Fish Restoration Program Tidal Wetland Monitoring

3-panel image: 1) mud from a ponar grab sample; 2) lampara net set around submersed aquatic vegetation; 3) person conducting a sweep net sample.
Left: Ponar Grab. Middle: Lampara Net. Right: Sweep Net. CDFW images.

Program Overview

The Fish Restoration Program (FRP) is an inter-agency agreement between the California Department of Fish and Wildlife (CDFW) and the California Department of Water Resources (DWR) that will restore at least 8,000 acres of tidal wetlands in the Sacramento-San Joaquin Delta and Suisun Marsh. The rationale for restoration is that state or federally listed fish species, Delta Smelt (Hypomesus transpacificus), spring-run and winter-run Central Valley Chinook Salmon (Oncorhynchus tshawytscha), and Longfin Smelt (Spirinchus thaleichthys) will benefit from increased availability of habitat and food web resources. 

The CDFW FRP Monitoring Team is responsible for monitoring tidal wetlands through the collection of water quality, chlorophyll, phytoplankton, zooplankton, macroinvertebrates, and fish. Sampling is conducted on both project and reference sites before and after restoration actions. Sampling design and methods were developed in coordination with the IEP Tidal Wetland Monitoring Project Work Team following its conceptual models and monitoring framework.


  • 2010: DWR and CDFW sign FRP agreement
  • 2014: IEP Tidal Wetland Monitoring Project Work Team first convenes
  • 2015: FRP wetland sampling begins
  • 2017: Completion of tidal wetland conceptual models and monitoring framework
  • 2018: Decker Island and Yolo Flyway Farms restorations complete
  • 2019: Winter Island and Tule Red restorations complete
  • 2020: Wings Landing and Lower Yolo Ranch restorations complete

Water quality point measurements are taken concurrently with invertebrate and fish sampling using a YSI ProPlus, YSI 6600, Micro TPW Turbidity Meter, and/or YSI EXO2. The YSI ProPlus records water temperature, specific conductance, dissolved oxygen, and pH. The YSI 6600 records the previous measurements in addition to chlorophyll. The Micro TPW Turbidity Meter records turbidity. The YSI EXO2 records all of the previous water parameters in addition to fluorescent dissolved organic matter and phycocyanin.

Water for nutrient samples are collected at the water’s surface and analyzed for chloride, chlorophyll a, pheophytin a, nitrate, nitrite, total inorganic nitrogen, organic carbon, organic nitrogen, ortho-phosphate, phosphorus, total/dissolved solids, and total/volatile suspended solids by DWR’s Bryte Laboratory.

Water quality measurements were recorded at 15-minute intervals over several months at select restoration sites with YSI EXO2 sondes: Sensors include: temperature, specific conductance, dissolved oxygen, turbidity, chlorophyll, phycocyanin, and fluorescent dissolved organic matter.

A person uses a line on a pulley to lower a water quality sonde into the open water near the breach at Decker Island.
EXO2 being deployed at the Decker Island breach. CDFW image.

Phytoplankton samples are collected alongside nutrient samples. Each sample is stored in an amber glass bottle with Lugols solutions to act as a stain and preservative. All phytoplankton samples are sent to independent contracting laboratories for identification and enumeration.

Zooplankton are sampled using a 30-inch long microzooplankton net (150 µm mesh). The zooplankton tow is conducted at the water’s surface for 5 minutes. All samples are preserved in 70% ETOH with Rose Bengal dye and processed at the CDFW laboratories in Stockton, California.

long narrow net with catchment bottle at the end
Zooplankton net. CDFW image.

Macrozooplankton in the surface water are sampled using a 79-inch long net (500 µm mesh). Macroinvertebrates in vegetation are sampled using a sweep net (500 µm mesh). All collected samples are preserved in 70% ETOH with Rose Bengal dye and processed at the CDFW laboratories in Stockton, California.

A person removing a hoop-mouthed macrozooplankton net from the water.
Macrozooplankton net. CDFW image.

Emerging insects, Collembola, and other invertebrates found at the surface of the water are sampled with 39-inch long neuston net (500 µm mesh). The neuston net is towed where half of the net is sampling the water’s surface and the other half is under water for 5 minutes. The collected sample is preserved in 70% ETOH with Rose Bengal dye and processed at the CDFW laboratories in Stockton, California.

Neuston net sampling in the water. CDFW image.

A ponar grab or sediment core (aka clam gun) is taken periodically at the tidal wetland sites. The contents of each grab sample are placed on a 500 µm mesh steel sieve and rinsed to remove as much of the substrate as possible. The remaining contents are poured into a jar and preserved in 70% ETOH with Rose Bengal dye.

A ponar grab being lifted from the water by a rope.
Ponar grab. CDFW image.

Fish are sampled with a beach seine, otter trawl, or lampara net. The beach seine is 50 ft long and 4 feet high and used to sample fish along the water’s edge. The otter trawl net is 22 ft long and samples the bottom of a channel for demersal fish. The lampara net is 120 ft wide and used in instances where neither a beach seine nor an otter trawl can sample the top 13 feet of surface water in channels or in aquatic vegetation. All captured fish are put into a bin of water and counted by species. The first 30 fish of each species are measured for fork length and then released back into the water.

3-panel figure, all photographs: 1) beach seine being brought back onto shore; 2) lampara net fished like a purse seine just prior to being pulled onto the boat; and 3) underwater view of an otter trawl
Fish sampling types. Top left: beach seine. Top right: lampara. Bottom: otter trawl. CDFW images.

Submersed aquatic vegetation (SAV) transects are taken at select tidal wetland locations. Randomly generated points are sampled by lowering a thatch rake into the water, spinning the rake three times, and then bringing it onboard. A visual assessment is made of the SAV species caught on the rake. The contents are then placed in a salad spinner to shake water off the sample and weighed.

Photograph of a thatch rake being pulled onto the boat, full of submersed aquatic vegetation.
SAV sampling with a thatch rake. CDFW image.

Relevant Reports

Additional Information

Program Manager

Stacy Sherman,
California Department of Fish and Wildlife

Program Staff

Daniel Cox – Environmental Scientist

Emma Davidson – Environmental Scientist

Michelle Avila – Environmental Scientist

Gabriel Ng – Environmental Scientist 

Christy Bowles – Senior Environmental Scientist (Specialist)

Looking for Data?

Contacts for data related to:
Discrete water quality, phytoplankton, zooplankton, macrozooplankton, surface invertebrates, benthic, fish and submerged aquatic vegetation samples

Christy Bowles,
Daniel Cox,
Emma Davidson,

Map showing locations of planned tidal restoration sites, reference wetland sites, and restored wetland locations with the Sacramento-San Joaquin Delta
Map of the tidal wetland restoration project and reference sites. CDFW image.