 15 lakes in the Pacific Northwest using high frequency hydroacoustics. We estimated that during the day fish used as little as 10 percent of available lake volume. Fish occupied a greater proportion of lake volume during the night as they became less aggregated. The degree of aggregation also changed across a lake productivity gradient suggesting shifts in the use of benthic and pelagic prey. These findings support the contention that ecosystem models incorporating predator-prey interactions give consideration to the spatial dynamics of both predators and their prey, and are especially relevant to studies that try to extrapolate the results of small scale experiments to entire ecosystems.
 
Day: Thursday, Feb. 4
Time: 09:15 - 09:30am
Location: Hilton of Santa Fe
 
Code: SS22TH0915H