California Biota Home Page

Rapid Assessment Survey of Exotic Organisms in 
San Francisco Bay: May 23-28, 2004

Biological invasions, the transport and introduction of organisms beyond their natural range, have been widely documented in marine environments and can have consequences that are ecologically and economically devastating. Unprecedented and accelerating rates of biological invasions create a unique set of environmental, economic, public health and social challenges.

These exotic organisms may constitute the largest single threat to the biological diversity of the world's coastal waters. The waters and wetlands of the San Francisco Estuary host over 250 nonindigenous saltwater, brackish-water and freshwater species, including plants, protists and invertebrate and vertebrate animals. Several important biological communities San Francisco Bay waters are now dominated by species that are not native to the west coast.

Prior to the early 20th century, these invaders primarily arrived as fouling on the hulls of ships; with mud, sand or rock carried as ballast in ship's holds; or with oysters imported from the Atlantic and grown in Pacific Coast bays. Today, exotic organisms are most commonly carried in the enormous volumes of ballast water exchanged daily between ports by modern shipping.

Rapid Assessment surveys have been used to document the arrival and spread of exotic organisms in marine ecosystems. A one week Rapid Assessment of San Francisco Bay was conducted from May 23 - 28, 2004 by Andrew N. Cohen (San Francisco Estuary Institute), James T. Carlton (Williams College), John W. Chapman (Oregon State University), Leslie H. Harris (Natural History Museum of Los Angeles County), Dale R. Calder (Royal Ontario Museum), Gretchen and Charles C. Lambert (University of Washington Friday Harbor Laboratory), Christina Piotrowski (California Academy of Sciences), Michelle Shouse (U.S. Geological Survey), Luis A. Solorzano (U.S. Food and Drug Administration) and Taiju Kitayama (Tokyo National Science Museum), with funding from the National Geographic Society,  the San Francisco Bay-Delta Science Consortium and CALFED Science Program,  the California Coastal Conservancy,  and the Rose Foundation. Several institutions loaned equipment,  provided supplies and facilities.

A total of 15 sites were sampled, primarily marina or boat-launch docks, including several examined in previous surveys in 1993-1997 (documented at: Some of the species collected (including natives)  are listed below, with links to photo images on the California Biota webpage.

Primary background for this project can be found in the PhD dissertations of James T. Carlton ("History, Biogeography, and Ecology of the Introduced Marine and Estuarine Invertebrates of the Pacific Coast of North America," University of California at Davis, 904 pp, 1979 - new index available on the web) and Andrew N. Cohen ("Biological Invasions in the San Francisco Estuary: A Comprehensive Regional Analysis," University of California at Berkeley, 465 pp, 1996). These 2 studies, 20 years apart, provide the basis for our understanding of bioinvasions in San Francisco Bay.

A comprehensive report on invasions in the San Francisco Estuary system is "Nonindigenous Aquatic Species in a United States Estuary: a Case Study of the Biological Invasions of the San Francisco Bay and Delta" by Andrew N. Cohen and James T. Carlton, 1995; and a short review is "Accelerating invasion rate in a highly invaded estuary" also by Cohen and Carlton, in Science, Jan. 22, 1998. The subject was also explored in an interview on National Public Radio's Science Friday on Jan. 23, 1998.  Some species collected and photographed on the San Francisco Bay Rapid Assessment Survey, are found below at the bottom of this page. 

Jim T. Carlton, Andrew N. Cohen, Christina Piotrowski, and                  Collecting at the Brisbane Lagoon.                                                            
Gretchen Lambert at the  Richmond Marina.

Andrew N. Cohen and Luis A. Solorzano collecting specimens            Christina Piotrowski, Michelle Shouse, Andrew N. Cohen,  John W.  at the Coyote Point Marina.                                                                                    Chapman, collecting specimens at the San Leandro Marina.

Jim T. Carlton collecting specimens under ideal conditions.                    Jim T. Carlton, Gretchen  Lambert, and Dale R. Calder observing
                                                                                                                                     exotic organisms at the foot of the Fruitvale Bridge.

Some species collected and photographed on the San Francisco Bay Rapid Assessment Survey, May 23-28, 2004:

Porifera - (sponges)

Microciona prolifera

Cnidaria [Coelenterata] - (hydras, anenomes, jellyfish, corals, etc.)

Diadumene cincta Stephenson, 1925
Diadumene franciscana Hand, 1956
Diadumene lineata (Merrill, 1869)
Diadumene leucolena (Verrill, 1866)
Laomedea calceolifera (Hincks, 1871)
Garveia franciscana (Torrey, 1902)
Obelia longissima (Pallas, 1766)
Ectopleura crocea

Mollusca - (clams, snails, slugs, nudibranchs, octopuses, squids, etc.)

Philine auriformis Suter, 1909
Philine sp A SCAMIT
Janolus fuscus O'Donoghue, 1924
Mytilus californianus Conrad, 1837
Teredo navalis L. 1758 "Shipworm"
Ancula lentiginosa Farmer & Sloan, 1964
Cuthona albocrusta (MacFarland, 1966)
Catriona rickettsi ? Behrens, 1984
Sakuraeolis enosimensis (Baba, 1930)
Haminoea cf. japonica
Crassostrea gigas (Thunberg, 1795)
Potamocorbula amurensis (Schrenck, 1867)
Macoma petalum (Valenciennes, 1821)
Musculista senhousia (Benson, 1842)
Mya arenaria L.
Venerupis philippinarum
Urosalpinx cinerea
(Say 1822)
Crepidula plana Say, 1822

Annelida (segmented worms)

Amaeana sp. A. Harris
Ficopomatus enigmaticus
(Fauvel, 1923)
Marenzelleria viridis (Verrill 1873)

Arthropoda - (crustaceans, insects, arachnids, etc.)

Balanus improvisus Darwin, 1854
Synidotea laevidorsalis (Miers, 1881)
Caprella mutica Schurin, 1935
Melita rylovae Bulycheva, 1955
Ammothea hilgendorfi (Boehm, 1879)
Carcinus maenas (Linnaeus, 1758)
Jassa sp.
Ampithoe lacertosa Bate, 1958

Ectoprocta [Bryozoa] - (moss animals)

Watersipora subtorquata (d'Orbigny, 1842)
Smittoidea prolifica Osburn, 1952
Victorella pavida Saville Kent, 1870
Conopeum cf tenuissima 
Bugula neritina
(Linnaeus, 1758)
Nolella cf gigantea

Urochordata (tunicates, ascidians, "sea squirts")

Styela clava Herdman, 1881 
Molgula manhattensis (De Kay, 1843)
Ciona savignyi
  Herdman, 1882 
Ascidia zara Oka, 1935
Aplidium californicum (Ritter and Forsyth, 1917)
Botrylloides diegensis (Ritter and Forsyth, 1917)
Botryllus schlosseri (Pallas, 1766)
Botrylloides violaceus  Oka, 1927

Echinodermata - (sea urchins, starfishes, sea cucumbers, etc.)

Pisaster brevispinus (Stimpson, 1857)


Cuscuta salina Engelm 


Bryopsis corticulans Setchell
Codium fragile (Suringar) Hariot subsp. tomentosoides (van Goor) Silva
Grateloupia doryphora (Montagne) Howe

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