| Sampling has occurred within Big Bend National Park (BBNP) and the lower canyon reaches of the Rio Grande and its associated tributaries sporadically in the past. Throughout the sampling record, 43 fish species have been known to occur within this reach. Of these, two fish species are considered extinct, and five are considered extirpated. Sampling was conducted for a period of six months in 1999 and 2000, using methods which would allow for an assessment of the current status of the ichthyofauna within the study area and a feasibility study investigating the establishment of a sampling protocol for BBNP personnel. Historical collection data were also compiled. A total of 20 species were collected from 43 sample sites using three collection methods. Twenty species were captured using seines at 32 sites, six species were captured using gill nets at six sites, and two species were captured using jug fishing equipment at eight sites. Notropis braytoni was the most abundant species in collections. Species composition of this study was most similar to a survey in 1991 (S. Platania, University of New Mexico, unpublished data) and least similar to surveys by Hubbs et al. (1973) and Platania (1990) when compared using Sorenson's index. |
