Diel and Seasonal Patterns of Spotted Gar Movement and Habitat Use in the Lower Atchafalaya River Basin, Louisiana

Abstract

Abstract We used radiotelemetry to determine diel and seasonal movements, habitat use, and home range behavior of 37 adult spotted gars Lepisosteus oculatus in the Atchafalaya River basin, Louisiana. The Atchafalaya River exhibits a distinct spring flood pulse each year, inundating a 3,640-km2 floodplain that includes a complex network of canals, bayous, and lakes. During nonflood months, diel locations of 27 fish recorded at 2-h intervals (median = 24 locations/fish) indicated that most spotted gars were shoreline oriented (P < 0.0001), preferred submerged branches as cover, and avoided areas of exposed bank (P < 0.0001). Median spotted gar movement rates were higher during summer (40.4 m/h) than fall–winter (15.1 m/h), and during both seasons, rate of movement and percentage of home range used were significantly greater at night than during dawn, day, or dusk periods (P < 0.03). Increased nocturnal activity appeared to be related to feeding periodicity, as a substantially greater proportion (70%) of spo...