Relation of Habitat to Fish Community Characteristics in Small South Dakota Impoundments

Although general habitat characteristics are available for many South Dakota waters, the relation of habitat to fish populations and communities in small South Dakota impoundments has not been extensively researched. Most of the research on small South Dakota impoundments has focused on fish community structure and predator/prey relationships. Previous research revealed that largemouth bass Micropterus salmoides relative abundance in small South Dakota impoundments was positively correlated with aquatic vegetation coverage and Secchi disk transparency. The objectives of my research were tri-fold: 1) to quantify the available aquatic habitat in 24 small South Dakota impoundments, 2) to investigate the use of geographic information system technology to create aquatic habitat layers, and 3) to determine the relation of abiotic and biotic habitat characteristics to fish growth, size structure, body condition, and relative abundance in small South Dakota impoundments by June 2003. Aquatic habitat was surveyed during the summers of 2000, 2001, and 2002 and was highly variable among small South Dakota impoundments. Typically, these waters were categorized as having relatively shallow depths, moderate-high aquatic vegetation coverage, and irregular shorelines. In addition, many of the study impoundments appear to have been impacted by moderate to severe siltation rates since their creation in the 1930\u27s. Drought conditions during summer 2002 resulted in low water l evels in several impoundments and thus emergent vegetation was likely under-represented in these impoundments. Accuracy assessment of habitat layers created using various geographic information system techniques suggested that reasonable accuracy (\u3e 70%) can be obtained using various techniques. However, the use of a modified point-interpolation technique tended to create a more realistic and accurate map. In addition, results suggested that to obtain the most accurate map, researchers should reference all known habitat areas (e.g., boulder rip-rap and emergent vegetation) using global positioning system units and then incorporate an adaptive sampling regime, and finally utilize the modified point-interpolation technique. My results did not reveal any statistically significant associations between habitat and fish community characteristics in small South Dakota impoundments. Results could have been strongly influenced by a reduction in sample size from 24 to 13 impoundments, which was the result of compounded environmental effects on the fish communities (i.e., fish kills). In addition, the small sample size and concerns with reliability of standard fish community survey data (seasonal variation) limited my investigation of the relationship between habitat and species relative abundance and growth. Overall, aquatic habitat in small South Dakota impoundments was quite diverse yet readily supports aquatic life in almost every system. Additional aquatic habitat surveys, integration of an aquatic habitat monitoring system, and incorporation of recent technologies into standard fish community surveys would greatly assist in small South Dakota impoundment fishery management