Search

There have been few surveys of intertidal invertebrates in San Francisco Bay, California, USA. Most prior intertidal surveys were limited spatially or taxonomically. This survey of the intertidal invertebrates of San Francisco Bay was conducted over 13 months between 1970 and 1971, generating what is now a legacy data set of invertebrate diversity. Specimens were hand collected at land access points at 34 sites around the Bay. In all 139 living species in 9 phyla were collected; 28.8% were introduced species, primarily from the Atlantic Ocean (62.5%) and the Northwest Pacific and Indo-West Pacific Oceans (30%). [ABSTRACT FROM AUTHOR]

Aim: While warming temperatures are expected to facilitate the poleward movement of species previously restricted to more equatorial waters, the arrival and persistence of cold‐water species in more equatorward waters are relatively unprecedented. The native north‐east Pacific ascidian Corella inflata Huntsman, 1912, has spread southward and invaded new regions along the North American Pacific coast, a rare example of a marine species moving towards the equator. Here, we document C. inflata's equatorward movement and potential impact, assess several hypotheses for its spread and consider implications for invasion ecology. Location: North American Pacific Coast (Puget Sound to San Francisco Bay). Methods: We recorded the southward movement of C. inflata by compiling records from the literature, conducting informal searches and conducting standardized fouling community surveys at sites from the southern border of C. inflata's native range in Puget Sound to San Francisco Bay. Within San Francisco Bay, we recorded C. inflata's arrival and potential impact by conducting standardized surveys across an 18‐year period encompassing the invasion. Results: First collected outside its native range in Coos Bay, Oregon, in 2004, C. inflata was subsequently detected 1,000 km south of its historical distribution by 2008 in San Francisco and Humboldt Bays, California. At times, this large, conspicuous solitary ascidian became locally abundant in San Francisco Bay fouling communities, which showed significant shifts in species composition and relative abundance at invaded sites concomitant with C. inflata's arrival. Main conclusions: The recent southward movement of C. inflata runs counter to global warming expectations and may be linked to undetected changes in vessel traffic patterns, rather than natural range expansion. However, an understanding of the one or more processes that would serve to explain the equatorward movement of this cold‐water affinity marine species remains elusive. [ABSTRACT FROM AUTHOR]

The shallow-water hydroid Clava multicornis is reported from the west coast of North America for the first time in nearly six decades. A North Atlantic species often occurring on intertidal fucoid algae, it had been found elsewhere only in heavily-invaded San Francisco Bay, California, with records dating from the late 19th to mid-20th centuries. The species has not been reported from the Bay Area since 1954, in spite of intensive recent collecting, and it is presumed to no longer exist there. During the winter and summer of 2013, robust colonies (which were fertile in the winter) were discovered in fouling communities on floating docks further north in Coos Bay, Oregon. This estuary harbours a large number of introduced species from both the western Pacific and the North Atlantic. We suspect that C. multicornis was introduced to Coos Bay in one of two ways. One means of transport might have been in hull fouling on ships, either directly from the North Atlantic or possibly from another Pacific coast estuary where the species remains undetected. A second possibility is on fucoid algae used in the shipment of polychaete bait worms from the State of Maine, on the Atlantic coast of the United States. [ABSTRACT FROM AUTHOR]

Presents research which analyzed the San Francisco Bay and Delta ecosystem to reveal a large number of exotic species that dominate many habitats. Problem of biological invasions; How species dominate; Ecosystem perhaps being the most invaded estuary in the world; Possible causes.