Backwaters in the upper reaches of reservoirs produce high densities of age-0 crappies

North American Journal of Fisheries Management
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Abstract

Reservoir backwaters are aquatic habitats in floodplains of reservoir tributaries that are permanently or periodically flooded by the reservoir. Like many reservoir arms, backwaters are commonly shallow, littoral habitats, but they differ from arms in various respects, including their support of primarily wetland plant assemblages that are tolerant to flooding. Elsewhere, the reservoir floods mainly upland plants that are less tolerant to flooding, producing a band of barren shoreline along the fluctuation zone. We investigated differences in relative abundance of age-0 crappies Pomoxis spp. in backwaters and arms of widely fluctuating flood control reservoirs, examined the effect of water level, and estimated the likelihood and timing with which these habitats are flooded annually. Higher catch rates of age-0 crappies were obtained in backwater habitats than in arm habitats. When inundated during the crappie spawning season, backwaters provided vegetated habitat at lower water levels than arms. Backwaters flooded earlier than arms and remained flooded longer to provide prolonged nursery habitat. Whereas vegetated habitat was inundated almost yearly in backwaters and arms, inundation that was timed to the onset of spawning occurred less regularly. Because of differences in water elevation, vegetated habitats were flooded in time for crappie spawning about every other year in backwaters but only every third year in arms. Recruitment of age-0 crappies was inversely correlated with high water levels during the months preceding the spawning period, perhaps because early flooding degraded the vegetation. Our results suggest that water levels may be managed during late winter and spring to regularly flood wetland vegetation communities in backwaters; however, water levels should be maintained at or below normal pool and should only irregularly flood upland vegetation in reservoir arms to promote the preservation of such vegetation. Furthermore, management efforts to enhance crappie recruitment should consider the enhancement and preservation of backwaters.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Backwaters in the upper reaches of reservoirs produce high densities of age-0 crappies
Series title North American Journal of Fisheries Management
DOI 10.1080/02755947.2012.675948
Volume 32
Issue 4
Year Published 2012
Language English
Publisher Taylor & Francis
Contributing office(s) Coop Res Unit Atlanta
Description 9 p.
First page 626
Last page 634
Country United States
State Mississippi
Other Geospatial Arkabutla Lake, Sardis Lake, Enid Lake, Grenada Lake
Online Only (Y/N) N
Additional Online Files (Y/N) N
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