Life History of an Invasive Population of Allegheny Crayfish (Faxonius obscurus) in an Eastern Pennsylvania Stream

Abstract

Crayfish are key components of North American aquatic ecosystems, but information about their life history is typically lacking or incomplete. No such data are available for invasive populations of Faxonius obscurus (Allegheny Crayfish) in eastern Pennsylvania. I studied the life history of an invasive population in a small tributary in the Susquehanna River drainage of eastern Pennsylvania. Life-history characteristics (i.e., size at sexual maturity, sex ratios, seasonal shifts between reproductive and non-reproductive form in males, glair development, timing of ovigerous females, molting frequency, and size classes) were similar to those reported for many members of the genus Faxonius and largely similar to those reported for populations of Allegheny Crayfish across their native range. However, realized fecundity was greater than reported in West Virginia populations. Female body length was a predictor of realized fecundity, differing from southern populations of this species.