Movements and habitat use of a river leviathan, alligator gar

The Fourche LaFave River of Arkansas holds a viable alligator gar population.  The relatively unaltered river maintains connectivity with floodplain spawning locations.  During four expeditions over two winters, 32 adult alligator gar were captured on the Fourche LaFave River and tagged with radio transmitters, t-bar tags, and PIT tags.  Sizes (147.0 – 224.0 cm, 25.0 – 84.5 kg) ranged widely.  Fish were tracked from January 2009 through the summer of 2010.  Tracking focused on the 37-km reach ending at the confluence with the Arkansas River.  Analyses reflect behavioral seasonality in use of the main channel, floodplain, and tributary macrohabitats.  Before May 2008, a mean 78.9% of individuals’ locations were main channel locations versus other macrohabitats.  During the May-June spawning period, a mean 86.1% of individuals’ locations were tributary locations.  Analyses are for fish located three or more times on non-consecutive days.  Overwintering aggregations have been documented in the same area since 2007, with recaptures indicating site affinity.  During other seasons, the gar associated with structure in the main channel.  Most existing alligator gar life history data are not from riverine populations.  This study provides critical data and direction for future studies and stewardship for periodic fishes in similar watersheds.