Technical Report

Fish Community Monitoring and Fish Sampling Methodology Evaluation Final Report: Task 1 Report - Assessment of Current Techniques to Sample the Fish Assemblages of the Middle Rio Grande

URL: https://webapps.usgs.gov/mrgescp/documents/SWCA%20Environmental%20Consultants_2010_Fish%20Community%20Monitoring%20and%20Fish%20Sampling%20Methodology%20Evaluation%20Final%20Report%20Task%201%20Report%20-%20Assessment%20of%20Current.pdf

Date: 2010/07/01

Author(s): Widmer A.M., Burckhardt L.L., Gonzales E., Hatch M.D.

Publication: Report prepared for U.S. Bureau of Reclamation, 204 p.

Abstract:

Altogether, 37 datasets were evaluated to assess the current techniques used to sample the fish assemblages of the Middle Rio Grande, including the endangered Rio Grande silvery minnow (Hybognathus amarus; silvery minnow). The purpose of the assessment was to 1) document sampling gears and methods for fish escapement and catchability, 2) document the sampling effort for sampling gears and methods, and 3) document the statistical power of sampling gears and methods. Sampling gears and methods were evaluated to determine the most effective technique(s) for population monitoring and estimation, recruitment and survival, Population Viability Analysis modeling, evaluation of habitat restoration, and adaptive management. The four principal sampling techniques evaluated were seining, electrofishing, fyke or fyke netting, and egg sampling.

Quantitative fish sampling has been conducted in the Middle Rio Grande since 1993. Most data received were through 2008, although some datasets included data for 2009. The longest running datasets were associated with seining used primarily to monitor the silvery minnow. Evaluation of habitat restoration projects, principally in floodplain habitats, produced datasets from fyke nets and seines, sometimes collected simultaneously, as well as egg collections. Fish community surveys have been conducted with raft and all-terrain vehicle electrofishing since 2001 and constitute the only ongoing dataset of information for fish assemblages from the array of main channel mesohabitats. Fish rescue data for the silvery minnow have been collected annually since 2001 as the total numbers of silvery minnow salvaged and translocated. A variety of egg collections have been made, although much of these data were not available electronically. Egg monitoring data have been collected annually since 2004, although data after 2006 were not available.