Sanctuary Integrated Monitoring Network
Monitoring Project

Seafloor Mapping in Monterey Bay, Cordell Bank, and Gulf of the Farallones National Marine Sanctuaries

Principal Investigator(s)

  • Tara Anderson
    Geoscience Australia
  • Roberto Anima
    United States Geological Survey (USGS)
  • Erica Burton
    Monterey Bay National Marine Sanctuary
  • John Chin
    United States Geological Survey (USGS)
  • Jean DeMarignac
    Monterey Bay National Marine Sanctuary
  • Dale Roberts
    Cordell Bank National Marine Sanctuary


  • SIMoN
Start Date: March 31, 2004

In April 2004, scientists from the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS) conducted a 21-day research research cruise aboard the 224-ft NOAA ship McArthur II. This study was one of the most expansive efforts to document the seafloor of the continetal shelf in the three California Central Coast national marine sanctuaries, Monterey Bay (MBNMS), Cordell Bank (CBNMS), and Gulf of the Farallones (GFNMS).

Researchers mapped the seafloor with side-scan sonar and captured underwater video of the seafloor to characterize the habitat types and diversity and the benthic assemblages of sea life on the continetal shelf; including a first look at many areas. Side-scan sonar was used to map 167 line km of rocky areas at Fanny Shoal and 130 line km off Pescadero Point, and to conduct 467 line km exploratory transects of the continental shelf in CBNMS. Approximately 200 km of video transects were completed on the continetal shelf in CBNMS and MBNMS. The sampling area in MBNMS extanded from Pescadero Point in the north, to the Monterey Peninsula in the south.

This research cruise was a collaborative venture involving the MBNMS; CBNMS; GFNMS; USGS; National Marine Fisheries Service (NMFS), Southwest Fisheries Science Center, Santa Cruz, CA ; NMFS, Northwest Fisheries Science Center, Newport, OR; Washington State University Vancouver, Vancouver, WA; NOAA's Marine Protected Areas Center's Science Institute (MPA); and Deep Ocean Engineering (DOE).

Summary to Date

Goal of mission:
To acoustically image, document, and film extensive seafloor habitats and organisms on the continental shelf of MBNMS, CBNMS, and GFNMS as part of a multi-agency seafloor mapping project. The objectives were to: (1) map the seafloor in three West Coast national marine sanctuaries: MBNMS, CBNMS, and GFNMS, (2) groundtruth habitat maps in two West Coast national marine sanctuaries using a camera sled (MBNMS and CBNMS), (3) characterize habitats and associated benthic macroinvertebrates and fish assemblages in two West Coast national marine sanctuaries using a camera sled (MBNMS and CBNMS), and (4) make mapping information available to the public.

Technology and equipment used:
A small video-camera sled (1.3 m long x 0.4 m wide x 0.5 m high, 60 kg) was towed underwater behindthe NOAA Ship McArthur II to film and document habitats and organisms on the seafloor of the MBNMS, CBNMS, and GFNMS. A Klein 3000 side-scan sonar system was used to acoustically image several previously unmapped sections of the seafloor within these sanctuaries. During the cruise (April 1 to April 21) teams of scientists worked day and night to collect information on the seafloor using towed video and side-scan sonar. Seafloor descriptions were recorded by the scientists every 30 seconds during real-time observations, providing a wealth of information about habitats and organisms on the seafloor.

Monitoring Trends

  • Sand-wave habitats were occupied by sanddabs and often contained schools of juvenile rockfish.
  • Sediment-ripple habitats were commonly occupied by white brittle stars buried within the sediment.
  • Low-lying cobble beds were often occupied by encrusting sponges, gorgonians, and half-banded rockfishes.
  • High-relief bedrock habitats, although less common on the mid- to outer -shelf, were occupied by encrusting invertebrates, vase sponges, large anemones, gorgonians, and many species of rockfishes.


Results from this seafloor mapping study provide valuable characterization of sanctuary biology and geology that is useful as a foundation for management of the national marine sanctuaries.

Mapping, describing, and visualizing seafloor habitats and their biodiversity within the sanctuaries will help managers to protect important habitats, plants, and animals. The knowledge of what is present today will also provide the foundation to monitor changes in these important resources.

While the ability to record seafloor descriptions in real time at sea requires a team of dedicated researchers, this approach dramatically improves the speed at which seafloor information can be made available to managers, stakeholders, and the public. Importantly, this novel approach also enables web-users to examine the nature of the seafloor at locations of interest with the capability of viewing footage from these areas within weeks of completion of the survey.

This project demonstrates the quantity and quality of work accomplished between government agencies to conduct needed investigative work to ascertain what resources we have in our sanctuaries. The cooperating agencies pulled together sea-floor mapping tools and video-camera expertise to conduct both habitat mapping and biodiversity mapping.

Study Parameters

  • Habitat
  • Maps
  • Habitat association
  • Diversity
  • Distribution
  • Substrate characterization
  • Geological characterization

Figures and Images

Sunflower seastar.

Flag rockfish (Sebastes serriceps) captured by the digital camera sled.

Track lines from the MBNMS 2004 McArthur II cruise.

Camera sled provided by the Cordell Bank National Marine Sanctuary to document seafloor habitat and species.