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

Abstract

Harris mud crab, Rhithropanopeus harrisii, was first reported in Lake Texoma in 2008. Since that time, very little research regarding this population has been conducted. Goals of this study included determining reproductive periods, noting microhabitat preferences, and documenting the distribution of crabs in Lake Texoma. Six sampling sites were established on the Oklahoma side of Lake Texoma along a transect from the OU Biological Station to near the Denison Dam. Sites were sampled from August 2019 to August 2021. A total of 1,396 crabs were observed with 1,326 collected for analyses. Results indicated a significantly male-dominated sex ratio in the population. Abundance and distribution of crabs varied across the lake, likely due to salinity values and microhabitat availability of each site. Population densities in Lake Texoma were higher than those observed in other locations. Seasonal trends noted the difference in crab frequency during the warm and cool seasons. A rapid drop in lake level during late winter of 2020 provided evidence these crabs migrate to deeper water to take refuge from cold temperatures. The presence of larvae and gravid females suggests a reproductive period from June to October and confirms the successful establishment of Harris mud crab in Lake Texoma.