The fisheries potential of a new prairie reservoir : a management perspective

Abstract

Reservoirs are the predominant standing water in the prairie regions of North America and provide major sport fishing opportunities. Reservoirs are young aquatic ecosystems. This study investigates trophic dynamics of reservoirs from three different perspectives: littoral productivity by morphometry and hydrological regimes in reservoirs; zooplankton development and production in a new reservoir; and the impact on growth and recruitment of a top predatory fish lacking appropriate food resources. Water level fluctuations significantly reduce littoral productivity and shift trophic energy flows towards pelagic resources. Pelagic production is positively influenced by appropriate nutrients and increased water residence time. A lack of intermediate zooplanktivorous fish species weakens the link between pelagic primary production and higher trophic levels. The resulting simplified food webs reduce growth and recruitment of top predatory fish. Thus, management must consider introducing species capable of linking the various resources within a reservoir to optimize the fishery potential.