Description
Potentially Misidentified Species - Ligia oceanica, possibly introduced from Europe, has been reported from ME-RI on the Atlantic coast of the United States (United States National Museum of Natural History collections; Van Name 1936).
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Animalia | Crustacea | Malacostraca | Isopoda | Ligidae | Ligia |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1924 | Established | Stable | Introduced | Regular Resident | Western Atlantic | Western Pacific | Shipping(Fouling Community,Dry Ballast) |
History of Spread
Ligia exotica (Sea Roach) was described from docks at Marseilles, France, by Roux, in 1828. As its name indicates, L. exotica is not native in the Mediterranean, and is not established there (Roman 1977). This semi-terrestrial, supralittoral species has been widely distributed by shipping, and its original range is uncertain. It is native in the Indo-Pacific from Japan and China south to Madagascar and South Africa (Roman 1977). It is also found (and probably was introduced) on the West African coast, and in the Azores (United States National Museum of Natural History collections (Roman 1977). It is a recent introduction in the Hawiian Islands Harbor (1996, Eldredge and Smith 2002), but was probably introduced earlier on other Polynesian ilslands (first records from 1899 to 1927, US National Museum of Natural History 2008). Ligia exotica is abundant in warm-temperate and the milder tropical regions, but is 'apparently rare in the true tropics' (Schultz 1974).
In the West Atlantic, it was apparently first reported from Fort Macon NC (Harger 1880, cited by Van Name 1936), but in the 1880's, museum specimens were collected from FL (Key West, Cedar Key), Brazil, and Uruguay (United States National Museum of Natural History collections). Its wide distribution at that time suggests that it was introduced much earlier. However, museum and published records suggest that the extension of its range north of Cape Hatteras may have occured in the 20th century. Gould (1841) reported Ligia spp. (either exotica or oceanica) from docks in MA, probably Boston, 'but it is not likely that the present species could survive the winter at that latitude' (Van Name 1935). Ligia exotica is widely distributed in the Caribbean. United States Atlantic coast records are summarized below:
Gulf of Mexico, Caribbean- Key West FL, 1883; Key West 1898 (on wharf); Manitee River FL 1884; Tortugas FL 1908; St. Thomas, Virgin Islands 1915; Havana, Cuba 1915; Port Tampa FL (no date), Topelebampo, Mexico 1897; Biloxi Bay MS 1939; Galveston TX 1939 (United States National Museum of Natural History collections). It was apparently widely distributed by 1905 (Richardson 1905).
Atlantic Coast South of Chesapeake - Ligia exotica was first reported by Harger (1880) from Fort Macon NC. in 1891, it was found in Charleston SC at the Customs House Wharf (United States National Museum of Natural History collections). Its distribution may be somewhat local, because the first GA collection was in 1976, on St. Catherines Island (Schultz 1977). It is also known from the Indian River Lagoon (FL).
Chesapeake Bay Region - Ligia exotica (Sea Roach) was not included by Uhler (1878) in a list of marine invertebrates and insects from Fort Wool VA. It was first collected at Hog Island VA in 1924 (United States National Museum of Natural History collections). It was reported from Cape Charles VA 1929 (Richards 1931).
Delaware Bay North - There is a museum collection from NJ dated 1930, with no location given (United States National Museum of Natural History collections). Ligia exotica is not mentioned in Fowler (1911) account of Crustacea of NJ, but it is now abundant on the southern shore of Delaware Bay, and in the vicinity of Atlantic City NJ (Godwin 1997). NJ appears to be its northern range limit (Gosner 1978; Kensley and Schotte 1989).
Chesapeake Records:
Adjacent Ocean Regions - The first record of L. exotica is from Hog Island VA (1924). It was also found in Oyster VA, Hog Island Bay, 1934 (United States National Museum of Natural History collections), and at Cape Charles VA (1929), on rock jetties north of Cape Charles (Richards 1931). It is abundant on Atlantic coast jetties and Atlantic Bay shores (Godwin 1997).
Lower Bay - L. exotica was collected at Crisfield MD (1931), Norfolk VA (1940), Hampton Roads VA (1940), and Gloucester Point VA (1965) (United States National Museum of Natural History collections). It ws reported from 'shallows of Lafayette River, Norfolk (brackish), mudflats of Little Creek (brackish), and Lynnhaven Inlet, VA Beach (marine)' (Ferguson and Jones 1949).
Upper Bay- Ligia exotica in Chesapeake Bay extends into mesohaline waters on the north shore of the lower Potomac (e.g. Piney Point MD, Virnstein and Boesch 1975, cited by Lippson et al. 1979), and Crisfield MD (United States National Museum of Natural History collections, Godwin 1997), north to Shady Side, Sandy Point State Park, and North Point State Park (north of Baltimore) (Fofonoff, unpublished data).
History References - Ferguson and Jones 1949; Fowler 1911; Godwin 1997; Gosner 1978; Gould 1841; Kensley 1995; Kensley and Schotte 1989; Richards 1931; Roman 1977; Schultz 1974; Schultz 1977; Uhler 1878; United States National Museum of Natural History collections; Van Name 1936
Invasion Comments
Vector(s) of Introduction- Ligia exotica could be transported in damp crevices of wooden ships above water-line, and also in dry ballast or damp cargo (Lippson and Lippson 1984; Schultz 1977).
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | ||||
| Salinity (‰) | 7.0 | 55.0 | ||
| Oxygen | ||||
| pH | ||||
| Salinity Range | meso-eu |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | 16.0 | 21.0 |
| Typical Adult Size (mm) | 23.0 | |
| Maximum Adult Size (mm) | 38.5 | 32.0 |
| Maximum Longevity (yrs) | ||
| Typical Longevity (yrs | 1.3 | 1.3 |
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
Ligia exotica ( (Sea Roach) probably has no significant economic impact in the Chesapeake region, though ' a swarm of sea roaches ... scurrying over the dry surfaces of a piling, jetty, or sea wall is a common, but rather unpleasant sight, for they look too much like obnoxious cockroaches' (Lippson and Lippson 1984).
References- Lippson and Lippson 1984
Economic Impacts Outside of Chesapeake Bay
Although Ligia exotica (Sea Roach) is widely introduced, its economic impact is unknown. 'Sea roaches' may be aesthetically unpleasant, but their impact on coastal resources is presumably insignificant.
Ecological Impacts on Chesapeake Native Species
Ligia exotica's (Sea Roach's) abundance in upper intertidal tidal and spray-zone habitats in the lower Chesapeake Bay suggests that they may play an important role, but ecological impacts of L. exotica on the Atlantic coast and elsewhere seem to have been little studied.
Herbivory - L. exotica grazes on diatoms and encrusting algae growing on hard surfaces (Carefoot and Taylor 1996; Schultz 1977). The quantitative importance of its grazing is unknown.
Food/Prey - L. exotica is potentially a prey item, especially for shorebirds. However, we have found no information on its possible role as prey.
References - Carefoot and Taylor 1996; Schultz 1977
Ecological Impacts on Other Chesapeake Non-Native Species
Ligia exotica (Sea Roach) is not known to have significant interactions with other introduced organisms in the Chesapeake Bay region.
References
Carefoot, Thomas H.; Taylor, Barbara E. (1995) Ligia: a prototypal terrestrial amphipod, In: Alikhan, M. A.(Eds.) Terrestrial Isopod Biology. , Rotterdam. Pp. 47-60Farr, James A. (1978) Orientation and social behavior in the supralittoral isopod Ligia exotica (Crustacea: Oniscoidea), Bulletin of Marine Science 28: 659-666
Ferguson, F. F.; Jones, E. R. (1949) A survey of the shoreline fauna of the Norfolk Peninsula., American Midland Naturalist : 436-446
Fowler, Henry (1911) The Crustacea of New Jersey, Annual Report of the New Jersey State Museum, part 2 : 29-610
1997 conversation with Paul Fofonoff. conversation
Gosner, Kenneth L. (1978) A field guide to the Atlantic seashore., In: (Eds.) . , Boston. Pp.
Gould, Augustus A. (1841) Report on the invertebrata of Massachusetts, comprising the Mollusca, Crustacea, Annelida, and Radiata., , Cambridge. Pp.
Kaplan, Eugene H. (1988) A Field Gude to Southeastern and Caribbean Seashores, In: (Eds.) . , Boston. Pp.
Kensley, Brian; Nelson, Walter G.; Schotte, Marilyn (1995) Marine isopod biodiversity of the Indian River Lagoon, Florida, Bulletin of Marine Science 57: 136-142
Kensley, Brian; Schotte, Marilyn (1989) Guide to the marine isopod crustaceans of the Caribbean., , Washington, D.C.. Pp.
Lippson, Alice J.; Haire, Michael S.; Holland, A. Frederick; Jacobs, Fred; Jensen, Jorgen; Moran-Johnson, R. Lynn; Polgar, Tibor T.; Richkus, William (1979) Environmental Atlas of the Potomac Estuary, , Baltimore, MD. Pp.
Lippson, Alice Jane; Lippson, Robert L. (1984) Life in the Chesapeake Bay, , Baltimore. Pp.
Richards, Horace G. (1931) Notes on the marine invertebrate fauna of the Virgina Capes., Ecology 12: 443-445
Richardson, Harriet (1905) A monograph on the isopods of North America, United States National Museum Bulletin 54: 1-727
Roman, Marie-Louise (1977) Les oniscoides halophiles de Madagascar (Isopoda, Oniscoidea), Beaufortia 26: 107-151
Schultz, George A. (1974) Terrestrial isopod crustaceans (Oniscoidea) mainly from the West Indies and adjacent regions. I. Tylos and Ligia., Studies on the Fauna of Curaçao and Other Caribbean Islands 45: 162-173
Schultz, George A. (1977) Terrestrial isopod crustaceans (Oniscoidea) from St. Catherines Island, Georgia, Georgia Journal of Science 35: 151-158
Schultz, George A. (1982) Terrestrial isopods of North Carolina, Brimleyana 8: 1-26
Tsai, Min-Li; Chen, Hon-Cheng (1997) Variations of reproductive traits of two semi-terrestrial isopods, Ligia exotica and L. taiwanensis (Crustacea, Ligiidae) in southern Taiwan, Zoological Studies 36: 33-41
Tsai, Min-Li; Dia, Chang-Feng; Chen, Hon-Cheng. (1996) On the repsonses of two semiterrestrial isopods, Ligia exotica and Ligia taiwanensis (Crustacea), from Taiwan to osmotic stress and the routes of land colonization by isopods, Acta Zoologica Taiwanica 7: 19-28
Uhler, P. R. (1878) List of animals observed at Fort Wool, Va., , Baltimore. Pp.
Van Name, Willard G. (1936) The American land and fresh-water isopod Crustacea, Bulletin of the American Museum of Natural History 71: 1-535
Wass, Melvin L. (1972) A checklist of the biota of lower Chesapeake Bay, Special Scientific Report, Virginia Institute of Marine Science 65: 1-290