Invasion History

First Non-native North American Tidal Record: 1894
First Non-native West Coast Tidal Record: 1894
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

The native range of Geukensia demissa spans from the southern Gulf of St. Lawrence to Palm Beach, Florida (Bousfield 1960; Abbott 1974; Morris 1975; Gosner 1978; Krisberg 2009). The Gulf Ribbed Mussel (Geukensia granossisima), formerly considered a subspecies of G. demissa occurs from northwest Florida to Texas (Sarver et al. 1992). Specimens introduced to the West Coast have been identified as G. demissa by molecular methods (Sarver et al. 1992).

North American Invasion History:

Invasion History on the West Coast:

Geukensia demissa was first collected on the West Coast in South San Francisco Bay in 1894 (Carlton 1979). It was introduced with plantings of Eastern Oysters (Miller 2007). It is now one of the most abundant bivalves in San Francisco Bay, from San Pablo Bay to South Bay, where it lines the edges of salt-marsh creeks, channel banks, and retaining walls, attached to the substrate or plant roots by byssus threads (Carlton 1979; Cohen and Carlton 1995). One specimen was collected in Tomales Bay, California (CA) in 1952, and there are other unverified records, for instance, it was reported from Tomales Bay by Fairey et al. (2002), based on a 2001 survey. This mussel was found in 1986 in Morro Bay, CA but was not reported during subsequent surveys in 2001 (Needles 2007). In Southern California, G. demissa was found in Newport Bay in 1955, Alamitos Bay in 1968 (Reish 1968, cited by Carlton 1979; 2000, Cohen et al. 2002; Burnaford et al. 2011), Anaheim Bay in 1972 (Reish 1972, cited by Carlton 1979), and the adjacent Bolsa Chica Lagoon in 1992 (Carlton 1992). Occurrences in southern California could be associated with Eastern Oyster transfers, but the documented transfers were few and small. Introductions with ballast water or fouling are possible. Further south, it is established and very abundant in Estero de Punta Banda, Baja California Norte, Mexico, where it was introduced by the early 1980s (Torchin et al. 2005).

Invasion History Elsewhere in the World:

Geukensia 'demissa' has been reported and studied in Lake Maracaibo, Venezuela, where it was introduced by 1994, and is now established (Romero et al. 2003; Baez et al. 2005). However, these records could refer to G. granossisima (Gulf Ribbed Mussel), which was formerly considered conspecific with G. demissa.


Description

Geukensia demissa has a moderately thin, oblong-oval shell. The outer surface is marked by numerous strong radial ribs with widely spaced growth lines. The beak of the shell is subterminal, located somewhat above the hinge of the shell. Hinge teeth are absent. The ventral portion of the shell is slightly curved inward. The exterior color is yellowish-green to bluish brown, while the interior is silvery white, and often iridescent. Adult mussels range from 20 to 1400 mm (Abbott 1974; Brousseau 1984; Coan et al. 2000; Coan and Vantich-Scott 2007). Larvae are described and illustrated by Chanley and Andrews (1971). The larvae are planktotrophic, and settle at 215-305 µm (Chanley and Andrews 1971).


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Mollusca
Class:   Bivalvia
Subclass:   Pteriomorphia
Order:   Mytiloida
Family:   Mytilidae
Genus:   Geukensia
Species:   demissa

Synonyms

Arcuatula demissa (None, None)
Brachidontes demissus (None, None)
Ischadium demissum (None, None)
Modioulus plicatulus (Lamarck, 1819)
Volsella demissus (None, None)

Potentially Misidentified Species

Geukensia granossisima
(Sowerby 1914). Gulf Ribbed Mussel- this species had been regarded as a subspecies of G. demissa, but molecular analysis (enzyme electrophoresis) indicates that G. granossisimma and G. demissa are separate species (Sarver et al. 1992; Lee and O'Foighil 2004). Photographs posted by Krisberg (2009) show strong morphological differences between the forms, with a more hooked shape in G. granosissima, resembling mussels of the genus Ischadium, a similarity supported by molecular evidence (Lee and O'Foighil 2004).

Ischadium recurvum
Hooked Mussel- Young specimens are similar, but show strong curvature with growth.

Ecology

General:

Geukensia demissa has separate sexes. Animals mature at about one year of age. Sexes differ in the color of the mantle, with females being yellowish brown, while males are a cream color. Eggs are brooded, but sperm are released into the water column. Fertilized eggs develop into a planktonic trochophore larva, then into a shelled veliger. The larvae settle at 220-300 µm (Chanley and Andrews 1971).

Geukensia demissa larvae settle on rocks, wood, roots of marsh plants, and peat, though they are most abundant in marsh habitats (Abbott 1974; Morris 1975; Gosner 1978; Lippson and Lippson 1997). Marsh populations tolerate water temperatures from -1.8 to 37⁰C (Read and Cumming 1967, cited by Hicks and McMahon 2002), and doubtless survive higher air temperatures. They also tolerate wide ranges of salinity, from 5 to 70 PSU (Smithsonian Marine Station at Fort Pierce 2011).

Food:

Phytoplankton; Detritus

Consumers:

Birds, California Clapper Rail

Trophic Status:

Suspension Feeder

SusFed

Habitats

General HabitatUnstructured BottomNone
General HabitatOyster ReefNone
General HabitatMarinas & DocksNone
General HabitatSalt-brackish marshNone
General HabitatVessel HullNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeLow IntertidalNone
Tidal RangeMid IntertidalNone
Vertical HabitatEpibenthicNone
Vertical HabitatEndobenthicNone


Tolerances and Life History Parameters

Minimum Temperature (ºC)-2Based on geographical range
Maximum Temperature (ºC)37Experimental, ranges of 35-37 reported by Read and Cumming (1967), cited by Hicks and McMahon (2002)
Minimum Salinity (‰)5Field record (Miller 2000), Experimental, stepwise decrease (Wells 1961)
Maximum Salinity (‰)70Smithsonian Marine Station at Fort Pierce 2011.
Minimum Reproductive Temperature20Field data, North Carolina (Borerro 1987)
Maximum Reproductive Temperature28Field data, North Carolina (Borerro 1987)
Minimum Duration12Lab reared at 22 C (Loosanoff and Davis 1963)
Maximum Duration43Lab reared at 22 C (Loosanoff and Davis 1963)
Minimum Length (mm)20Minimum Adult Size (Brousseau 1984)
Maximum Length (mm)140Maximum Adult Size (Brousseau 1984)
Broad Temperature RangeNoneCold temperate-Subtropical
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Geukensia demissa is very abundant in San Francisco Bay, California. Possible economic impacts include structural effects on marsh channels and dikes. Since these mussels constitute a very large biomass, they could have a significant ecological impact by filtering phytoplankton and competing for food with native bivalves. Some of these impacts also appear probable in Estero Puerto Bando, Mexico, based on field studies by Torchin et al. (2005). However, economic and ecological (experimental) studies of G. demissa have not been conducted in its introduced range.

Ecological Impacts

Habitat Change- High densities of G. demissa in Estero de Punta Banda, Mexico, appear to facilitate growth of the native Pacific cordgrass Spartina foliosa, based on correlation of density of the two organisms (Torchin et al. 2005). The Ribbed Mussels also have a rather unusual impact on a native, endangered, bird. The rapidly closing shells of the mussels can trap chicks and sever toes of adult California Clapper Rails (Rallus longirostris obsoletus) in salt marshes (Carlton 1979; Cohen and Carlton 1995). Geukensia demissa represents a similar threat to another endangered subspecies, R. l. levipes, (Light-Footed Clapper Rail) in Estero Bando (Torchin et al., 2005).

Food/Prey- However, this abundant mussel is also a major food source for the California Clapper Rail (Moffitt 1941, cited by Cohen and Carlton 1995) and doubtless for other wading birds, raccoons, otters, and other salt-marsh predators.

Regional Impacts

NEP-VNorthern California to Mid Channel IslandsEcological ImpactHabitat Change
Closing shells can trap chicks and sever toes of adult endangered California Clapper Rails (Rallus longirostris obsoletus) in salt marshes (Carlton 1979; Cohen and Carlton 1995).
P090San Francisco BayEcological ImpactHabitat Change
Closing shells can trap chicks and sever toes of adult endangered California Clapper Rails (Rallus longirostris obsoletus) in salt marshes (Carlton 1979; Cohen and Carlton 1995).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactHabitat Change
High densities of G. demissa in Estero de Punta Banda, Baja California Norte, Mexico, appear to facilitate growth of the native Pacific cordgrass Spartina foliosa. They also present a hazard to the endangered Light-footed Clapper Rail (Rallus longirostrus levipes), in Estero Puerto Bando, based on the damage seen to the subspecies (R. l. oboletus) in San Francisco Bay (Torchin et al. 2005).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactCompetition
Based on the very high biomass seen in Estero de Punta Banda (4 X that of the next most abundant and native species, Tagelus spp.), competition for phytoplankton and other suspended food particles is likely (Torchin et al. 2005).
NEP-VNorthern California to Mid Channel IslandsEcological ImpactFood/Prey
Geukensia demissa comprised 57% of the diet of the endangered California Clapper Rail (Rallus longirostris obsoletus) (Moffitt 1941, cited by Cohen and Carlton 1995).
P090San Francisco BayEcological ImpactFood/Prey
Geukensia demissa comprised 57% of the diet of the endangered California Clapper Rail (Rallus longirostris obsoletus) (Moffitt 1941, cited by Cohen and Carlton 1995).
CACaliforniaEcological ImpactFood/Prey
Geukensia demissa comprised 57% of the diet of the endangered California Clapper Rail (Rallus longirostris obsoletus) (Moffitt 1941, cited by Cohen and Carlton 1995)., Geukensia demissa comprised 57% of the diet of the endangered California Clapper Rail (Rallus longirostris obsoletus) (Moffitt 1941, cited by Cohen and Carlton 1995).
CACaliforniaEcological ImpactHabitat Change
Closing shells can trap chicks and sever toes of adult endangered California Clapper Rails (Rallus longirostris obsoletus) in salt marshes (Carlton 1979; Cohen and Carlton 1995)., Closing shells can trap chicks and sever toes of adult endangered California Clapper Rails (Rallus longirostris obsoletus) in salt marshes (Carlton 1979; Cohen and Carlton 1995).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
P058 _CDA_P058 (San Pedro Channel Islands) 2011 Def Unk
P110 Tomales Bay 2001 Def Estab
P070 Morro Bay 1986 Def Unk
P050 San Pedro Bay 1968 Def Estab
NEP-VI Pt. Conception to Southern Baja California 1955 Def Estab
P040 Newport Bay 1955 Def Estab
P029 _CDA_P029 (Newport Bay) 1944 Def Estab
P090 San Francisco Bay 1894 Def Estab
P093 _CDA_P093 (San Pablo Bay) 1894 Def Estab
NEP-V Northern California to Mid Channel Islands 1894 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
697309 Introduced Species Study 2005 2005-11-14 Cal Maritime Academy/Vallejo Def 38.0661 -122.2299
697531 Reish 1968, cited in Carlton 1979; Reish 1972 1957 Colorado Lagoon Def 33.7711 -118.1347
697984 Pestrong 1965, cited in Carlton 1979; Mariscal 1965 1965 Palo Alto, San Francisco Bay Def 37.4584 -122.1052
699067 Introduced Species Study 2010 2010-07-13 Petaluma River Turning Basin Def 38.2344 -122.6354
699155 ISS 2000-2002 Survey Data 2001 2001-07-10 Channel Islands Harbor Epifaunal 02 Def 34.1811 -119.2319
699578 Introduced Species Study 2005 2005-09-07 Redwood Creek - Shipping Def 37.5120 -122.2109
699984 ISS 2000-2002 Survey Data 2001 2001-08-01 Avalon Harbor Epifaunal 01 Def 33.3441 -118.3245
700235 Introduced Species Study 2011 2011-05-06 The Tuna Club Def 33.3461 -118.3268
700728 Reish 1968; McLean 1969, both cited in Carlton 1979 1940 Newport Bay Def 33.6092 -117.9067
700927 Stearns 1899, 1900 1894 Western shore, South San Francisco Bay Def 37.4981 -122.1779
700935 Cohen and Carlton 1995 1995 South San Francisco Bay Def 37.5457 -122.1645
701047 Cohen et al. 2002 (So Cal Exotics RAS) 2000 2000-08-31 Colorado Lagoon Def 33.7711 -118.1347
701219 Degroot 1927 1927 San Francisco Bay Def 37.8494 -122.3681
701316 Introduced Species Study 2011 2011-05-06 Ferry Terminal Docks Def 33.3442 -118.3225
701907 ISS 2000-2002 Survey Data 2001 2001-09-19 Tomales Bay Epifaunal 02 Def 38.1467 -122.8835
701923 Reish 1972; Reish et al. 1975 1972 Anaheim Bay Def 33.7333 -118.0894
702157 Cohen et al. 2005 (SF Bay Area RAS) 2004 2004-05-24 San Leandro Marina, San Francisco Bay Def 37.6966 -122.1932
702786 Cohen and Carlton 1995 1995 Central San Francisco Bay Def 37.8595 -122.3884
703258 Introduced Species Study 2005 2005-11-15 China Camp Def 38.0025 -122.4617
703259 Introduced Species Study 2010 2010-06-12 China Camp Def 38.0025 -122.4617
703749 Carlton 1979 1979 Lake Merritt, Oakland, San Francisco Bay Def 37.8025 -122.2578
704088 Cohen and Carlton 1995 1995 San Pablo Bay Def 38.0600 -122.3900
704528 Introduced Species Study 2005 2005-10-19 Napa Valley Marina Def 38.2198 -122.3119
716756 Miller et al. 2007 2005 Redwood City Def 37.5133 -122.2086
716757 Cohen 2005 2005 Petaluma Def 38.2219 -122.6250
716758 Cohen 2005 2005 Alviso Def 37.4261 -121.9752
716759 Robinson et al. 2011 2005 China Camp Def 38.0008 -122.4616
716760 Needles 2007; Needles and Wendt 2013 1986 Morro Bay Def 35.3378 -120.8513
716763 M. Wicksten pers. comm. 1979, in Carlton 1992 1979 Bolsa Chica Lagoon Def 33.6891 -118.0346
759719 Keep 1901 1901 Southwestern shore, San Francisco Bay Def 37.4981 -122.1779
759720 Carlton 1979; California Academy of Sciences Invertebrate Zoology Collection Database 1903 1903-10-20 Cooley Landing Def 37.4768 -122.1214
759721 Hanna 1966 1913 1913-03-13 San Francisco Bay Def 37.8494 -122.3681
759722 Packard 1918 1918 South San Francisco Bay Def 37.5457 -122.1645
759723 I.S. Oldroyd, pers. comm., in Hanna 1921 1921 Alameda Def 37.7740 -122.3040
759724 Hanna 1921 1921 Bay Farm Island Def 37.7453 -122.2183
759725 Baily 1932 1932 Lake Merritt Def 37.8025 -122.2578
759726 W. Hartman, pers. comm. 1977, in Carlton 1979 1952 Tomales Bay Def 38.2100 -122.9400
759727 Reish 1968, cited in Carlton 1979 1968 Cerritos Channel Def 33.7665 -118.2375
759728 Crane et al. 1975 1972 Colorado Lagoon Def 33.7711 -118.1347
759729 Murphy 1985 1979 Colorado Lagoon Def 33.7711 -118.1347
759730 Burnaford et al. 2011 2010 Colorado Lagoon Def 33.7711 -118.1347
759731 Recher 1966 1962 near Mouth of San Francisquito Creek Def 37.4658 -122.1156
759732 J.T. Carlton, field observations, in Carlton 1979a 1977 Colorado Lagoon Def 33.7711 -118.1347
759733 Carpelan 1957 1951 Floodgate at Charleston Slough Def 37.4557 -122.1009
759734 Zucca 1954 1950 Dumbarton Bridge Marsh Def 37.5006 -122.1311

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