Effects of red shiner (Cyprinella lutrensis) on Red River pupfish (Cyprinodon rubrofluviatilis)

A proposed desalinization project that would affect the entire upper Red Ri ver basin, Oklahoma-Texas, would, if completed, raise the possibility of in vasion by red shiner, Cyprinella lutrensis, into stream reaches from which it has been restricted by naturally high salinity. Because introduced red s hiners are known to impact native fish communities, we asked if red shiner could have an adverse effect on Red River pupfish, Cyprinodon, rubrofluviat ilis, which typically occurs in reaches of the Red River with high salinity . In an array of artificial streams we examined effects of red shiner on su rvival, condition, and reproduction of Red River pupfish. In the presence o f red shiner, pupfish successfully produced larvae, but fewer juvenile pupf ish survived to potentially recruit.