Fisheries & Aquatic Resources

Steelhead at Nimbus Dam Folsom

HELIX Environmental Planning provides aquatic resources assessment and fisheries science services to clients with projects involving threatened or endangered fish species, ecosystem restoration, watershed planning, water transfers, water supply, water quality, land/resource management, urban development, and energy development.

Experience Across California's Ecosystems

Unique amongst the industry, HELIX’s qualified aquatic biologists and fisheries scientists are experienced with federal and state listed fish and other sensitive aquatic species throughout all of California. We routinely conduct habitat assessments and focused surveys for a wide variety of aquatic species within most habitats, and are well versed with regulatory requirements. We specialize in anadromous and resident salmonids (e.g., Chinook salmon, Coho salmon, steelhead, and cutthroat trout), and other native and non-native species in the following areas.

  • Sacramento-San Joaquin River Basin and the San Francisco Bay-Delta
  • Northern California coastal and Cascadian/Sierran streams
  • Central California coastal, Central Valley and Sierran streams
  • Southern California coastal streams
  • Coastal estuaries, marine ecosystems, and lakes/reservoirs throughout California

A Full Range of Services

HELIX’s fisheries and aquatic resource services include:

  • Freshwater, marine, and estuarine fisheries sciences
  • Aquatic ecology
  • Threatened, endangered, and special-status fish species
  • Fish population dynamics and modeling
  • Fish passage and engineering support
  • Fish movement and behavior (e.g., acoustic tagging, DIDSON, and ARIS)
  • Aquatic habitat assessment (e.g., mapping and spatial information)
  • Spawning gravel and large woody material assessment, augmentation, and placement
  • Benthic macroinvertebrate bioassessments (e.g., SWAMP)
  • State and Federal Endangered Species Act compliance
  • Clean Water Act compliance
  • Environmental permitting
  • Water quality
  • Underwater sound assessment

In-Depth Expertise

HELIX conducts fisheries population assessments using electrofishing, snorkeling, seining, trapping, and remote sensing methodologies, including PIT and acoustic tagging and DIDSON/ARIS sonar cameras. Our aquatic biologists and fisheries scientists have training and statewide expertise in benthic macroinvertebrate (i.e., SWAMP) sampling, sensitive amphibian species survey, and water quality sampling. We are routinely approved by the National Marine Fisheries Service (NMFS), U.S. Fish and Wildlife Service (USFWS), and California Department of Fish and Wildlife (CDFW) to oversee special-status fish species relocation actions, assist project engineers with planning and conducting dewatering actions, and provide the necessary gear and staff for freshwater and estuarine special-status fish relocation projects. Additionally, we evaluate aquatic habitat, especially for spawning and rearing salmonids. Our biologists can inventory and predict stream habitat conditions, based on model output (e.g., River2D, PHabSim, and HECRAS).


Featured Projects
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