Morphometric Analysis of the Harris Mud Crab (Rhithropanopeus harrisii) in Lake Texoma

Abstract

Harris mud crab, Rhithropanopeus harrisii, is a small crab native to the brackish waters of the Atlantic coast of North America. Today, R. harrisii exists well beyond its native range and in a wide variety of habitats, including freshwater reservoirs. R. harrisii was discovered in Lake Texoma in 2008 and is thought to have originated from Texas estuaries. The objectives of this study were to gather and describe the morphometrics of R. harrisii from Lake Texoma and document sex ratio, carapace size distributions, and handedness. Individuals were collected from August 2019 to August 2021 from six sampling sites located along the Oklahoma side of Lake Texoma. Various morphometrics were recorded from 1,326 crabs. Most crabs in the study were right-handed and they were smaller than crabs reported from other locations. Small size could be result from stressful conditions or early fatality. While there was no significant difference in average carapace size between males and females, males made up the highest percentage of large size classes. Males were also more numerous in the population and often attained larger claw sizes than the females. This is thought to be beneficial in intraspecific competition for females.