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Biological Sampling:

RTA has the expertise and equipment to conduct a variety of fisheries sampling, including: 

 

  • Population estimates of stream-dwelling fish.  Mark-recapture and/or depletion methods with electro-fishing equipment.  Modified Hankin-Reeves methodology (direct observation calibrated with electrofishing).

 

  • Presence/absence verification surveys with electrofishing and/or snorkeling.

 

  • Fish relocation in conjunction with stream crossing replacement and channel enhancement projects. RTA has worked with private contractors, non-profits, tribal, city, county, and state entities in providing this service.

  • Non-native species eradication and suppression. RTA has conducted several projects to remove non-native fish and amphibians (bullfrogs) from small impoundments. in 2023 and 2024, bullfrogs and three species of non-native were eradicated in Neefus Gulch, prior to dewatering and dam removal.

  • Estuary sampling. RTA is experienced in sampling brackish-water tidal areas. RTA also holds a USFWS Section-10 research permit for sampling and handling tidewater gobies in Humboldt and Del Norte counties.

  • Spawning surveys for Chinook salmon, Coho salmon, steelhead, and all species of trout.

  • Seine netting and minnow trapping to determine presence/absence and distribution.

  • Underwater videography to determine presence/absence in water conditions unsuitable for snorkeling or electrofishing.

  • Radio-telemetry studies. RTA co-lead a three-year radio telemetry-movement study of brown trout in Rush Creek using both fixed antenna arrays and mobile receivers. Radio tags were surgically implanted in 90 trout. Study results included movement behavior and focal-point habitat measurements. 

  • PIT tagging. Over a 15-year period, RTA has implanted approximately 9,800 PIT tags in brown and rainbow trout in Rush and Lee Vining Creeks to determine movement, survival and specific growth rates. RTA has also used PIT tags to evaluate the growth of non-natal coho salmon rearing in off-channel habitats in Martin Slough, Freshwater Creek, and Dry Dock Gulch.

© 2025 Ross Taylor and Associates.

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