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Evaluation of Historical Trends in Trinity River Fish Communities


The primary goal was to compile and organize historical information on the hydrology, biology, physical habitat, physical processes (geomorphology), and water quality of the Trinity River Watershed. This was used to produce a synthesis and summary report documenting past and present conditions and trends in the watershed for these variables.

Study Area

Trinity River Watershed, Texas

Project Period



EIH conducted a review of past literature both published and compiled by universities and government agencies. This compilation of existing literature involved an intensive literature search of both government agency and library bibliographic databases including master's theses and doctoral dissertations. These publications were compiled into an annotated bibliography and, where needed and legally possible, scanned into Adobe Acrobat digital format. EIH translated the non-digital data found in publications into a digital format in an Access database for use in future population trend analysis. Data that were evaluated include fish community composition, catch per unit effort, size data summaries if available and important water quality variables including flow, temperature, pH, conductivity, dissolved oxygen, and turbidity. All environmental data were geo-referenced to link observed collections to specific portions of the watershed.

Using these data, an analysis of existing fish population data for the Trinity River was conducted. This project consisted of a time series and spatial analysis of fish community composition, size/age composition, and population densities in the Trinity River. EIH also evaluated the relationship between land use changes, wastewater loading, and water quality and fish community composition.

Publications and Presentations

Guillen, G., Wrast, J., and Ramirez, D. 2010. Construction of river fish community guilds using life history characteristics and multivariate classification methods: case study Trinity River, Texas. In Texas Chapter of the American Fisheries Society, Athens, TX. Poster.

Guillen, G., Wrast, J., Ramirez, D., and Lokanath, P. 2010. Geographic distribution and historical trends of fish species within the Trinity River Basin, Texas. In Texas Chapter of the American Fisheries Society, Athens, TX. Poster.

Guillen, G., Wrast, J., and Ramirez, D. 2009. Ecological overlay for the Trinity River for the support of development of instream flow recommendations for environmental flows. EIH Technical Report 09-003:178.

Guillen, G., Ramirez, D., and Crossen, D. 2008. Database development for evaluation of historical trends in fish communities of the Trinity River, TX. Texas Chapter of the American Fisheries Society, Junction, TX. Poster.

Project Sponsors