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Monitoring marine protected areas in deep water off Central California

The Issue

Deep rocky banks and outcrops, underwater pinnacles, and submarine canyons, ranging in depth from 30 to more than 1,000 meters, are important habitats in California waters. These deepwater habitats comprise 75 percent of the seafloor in state waters within the Central Coast region, and are home to hundreds of species of fishes and macroinvertebrates. Although deep habitats on the continental shelf and upper slope contain a high diversity of species that have been fished for decades, far less is known about deep habitats than those occurring in shallow water. In September 2007, 29 Marine Protected Areas (MPAs) were established in Central California, many of which extend into deep water. To monitor and adaptively manage the new MPAs in the future, it is imperative to have a comprehensive baseline survey of the fishes and invertebrates in the MPAs.

What Has ANR Done?

Cooperative Extension marine advisor Rick Starr and National Marine Fisheries Service research biologist Mary Yoklavich led a large team of scientists to study the deep portions of new MPAs by using the Delta submersible, an un-tethered submersible containing a pilot and a scientific observer. The team surveyed all fishes and structure-forming invertebrates in the deep portions of eight new MPAs and associated reference sites. Sampling locations were chosen based on the occurrence of rocky habitats from sea floor relief maps and previous knowledge of seafloor habitats. Quantitative visual strip transects were conducted to classify seafloor habitats and to identify, count and measure species of fishes and macro-invertebrates on or near the seafloor. Additionally, GPS location and water quality measurements were collected throughout each transect. During the 2007 season, 337 quantitative transects were conducted with nearly 66,000 fishes and 158,000 aggregating and 14,000 structure-forming invertebrates observed. In 2008, the 2007 dives were replicated and new locations were added to the sampling regime to more thoroughly survey different habitat types and depths.

The Payoff

Scientists collect comprehensive baseline data of new marine protected areas

The submersible surveys conducted in 2007 and 2008 provide the first comprehensive evaluation of deep-water fish and invertebrate communities in Central California. These baseline surveys are critical to the future evaluation of the effectiveness of the new MPAs because the data will enable scientists to quantitatively assess changes in the diversity, density and size of species inhabiting the deeper portions of the MPAs. Additionally, the submersible surveys provided information about deepwater rocky habitats that have received little research attention.


Supporting Unit: Sea Grant Extension Program

Santa Cruz and Monterey Counties
Richard M. Starr, (831) 771-4442, cesantacruz@ucdavis.edu

Mary Yoklavich, (831) 420-3940, Mary.Yoklavich@noaa.gov

Kristin Hunter-Thomson, (831) 771-4479, khunterthomson@mlml.calstate.edu