Document Type
Article
Journal/Book Title/Conference
North American Journal of Fisheries Management
Volume
29
Issue
4
Publisher
American Fisheries Society
Publication Date
2009
Keywords
bass, habitat, Micropterus, prey, periphyton, chlorophyll, algae, benthic, invertebrates, insects, density, abundance, artificial, vegetation, reservoir, structure, nutrients, fish, fisheries, management, juvenile, food, survival
First Page
1119
Last Page
1129
Abstract
Many reservoirs in arid regions experience highly variable water levels caused by seasonal inflow fluctuations and designated outflow requirements. At Shasta Lake, California, managers plant cereal-grain grassbeds on exposed drawdown shorelines to increase juvenile fish habitat, localize productivity, and increase invertebrate fish prey. To determine the efficacy of these plantings, the abundance of juvenile black basses Micropterus spp. (20–55 mm standard length) and the amount of periphyton and macroinvertebrate prey were compared among three treatment types: (1) planted grassbeds of cereal barley Hordeum vulgare; (2) artificial rope grassbeds, which eliminated physical deterioration and nutrient release; and (3) nonplanted control sites with predominately sand and gravel substrates. In comparison with control areas, juvenile black bass abundance averaged 54 times higher in planted grassbeds and 230 times higher in artificial grassbeds. Periphyton (chlorophyll a) and benthic invertebrate biomass did not differ significantly between planted grassbeds and control sites. In artificial grassbeds, periphyton was more than two times the control levels, and benthic invertebrate biomass was more than 12 times the control levels. We conclude that the long-term availability of physical structure, rather than nutrient release associated with decomposition of grassbed materials, drives use and effectiveness of grassbed treatments. Future management decisions in drawdown reservoirs should emphasize increasing long-term availability and integrity of physical habitat for juvenile fishes in the littoral zone.
Recommended Citation
Ratcliff, D.R., W.A. Wurtsbaugh and J. Zustak. 2009. Evaluating the effectiveness of grass bed treatments as habitat for juvenile bass in a drawdown reservoir. N. Am. J. Fisheries Management. 29:1119-1129.
Comments
Originally published by the American Fisheries Society.
Note: This article appears in the North American Journal of Fisheries Management and has been posted here with permission from the publisher.