Diel and seasonal patterns of spotted gar movement and habitat use in the lower atchafalaya river basin, louisiana

Document Type

Article

Publication Date

1-1-1999

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 werehigher 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 spotted gars collected at night (N = 30) contained food compared with dawn, day, and dusk samples (29%; N = 90). Seasonal movement studies (twice-weekly locations; N = 37 fish) indicated that spotted gar activity increased as water temperature and river stage rose in the spring, resulting in greater median movement rates (130.1 m/d) and home ranges (265.1 ha) than during fall–winter (35.8 m/d; 6.2 ha) and summer (34.6 m/d; 10.5 ha). Spotted gar home ranges established during the flood pulse typically includedlarge areas of inundated floodplain, which provided extensive areas of suitable spawning and nursery habitat. © 1999 Taylor & Francis Group, LLC.

Publication Source (Journal or Book title)

Transactions of the American Fisheries Society

First Page

144

Last Page

154

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