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Gary Greene, Moss Landing Marine Laboratories Using multibeam bathymetry to characterize rockfish habitat in San Juan County, Washington Marine Reserves, USA |
| Abstract The establishment of Marine Protected Areas (MPAs) has recently become an important part of marine resource management efforts around the world and in San Juan County. Rockfish are economically important bottomfish whose populations have declined since the 1970s to such an extent that they are being considered threatened or endangered under the Endangered Species Act. During October of 2000, Moss Landing Marine Laboratories, Center for Habitat Studies surveyed five sites within the San Juan Archipelago (SJA) using a RESON 8101 multibeam bathymetric system. Both bathymetry and backscatter data were collected, although the system was maximized for the collection of accurate bathymetry. The main objective of this survey was to gather high-resolution bathymetric data to be used in mapping adult and juvenile rockfish habitat as part of an effort to identify potential marine reserves within the SJA. Sites were chosen based upon previous knowledge of the areas' physical oceanographic and biological conditions. Surveys were undertaken within San Juan Channel, southern Haro Strait, and southern Rosario Strait. Areas of rugged rocky seafloor were identified using both qualitative and quantitative methods, and were interpreted to be potential adult and juvenile rockfish habitat. Potential habitat bridges radiating outwards from protected areas were outlined based upon visual interpretation of multibeam imagery. Three voluntary no-take zones (VNTZs); Pile Point, Charles Island, and Bell Island established by the San Juan County Marine Resource Committee (MRC) in 1997 were evaluated based upon the presence of potential adult and juvenile rockfish habitat and the existence of possible habitat bridges that radiate outward from the protected areas. Results show that Pile Point, Charles Island, and Bell Island VNTZs appear to contain viable refugia for adult and juvenile rockfish and prospective habitat bridges that radiate outwards from the VNTZs. Alternative reserve locations were also identified that may provide protection for species other than bottomfish |
| Publications resulting from this research |
| Barnhardt, W., M. Fisher, W. Palsson, H.G. Greene, J. Tilden, D. Mosher, G. Baker, P. Dartnell, G. Gelfenbaum, C. Sherwood. 2001. Geologic mapping of marine benthic habitats in Puget Sound, Washington. Proceedings of 5th Puget Sound Research Conference 2001: abstracts of poster presentations. p. 29. Greene, H.G., W.A. Palsson, J.E. Tilden. 2003. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, WA marine reserves, Proceedings of the Georgia Basin/Puget Sound Research Conference, Vancouver 2003. Greene, H.G. and J.E. Tilden. 2002. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, Washington marine reserves, USA. MEHP final report 5 plates, 21. Greene, H.G., J.V. Barrie., J.E. Tilden, H.L. Lopez, and M.E. Fisher. 2002. Habitat mapping in the transboundary region of Canada and the U.S.: a new U.S. Canada Co-op, GEOHAB: Marine Geological Habitat Mapping, Moss Landing Marine Laboratories, CA. 58. Greene, H.G. and J.E. Tilden. 2002. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, WA marine reserves, 1st Biennial Marine Ecosystem Health Program Science Symposium, Rosario Resort, Orcas Island, WA. Tilden, J.E. and H.G .Greene. 2001. Using multibeam bathymetry to investigate marine geology and potential marine reserves in the San Juan Islands, Washington, USA. Eos Trans. AGU, 82(47), Fall Meet. Suppl., Abstract OS12C-0436. Tilden, J.E., H.G. Greene, T. Klinger, W. Palsson. 2002. Using multibeam bathymetry and GIS to identify potential marine reserves in the San Juan Islands, Washington, USA, (abstract). 2002 Western Groundfish Conference, Ocean Shores, WA. 77 (World Meeting Number 000 5815). Tilden, J.E. and H.G. Greene. 2002. Using multibeam bathymetry to investigate marine geology and potential marine reserves in the San Juan Islands, Washington, USA, GEOHAB: Marine Geological Habitat Mapping, Moss Landing Marine Laboratories, CA. 70. |
| Presentations resulting from this research |
| Greene, G. 2002. Using multibeam bathymetry to investigate marine geology and potential marine reserves in the San Juan Islands, Washington, USA. GEOHAB: Marine Geological and Biological Habitat Mapping, Moss Landing Marine Laboratories, Moss Landing, CA. Greene, G. 2002. Habitat mapping in the transboundary region of Canada and the United States: A new U.S.-Canada cooperative. GEOHAB: Marine Geological and Biological Habitat Mapping, Moss Landing Marine Laboratories, Moss Landing, CA. Greene, G. and J.E. Tilden. 2002. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, WA marine reserves. 1st Biennial Marine Ecosystem Health Program Science Symposium, Rosario Resort, Orcas Island, Eastsound, WA. Greene, G. 2002. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, Washington marine reserves. University of Washington, Friday Harbor Laboratories Marine fish ecology class. Friday Harbor, WA. Tilden, J.E. 2001. Using multibeam bathymetry to investigate marine geology and potential marine reserves in the San Juan Islands, Washington, USA. AGU Fall Meeting, Moscone Center, San Francisco, CA. Tilden, J.E. 2002. Using multibeam bathymetry and GIS to identify potential marine reserves in the San Juan Islands, Washington, USA. Western Groundfish Conference, Ocean Shores, WA. Tilden, J.E. 2002. Multibeam bathymetry and GIS: tools for multidisciplinary research in the San Juan Islands, Washington. Student Presentation at San Jose State Science Deans Conference, Moss Landing Marine Laboratories. Moss Landing, CA. Tilden, J.E. 2002. Seafloor mapping and habitat studies in and around the San Juan Islands: a collaborative effort. San Juan County MRC meeting. Friday Harbor, WA. Tilden, J.E. 2003. Using multibeam bathymetry to characterize rockfish habitat in San Juan County, Washington marine reserves, USA. Georgia Basin/Puget Sound Research Conference. Vancouver, British Columbia, Canada. (PDF) |
| Management outcomes |
| Using multibeam bathymetry to characterize rockfish habitat Rockfish (Sebastes spp.) populations in Washington state have declined since the 1970s and one-third of the 36 species found in the inland waters region are now listed by the state as species of concern. Many of these species have been shown to spend the majority of their life in very small areas on rocky reefs. Because studies have shown that some species of rockfish increase in abundance and size with harvest closures even in small areas, marine protected areas (MPAs) are being evaluated as tools to enhance these populations. To be effective, MPAs must be sited in good rockfish habitat. In 2001, the SeaDoc Society supported Gary Greene at the Moss Landing Marine Laboratories, Center for Habitat Studies to gather high resolution data to evaluate areas for potential rockfish habitat. Five sites within the San Juan Archipelago were surveyed using a RESON 8101 multibeam bathymetric system to collect bathymetry and backscatter data. The information collected was used to evaluate habitat inside and adjacent to pre-existing MPAs as well as to evaluate other potential sites. Thanks to SeaDoc Society funding, San Juan County and the Washington Department of Fish and Wildlife now have previously unavailable data that will help them determine if existing MPAs have been sited in the best locations, if they offer contiguous rockfish habitat adjacent to the protected area, and if there are other areas of good rockfish habitat that should be evaluated as potential reserve sites. In addition to identifying rockfish habitat, this study was the first high-resolution marine mapping effort undertaken in the San Juan Islands area and was used to create the first marine habitat maps within the area. A total of 16 discrete habitat types were identified and mapped from the surface to the sea floor, regardless of depth. Once processed these data will be used by biologists from different state and non-governmental agencies to develop regional conservation plans, to help understand oceanographic properties in the area, and to plan and evaluate recovery efforts for other threatened species, such as northern abalone. |