Fisheries Consulting

Fisheries Studies

  • Fisheries sampling:
  • Direct observation (snorkel surveys)
  • Active capture (back pack and boat electrofishing, seining, hook and line sampling)
  • Passive capture techniques (gill netting, minnow trapping, fyke netting)
  • eDNA collection and analysis
  • PIT Tag implantation, array installation and management, data analysis
  • Quantitative population assessments (“Single Stream” and “Regional” estimates of fish abundance, Hankin and Reeves 1988; Dollof and Hankin 1993)
  • Mark Recapture studies
  • In-stream and riparian habitat assessments (habitat mapping, Large Woody Debris inventories)
  • Invasive species suppression
  • Regulatory permitting and compliance
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Project: Potter Valley Hydroelectric Project (ongoing)

  • Client: Kleinfelder and Pacific Gas and Electric Company

Thomas Gast & Associates Environmental Consultants (TGAEC) has provided and continues to aid with the suppression of the invasive pikeminnow population in the Van Arsdale Reservoir. TGAEC provides an electrofishing boat, services, and staff to assist with the eradication of the prolific invasives found in the Eel River. TGAEC staff helps with pikeminnow suppression throughout the season, helping with the netting, eradication, and data on the invasives removed from the Van Arsdale Reservoir.

Project:Little Sur Steelhead Population Monitoring (2025)

  • Chuck Hanson and El Sur Ranch

Thomas Gast & Associates Environmental Consultants (TGAEC) was contracted through a private landowner to complete Steelhead population surveys on the Little Sur River. TGAEC staff had designated reaches that needed to be surveyed in compliance with the USFWS and CDFW. The TGAEC fisheries biologist led a crew to complete the required sampling. TGAEC staff safely handled and processed South-Central California Coast Steelhead, a federally threatened species. Electrofishing techniques, along with snorkel survey methods, were enlisted to complete the survey. Multi-pass electrofishing was completed until depletion thresholds were reached. Data quality was upheld to high standards. Data analysis and reports were written and made available by TGAEC staff.

Project: Ravenswood Tidal Marsh Monitoring (2023-2025)

  • Client: Helix and Ducks Unlimited

TGAEC was responsible for collecting data from physical fish sampling methods, including gillnetting and beach seining at a Ducks Unlimited Salt Pond restoration site, pre and post inundation. The staff was also responsible for instantaneous water quality measurements and analysis. TGAEC produced seasonal, annual, and final reports documenting fish sampling and water quality results. Analysis of sonde data was also TGAEC's responsibility.

Project: Trinity River Chinook Long Term Outmigrant Data Analysis (September 2017-October 2019) )

  • Client: Yurok Tibe

Thomas Gast & Associates Environmental Consultants (TGAEC) contracted with the Yurok Tribe to analyze the long-term data collected at the Willow Creek outmigrant trap on the Trinity River in order to determine the relationship between Chinook salmon emigrant abundance, river flow, and water temperature. The Trinity River Restoration Program (TRRP) science and monitoring activities support adaptive management, including numerous long-term investigations across multiple scientific disciplines that predict, measure, and evaluate progress toward long-term program goals, ranging from hydrology and geomorphology to fisheries and wildlife biology and riparian vegetation ecology. TRRP has identified the need to develop a “Fish Production Model” for the Trinity River that will link to existing Trinity River physical models and a future Klamath River fish production model. The TGAEC project team developed statistical approaches to incorporate more than 25 years of out-migrant trapping data, redd/carcass data, dam releases, water temperatures, water year types, and other environmental parameters to support the Yurok Tribe and TRRP efforts to better evaluate fish response to management decisions.

Project: Spring Gap Stanislaus PG&E Fish Monitoring (2015)

  • Client: Douglas Parkinson & Associates and PG&E

Pacific Gas & Electric’s (PG&E) current license for the Spring Gap- Stanislaus Hydroelectric project (FERC No. 2130) had mandatory biological monitoring requirements, including electrofishing surveys to characterize trout populations in the Stanislaus River. The Spring Gap- Stanislaus project is located on the Middle Fork Stanislaus River (Middle Fork) and South Fork Stanislaus River (South Fork) in Calaveras and Tuolumne Counties, California, and occupies over 1,000 acres within the Stanislaus National Forest, managed by the U.S. Forest Service. Douglas Parkinson & Associates retained TGAEC as a subcontractor to assist in conducting three-pass depletion electrofishing for the estimation of trout abundance in the Middle Fork Stanislaus River.

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