Identifier

etd-11132007-104055

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

This study was designed to examine home range sizes and habitat use of blacktail redhorse Moxostoma poecilurum in West Fork Thompson Creek, Louisiana. Blacktail redhorse are a common non-game species found in Louisiana and other southeastern states. Adult blacktail redhorse (N=40; 187-273 mm total length) were implanted with radio transmitters and tracked twice weekly from February to September 2006 and from February to July 2007. To assess blacktail redhorse diet I analyzed 32 stomachs from fish collected by backpack electrofishing. I also conducted mark-recapture surveys of fish sampled monthly from May 2006 until July 2007. To assess homing ability in blacktail redhorse, I radio-tagged 10 individuals in 2007 and relocated them downstream (0.8 or 1.6 km) from their capture location. Results showed that implanted fish exhibited extremely high mortality or expulsion rates with 70% of all implanted transmitters being lost, even though retention rates in the laboratory were very high. On numerous occasions, I directly and indirectly observed avian and mammalian predators foraging in the study area, which likely explains high transmitter loss. Individual 95% linear home range sizes varied from 25 to 3,900 meters, with several fish having multiple home ranges, while others remained in the same pool throughout the study. Blacktail redhorse were observed foraging throughout the diel period, and their diet was primarily composed of chironomid (55%) and heptageniid larvae (17%). Similar to other redhorse species, blacktail redhorse were benthic feeders and foraging behaviors appear very similar to that of black redhorse Moxostoma duquesnei. Few marked individuals were recaptured (6 of 130) as indicated by mark-recapture sampling. The homing study showed only one individual moved back to its capture location. Small sample sizes and short study times limited both the mark-recapture and homing studies. Overall, blacktail redhorse exhibited a preference for pools with clay boulders, complex habitat, and undercut banks. The high levels of predation observed throughout this study and its impact on blacktail redhorse abundance suggest that local predation pressures structure this portion of the population and may be a driving force in structuring the entire headwater stream fish community in this area.

Date

2007

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

D. Allen Rutherford

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