Relative Abundance, Distribution, and Population Metrics of Shoal Bass in Alabama

Abstract

ABSTRACT The shoal bass (Micropterus cataractae) is native to the Chattahoochee drainage in Alabama and is considered a lotic habitat specialist that prefers rocky and shoal areas. In 2004, shoal bass was listed as a species of conservation concern within Alabama, but recent surveys on the status of this fish in the state have not been conducted. From 2005 to 2007. we sampled four tributaries of the Chattahoochee River in east central Alabama to determine the amount of shoal habitat and estimate shoal bass relative abundance and occurrence. Fifty kilometers of the four streams were surveyed, and onl) 5.5 kin of shoal habitat were found. The amount of shoal habitat was similar among all four streams but shoal bass were common (N = 110) at only one site. Shoal bass were infrequently collected in the other three streams (N total = 10); spotted bass (Micropterus punctulutus) and to a lesser extent largemouth bass (Micropterus salmoides) dominated the black bass communities even though suitable shoal habitat was present. At one site that contained 1.7 ha of shoal habitat, shoal bass survival was 82% over a six-month period during normal flow conditions but declined to 22% as a severe drought greatly reduced water flows. Corresponding to this decline in survival, population estimates declined from 69–107 shoal bass (≤ 150 mm) to 13–23 fish over a two-year period. Anecdotal evidence indicated shoal bass were previously more common in Alabama tributaries of the Chattahoochee River, but currently this fish is in low abundance and in isolated populations with little or no connectivity among them.