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Biofouling Organisms and Their Salinity Tolerance on Navigational Buoys in Upper San Francisco Bay.

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Master's thesis,

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The navigational buoys situated along the main shipping channel of San Francisco Bays upper portions - through San Pablo and Suisun Bays - provide biofouling surfaces of constant depth with known maintenance histories and fixed locations through a mean salinity range of 4 to 24 parts per thousand ppt. Investigation of the biofoulers of these buoys indicates the typical communities and which species are salinity constrained in range and by what salinity. Twelve sets of samples were taken, each consisting of the surface scrapings of two 929 square centimeter cm one square foot areas, one with its top margin at the mean waterline, the other with its upper margin at the 61 cm depth level. This was done with a few exceptions resulting in 23 individual samples being obtained with 41 species identified and 48,376 individual organisms counted. San Pablo Bays dominant biofouler is the mussel Mytilus edulis growing in heavy colonies with worms, amphipods, tunicates, and bryozoans. Suisun Bays biofouling growth is of three parts - algal from the surface to 15 cm depth, a low biomass of barnacles and amphipods to a depth of 61 cm and thereafter the erect bryozoan Membranipora perfragilis dominates. In San Pablo Bay, the barnacle Balanus crenatus is replaced by Balanus improvisus at salinities of less than 21 ppt. Some less well defined salinity tolerances were found, but higher population values per buoy were needed to make reliable statements about most species. Author

Subject Categories:

  • Biology
  • Biological Oceanography
  • Marine Engineering

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