Summer Habitat Use of Large Adult Striped Bass and Habitat Availability in Lake Martin, Alabama

Abstract

AbstractTo identify the summer habitat use by Gulf strain Striped Bass Morone saxatilis in Lake Martin, Alabama, 36 fish greater than 4 kg were tracked weekly from June through September in 2009 and 2010. Temperature and dissolved oxygen profiles were collected biweekly from July to October each year and were incorporated into a hypsographic curve to estimate summertime volumes of Striped Bass habitat. Striped Bass moved downstream in the reservoir and deeper in the water column as the summer progressed in both years. Across all temperatures and dissolved oxygen concentrations (DOCs) measured, fish generally selected cooler temperatures when DOCs were greater than 3.1 mg/L, but below that level, fish selected warmer temperatures. By early July each year, quality Striped Bass habitat (≤21.0°C and ≥3.2 mg/L DOC) comprised 40–50% of the total habitat available in Lake Martin. However, in 2009 all quality habitat was gone from the reservoir by August 1, and total habitat (≤25.0°C and ≥1.6 mg/L DOC) rapidly decreased until there was no suitable habitat found in Lake Martin by mid‐September. The quantity of quality and total habitat declined more rapidly in 2009 than in 2010; although quality habitat was eliminated from the reservoir by the end of August 2010, total habitat persisted throughout the summer. In both years, habitat availability increased when reservoir destratification began. Analysis of historical data indicated that quality habitat was found in the lower portion of the reservoir during the latter half of August in only 6 of 15 years; total Striped Bass habitat was available in all but 1 year. The amount of water flowing through the system during the spring and summer was a key determinant of Striped Bass habitat availability by late summer.Received September 26, 2012; accepted May 15, 2013