Contemporary extent of the Blackspotted Topminnow invasion and frequency of hybridization with native Blackstripe Topminnow in the Spring River subbasin

The current extent of the Blackspotted Topminnow invasion and the contemporary frequency with which it is hybridizing with the phenotypically similar Blackstripe Topminnow (Fundulus notatus) in the SRS of KS is presently unknown. Furthermore, documenting the Blackspotted Topminnow invasion is complicated by the fact that F. olivaceus and F. notatus phenotypic characteristics vary with environmental gradients, making visual identification unreliable. As such, this project used genetic techniques to 1) investigate the extent of the Blackspotted Topminnow invasion in the SRS of KS, 2) address how the frequency of hybridization between Blackspotted and Blackstripe Topminnow varies spatially, and 3) evaluate how invasion and hybridization are influenced by water clarity and stream fragmentation (i.e., Empire Lake). Blackspotted Topminnow were collected from numerous sites distributed along the Spring River and Shoal Creek using dipnetting and seining. We used restriction fragment length polymorphism (RFLS) assays to identify pure Blackspotted and Blackstripe Topminnow and their hybrids. This research will help inform the management of nonnative species and native species conservation in the SRS, while also contributing to the field of fish ecology by examining how a dispersal barrier (i.e., Empire Lake) impacts the outcome of an invasion