by Adam Cohen, Melissa Casarez, and Ryan Rash
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Figure adapted from Dennis Rose's thesis showing the major streams in the Little River Basin. |
Staff from the Biodiversity Center’s fish collection (home of the Fishes of Texas Project) recently teamed up with Texas Parks and Wildlife Department’s River Studies Program (TPWD) to conduct a fish survey of the Little River in Central Texas. The Little River is little in name only and covers nearly 3% of the state of Texas, from Eastland southeast to Hearne, and includes well-known tributaries such as the Leon, San Gabriel, and the Lampasas Rivers. We collected fish at 63 sites from March to July of this year. All fish have been identified, counted, measured, and cataloged and are soon to be shelved and made available to the world’s taxonomists, ecologists, and researchers in general. We collected 52 species altogether, including 12 non-native species (see full list below). This survey is part of a larger on-going project which targets undersampled watersheds throughout the state, filling in critical research needs to aid in conservation efforts of native species and restoration of the rivers they inhabit. Other participants in this survey include Austin Youth River Watch, a non-profit focusing on environmental education of underserved youth, and Dr. Michael Collins of the Gault School of Archaeological Research, who provided access to Buttermilk Creek, a perennially flowing creek that runs through the Gault archeological site.
The Little River basin was heavily collected by Dennis Rose in the late 1970s. This survey will now allow us to compare his findings from 40 years ago to our own and allow us to better understand how the fauna has changed over time. Unfortunately, most of Rose’s collections are not documented with vouchered museum specimens and, although we have no specific reason to doubt his data, they are unverifiable and thus subject for dispute (species ID disagreement primarily). Some however, are cataloged at Baylor University and all 1,776 of those records can be perused on our Fishes of Texas Project website, where we’ve made significant efforts to compile museum records in one place. There still remains a large backlog of his specimens uncataloged at Baylor – work for the future.
Our preliminary comparison to Rose’s collections suggests the fauna has remained relatively stable over the last 40 years. Some new findings we discovered include, our collection of an isolated population of Redspotted Sunfish in Sulphur Creek in Lampasas. This species is native to Texas but not previously collected from the Little River system. Other Texas native species we found in the basin that apparently didn’t occur when he collected include Sailfin Molly, Blue Catfish, and Brook Silverside. In contrast, a couple of Texas native species that were once there and appear to be gone, or at least are now very rare, are Chub Shiner and Smalleye Shiner. We will be working on a more thorough comparison of the results.
Four species of bass, known to hybridize, occur in the Little River system: Smallmouth Bass (non-native), Largemouth Bass, Spotted Bass and Guadalupe Bass. In an effort to better understand the distribution and how better to conserve pure strains of the Guadalupe Bass (our state fish), TPWD geneticists are analyzing 210 bass tissues we took during the survey. Those results will be ready in the near future and included in a comprehensive bioassessment report of the study.
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| Guadalupe Bass (Micropterus treculii). The state fish of Texas endemic mostly to the Edwards Plateau. Image copyright by Joseph Tomelleri. | Largemouth Bass (Micropterus salmoides). Native to Texas, but introduced widely around the state for sport fishing. Image copyright by Joseph Tomelleri. |
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Spotted Bass (Micropterus punctulatus). At the western edge of its native range in the Little River system. Image copyright by Joseph Tomelleri. |
Smallmouth Bass (Micropterus dolomeiu). Not native to Texas and widely introduced as a sport fish. Image copyright by Joseph Tomelleri. |
Here is the complete list of species with links to more info on our Fishes of Texas Project website. For more photos of the specimens we collected on this trip including more recent efforts, check out our observations on iNaturalist.
SPECIES LIST
PHOTOS
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| Seining in a deep pool. | Seining in a shallow pool. |
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| Boat shocking with TPWD below Granger Dam. | Working with Austin Youth River Watch, demonstrating how we take tissue samples and process specimens in the Brushy Creek drainage, north of Austin. |
