SEASONAL ACTIVITY, RELATIVE ABUNDANCE, AND SIZE-CLASS STRUCTURE OF THE AMERICAN ALLIGATOR (ALLIGATOR MISSISSIPPIENSIS) IN A HIGHLY DISTURBED INLAND LAKE

Abstract

We monitored an inland population of American alligator (Alligator mississipiensis) in Lake Raven, Huntsville State Park, Walker County, Texas from September 2000 to August 2001. We found alligators exhibited year-round activity in Lake Raven, with the lowest occurrence of alligators in December and January. The greatest numbers of alligators were surveyed in June and September. However, in September, 47% of the observed individuals were hatchlings. Water temperature was a significant predictor of alligator activity over air temperature and explained 37% of the observed variation in seasonal activity. A population index estimated that Lake Raven supported 0.19 alligators per hectare, with most of these alligators being juveniles and in the size class of 0.6 to 0.9 m. We also found alligators used all regions of the perimeter of the lake and were observed mostly 5 m from the shoreline. Because there is limited information on inland alligator populations in Texas, this study offers information on the seasonal activity, relative abundance, and size-class structure of alligators inhabiting a relatively small (85 ha) and highly disturbed inland lake. This information might be useful for future studies and comparisons with coastal alligator populations.