Invasion History

First Non-native North American Tidal Record: 1898
First Non-native West Coast Tidal Record: 1898
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Sphaeroma quoianum is native on the eastern coast of Australia (Tasmania and Victoria to Cairns, Queeensland) and New Zealand (Jansen 1971; Harrison and Holdich 1984; Davidson 2006; Davidson et al. 2008; Atlas of Living Australia 2015). A population in the Swan River estuary, Western Australia (Hass and Knott 1998) is of uncertain native status. It appears to be less abundant and conspicuous in Australian and New Zealand estuaries than in its introduced habitats on the West Coast of North America (Davidson et al. 2008). In its native region, it is primarily considered a woodborer, though it is also found in marsh banks, clay, and soft rock (Davidson et al. 2008).

North American Invasion History:

Invasion History on the West Coast:

Sphaeroma quoianum was first found in North America around 1898 at Sausalito, California (CA), on San Francisco Bay (Richardson 1898, cited by Carlton 1979). By the 1930s, it had been collected in South Bay (in 1920, USNM 89805, 1989, United States Museum of Natural History 2007), San Pablo Bay (in 1912, USNM 64473, United States Museum of Natural History 2007); and as far inland as Antioch (Koifoid and Miller 1927, cited by Cohen and Carlton 1995). To the south, it was established in Los Angeles Harbor and San Diego Bay by 1927 (Johnson and Snook 1927, cited by Carlton 1979), but was not collected in Elkhorm Slough until 1998 (Wasson et al. 2001). South of San Francisco Bay, S. quoianum was collected in Morro Bay in 1974 (Iverson 1976, cited by Carlton 1979); Newport Bay in 1962 (Menzies 1962, cited by Carlton 1979); and Bahia San Quintin, Baja California, Mexico in 1960 (Menzies 1962, cited by Carlton 1979; USNM 109311, United States National Museum of Natural History 2007). North of San Francisco Bay, it was collected in Tomales Bay in 1929 (USNM 65813, US National Museum of Natural History 2007) and Humboldt Bay in 1931 (USNM 113887, United States Museum of Natural History 2007). Some smaller estuaries were either subsequently colonized or just sampled at a later date – these include Bolinas Lagoon in 1958 (Riegel 1959, cited by Carlton 1979) and Bodega Harbor in 1972 (Rotramel 1972, cited by Carlton 1979). It was most likely introduced to San Francisco Bay in soft rotten wood on a ship hull, but has become a prominent species boring into marsh sediments and riddling Styrofoam floats in marinas (Cohen and Carlton 1995). This isopod is extending its range northward. It became established in Coos Bay, Oregon (OR) in 1995, and reached Yaquina Bay, OR in 2005 (Davidson 2006).

Invasion History in Hawaii:

In 1915, Sphaeroma quoianum was collected in Pearl Harbor, Hawaii (USNM 113915, United States Museum of Natural History 2007), but has not become established (Davidson 2006).

Invasion History Elsewhere in the World:

In 1961, Sphaeroma quoianum was reported from the coast of Vietnam, in the Gulf of Tonkin, where it is possibly introduced (Kussakin and Malyutuna 1993).


Description

Sphaeroma quoianum has a compact, convex, elliptical body, which is about twice as long as it is wide. The head is crescent-shaped, with prominent eyes, composed of many ocelli. Antenna 1 has a flagellum of 9 segments, and extends to the posterior edge of Peraeonite 1. Antenna 2's flagellum has 16 segments, and reaches the posterior edge of Peraeonite 2. The peraeonites are roughly equal in width, except for Peraeonite 1, which is somewhat broader than the others. Peraeonites 2-7 each bear a broad transverse ridge. Pereiopods 1-3 bear dense plumose setae on the upper (anterior) surface of segments 3-4, an adaptation for filter-feeding. The pleon has several tubercles. The pleotelson is broad and shield-like, with the terminal edge bluntly curved. The pleotelson has two parallel rows of 4-5 tubercles each, and an elliptical raised transverse ridge near the terminus. The outer edges of the exopods of the uropods each bear 5 prominent teeth. Adults are 8-16 mm long. The color is variable, from sandy brown, gray-green to solid black, and/or with various mottling of brown, black, and red. Description is based on: Richardson 1904, Schultz 1969, Harrison and Holdich 1984, Davidson 2006, and Brusca et al. 2007.


Taxonomy

Taxonomic Tree

Kingdom:   Animalia
Phylum:   Arthropoda
Subphylum:   Crustacea
Class:   Malacostraca
Subclass:   Eumalacostraca
Superorder:   Peracarida
Order:   Isopoda
Suborder:   Flabellifera
Family:   Sphaeromatidae
Genus:   Sphaeroma
Species:   quoianum

Synonyms

Sphaeroma pentodon (Richardson, 1904)
Sphaeroma quoyanum (Neirstrasz, 1931)
Sphaeroma quoyana (Hedley, 1901)
Sphaeroma verrucauda (White, 1847)

Potentially Misidentified Species

Sphaeroma walkeri
Sphaeroma walkeri is native to the Indian Ocean, and is widely introduced to tropical, subtopical and warm-temperate waters, including San Diego Bay, and possibly San Francisco Bay (Carlton and Iverson 1981; Carlton 2000). Unlike S. quoianum, S. walkeri is not a borer, though it does dwell in crevices, and it is also stenohaline, limited to salinities of 24-40 PSU (Carlton and Iverson 1981).

Ecology

General:

Sphaeroma quoianum has separate sexes and fertilization is internal. The young are brooded by the female and development is direct. Breeding takes place year-round, but brood size varies, with means of 64 in spring and 19 in fall in the San Francisco region. Its young mature in about 6 months and live for about 1.5 to 2 years (Schneider 1976, cited by Davidson 2006). Reported sizes for adults range from 8 to 16 mm (Schultz 1969; Hurley and Jansen 1977, cited by Davidson 2006; Harrison and Holdich 1984).

Sphaeroma quoianum inhabits intertidal estuarine coastlines in cold-temperate to tropical climates, and tolerates a wide range of temperature and salinity. In experiments with rapid heating (1C/min.), the lethal temperature was 42C, but limits for long-term survival are probably considerably lower. This isopod survived for 3 days at 5C. Sphaeroma quoianum is a burrower, in substrates including decaying wood, soft sandstone, salt-marsh peat and Styrofoam. In substrate preference experiments, S. quoianum most frequently colonized decayed wood in the intertidal zone (Davidson et al. 2008b). In experiments, the extent of burrowing (per isopod) varied with temperature, being greatly reduced below 10 C and reaching a maximum between 15 and 20 C (Davidson et al. 2013). Colonization of new sites is primarily by juveniles under 5 mm in length (Davidson et al. 2008b).

Sphaeroma quoianum burrows by chewing the substrate with its mandibles and expelling the particles with the current created by its beating pleopods. This animal is not known to get any nutrition from the substrate. Within its burrow, S. quoinaum sits head inward, creating a current with its pleopods, flowing inward dorsally, and outward ventrally. Phytoplankton and detritus are caught on the dense setae of the legs (Pereiopods 1-3). Periodically, the animal ceases beating of its pleopods and cleans particles off the legs with the maxillipeds (Rotramel 1975). The burrows and the flow of food particles provide food and shelter for at least two specialized symbionts and a variety of more casual visitors. The isopod Iais californica, also introduced from New Zealand or Australia, is a common obligate commensal of S. quoianum, now occurring from San Diego to Coos Bay (Rotramel 1972; Coos 1979; Davidson 2006). In experiments, I. californica had little or no effect on the survival of S. quoianum (Rotramel 1972). Another symbiont is the ciliate, Lagenophrys cochinensis, which occurs on the appendages of S. quoianum and other Sphaeroma spp. in their native and introduced ranges (Clamp 2006). Impacts of this commensal have not been studied. A wide variety of native and introduced free-living benthic invertebrates use the burrows of S. quoianum for shelter (Davidson et al. 2010).

Food:

Detritus; Phytoplankton

Trophic Status:

Suspension Feeder

SusFed

Habitats

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


Tolerances and Life History Parameters

Minimum Temperature (ºC)5Experimental, lowest tested. No mortality in 3 days (Jansen 1971).
Maximum Temperature (ºC)42 In short-term experiments, heating at 1 C/min, 90% of animals died at 42 C (Jansen 1971). Long-term survival limits are probably much lower.
Minimum Salinity (‰)5Field, Not found at salinities below 5 PSU (Davidson 2006). Experimental, 50% survival after 11 days (Riegel 1959, cited by Davidson 2008). Absent at salinities below 5 PSU in Coos Bay, Oregon, and Port Philip Bay and Tamar estuary, Australia (Davidson 2006; Davidson 2008).
Maximum Salinity (‰)40Field Data, Swan Estuary, Western Australia (Hass and Knott 1998).
Maximum Length (mm)16(Hurley and Jansen 1977, cited by Davidson 2006)
Broad Temperature RangeNoneCold temperate- Warm temperate
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Sphaeroma quoianum is an estuarine isopod which burrows into wood, marsh peat, sandstone, and Styrofoam. It creates complex habitats by boring, and can alter shorelines by increasing erosion. Consequently, its invasion on the West Coast has had significant ecological and economic impacts (Cohen and Carlton 1995; Talley et al. 2001; Davidson 2006; Davidson and de Rivera 2010; Davidson 2010; Davidson et al. 2010; Davidson and de Rivera 2012).

Economic Impacts

Shipping and Boating- Sphaeroma quoianum burrows into the walls of marsh channels and levees, contributing to erosion, increasing flood threats, and damaging Styrofoam floats in marinas. However, the extent of this damage in San Francisco Bay, California (CA) has not been quantified (Carlton 1979; Cohen and Carlton 1995). In Coos Bay, Oregon (OR), burrowing by S. quoianum destroyed one floating dock with Styrofoam floats and is damaging wooden pilings (Davidson 2006; Davidson 2008). 'Dikes infested with S. quoianum failed in Coalbank Slough, Coos Bay during winter storms of 2005-06 causing tens of thousands of dollars of damage to several residences (S. Rumrill, pers. comm.)' (Davidson 2008). In Coos Bay, marshes colonized by S. quoianum eroded at a much faster rate than uninfested marshes (Davidson and de Rivera 2010), with implications for waterfront property. Sphaeroma quoianum's habit of burrowing into Styrofoam floats has ecological impacts, by releasing millions of plastic particles, with serious implications for marine food webs (Davidson 2012).

Fisheries- Aquaculture facilities involving cages and ropes, suspended from floats, are vulnerable to S. quoianum. An oyster-rearing facility in Yaquina Bay had its floating docks extensively damaged (Davidson 2012).

Ecological Impacts

Habitat Change- Sphaeroma quoianum burrows into the walls of marsh channels, contributing to erosion, and modifying the marsh habitat. Higgins (1956, cited by Davidson 2008) observed that this isopod increased the erosion of sandstone terraces in San Francisco Bay. Carlton (1979) suggested that the isopod was responsible for the loss of 'tens or scores of meters of shoreline since the 19th century'. In San Diego Bay, S. quoianum creates dense networks of tunnels in walls of marsh channels. Enclosure experiments showed that S. quoianum increases the rate of marsh erosion, roughly doubling it in steeply sloping areas. Estimated marsh loss due to S. quoianum in San Diego Bay can be as great as 1 m per year in some locations (Talley et al. 2001). Burrowing by S. quoianum is accelerating erosion of marsh banks and sandstone terraces in Coos Bay, Oregon. Burrows were present at 75% of the sites examined within the Bay (Davidson 2006; Davidson 2008). In experiments, the extent of burrowing (per amphipod) varies with temperature, greatly reduced below 10C, reaching a maximum between 15 and 20C, and declining at higher temperatures. Projected global warming is likely to increase erosive impacts of S. quoianum in Coos Bay by 15-38%. This isopod's impact on erosion in other West Coast bays is likely to vary, increasing greatly in the northern portions of the invasion range, but increasing less (San Francisco Bay, Elkhorn Slough) or decreasing in the southern portion of the range (e.g. San Diego Bay and the Tijuana estuary) (Davidson et al. 2013).

Regional Impacts

P090San Francisco BayEconomic ImpactShipping/Boating
Sphaeroma quoianum burrows into the walls of marsh channels and levees, contributing to erosion, increasing flood threats, and damaging Styrofoam floats in marinas. However, the extent of this damage has not been quantified (Carlton 1979; Cohen and Carlton 1995). Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012).
NEP-VNorthern California to Mid Channel IslandsEconomic ImpactShipping/Boating
Sphaeroma quoianum burrows into the walls of marsh channels and levees, contributing to erosion, increasing flood threats, and also damaging Styrofoam floats in marinas. However, the extent of this damage has not been quantified (Carlton 1979; Cohen and Carlton 1995). Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012).
NEP-VNorthern California to Mid Channel IslandsEcological ImpactHabitat Change
Sphaeroma quoianum burrows into the walls of marsh channels, contributing to erosion, and modifying the marsh habitat. Higgins (cited by Davidson 2008) observed that this isopod increased the erosion of sandstone terraces in San Francisco Bay. Carlton (1979) suggested that the isopod was responsible for the loss of 'tens or scores of meters of shoreline since the 19th century'. Boring by S. quoianum in plastic foam floats contributes to pollution from plastic particles, with adverse consequences for marine food webs (Davidson 2012).
NEP-VIPt. Conception to Southern Baja CaliforniaEcological ImpactHabitat Change

Sphaeroma quoianum creates dense networks of tunnels in walls of marsh channels in San Diego Bay. Enclosure experiments showed that S. quoianum increases the rate of marsh erosion, roughly doubling it in steeply sloping areas. Estimated marsh loss due to S. quoianum in San Diego Bay can be as great as 1 m per year in some locations (Talley et al. 2001). In the Bolsa Chica Reserve, Huntington Brach CA, S. quoianum decreased carbon content in sediement, and increased erosion rates (Brown et al. 2022).

P020San Diego BayEcological ImpactHabitat Change
Sphaeroma quoianum creates dense networks of tunnels in walls of marsh channels in San Diego Bay. Enclosure experiments showed that S. quoianum increases the rate of marsh erosion, roughly doubling it in steeply sloping areas. Estimated marsh loss due to S. quoianum in San Diego Bay can be as great as 1 m per year in some locations (Talley et al. 2001).
P090San Francisco BayEcological ImpactHabitat Change
Sphaeroma quoianum burrows into the walls of marsh channels, contributing to erosion, and modifying marsh habitat. Higgins (cited by Davidson 2008) observed that this isopod increased the erosion of sandstone terraces in San Francisco Bay. Carlton (1979) suggested that the isopod was responsible for the loss of 'tens of scores of meters of shoreline since the 19th century'.
NEP-IVPuget Sound to Northern CaliforniaEconomic ImpactShipping/Boating
In Coos Bay, burrowing by S. quoianum destroyed one floating dock with Styrofoam floats, and is damaging wooden pilings(Davidson 2006; Davidson 2008; Davidson 2012). Damage to plastic floats was extensive in Yaquina and Coos Bays, OR (Davidson 2012).
NEP-IVPuget Sound to Northern CaliforniaEcological ImpactHabitat Change
Burrowing by S. quoianum is accelerating erosion of marsh banks and sandstone terraces in Coos Bay, Oregon. Burrows were present at 75% of the sites surveyed within the Bay (Davidson 2006; Davidson 2008). Burrowed areas had rates of erosion that were 300% higher than those of adjacent unburrowed areas (Davidson and de Rivera 2010). Burrows in marsh peat were, on average, to 15X individual body volume, but only 2.5X body volume in wood. Individual impacts are smaller than those of some borers and burrowers, but high abundances can result in large population impacts (Davidson and de Rivera 2012). Boring by S. quoianum in plastic foam floats contributes to pollution by plastic particles, with adverse consequences to marine food webs (Davidson 2012). In experiments, the extent of burrowing (per amphipod) varies with temperature, greatly reduced below 10C, reaching a maximum between 15 and 20C, and declining at higher temperatures. Projected global warming is likely to increase erosive impacts of S. quoianum in Coos Bay by 15-38% (Davidson et al. 2013).
P080Monterey BayEconomic ImpactShipping/Boating
Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012).
P080Monterey BayEcological ImpactHabitat Change
Boring by S. quoianum in plastic foam floats contributes to pollution by plastic particles, with adverse consequences to marine food webs (Davidson 2012).
NEP-IVPuget Sound to Northern CaliforniaEconomic ImpactFisheries
In Yaquina Bay OR, burrowing by S. quoianum riddled ~60 Styrofoam floats in a n oyste-rearing facility, requiring replacement and extensive repairs (Davidson 2012).
P050San Pedro BayEcological ImpactHabitat Change

). In the Bolsa Chica Reserve, Huntington Beach CA, S. quoianum decreased carbon content in sediement, and increased erosion rates (Brown et al. 2022).

CACaliforniaEcological ImpactHabitat Change
Sphaeroma quoianum burrows into the walls of marsh channels, contributing to erosion, and modifying the marsh habitat. Higgins (cited by Davidson 2008) observed that this isopod increased the erosion of sandstone terraces in San Francisco Bay. Carlton (1979) suggested that the isopod was responsible for the loss of 'tens or scores of meters of shoreline since the 19th century'. Boring by S. quoianum in plastic foam floats contributes to pollution from plastic particles, with adverse consequences for marine food webs (Davidson 2012)., Sphaeroma quoianum creates dense networks of tunnels in walls of marsh channels in San Diego Bay. Enclosure experiments showed that S. quoianum increases the rate of marsh erosion, roughly doubling it in steeply sloping areas. Estimated marsh loss due to S. quoianum in San Diego Bay can be as great as 1 m per year in some locations (Talley et al. 2001).,

). In the Bolsa Chica Reserve, Huntington Beach CA, S. quoianum decreased carbon content in sediement, and increased erosion rates (Brown et al. 2022).

, Sphaeroma quoianum burrows into the walls of marsh channels, contributing to erosion, and modifying marsh habitat. Higgins (cited by Davidson 2008) observed that this isopod increased the erosion of sandstone terraces in San Francisco Bay. Carlton (1979) suggested that the isopod was responsible for the loss of 'tens of scores of meters of shoreline since the 19th century'., Boring by S. quoianum in plastic foam floats contributes to pollution by plastic particles, with adverse consequences to marine food webs (Davidson 2012).
CACaliforniaEconomic ImpactShipping/Boating
Sphaeroma quoianum burrows into the walls of marsh channels and levees, contributing to erosion, increasing flood threats, and also damaging Styrofoam floats in marinas. However, the extent of this damage has not been quantified (Carlton 1979; Cohen and Carlton 1995). Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012)., Sphaeroma quoianum burrows into the walls of marsh channels and levees, contributing to erosion, increasing flood threats, and damaging Styrofoam floats in marinas. However, the extent of this damage has not been quantified (Carlton 1979; Cohen and Carlton 1995). Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012)., Damage to plastic floats was extensive in San Francisco Bay and Elkhorn Slough, CA (Davidson 2012).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
P080 Monterey Bay 1998 Non-native Established
P070 Morro Bay 1974 Non-native Established
P112 _CDA_P112 (Bodega Bay) 1972 Non-native Established
P095 _CDA_P095 (Tomales-Drakes Bay) 1958 Non-native Established
P040 Newport Bay 1957 Non-native Established
P130 Humboldt Bay 1931 Non-native Established
NEP-IV Puget Sound to Northern California 1931 Non-native Established
P110 Tomales Bay 1929 Non-native Established
P050 San Pedro Bay 1927 Non-native Established
NEP-VI Pt. Conception to Southern Baja California 1927 Non-native Established
P020 San Diego Bay 1927 Non-native Established
P090 San Francisco Bay 1898 Non-native Established
P093 _CDA_P093 (San Pablo Bay) 1898 Non-native Established
NEP-V Northern California to Mid Channel Islands 1898 Non-native Established

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
717760 National Museum of Natural History Database 1920 1920-12-30 Dumbarton Cut-Off Bridge (Station N-10) Non-native 37.4988 -122.1277
717765 National Museum of Natural History Database 1931 1931-01-17 Humboldt Bay Non-native 40.7195 -124.2426
717833 Rotramel 1972 1972 Bodega Bay [sic] Non-native 38.3262 -123.0495
717834 National Museum of Natural History Database 1929 Tomales Bay Non-native 38.1713 -122.9128
717836 Richardson 1904a, 1905 1904 Sausalito Non-native 37.8564 -122.4783
717855 National Museum of Natural History Database 1960 1960-11-15 San Mateo Bridge Non-native 37.5806 -122.2543
717901 National Museum of Natural History Database 1989 1989-12-27 Lake Merritt, Oakland Non-native 37.8025 -122.2579
756242 ISS 2000-2002 Survey Data 2000 2000-10-25 Monterey Harbor Epifaunal 01 Non-native 36.6032 -121.8920
756243 ISS 2000-2002 Survey Data 2000 2000-10-25 Monterey Harbor Epifaunal 02 Non-native 36.6034 -121.8907
756244 ISS 2000-2002 Survey Data 2000 2000-10-25 Monterey Harbor Epifaunal 03 Non-native 36.6043 -121.8918
756245 ISS 2000-2002 Survey Data 2000 2000-10-25 Monterey Harbor Epifaunal 04 Non-native 36.6039 -121.8896
756246 Introduced Species Study 2005 2005-06-07 Aquatic Park Non-native 37.8080 -122.4216
756247 Introduced Species Study 2005 2005-06-08 Yerba Buena Non-native 37.8146 -122.3712
756248 Introduced Species Study 2005 2005-08-19 Ayala Cove Non-native 37.8680 -122.4350
756249 Introduced Species Study 2005 2005-09-07 Dumbarton Bridge Non-native 37.5070 -122.1168
756250 Introduced Species Study 2005 2005-09-07 Railroad Bridge Non-native 37.4602 -121.9750
756251 Introduced Species Study 2005 2005-09-07 Redwood Creek - Marina Non-native 37.5021 -122.2130
756252 Introduced Species Study 2005 2005-09-08 Pier 45 Non-native 37.8111 -122.4196
756253 Introduced Species Study 2005 2005-09-09 Sea Plane Harbor Non-native 37.6349 -122.3848
756254 Introduced Species Study 2005 2005-09-09 Sierra Point Marina Non-native 37.6740 -122.3792
756255 Introduced Species Study 2005 2005-10-04 Berkeley Marina Non-native 37.8676 -122.3172
756256 Introduced Species Study 2005 2005-10-06 Richmond Marina Non-native 37.9137 -122.3504
756257 Introduced Species Study 2005 2005-10-06 Santa Fe Channel - Front Non-native 37.9101 -122.3644
756258 Introduced Species Study 2005 2005-10-07 Martinez Marina Non-native 38.0276 -122.1371
756259 Introduced Species Study 2005 2005-10-18 Pacheco Creek Oil Pier Non-native 38.0489 -122.0903
756260 Introduced Species Study 2005 2005-10-19 Hercules Wharf Non-native 38.0231 -122.2928
756261 Introduced Species Study 2005 2005-10-19 Mare Island Strait - Marina Non-native 38.1051 -122.2667
756262 Introduced Species Study 2005 2005-10-19 Mare Island Strait - Navy Non-native 38.1015 -122.2695
756263 Introduced Species Study 2005 2005-10-19 Napa Valley Marina Non-native 38.2198 -122.3119
756264 Introduced Species Study 2005 2005-10-19 Rodeo Marina Non-native 38.0394 -122.2717
756265 Introduced Species Study 2005 2005-10-20 Loch Lomond Marina Area Non-native 37.9720 -122.4832
756266 Introduced Species Study 2005 2005-10-20 Port Sonoma/Petaluma R. Non-native 38.1157 -122.5026
756267 Introduced Species Study 2006 2006-11-01 B-Dock Non-native 36.8027 -121.7851
756268 Introduced Species Study 2006 2006-11-01 MLML Small Boats Non-native 36.8041 -121.7860
756269 Introduced Species Study 2006 2006-11-01 The Steelhead/MBARI Bridge Non-native 36.8005 -121.7877
756270 Introduced Species Study 2010 2010-05-31 Railroad Bridge Non-native 37.4602 -121.9750
756271 Introduced Species Study 2010 2010-05-31 Redwood Creek - Marina Non-native 37.5021 -122.2130
756272 Introduced Species Study 2010 2010-05-31 Redwood Creek - Shipping Non-native 37.5120 -122.2109
756273 Introduced Species Study 2010 2010-06-01 Sea Plane Harbor Non-native 37.6349 -122.3848
756274 Introduced Species Study 2010 2010-06-11 Cal Maritime Academy/Vallejo Non-native 38.0661 -122.2299
756275 Introduced Species Study 2010 2010-06-12 China Camp Non-native 38.0025 -122.4617
756276 Introduced Species Study 2010 2010-06-29 Martinez Marina Non-native 38.0276 -122.1371
756277 Introduced Species Study 2010 2010-06-30 Hercules Wharf Non-native 38.0231 -122.2928
756278 Introduced Species Study 2010 2010-06-30 Mare Island Strait - Marina Non-native 38.1051 -122.2667
756279 Introduced Species Study 2010 2010-06-30 Napa Valley Marina Non-native 38.2198 -122.3119
756280 Introduced Species Study 2010 2010-07-13 Port Sonoma/Petaluma R. Non-native 38.1157 -122.5026
756281 Introduced Species Study 2011 2011-06-21 B-Dock Non-native 36.8027 -121.7851
756282 Introduced Species Study 2011 2011-06-21 North Harbor/Boat Launch Non-native 36.8128 -121.7880
760613 National Museum of Natural History Database 1893 Sausalito Non-native 37.8564 -122.4783
760614 Holmes 1904 1904 San Francisco Bay Non-native 37.8494 -122.3681
760615 National Museum of Natural History Database and Carlton 1979a 1912 1912-11-27 USS Albatross Station 5812 (0.7 mile NW of No. 7 Beacon) Non-native 37.4783 -122.0859
760616 National Museum of Natural History Database and Carlton 1979a 1916 San Pablo Bay, 0.5 mile S of Rocks [sic] Non-native 38.0700 -122.3800
760617 Barrows 1919 1919 Rodeo Non-native 38.0394 -122.2749
760618 National Museum of Natural History Database and Carlton 1979a 1920 1920-11-09 Mare Island Silt Barrier Dikes, San Pablo Bay Non-native 38.0643 -122.2885
760619 Johnson and Snook 1927, cited in Iverson 1974 and Carlton 1979a 1927 Inner Los Angeles Harbor (San Pedro) Non-native 33.7513 -118.2705
760620 Johnson and Snook 1927, cited in Carlton 1979a 1927 San Diego Bay at Chula Vista Non-native 32.6350 -117.1077
760621 Kofoid and Miller 1927 1927 Antioch, Delta Non-native 38.0172 -121.8078
760622 National Museum of Natural History Database 1929 Tomales Bay Non-native 38.1700 -122.9200
760623 Copeland 1941, cited in Carlton 1979a 1941 Tomales Bay Non-native 38.2100 -122.9400
760624 Light 1941, cited in Carlton 1979a 1941 Lake Merritt Non-native 37.8025 -122.2579
760625 Light 1941, cited in Carlton 1979a 1941 Point Richmond Non-native 37.9230 -122.3940
760626 Menzies and Barnard 1951 1948 1948-08-18 Hamlet, Tomales Bay Non-native 38.2069 -122.9259
760627 Zucca 1954 1950 Dumbarton Bridge Marsh Non-native 37.5006 -122.1311
760628 Carpelan 1957 1951 Floodgate at Charleston Slough Non-native 37.4557 -122.1009
760629 Riegel 1959a; Carlton 1979a 1958 Bolinas Lagoon Non-native 37.9189 -122.6816
760630 Iverson 1974 1972 1972-04-29 Near Samoa, Humboldt Bay Non-native 40.8195 -124.1787
760631 Iverson 1974 1972 1972-09-24 Morro Bay Non-native 35.3500 -120.8500
760632 Rotramel 1972 1972 Bolinas Lagoon Non-native 37.9210 -122.6800
760633 Rotramel 1972 1972 Tomales Bay Non-native 38.2100 -122.9400
760634 Rotramel 1972 1972 San Francisco Bay Non-native 37.8494 -122.3681
760635 Carlton 1979a 1973 Hyde Street Pier Non-native 37.8092 -122.4217
760636 Wasson et al. 2001 1998 Elkhorn Slough Station 1 (North side of bridge over Old Salinas River channel; south of Moss Landing) Non-native 36.7908 -121.7906
760637 Wasson et al. 2001 1998 Elkhorn Slough Station 5 (South Marsh Trail, near footbridge) Non-native 36.8193 -121.7378
760638 Wasson et al. 2001 1998 Elkhorn Slough Station 6 (Whistlestop Lagoon) Non-native 36.8230 -121.7417
760639 Wasson et al. 2001 1998 Elkhorn Slough Station 9 (Kirby Park, near boat ramp) Non-native 36.8398 -121.7435
760640 Wasson et al. 2001 1998 Elkhorn Slough Station 10 (Hudson's Landing, W of Elkhorn Slough) Non-native 36.8578 -121.7572
760641 Boyd et al. 2002 2002 Bracut Non-native 40.8313 -124.0845
760642 Boyd et al. 2002 2002 Hookton Slough Non-native 40.6775 -124.2218
760643 Boyd et al. 2002 2002 Jacoby Creek Non-native 40.8435 -124.0838
760644 Boyd et al. 2002 2002 Southport Landing Non-native 40.6952 -124.2494
760645 Cohen et al. 2002 2000 2000-08-31 Colorado Lagoon Non-native 33.7711 -118.1347
760646 Cohen et al. 2002 2000 2000-08-24 Island Yacht Anchorage Non-native 33.7728 -118.2478
760647 Cohen et al. 2005 2004 2004-05-23 Brisbane Lagoon, San Francisco Bay Non-native 37.6862 -122.3906
760648 Cohen et al. 2005 2004 2004-05-24 Coast Guard Island Marina, San Francisco Bay Non-native 37.7812 -122.2458
760649 Cohen et al. 2005 2004 2004-05-25 Port Sonoma, San Pablo Bay Non-native 38.1156 -122.5026
760650 Cohen et al. 2005 2004 2004-05-27 Pete's Harbor, San Francisco Bay Non-native 37.5006 -122.2242
760651 Cohen et al. 2005 2004 2004-05-28 Napa Valley Marina, San Pablo Bay Non-native 38.2200 -122.3128
760652 Cohen et al. 2005 2004 2004-05-28 Rodeo Marina, San Pablo Bay Non-native 38.0391 -122.2711
760653 Cohen and Chapman 2005 2005 2005-11-27 Buoy # 12 Non-native 37.9138 -122.4443
760654 Cohen and Chapman 2005 2005 2005-11-27 Carquinez Buoy Non-native 38.0696 -122.2273
760655 Cohen and Chapman 2005 2005 2005-11-27 Dumbarton Bridge (pylon) Non-native 37.5047 -122.1227
760656 Heiman and Micheli 2010; Hobbs et al. 2015 2002 Elkhorn Slough (Upper) Non-native 36.8547 -121.7600
760657 National Museum of Natural History Database 1912 1912-02-01 USS Albatross Station A5703 (Central Bay) Non-native 37.8792 -122.4203
760658 Hoestlandt 1969 1969 Shallow Beach, Tomales Bay Non-native 38.1234 -122.8820
760659 Hoestlandt 1969 1969 Shell Beach, Tomales Bay Non-native 38.1171 -122.8738
767981 Ruiz et al., 2015 2012 2012-08-24 Richmond Marina Bay Yacht Harbor, San Francisco Bay, CA, California, USA Non-native 37.9134 -122.3523
768126 Ruiz et al., 2015 2012 2012-09-04 Redwood City Marina, San Francisco Bay, CA, California, USA Non-native 37.5023 -122.2130
768333 Ruiz et al., 2015 2013 2013-08-23 Loch Lomond Marina, San Francisco Bay, CA, California, USA Non-native 37.9723 -122.4829
768374 Ruiz et al., 2015 2013 2013-08-14 Redwood City Marina, San Francisco Bay, CA, California, USA Non-native 37.5024 -122.2134
771681 Ruiz et al., 2021a 2018 2018-09-12 Glen Cove Marina, San Francisco Bay, California, USA Non-native 38.0675 -122.2142
772252 Ruiz et al., 2021a 2018 2018-09-20 San Leandro Marina, San Francisco Bay, California, USA Non-native 37.6981 -122.1907
772276 Ruiz et al., 2021a 2018 2018-09-18 Richmond Marina Bay Yacht Harbor, San Francisco Bay, California, USA Non-native 37.9139 -122.3461
775247 Ruiz et al., 2022 2014 2014-09-04 Glen Cove Marina, San Francisco Bay, California, USA Non-native 38.0674 -122.2131
775266 Ruiz et al., 2022 2014 2014-09-18 Oakland Yacht Club, San Francisco Bay, California, USA Non-native 37.7835 -122.2630
775317 Ruiz et al., 2022 2015 2015-09-10 Glen Cove Marina, San Francisco Bay, California, USA Non-native 38.4096 -122.1247

References

Atlas of Living Australia 2013-2016 Atlas of Living Australia. <missing URL>



Boyd, Milton J.; Mulligan, Tim J; Shaughnessy, Frank J. (2002) <missing title>, California Department of Fish and Game, Sacramento. Pp. 1-118

Brown, Morgan E.; ·Keller, Jason K.; ·Whitcraft, Christine R. (2022) Relationship of Sphaeroma quoianum to sediment characteristics and invertebrate community, Biological Invasions <missing volume>: Published online
https://doi.org/10.1007/s10530-022-02867-7

Brusca, Richard C.; Coeljo, Vania R. Taiti, Stefano (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of Calfiornia Press, Berkeley CA. Pp. 503-542

California Department of Fish and Wildlife (2014) Introduced Aquatic Species in California Bays and Harbors, 2011 Survey, California Department of Fish and Wildlife, Sacramento CA. Pp. 1-36

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

Carlton, James T. (2000) Invasive species in a changing world., Island Press, Covelo, CA. Pp. 19-31

Carlton, James T.; Iverson, Ernest W. (1981) Biogeography and natural history of Sphaeroma walkeri Stebbing (Crustacea: Isopoda) and its introduction to San Diego Bay, California, Journal of Natural History 15: 31-48

Clamp, John C. (2006) Redescription of Lagenophrys cochinensis (Ciliophora, Peritrichia, Lagenophryidae), anectosymbiont of marine isopods, including new information on morphology, geographic distribution, and intraspecific variation., Journal of Eukaryotic Microbiology 53(1): 58-64

Cohen, Andrew N. and 10 authors (2005) <missing title>, San Francisco Estuary Institute, Oakland CA. Pp. <missing location>

Cohen, Andrew N. and 12 authors (2002) Project report for the Southern California exotics expedition 2000: a rapid assessment survey of exotic species in sheltered coastal waters., In: (Eds.) . , Sacramento CA. Pp. 1-23

Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Cohen, Andrew N.; Chapman, John T. (2005) <missing title>, San Francisco Estuary Institute, San Francisco. Pp. <missing location>

Crooks, Jeffrey A. (1998) <missing title>, University of California, San Diego, <missing place>. Pp. <missing location>

Davidson, Timothy M. (2006) <missing title>, University of Oregon, MS Thesis, Eugene. Pp. <missing location>

Davidson, Timothy M. (2008) Prevalence and distribution of the introduced burrowing isopod, Sphaeroma quoianum, in the intertidal zone of a temperate northeast Pacific estuary (Isopoda, Flabellifera), Crustaceana 81(2): 155-167

Davidson, Timothy M. (2012) Boring crustaceans damage polystyrene floats under docks polluting marine waters with microplastic, Marine Pollution Bulletin 64: 1821-1828

Davidson, Timothy M.; Hewitt, Chad L.; Campbell, Marnie (2008) Distribution, density, and habitat use among native and introduced populations of the Australasian burrowing isopod Sphaeroma quoianum, Biological Invasions 10: 399-410

Davidson, Timothy M.; de Rivera, Catherine E. (2010) Accelerated erosion of saltmarshes infested by the non-native burrowing crustacean Sphaeroma quoianum, Marine Ecology Progress Series 419: 129–136

Davidson, Timothy M.; de Rivera, Catherine E. (2012) Per capita effects and burrow morphology of a burrowing isopod (Sphaeroma quoianum) in different estuarine substrata, Journal of Crustacean Biology 32(1): 25-30

Davidson, Timothy M.; de Rivera, Catherine E.; Carlton, James T. (2013) Small increases in temperature exacerbate the erosive effects of a non-native burrowing crustacean, Journal of Experimental Marine Biology and Ecology 446: 115-121

Davidson, Timothy M.; Rumrill, Steven S.; Shanks, Alan L. S (2008) Colonization and substratum preference of an introduced burrowing crustacean in a temperate estuary., Journal of Experimental Marine Biology and Ecology 354: 144-149

Davidson, Timothy M.; Shanks, Alan L.; Rumrill, Steven S. (2010) The composition and density of fauna utilizing burrow microhabitats created by a non-native burrowing crustacean (Sphaeroma quoianum), Biological Invasions 12: 1403-1413

Graening, G. O.; Rogers, D. Christopher (2013) Checklist of inland aquatic Isopoda (Crustacea: Malacostraca) of California, California Fish and Game 99(4): 176-192

Harrison, K.; Ellis, J. P. (1991) The genera of the Sphaeromatidae (Crustacea: Isopoda): a key and distribution list, Invertebrate Taxonomy 5: 915-952

Harrison, K.; Holdich, D. M. (1984) Hemibranchiate sphaeromatids (Crustacea: Isopoda) from Queensland, Australia, with a world-wide review of the genera discussed, Zoological Journal of the Linnean Society 81: 275-387

Hass, C. G.; Knott, B. (2000) Sphaeromatid isopods (Crustacea: Isopoda from the Leschenault estuary, Collie River and Bunbury Harbour., Journal of the Royal Society of Western Australia 83(4): <missing location>

Hass, Christine G.; Knott, Brenton (1998) Sphaeromatid isopods from the Swan River, Western Australia: diversity, distribution, and geographic sources., Crustaceana 71(1): <missing location>

Iverson, Ernest W. (1974) Range extensions for some California marine isopod crustaceans, Bulletin of the Southern California Academy of Sciences 73: 164-169

Jansen, K. P. (1971) Ecological studies on New Zealand Sphaeromatidae (Isopoda, Flabellifera), Marine Biology 11: 263-285

Kussakin, Oleg G.; Malyutina, Marina V. (1993) Sphaeromatidae (Crustacea: Isopoda: Flabellifera) from the South China Sea., Invertebrate Taxonomy 7: 1167-203

Llansó, Roberto J.; Sillett, Kristine; Scott, Lisa (2011) <missing title>, Versar, Inc., Columbia MD. Pp. <missing location>

Low-Pfeng, Antonio; Recagno, Edward M. Peters (2012) <missing title>, Geomare, A. C., INESEMARNAT, Mexico. Pp. 236

Museum of Comparative Zoology 2008-2015 Invertebrate Zoology Collections Database http://mczbase.mcz.harvard.edu/SpecimenSearch.cfm. <missing URL>



Pillai, N. Krishna (1967) Proceedings of the symposium on Crustacea, Pt. V Marine Biological Association of India, <missing place>. Pp. 1274-1283

Richardson, Harriet (1905) A monograph on the isopods of North America, United States National Museum Bulletin 54: 1-727

Riegel, J. A. (1959) Some aspects of osmoregulation in two species of sphaeromid isopod Crustacea, Biological Bulletin 116(2): 272-284

Robinson, April; Cohen, Andrew N.; Lindsey, Brie; Grenier, Letitia (2011) Distribution of macroinvertebrates across a tidal gradient, Marin County, California, San Francisco Estuary and Watershed Science 9(3): published online

Rodríguez-Almaraz, Gabino A.; García-Madrigal, María del Socorro (2014) [Aquatic Invasive Species in Mexico], Comisión Nacional para el Conocimiento y Uso de la Biodiversidad, <missing place>. Pp. 337-371

Rotramel, George (1972) Iais californica and Sphaeroma quoyanum, two symbiotic isopods introduced to California (Isopoda, Janiridae and Sphaeromatidae), Crustaceana Suppl. Ill: 193-197

Schultz, G.A. (1969) The Marine Isopod Crustaceans, Wm. C. Brown Company, Dubuque, Iowa. Pp. <missing location>

Talley, T. S.; Crooks, J. A.; Levin, L. A. (2001) Habitat utilization and alteration by the invasive burrowing isopod, Sphaeroma quoyanum, in California salt marshes, Marine Biology 138: 561-573

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database. http://collections.nmnh.si.edu/search/iz/



Wasson, Kerstin; Zabin, C. J.; Bedinger, L.; Diaz, M. C.; Pearse J. S. (2001) Biological invasions of estuaries without international shipping: the importance of intraregional transport, Biological Conservation 102: 143-153