POPULATION STATUS OF THE RAZORBACK SUCKER IN THE MIDDLE GREEN-RIVER (USA)

The razorback sucker, Xyrauchen texanus, in the middle Green River (U. S.A.) has been described as a static population consisting of old indi viduals that will eventually disappear through attrition. Capture data between 1980 and 1992 indicated a constant length frequency despite a slow but positive Growth rate of individual fish. Abundance and survi val estimates indicated that the population of razorback sucker in the middle Green River is precariously low brat dynamic. Although high va riation existed among survival estimates, no significant decrease in t he population between 1982 and 1992 could be detected. The low level o f recruitment occurring in the razorback sucker population of the midd le Green River was related to high-flow years, indicating that floodpl ain habitats may be necessary for survival of the species.