Invasion History

First Non-native North American Tidal Record: 2001
First Non-native West Coast Tidal Record:
First Non-native East/Gulf Coast Tidal Record: 2001

General Invasion History:

Arbopercula bengalensis was first described from West Bengal, India (Stoliczka 1896, cited by Rao and Ganapati 1978) and is native throughout India and perhaps the warm-temperate and tropical coast of China. The status of this species in China is currently unknown and it may have been introduced there. Its type locality was 'only 1/5 as saline as sea-water’ (Stoliczka 1869, cited by Rao and Ganapati 1978), and it is considered a characteristically brackish-water species (Winston 1977; Rao and Ganapati 1978). However, it is also abundant at sites with salinities above 30 PSU (Menon and Nair 1972). In India, it occurs along the shores of the Arabian Sea from Mumbai (Pillai and Madhaven 1981; Udhayakumar and Karande 1989) to Cochin (Menon and Nair 1972), and on the shores of the Bay of Bengal at Visakhapatnam (Rao and Ganapati 1978) and Port Canning (Calcutta area, Stoliczka 1869, cited by Rao and Ganapati 1978 ). On the coast of China, it has been found from Hainan Island (Huang et al. 2001) to Xiamen on the Taiwan Straits (Liu et al. 2001). Outside the southern coasts of Asia, A. bengalensis has been introduced to Australia, West Africa, Panama, and Florida (Osburn 1950; Powell 1971; Cook 1968; Saenger et al. 1979; Hall 1984; McCann et al. 2007). Arbopercula bengalensis has planktotrophic cyphonautes larvae (Udhayakumar and Karande 1989), which may have sufficient duration for ballast water transport.

North American Invasion History:

Invasion History on the East Coast:

In 2001, Arbopercula bengalensis was found on SERC fouling plates in the St. Johns River estuary, near Jacksonville, and in 2005, it was collected on plates in the Fort Pierce Inlet, Indian River Lagoon, both in Florida (McCann et al. 2007). It was abundant in both estuaries. In 2007, A. bengalensis was found on fouling plates in Puerto Rico (Ruiz et al., unpublished data).

Invasion History Elsewhere in the World:

Arbopercula bengalensis was collected near Balboa, on the Pacific side of the Panama Canal by Osburn before 1950 (Osburn 1950; Osburn 1953), and by Powell (1971). It was not collected by the 'St. George' expedition of 1924 (Powell 1971). Powell described it as 'one of the two dominant fouling bryozoans in Balboa Harbor and Panama Bay, the colonies forming large bushy lumps on the navigation buoys' (Powell 1971). He found it only on the Pacific side of the canal. During SERC fouling plate collections in 2004, Ruiz et al. (unpublished data), found this species at most stations sampled on the Caribbean side of the canal, as well as on the Pacific side. The Panama Canal seems a likely route for the transport of A. bengalensis into the Atlantic.

In West Africa, it was collected in Lagos, Nigeria, in 1959 (Cook 1968). In Australia, A. bengalensis has been collected at Townsville Harbor (Hall 1984), and the Calliope River (Saenger et al. 1979).


Arbopercula bengalensis forms encrusting colonies. Its zooids are moderately large, about 0.60 mm long by 0.25-0.30 mm wide, and elongate-rectangular in shape, with an elongate ovoid membranous area that covers most of the frontal surface and is edged by smooth gymnocrystal calcification (calcification deposited on the outside of the body wall). From the lateral and proximal margins of zooids, 11-14 slender, flattened spines arch over the frontal membrane. A distinct proximal spine, sometimes forked, may be present. A pair of distal spines occurs on either side of the operculum. They may bifurcate at the tips, and may overlap, but do not fuse. The most striking feature of the species is the pair of long, branching, chitinous spines which project outward from the outer surface of the D-shaped operculum. The zooids have no avicularia and no specialized ovicells (Description from McCann et al. 2007; Nikulina 2010).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Bryozoa
Class:   Gymnolaemata
Order:   Cheilostomata
Suborder:   Anasca
Family:   Electridae
Genus:   Arbopercula
Species:   bengalensis


Electra anomala (Osburn, 1950)
Electra anormata (Huang et al., 1990)
Membranipora bengalensis (Stoliczka, 1860)
Electra bengalensis ((Stoliczka), 1860)

Potentially Misidentified Species



Life History- Arbopercula bengalensis is an encrusting, calcified bryozoan colony composed of many individual zooids. The zooids feed by extending the ciliated tentacles of the lophophore as a funnel, creating a current, and driving food particles into their mouths. The food is guided along the tentacles and through the pharynx by the cilia. Larger food particles can be moved or captured by flicking or contracting the tentacles (Barnes 1983). Larvae of A. bengalensis have a planktotrophic cyphonautes larva, but may have a fairly short planktonic period. Fouling plates placed in the Indian River Lagoon, Florida, in September, had developing colonies after two weeks in the water (McCann et al. 2007). Larvae settle on a substrate and metamorphose into the first zooid of a colony, an ancestrula. (Barnes 1983).

Ecology- Arbopercula bengalensis is known from mangroves, rocky areas, pilings, and buoys (Powell 1971; McCann et al. 2007). It is characteristic of brackish water, but also occurs at marine salinities (Menon and Nair 1972; Rao and Ganapati 1978; McCann et al. 2007).

Trophic Status:

Suspension Feeder



General HabitatCoarse Woody DebrisNone
General HabitatMarinas & DocksNone
General HabitatRockyNone
General HabitatMangrovesNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEpibenthicNone

Tolerances and Life History Parameters

Minimum Depth (m)0None
Maximum Depth (m)10None
Maximum Temperature (ºC)31.6Cochin Backwater (Menon and Nair 1972)
Minimum Salinity (‰)7Type locality "only 1/5 as saline as sea-water" (Stoliiczka 1869, cited by Rao and Ganapati (1978)
Maximum Salinity (‰)33.6Cochin Backwater (Menon and Nair 1972)
Broad Temperature RangeNoneWarm temperate-Tropical
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Economic Impacts 

Shipping- Arbopercula bengalensis is an abundant fouling organism in its native and introduced waters and a frequent fouler of ships and buoys (Powell 1971; Menon and Nair 1972; Rao and Ganapati 1974; Rao and Ganapati 1978). 'Electra' spp. in Mumbai Harbor were resistant to copper antifouling compounds (Rao and Ganapati 1975). However, the economic importance of A. bengalensis as a fouling organism has not been studied.

Ecological Impacts 

Competition- Arbopercula bengalensis is considered to be a competitive, fast-growing member of the fouling community in Indian waters, owing to its year-round breeding, early maturity, and tolerance of varied salinity and pollution, although it rarely overgrows or displaces colonies of other species (Udhayakumar and Karande 1989; Karande and Udhayakumar 1992). It was considered one of two dominant fouling species in Balboa Harbor and Panama Bay, by 1971 (Powell 1971). In many areas it is the dominant bryozoan, occupying more than 70% of the space covered by bryozoans and most of the available substrate (Udhayakumar and Karande 1989; Ruiz, unpublished data). However, experimental studies of its effects on other fouling species have not been conducted in invaded waters.

Regional Impacts

SEP-HNoneEcological ImpactCompetition
Arbopercula bengalensis was considered one of two dominant fouling species in Balboa Harbor and Panama Bay, by 1970 (Powell 1971).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CIO-III None 1869 Native Estab
CIO-I None 0 Native Estab
CIO-II None 0 Native Estab
AUS-XII None 1977 Def Estab
WA-II None 1936 Def Estab
SEP-H None 1950 Def Estab
CAR-VII Cape Hatteras to Mid-East Florida 2001 Def Estab
NWP-2 None 0 Crypto Estab
S180 St. Johns River 2001 Def Estab
NWP-3a None 0 Crypto Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 2005 Def Estab
S190 Indian River 2005 Def Estab
CAR-IV None 2007 Def Estab
CAR-III None 2004 Def Estab
S080 Charleston Harbor 2004 Def Estab
PAN_PAC Panama Pacific Coast 1950 Def Estab
PAN_CAR Panama Caribbean Coast 2004 Def Estab
SA-III None 1997 Def Estab
EAS-VI None 2010 Crypto Estab
SA-II None 0 Def Estab
AG-5 None 0 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude
6112 Udhayakumar and Karande 1989 None 9999-01-01 Bombay (Mumbai)/ Native 18.9750 72.8258
6113 Menon and Nair 1971 None 9999-01-01 Cochin Native 9.9667 76.2333
6114 Rao and Ganapati 1978 None 9999-01-01 Visakhapatnam/ Native 17.7000 83.3000
6115 Stolickza 1869, cited by McCann et al. 2007 1869 1869-01-01 Port Canning, Calcutta Native 22.3189 88.6714
6116 Huang et al. 2001 2001 2001-01-01 None Native 22.9624 113.4874
6117 Huang et al. 2001 2001 2001-01-01 Hainan Island Native 18.9394 109.4842
6118 Liu et al., 2001, cited by McCann et al. 2007 2001 2001-01-01 Xiamen Native 24.4675 118.0931
6119 Hall 1984, cited by McCann et al. 2007 1984 1984-01-01 Townsville Def -19.4450 146.9110
6120 Saenger et al. 1977, cited by McCann et al. 2007 1977 1977-01-01 None Def -23.8333 151.2167
6121 Cook 1968 1959 1959-01-01 Lagos Def 6.4531 3.3958
6122 Osburn 1950, Powell 1971 None 9999-01-01 Balboa Def 8.9500 -79.5667
6130 Raveendran and Wagh 1993 1993 1993-01-01 Mormugao Native 15.4000 73.8000
6159 Ruiz et al. Unpublished Data 2004 2004-01-01 Colon Container Terminal Def 9.3733 -79.8837
6229 Ruiz et al. Unpublished Data 2005 2005-09-01 Little Jim Marina Def 27.4800 -80.3100


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