Pacific Rocky Intertidal Monitoring: Trends and Synthesis
The San Francisco Bay region is an extensive estuarine system (approximately 4000 km2) formed by the drowning of the coastal valley created by the Sacramento-San Joaquin drainage system, which connects to the Pacific Ocean at the Golden Gate. The streams and rivers that empty into the bay drain 40% of California’s land and carry high levels of sand and silt, resulting in shallow waters (less than 20m deep in most areas). The region contains mainly soft-sediment habitat, including mudflats, and wetlands. Rocky habitat primarily consists of areas that have been fortified by rip-rap/boulders, but a small amount of naturally occurring bedrock exists as well.
Home to seven million people, the San Francisco Bay Area has been highly modified to meet the transportation, agricultural, industrial, housing, and recreational needs of the community. Approximately 85% of the bay’s tidal wetlands have been lost since the Gold Rush. In addition to physical modification, the San Francisco Bay has experienced extensive biological modification due to numerous introductions of non-native species. The bay is one of the most highly invaded aquatic ecosystems on earth, with estimates as high as 90% of the total number of species documented in the region classified as non-native. Despite extensive habitat loss, modification and degradation, the region remains an important habitat for migratory birds, fish, and numerous endangered species and efforts are underway to reclaim and restore habitat, and reduce the presence and impacts of non-native species. Marine Protected Areas for the region are currently under consideration.
Another substantial threat to marine communities in the San Francisco Bay region is oil spills. The region’s economy is dependent on the countless tankers and cargo ships that enter the bay every year, and the associated refineries and pipelines, but two recent spills (Cosco-Busan 2007 and Dubai Star 2009) have raised awareness about the need to improve safety and better prepare for oil spill response and clean up.
Most monitoring within San Francisco Bay was done for oil spill impact assessment in 2007/2008 & 2009/2010, using a special protocol developed explicitly for this purpose. One Long-Term site has been monitored on Alcatraz Island since 1989 and Biodiversity sampling was first done on Alcatraz in 2005.
The Pacific Rocky Intertidal Monitoring sites located within the San Francisco Bay region are listed below (arranged roughly clockwise around the bay):