Description
Potentially Misidentified Species - Stenothoe appears to be a difficult genus, with many very similar and widely distributed species. Many specimens from the Chesapeake, and NC, which did not quite match the description of 'S. minuta' (Fox and Bynum 1975; Feeley and Wass 1971) were re-identifed as a new species, S. georgianus (Bynum and Fox 1975; Feeley and Wass 1971). Two apparently introduced amphipods of the genus Amphilochidae, Amphilochus sp. and Gitanopsis sp. resemble members of the family Stenothoidae to the casual observer (McCann 1997 personal communication).
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Animalia | Crustacea | Malacostraca | Amphipoda | Stenothoidae | Stenothoe |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1960 | Established | Stable | Introduced | Regular Resident | Western Atlantic | Western Pacific | Shipping(Ballast Water,Fouling Community) |
History of Spread
'Stenothoe gallensis' now regarded is a complex of amphipod species, associated with fouling communties, with a rather cosmopolitan distribution in warm waters (Krapp-Schickel 2015). The type species was described in 1904 from Sri Lanka (Ceylon), and occurs widely in the Indian Ocean.
Three similar species have been described in various locations around the world, eg. S. crenulata in 1907, in the Mediterranean, and then later synonymized with S. gallensis . Krapp-Schickel (2015) re-split these species and described four others, all roughly resembling the type species, S. gallensis. Some of these species have limited known ranges, while others have been collected in both the Atlantic and Indo-Pacific. At least four of Krapp-Schickel's (2015) species (S. cattai, S. clavetta, S. crenulata, S. dentirama) have been reported from Bermuda or the Caribbean. The specific identity of the 'S. gallensis' in North American waters is unknown, but we will treat the entire complex as introduced. Members of the complex are listed below under 'Potentially Misidentified Species'. We will use a description by LeCroy (2011) of animals from Florida waters. A detailed morphological examination is needed to assign East Coast and Hawaii animals to one of the species in the S. gallensis complex as described by Krapp-Schickel (2015).
In the Mediterranean, S. gallensis' was considered a possible 'Lessespsian migrant', through the Suez Canal (Por 1978; Bellan-Santini et al. 1993; Galil et al. 2009). 'Stenothoe gallensis' has been listed as likely introduction in Senegal (Reid 1951), Chesapeake Bay (Fofonoff et al. 2016), Hawaii (Carlton and Eldredge 2009), and New Zealand (Ahyong and Williams 2011). It is an amphipod associated with fouling communities, including algae, hydroids, tubeworms, and tunicates, on pilings, floats, ship bottoms, buoys, mangrove roots, etc., (Shoemaker 1935; Reid 1951; LeCroy 2011). It is considered introduced in the Hawai'ian Islands, where it was first reported in 1935 from Oahu, and now is known also from Hawaii and Molokai (Carlton and Eldredge 2009).
.
The first Western Atlantic collection of Stenothoe gallensis (as S. crenulata') from the west Atlantic was from St. Thomas, Virgin Islands, in 1905. It was subsequently collected from two locations in Puerto Rico in 1915, as S. crenulata (Shoemaker 1935). - On St. Thomas, Virgin Islands, in 1905, S. gallensis was collected 'from branchial sac of Microcosmos exasperatus' (tunicate), Ensenada, Puerto Rico, 1915 'Cane wharf, ... wharves,' (Shoemaker 1935). It was also collected in the Indian River Lagoon (Nelson 1995), at the Crystal River inlet FL (Gulf of Mexico) at several locations in 1980 (United States National Museum of Natural History collections), in Tampa Bay (Grabe et al. 2006), and in coral reefs near Veracruz, Mexico(2006, Winfield et al. 2007). Near Beaufort NC, and also in the Pamlico River NC, S. gallensis was a 'common fouling species, taken occasionally in plankton' during 1957-1966, (Williams and Bynum 1972: Fox and Bynum 1975).
Chesapeake Bay - The first Chesapeake record is from Cherrystone Inlet VA (lower Bay, Eastern Shore, 1960 (United States National Museum of Natural History collections; Feeley and Wass 1971). It was subsequently found on Zostera marina in the lower York River (Marsh 1973). In 1994 and 1995, S. gallensis was collected from fouling plates in Scotts Creek (Elizabeth River), and Hampton Roads, Norfolk VA, and Lynnhaven Bay, Virginia Beach (Ruiz et al. unpublished data).
History References - Bellan-Santini et al. 1993; Feeley and Wass 1971; Fox and Bynum 1975; Marsh 1973; Karapp-Schickel 2015; Por 1978; Reid 1951; Ruiz et al. unpublished data; Shoemaker 1935; United States Natioanl Museum of Natural History collections
Invasion Comments
Invasion Status - We consider this species introduced in the Western Atlantic. It appears to be a recent arrival in Chesapeake Bay. Clarence Shoemaker, of the United States National Museum of Natural History had identified numerous species of amphipods from the Chesapeake Bay biological survey (Cowles 1930), and was working on the taxonomy of the Stenothoidae at the time of his death (Bynum and Fox 1977). The oldest specimen of S. gallensis in the collections catalog was identified after his death, in 1960.
The absence of this species iin Feeley and Wass's (1971) and Marsh's (1973) survey, and the localized nature of Fox and Bynum's (1975) NC records suggest an anthropogenic or natural range extension from southern waters.
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | ||||
| Salinity (‰) | 16.0 | 40.0 | ||
| Oxygen | ||||
| pH | ||||
| Salinity Range | poly-eu |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | 3.0 | |
| Typical Adult Size (mm) | 3.0 | |
| Maximum Adult Size (mm) | 3.5 | |
| Maximum Longevity (yrs) | ||
| Typical Longevity (yrs |
Reproduction
| Start | Peak | End | |
|---|---|---|---|
| Reproductive Season | |||
| Typical Number of Young Per Reproductive Event |
|||
| Sexuality Mode(s) | |||
| Mode(s) of Asexual Reproduction |
|||
| Fertilization Type(s) | |||
| More than One Reproduction Event per Year |
|||
| Reproductive Startegy | |||
| Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
Stenothoe gallensis probably has no significant economic impacts in Chesapeake Bay, due to its small size and scarcity.
Economic Impacts Outside of Chesapeake Bay
'Stenothoe gallensis' is rare in Chesapeake Bay (Feeley and Wass 1971; Ruiz et al. unpublished data), but common in NC (Fox and Bynum 1975). It may be a common food of juvenile fishes, but probably has no significant economic impact.
Ecological Impacts on Chesapeake Native Species
The amphipod 'Stenothoe gallensis' is presumed to have no significant impacts in the Chesapeake region, based on its low abundance. However, very little is known of its biology.
Ecological Impacts on Other Chesapeake Non-Native Species
The amphipod 'Stenothoe gallensis' is presumed to have no significant impacts on introduced fauna in the Chesapeake region, based on its low abundance. Hourstonius sp. is the most similar probable introduction in the region, and could overlap with it in feeding and habitat preferences.