Ampithoe valida

Invasion History

First Non-native North American Tidal Record: 1941
First Non-native West Coast Tidal Record: 1941
First Non-native East/Gulf Coast Tidal Record:

---

General Invasion History:

Ampithoe valida was described from Great Egg Bay, New Jersey by S. I. Smith in 1873. It occurs on the East Coast of North America from Maine to Cape Canaveral, Florida (Mills et al. 1964b; Bousfield 1973; Fox and Bynum 1975; Power et al. 2006). It is associated with seaweeds and seagrasses in lower intertidal and shallow coastal waters (Bousfield 1973). Amphipods identified as A. 'valida' have been introduced to the West Coast of North America from Haida Gwai, British Columbia to San Diego Bay, California (Barnard 1965; Carlton 1979; Fairey et al. 2002; Sloan and Bartier 2004). West Coast populations appear to be introduced, based on historical (Carlton 1979) and genetic data (Pilgrim and Darling 2010). Genetic data suggest multiple introductions of at least three genotypes, A, B, and C, only one of which (A) was found at the two East Coast sites sampled (Pilgrim and Darling 2010). Clade C was found in northern Japan, Elkhorn Slough, Tomales Bay, and Willapa Bay. Clade B was found in southern Japan, and in San Francisco Bay (Harper et al. 2022). Shipping and the transfer of eastern oysters (Crassostrea virginica) are likely vectors for Clade A from the East Coast. Shipping and the transfer of Pacific oysters (Magallana gigas) from Japan are likely vectors for Clades B and C (Harper et al. 2022). Clade A of A. valida is introduced and established in Portugal (Pardal et al. 2000) and Argentina (Alonso de Pina 1997; Harper et al. 2022). We consider a population in Venezuela (Martin and Diaz 2003, Ortiz et al. 2007) to be cryptogenic.

Amphitoe valida has been regarded as either conspecific with the East Coast form, or a separate subspecies or full species (Nagata 1960; Barnard 1965; Kim and Kim 1988). Further molecular studies are needed to determine the taxonomy of the complex (Pilgrim and Darling 2010; Harper et al. 2022). The Ampithoe valida complex is believed to have evolved in the North Pacific, and colonized the Atlantic in pre-glacial times (Pilgrim and Darling 2015; Sotka et al. 2015; Harper et al. 2022).

 

 

North American Invasion History:

Invasion History on the West Coast:

Ampithoe valida was first reported in Tomales Bay and San Francisco Bay in 1941 (Light 1942, cited by Carlton 1979; Pitelka and Paulson 1942, cited by Carlton 1979; Cohen and Carlton 1995). It was also collected off Newport Bay in 1942 (Barnard 1965; Carlton 1979). Two early records were far to the north in Coos Bay, Oregon in 1950 (Barnard 1954, cited by Carlton 1979; Barnard 1965) and Haida Gwai, British Columbia in 1957 (Sloan and Bartier 2004). Subsequently, A. valida was found in many intermediate harbors and estuaries, including Prince Rupert and Vancouver Harbors in 2005 (Lu et al. 2007); Puget Sound, Washington (Cohen et al. 1998); Willapa Bay, Washington in 2000 (Cohen et al. 2001); Yaquina Bay, Oregon in 2006 (Pilgrim and Darling 2010); Humboldt Bay, California in 2000 (Boyd et al. 2002); Bodega Harbor in 1975 (Carlton 1979). The sequence of successive first records suggests an invasion. Pilgrim and Darling's study, found three distinct genetic clades (A, B, and C) of 'A. valida' on the West Coast. However, a later genetic study, including specimens from several locations in Japan, suggest that 'A. valida' on the West Coast is a mix of Atlantic and Northwest Pacific genotypes (Harper et al. 2022). Further sampling is needed to determine the extent of genetic exchange with the Northwest Atlantic and across the Pacific. Harper at al. (2022) examined multiple mitochondrial genes of 'A. valida' from six Japanese bays, five West Coast bays, four East Coast bays, and one Argentinean bays. They found that clade A was characteristic in the East Coast bays, while Clade B was found in southern Japan, and San Francisco Bay, and Clade C was found in northern Japan, Willapa, Tomales Bays, and Elkhorn Slough. The East Coast genotype, Clade A, was found in San Francisco Bay, and to be the dominant form in Humboldt Bay (Harper et al. 2022). Harper et al. sampled only a few West Coast bays, but it is clear the 'A. valida' on the West Coast consists of a mixture of introduced East Coast genotypes, and native northeast or introduced northwest Pacific genotypes (Harper et al. 2022).

To the south of San Francisco Bay, aside from the 1942 offshore Newport Bay record, reports of A. valida were spotty: Morro Bay in 1965 (Carlton 1979); Elkhorn Slough in 1998 (Wasson et al. 2001); Channel Islands Harbor in 2000–2001 (Cohen et al. 2002); and Los Angeles-Long Beach Harbors, Newport Bay, Oceanside Harbor, Mission Bay, and San Diego Bay in 2001 (Fairey et al. 2002). In a 2011 survey, A. valida was collected in all of these southern California bays, except Mission Bay (California Department of Fish and Wildlife 2014).

In San Francisco Bay, A. valida occurs in the central, south, and San Pablo Bays (Cohen and Carlton 1995; Carr et al. 2011). It is one of the most abundant amphipods in eelgrass beds in San Francisco Bay (Carr et al. 2011). In 2010, it was found at Martinez, in the Carquinez Strait (Foss 2009), and in the fouling of a decommissioned ship in Suisun Bay (Llansó et al. 2011). Possible vectors include ballast water, fouling, shipments of eastern oysters, and seaweeds used to pack seafood or baitworms. A genetic analysis (Pilgrim et al. 2011) indicates that at least three genotypes were introduced and that multiple introductions have occurred from different source populations. Further molecular studies, including more sampling of East Coast and Northwest Pacific populations will be needed to determine the origin of the different West Coast populations (Pilgrim et al. 2010; Harper et al. 2022).

Invasion History on the East Coast:

In a recent study, most 'Ampithoe valida' from the East Coast sites were grouped into Clade A, native, but two specimens matched Northwest Pacific genotypes. A single specimen from Allens Harbor, in Narragansett Bay, Rhode Island was grouped with Clade B, from southern Japan. Another specimen, from Chesapeake Bay, fits into Clade B, from southern Japan (Harper et al. 2022). Much more sampling would be needed to establish the extent and significance of these ‘trace invasions'.

Invasion History Elsewhere in the World:

Ampithoe valida has been reported from the Mondego estuary (in 1992, Pardal et al. 2000) and the Ria de Aveiro (Cunha et al. 1999), Portugal where it is abundant and well-established. Additional populations were found in Mediterranean lagoons along the French coast in 2000–2003, and in Vlissingen, Netherlands in 2014 (Faasse 2015). Without molecular analysis, the origin of European populations is unclear (Faasse 2015), while introductions from the Northwest Atlantic and in Northwest Pacific are both possible.

This amphipod was first collected in Argentina in 1980, at Puerto Madryn (42.8 S), and ranges to Santa Clara del Mar (38.0 S to 43.3 S) (Alonso de Pina 1997; Orensanz et al. 2002). Molecular analysis of Argentine specimens indicated a Northwest Atlantic origin (Harper et al. 2022). We consider a population in Venezuela (Martin and Diaz 2003, Ortiz et al. 2007) to be cryptogenic.

As noted above, the identity and status of populations in Japanese, Korean, and Chinese waters is uncertain. Stephensen (1944, cited by Barnard 1965; Nagata 1960) identified Japanese specimens as a separate species, A. shimizuensis. Kim and Kim (1988) treated A. shimizuensis as a subspecies of A. valida and reportedly found both A. v. shimizuensis and the original form of A. valida in Korean waters. Nagata (1960) considered Japanese specimens to match the original description of A. valida. The A. v. shimizuensis form could represent a cryptic species, perhaps mixed with introduced populations of Northwest Atlantic A. valida. Molecular analysis would be needed to determine the species status and origin of Northwest Pacific populations.

---

Description

Ampithoe valida is a tube-dwelling amphipod, found in coastal waters and estuaries. It has two small black eyes. The coxal plates 1–4 are deep, with short rows of slender setae at the postero-distal margins. Coxa 5 is longest. Antenna 1 is about half of the body length, and is equal (Barnard 1965) or longer (Bousfield 1973) than antenna 2. The flagellum of antenna 1 is much longer than that of antenna 2.

The gnathopods are somewhat sexually dimorphic in this genus. In males, segment 5 of gnathopod 1 is longer and deeper, than segment 6. The posterior lobe of segment 5 is broad and bears many setae on its lower surface. In the female, segments 5 and 6 are roughly equal in length and breadth. Gnathopod 2 is larger than Gnathopod 1 in both sexes. In males, segment 6 is very large and stout, and roughly rectangular, with a vertical palm, and a median tooth, with a squared-off tip. In females, segment 6 is also larger than segment 5, but is less inflated.

In A. valida, abdominal side plate 3 is convex, with the hind corner forming a blunt curve and lacking a notch. Uropod 1 has a strong peduncle, with 8–10 marginal spines. The outer ramus is half as long as the peduncle, with 6–10 marginal spines. The outer ramus of Uropod 2 is shorter than Uropod 1, with 3–4 spines. Uropod 3 has a short peduncle, with two groups of distal spines. The outer ramus has one group of outer marginal setae. The telson is short, with a rounded apex, with low cusps. Adult males and females are about 10–12 mm long. Description based on Mills 1964b, Barnard 1965, Bousfield 1973, and Chapman 2007.

'Ampithoe valida' was described from the Northwest Atlantic, but it has a wide global distribution being known from the Northeast Atlantic (Portugal, Pardal et al. 2000), the Southwest Atlantic (Argentina, Alonso de Pina 1997), the Northeast Pacific (British Columbia to San Diego, California, Barnard 1965; Carlton 1979; Pilgrim and Darling 2010). Northwest Pacific (China, Korea, Japan, Nagata 1960; Kim and Kim 1988) records have been variously treated as a separate species (A. shimizuesis Stephensen 1944), a subspecies, or as conspecific (Barnard 1954, cited by  Nagata 1960). Genetic analysis of populations in Japan and the coasts of North America support the view of 'A. valida' as a complex of three species, one from the Northwest Atlantic  (Clade A), northern Japan (Clade C, A. shimizuensis?) and southern Japan (Clade B).

These populations show evidence of cryptic diversity. Some taxonomists have reported consistent morphological differences in Northwest Pacific populations, and identified them as a separate species (A. shimizuensis, Stephensen 1944, cited by Nagata 1960), or subspecies (A. v. shimizuensis, Kim and Kim 1988), while others have considered the differences insignificant (Nagata 1960). Pilgrim and Darling (2010) have found three distinct mitochondrial COI DNA lineages on North American coasts. One, Clade A was found on the East Coast (Connecticut and South Carolina), and in Humboldt and San Francisco Bays. Two other lineages, B and C, were found on the West Coast and in Japan, with Clade C having the widest distribution on the West Coast. The historical evidence suggests that all three clades were introduced from the East coast, but the genetic evidence suggests multiple introductions (Pilgrim and Darling 2010). However, a more complete comparison of multiple genetic markers, including Japan, suggests that only Clade A was introduced from the East Coast, while Clade B, from southern Japan, was only detected in San Francisco Bay, and Clade C, from northern Japan, was found in Elkhorn Slough, Tomales Bay, and Willapa Bay. Note that only a few West Coast bays were sampled, so the identity of most populations is still unknown (Harper et al. 2022).

 

---

Taxonomy

Ecology

General:

Ampithoe valida is a tube-dwelling amphipod occurring in coastal waters and estuaries (Bousfield 1973; Borowsky 1983). Gammarid amphipods have separate sexes, brooded embryos, and direct development. Female A. valida in New England breed from May to September, with several broods per year (Bousfield 1973). Females mature at 5 mm, males at 6 mm, and they reach 12.5 and 12 mm respectively (Conlan and Bousfield 1982). Males leave their tubes, and cruise around to join a nearby female in her tube before molting (Borowsky 1983). Females in Portugal carried means of six to 24 embryos (Pardal et al. 2000), while cultured A. 'valida' in China had 6–192 embryos per brood (Zheng et al. 2013). Ampithoe valida has a semi-annual life cycle in Portugal, with short-lived spring and summer generations (seven to eight months) and long-lived autumn and winter generations (nine months) (Pardal et al. 2000). In North American waters, there at least three genetic lineages of A. valida (Pilgrim and Darling 2010), so life history characteristics may vary among populations

Ampithoe valida has a wide native latitudinal range and temperature tolerance, from the Gulf of Maine (New Hampshire) to Florida and Texas (Bousfield 1973; LeCroy 2002; Redmond et al. 1994). This amphipod ranges from marine to brackish waters—it was collected at 9 PSU in Willapa Bay, Washington (Cohen et al. 2001), and occurs in Carquinez Strait and Suisun Bay in San Francisco Bay (Foss 2009; Llanso et al. 2011). Ampithoe valida is usually associated with green algae (eg. Ulva spp.) and/or eelgrass (Zostera marina) (Bousfield 1973). This amphipod constructs tubes of bits of detritus glued together with secretions (Borowsky 1983). In most estuaries, A. valida feeds on algae, including Ulva and other relatively soft algae (Best et al. 2013; Nicotri 1980; Pardal et al. 2000; Zheng et al. 2013). However, in San Francisco Bay, A. valida feeds on the leaves of eelgrass (Zostera), but had a strong preference for the grasses' flowers and seeds (Reynolds et al. 2012). In mesocosm experiments, predation by fishes (Shiner Seaperch—Cymatogaster aggregata; Pinfish—Lagodon rhomboides) reduced abundance of A. valida (Carr and Boyer 2014).

Food:

Macroalgae; Eelgrass

Trophic Status:

Herbivore

Herb

---

Habitats

General Habitat	Grass Bed	None
General Habitat	Unstructured Bottom	None
General Habitat	Coarse Woody Debris	None
General Habitat	Salt-brackish marsh	None
General Habitat	Marinas & Docks	None
General Habitat	Vessel Hull	None
Salinity Range	Mesohaline	5-18 PSU
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Tidal Range	Low Intertidal	None
Vertical Habitat	Epibenthic	None

---

Life History

Ampithoe valida has a wide native latitudinal range and temperature tolerance, from the Gulf of Maine (New Hampshire) to Florida and Texas (Bousfield 1973; LeCroy 2002; Redmond et al. 1994). This amphipod ranges from marine to brackish waters—it was collected at 9 PSU in Willapa Bay, Washington (Cohen et al. 2001), and occurs in Carquinez Strait and Suisun Bay in San Francisco Bay (Foss 2009; Llanso et al. 2011). Ampithoe valida is usually associated with green algae (eg. Ulva spp.) and/or eelgrass (Zostera marina) (Bousfield 1973). This amphipod constructs tubes of bits of detritus glued together with secretions (Borowsky 1983). In most estuaries, A. valida feeds on algae, including Ulva and other relatively soft algae (Best et al. 2013; Nicotri 1980; Pardal et al. 2000; Zheng et al. 2013). However, in San Francisco Bay, A. valida feeds on the leaves of eelgrass (Zostera), but had a strong preference for the grasses' flowers and seeds (Reynolds et al. 2012). In mesocosm experiments, predation by fishes (Shiner Seaperch-—Cymatogaster aggregata; Pinfish—Lagodon rhomboides) reduced abundance of A. valida (Carr and Boyer 2014).

---

Tolerances and Life History Parameters

Minimum Temperature (ºC)	-2	Field, Narragansett Bay RI (Redmond et al. 1994)
Maximum Temperature (ºC)	27	Field, Narragansett Bay RI (Redmond et al. 1994)
Minimum Salinity (‰)	9	Field Data, Willapa Bay WA (Cohen et al. 2001).
Maximum Salinity (‰)	35	Field, Bousfield 1973
Minimum Length (mm)	5	LeCroy 2002
Maximum Length (mm)	12	Bousfield 1973
Broad Temperature Range	None	Cold temperate-Warm temperate
Broad Salinity Range	None	Mesohaline-Euhaline

General Impacts

Ampithoe valida is a widespread hebivorous tube-dwelling amphipod. In most of its range, it is known as a grazer on benthic algae, including Ulva, Cladophora, and other soft algae (Nicotri 1980; Pardal et al. 2000; Zheng et al. 2013). For unknown reasons, in San Francisco Bay, it shows a strong preference for the flowers and seeds of eelgrass (Zostera marina), and also feeds on the leaves. Experiments and field studies suggest that A. valida has negative impacts on eelgrass meadows (Carr et al. 2011; Reynolds et al. 2012; Lewis and Boyer 2014). Harper et al. (2022) suggest that the impacts on eelgrass in San Francisco Bay may result from a combination of Pacific (Clade C) and Atlantic (Clade A) genotypes, not present in other West Coast estuaries. In mesocosm experiments, fish predation reduced the impact of A. valida on eelgrass (Carr and Boyer 2014). This amphipod is potentially an important prey for fish, but its impact on fish populations is unknown.

---

Regional Impacts

NEP-V	Northern California to Mid Channel Islands		Ecological Impact	Herbivory
Ampithoe valida feeds selectively on Eelgrass (Zostera marina) flowers and seeds during the flowering period in San Francisco Bay, in preference to algae or eelgrass leaves. 'Field densities and laboratory consumption rates suggest that this non-native amphipod could remove all seeds in a California eelgrass meadow in 1-3 wk, thus challenging maintenance of genetic diversity and long-term meadow persistence' (Reynolds et al. 2012; Lewis and Boyer 2014).
P090	San Francisco Bay		Ecological Impact	Herbivory
Ampithoe valida feeds selectively on Eelgrass (Zostera marina) flowers and seeds during the flowering period in San Francisco Bay, in preference to algae or eelgrass leaves. 'Field densities and laboratory consumption rates suggest that this non-native amphipod could remove all seeds in a California eelgrass meadow in 1-3 wk, thus challenging maintenance of genetic diversity and long-term meadow persistence' (Reynolds et al. 2012; Lewis and Boyer 2014).
CA	California		Ecological Impact	Herbivory
Ampithoe valida feeds selectively on Eelgrass (Zostera marina) flowers and seeds during the flowering period in San Francisco Bay, in preference to algae or eelgrass leaves. 'Field densities and laboratory consumption rates suggest that this non-native amphipod could remove all seeds in a California eelgrass meadow in 1-3 wk, thus challenging maintenance of genetic diversity and long-term meadow persistence' (Reynolds et al. 2012; Lewis and Boyer 2014)., Ampithoe valida feeds selectively on Eelgrass (Zostera marina) flowers and seeds during the flowering period in San Francisco Bay, in preference to algae or eelgrass leaves. 'Field densities and laboratory consumption rates suggest that this non-native amphipod could remove all seeds in a California eelgrass meadow in 1-3 wk, thus challenging maintenance of genetic diversity and long-term meadow persistence' (Reynolds et al. 2012; Lewis and Boyer 2014).

References

Sotka, Erik E.; Bell; Tina; Hughes, Laurn E. ; Lowry, James K.; Poore, Alistair G. B. (2016) A molecular phylogeny of marine amphipods in the herbivorous family Ampithoidae, Zoologica Scripta 46(1): 85-95
doi:10.1111/zsc.12190

Alonso de Pina, Gloria M. (1997) Records of intertidal amphipods from the southwest Atlantic, with the description of a new species of Elasmopus, Journal of Crustacean Biology 17(4): 745-757

Baldwin, Andy; Leason, Diane (2016) Potential Ecological impacts of Emerald Ash Borer on Maryland's Eastern Shore, In: None(Eds.) None. , <missing place>. Pp. <missing location>

Barnard, J. Laurens (1965) Marine Amphipoda of the family Ampithoidae, Proceedings of the U. S. National Museum 118(3522): 1-46

Best, R. J.; Caulk, N. C.; Stachowicz, J. J. (2013) Trait vs. phylogenetic diversity as predictors of competition and community composition in herbivorous marine amphipods, Ecology Letters 16: 72-80

Borowsky, B. (1983) Reproductive behavior of three tube-building peracarid crustaceans: Jassa falcata, Ampithoe valida, and the taniad Tanais cavolinii, Marine Biology 77(3): 257-263

Bousfield, E.L. (1973) <missing title>, Comstock Publishing Associates, Ithaca, NY. Pp. <missing location>

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

California Academy of Sciences 2005-2015 Invertebrate Zoology Collection Database. <missing URL>



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. (1989) Man's role in changing the face of the ocean: biological invasions and implications for conservation of near-shore environments, Conservation Biology 3(3): 265-273

Carlton, James T. (1989) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Carr, Lindsey A.; Boyer, Katharyn E. (2014) Variation at multiple trophic levels mediates a novel seagrass-grazer interaction, Marine Ecology Progress Series 508: 117-128

Carr, Lindsey A.; Boyer, Katharyn E.; Brooks, Andrew J. (2011) Spatial patterns of epifaunal communities in San Francisco Bay eelgrass (Zostera marina) beds, Marine Ecology 32: 88-103

Chapman, John W. (2007) The Light and Smith Manual: Intertidal invertebrates from Central California to Oregon (4th edition), University of California Press, Berkeley CA. Pp. 545-611

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. and 22 authors (2001) <missing title>, Washington State Department of Natural Resources, Olympia. Pp. <missing location>

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; and 16 authors. (1998) <missing title>, Washington State Department of Natural Resources, Olympia, Washington. Pp. 1-37

Conlan, K. E.; Bousfield, E. L. (1982) The amphipod superfamily Corophioidea in the northeastern pacific region. Family Ampithoidae: systematics and distributional ecology., National Museum of Natural Sciences 10: 41-75

Cunha, M. R.; Sorbe, J. C.; Moreira, M. H. (1999) Spatial and seasonal changes of brackish peracaridan assemblages and their relation to some environmental variables in two tidal channels of the Ria de Aveiro (NW Portugal), Marine Ecology Progress Series 190: 69-187

Droual, Gabin; Curd, Amelia; Gauff, Robin; Gouillieux, Benoit; Gélinaud, Guillaume; Cabelguen, Jérôme; Grall, Jacques (2024) The French benthic newcomers: new records of Ampithoe valida S.I. Smith, 1873 and Polydora colonia Moore, 1907 in Brittany, first record of Bispira polyomma Giangrande & Faasse, 2012 in the North-East Atlantic and northernmost record of Prostheceraeus moseleyi Lang, 1884 in Europe, Bioinvasions Records 31(1): 37–56
https://doi.org/10.3391/bir.2024.13.1.05

Faasse, M. A. (2015) New records of the non-native amphipod Ampithoe valida in Europe, Marine Biodiversity Records 8: e87

Faasse, Marco (2012) The exotic isopod Synidotea in the Netherlands and Europe, A Japanese or American invasion (Pancrustacea: Isopoda)?, Nederlandse Faunistiche Mededelingen 108: 103-106

Fairey, Russell; Dunn, Roslyn; Sigala, Marco; Oliver, John (2002) Introduced aquatic species in California's coastal waters: Final Report, California Department of Fish and Game, Sacramento. Pp. <missing location>

Feeley, James B.; Wass, Marvin L. (1971) The distribution and ecology of the Gammaridea (Crustacea: Amphipoda) of the lower Chesapeake estuaries., Special Papers in Marine Science 2: 1-58

Foss, Stephen (2009) <missing title>, California Department of Fish and Game, Sacramento CA. Pp. <missing location>

Fox, Richard S.; Bynum, Kenneth H. (1975) The amphipod crustaceans of North Carolina estuarine waters, Chesapeake Science 16(4): 223-237

Gartner, Heidi N.; Murray, Cathryn Clarke; Frey, Melissa A.; Nelson, Jocelyn C.; Larson, Kristen J.; Ruiz, Gregory M.; Therriault, Thomas W. (2016) Non-indigenous invertebrate species in the marine fouling communities of British Columbia, Canada, BioInvasions Records <missing volume>: <missing location>

Graening, G. O.; Rogers, D. Christopher; Holsinger, John R.; Barr, Cheryl; Bottorff, Richard (2012) Checklist of inland aquatic Amphipoda (Crustacea: Malacostraca) of California, Zootaxa 3544: 1-27

Harper, Katherine E.; Scheinberg, Lauren A.; Boyer, Katharyn E.; Sotka, Erik E. (2022) Global distribution of cryptic native, introduced and hybrid lineages in the widespread estuarine amphipod Ampithoe valida, Conservation Genetics 23: 791-806
https://doi.org/10.1007/s10592-022-01452-8

Kim, Hoon Soo; Kim, Chang Bae (1988) Marine Gammaridean Amphipoda (Crustacea) of the family Ampithoidae from Korea., Korean Journal of Systematic Zoology 2: 107-134

LeCroy, Sara E. (2002) <missing title>, Florida Department of Environmental Protection, Division of Resource Assessment and Management, <missing place>. Pp. <missing location>

Lewis, Jeffrey T.; Boyer, Katharyn E. (2014) Grazer functional roles, induced defenses, and indirect interactions: implications for eelgrass restoration in San Francisco Bay, Diversity 6: 751-770

Liu, Wenliang; Liang, Xiaoli ; Zhu, Xiaojing (2015) A new record and mitochondrial identification of Synidotea laticauda Benedict, 1897 (Crustacea: Isopoda: Valvifera: Idoteidae) from the Yangtze Estuary, China, Zootaxa 4294: 371-380

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

Lu, L.; Levings, C. D.; Piercey, G. E. (2007) Preliminary investigation on aquatic invasive species of marine and estuarine macroinvertebrates on floating structures in five British Columbia harbours, Canadian Manuscript Report of Fisheries and Aquatic Sciences 2814: 2-30

Mach, Megan E.; Levings, Colin D.; Chan, Kai M. A. (2016) Nonnative species in British Columbia eelgrass beds spread via shellfish aquaculture and stay for the mild climate, Estuaries and Coasts Published online: <missing location>

Mach, Megan E.; Wyllie-Echeverria, Sandy; Chan, Kai M. A. (2014) Ecological effect of a nonnative seagrass spreading in the Northeast Pacific: A review of Zostera japonica, Ocean & Coastal Management 102: 375-382

Martín, A.; Díaz, Y. J. (2003) [The amphipod fauna (Crustacea: Amphipoda) of the coastal waters of eastern Venezuela], Boletin Insititute Espanol de Oceanografia 19(1-4): 327-344

Mills, Eric L. (1964b) Noteworthy amphipods in the collection of the Yale Peabody Museum, Postilla 79: 1-41

Nagata, Kizo (1960) Preliminary notes on benthic gammaridean amphipoda from the Zostera region of Mihara Bay, Seto Inland Sea, Japan, Publications of the Seto Marine Biological Laboratory 8(1): 163-182

Nava Ferrer, Mario L.; López, Cesar; Hernández, Mora, Dayrana C.; Pares, Guillermo; Manzano Marcano, José M.; Macías Serpa, Moisés S.; Sanchez, Roxana (2018) [Maximum salinity tolerance of the gastropod Pyrgophorus platyrachis (Littorinimorpha: Cochliopidae) in the Laguna Las Peonías, Maracaibo Lake system Venezuela, Ecotropica 30(e0004): Published online

Needles, Lisa A. (2007) <missing title>, M.S. Thesis, California Polytechnic State University, San Luis Obispo. Pp. <missing location>

Needles, Lisa A.; Wendt, Dean E. (2013) Big changes to a small bay: Introduced species and long-term compositional shifts to the fouling community of Morro Bay (CA), Biological Invasions 15(6): 1231-1251

Nicotri, M. E. (1980) Factors involved in herbivore food preference, Journal of Experimental Marine Biology and Ecology 42: 13-26

Orensanz, Jose Maria and 14 other authors (2002) No longer the pristine confines of the world ocean: a survey of exotic marine species in the southwestern Atlantic, Biological Invasions 4(1-2): 115-143

Ortíz, Manuel; Martín, Alberto; Díaz, Yusbelly J. (2007) [List and references of crustacean amphipods (Amphipoda: Gammaridea) of the Western Tropical Atlantic], Revista de Biologia Tropical 55(2): 479-498

Pardal, M. A.; Mrques, J. C.; Metelo, I.; Lilleboe, A. I.; Flindt, M. R. (2000) Impact of eutrophication on the life cycle, population dynamics and production of Ampihtoe valida along an estuarine spoatal gradient (Mondego estuary, Portugal), Marine Ecology Progress Series 196: 207-219

Pilgrim, Erik M.; Darling, John A. (2010) Genetic diversity in two introduced biofouling amphipods (Ampithoe valida & Jassa marmorata) along the Pacific North American coast: investigation into molecular identification and cryptic diversity, Diversity and Distributions 16: 827-839

Power, Alan; Mitchell, Marcy; Walker, Randal; Posey, Martin; Alphin, Troy; Belcher, Carolyn (2006) <missing title>, University of Georgia Marine Extension Service, Athens. Pp. <missing location>

Redmond, Michele; Scott, K. John; Swartz, Richard C.; Jones, Jill K. P. (1994) Preliminary culture and life-cycle experiments with the benthic amphipod Ampelisca abdita, Environmental Toxicology and Chemistry 13(8): 1355-1365

Reynolds, Laura K.; Carr, Lindsey A.; Boyer, Katharyn E. (2012) A non-native amphipod consumes eelgrass inflorescences in San Francisco Bay, Marine Ecological Progress Series 451: 107-118

Richoux, N. B.; Levings, C. D.; Lu, L.; Piercey, G. E. (2006) Preliminary survey of indigenous, non-indigenous and cryptogenic benthic invertebrates in Burrard Inlet, Vancover, British Columbia, Canadian Data Report of Fisheries and Aquatic Sciences 1183: 1-20

Riggs, Sharon R. (2011) <missing title>, Padilla Bay NERR, Padilla Bay WA. Pp. 5

Ruiz, Gregory M.; Geller, Jonathan (2018) Spatial and temporal analysis of marine invasions in California, Part II: Humboldt Bay, Marina del Re, Port Hueneme, and San Francisco Bay, Smithsonian Environmental Research Center & Moss Landing Laboratories, Edgewater MD, Moss Landing CA. Pp. <missing location>

Shin, Myung-Hwa; Kim, Il-Hoi; Lee, Kyung Sook (2005) Three species of gammaridean amphipods (Crustacea) associated with cultured abalones (Gastropoda) in Korea, Korean Journal of Systematic Zoology Molluscan Research 21(2): 157-169

Sloan, N. A., Bartier, P. M. (2004) Introduced marine species in the Haida Gwaii region, British Columbia., Canadian Field-Naturalist 118(1): 77-84

Sylvester, Francisco and 8 authors (2011) Hull fouling as an invasion vector: can simple models explain a complex problem?, Journal of Applied Ecology 48: 415-423

Torrano-Silva, Beatriz N.; Amancio, Carlos E.; Oliveira, Eurico C. (2013) Seaweeds in ornamental aquaria in Brazil: anticipating introductions, Latin American Journal of Aquatic Research 41(2): 344-350

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

Watling, Les; Maurer, Don (1972) Marine shallow water amphipods of the Delaware Bay area, U.S.A., Crustaceana <missing volume>: 251-266

Wilson, Sarah; Partridge, Valerie (2007) <missing title>, Washington State Department of Ecology, Olympia. Pp. 244

Wonham, Marjorie J.; Carlton, James T. (2005) Trends in marine biological invasions at local and regional scales: the Northeast Pacific Ocean as a model system, Biological Invasions 7: 369-392

Woods Hole Oceanographic Institution, United States Navy Dept. Bureau of Ships (1952) Marine fouling and its prevention., United States Naval Institute., Washington, D.C.. Pp. 165-206

Yamauchi, Takeo; Ariyama, Hiroyuki; Mukai, Tetsuya; Yamauchi, Kyoko (2006) Gammaridean fauna on a red alga Gracilaria asiatica and a green alga Enteromorpha prolifera in a brackish lake, Nakaumi, western Honshu, Japan, Japanese Journal of Limnology 67: 223-229

Zheng, Xinqing, ; Huang, Lingfeng; Huang, Bangqin; Lin, Yongqing (2013) Factors regulating population dynamics of the amphipod Ampithoe valida in a eutrophic subtropical coastal lagoon, Acta Oceanologica Sinica 32: 56-65

---