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You are viewing an archived site. The Chesapeake Bay Introduced Species Database project ended in 2020 and the database is no longer receiving updates. Learn more…

Clytia paulensis

Coelenterates-Hydrozoans

hydroid

The hydrozoan Moerisia lyonsi has both a fixed hydroid and a swimming jellyfish (medusa) stage in its life cycle- both are tiny. The jellyfish are only 2 to 8 mm wide, and the hydroids only 1-2 mm tall. This hydrozoan is only known from Lake Quarun Egypt, a lagoon of the Nile Delta, where it was first discovered, and the East and Gulf coasts of North America. Other similar species in the genus Moerisia are known from the Caspian Sea, Japan, and the Mediterranean and due to similarities within this group of Moerisia species we believe that Moerisia lyonsi likely evolved in Caspian and Black Seas. The first record of this hydroid in Chesapeake Bay was in 1965 when one was collected in low salinity waters of the James and Pamunkey Rivers. There have been few reports of the species, but in 1992-93 they were found in an experimental tank at the University of Maryland Horn Point Laboratory and the adjacent Choptank River, and SERC’s Marine Invasions Research Laboratory found specimens on settling plates from Baltimore Harbor in 1995. Because this hydroid is so small and poorly understood, there is some doubt as to its origin.

Description Taxonomy Invasion History Ecology Impacts References

Description

Medusae of Clytia paulensis are known (Calder 1972; Cornelius 1982), but have not been described, to our knowledge.

Synonymy - Calder notes 'However, there is nothing in Fraser's (1914) description of Clytia longitheca to distinguish it from C. paulensis, and the two species may be synonymous. Verification of this must await a critical examination of Fraser's specimens. C. longitheca is known from British Columbia to San Francisco Bay (Fraser 1937a)' (Calder 1971).

Potentially Misidentified Species - 'The whole genus is a difficult one and in need of revision' (Calder 1997).

Taxonomy

Kingdom Phylum Class Order Family Genus
Animalia Cnidaria Hydozoa Leptomedusae Campanulariidae Clytia

Synonyms

Campanularia paulensis; Clytia ulvae; Obelia paulensis; Clytia longitheca?

Invasion History

Chesapeake Bay Status

First Record Population Range Introduction Residency Source Region Native Region Vectors
1968 Established Unknown Cryptogenic Regular Resident Eastern Atlantic Unknown-Marine Shipping(Ballast Water,Fouling Community)

History of Spread

The hydrozoan Clytia paulensis was described from the crater lagoon of St. Paul Island, Indian Ocean, from material collected in 1903. It was subsequently found to be widespread in warm ocean waters, including eastern South Africa (Millard 1975), the Red Sea (Mergner and Wedler 1977), Australia (Watson 1994), the Mediterranean (Cornelius 1982), and possibly the Northeast Pacific (British Columbia to San Francisco Bay, as C. longitheca) (Calder 1971). In the NE Atlantic, it ranges north to southernmost England (Cornelius 1982). The first published English record was in 1973, from Plymouth, but subsequently, museum material from 1899 was found (Cornelius 1982). Relatively recent records first records of this species from several locations [Red Sea (Mergner and Wedler 1977)], southern Australia (Watson 1994), Northwest Atlantic, VA-SC (Calder 1971; Calder 1976) could reflect the taxonomic difficulty of this genus as well as possible introductions (Calder 1997). Clytia paulensis has not been specifically reported from ship fouling, but it frequently grows on other hydroids, some of which are known as common ship fouling organisms (e.g. Obelia dichotoma, Millard 1959).

Clytia paulensis was not listed among hydroids of the Atlantic coast of North America by Fraser (1944). The first West Atlantic records of this species were from Chesapeake Bay from the lower York and James Rivers, and from the Bay mouth, on pilings of the Chesapeake Bay Bridge-Tunnel (Calder 1971). Subsequently, C. paulensis was found to be common in SC (Calder 1976; Calder and Hester 1978), and also in the Caribbean Sea (Calder 1997).

We consider Clytia paulensis to be cryptogenic in Chesapeake Bay and elsewhere on the North American Atlantic coast. 'It could have been around the Chesapeake for hundreds, if not thousands of years, although admittedly it is curious that Fraser (1944) did not report the species from the western North Atlantic (Calder 1997).

Calder found Clytia paulensis in tributaries of the lower Bay. Previous and subsequent fouling studies usually did not identify Campanularidae to species (Abbe 1987; Cory 1967; Humphries et al. 1985), so there are no further definite records of C. paulensis. Most samples of Clytia from our fouling plates lacked gonophores and could not be identified to species (Calder 1997; Ruiz et al. unpublished data).

History References - Abbe 1987; Calder 1971; Calder 1972; Calder 1976; Calder 1997; Calder and Hester 1978; Cornelius 1982; Cory 1967; Fraser 1944; Humphries et al. 1985; Mergner and Wedler 1977; Millard 1959; Millard 1975; Ruiz et al. unpublished data; Watson 1994

Invasion Comments

Vector(s) of Introduction - Ballast water transport of medusae may be possible. Clytia spp. and other campanulariids are known to attach to such fauna as sea turtles, whales, and fishes (Cornelius 1982), so that natural transport cannot be ruled out.

Invasion Status- We have called Clytia paulensis cryptogenic, because the taxonomic difficulty of the genus may have delayed the recognition of C. kincaidi in the northwest Atlantic, and because of the possibility of natural transport by fauna.

Ecology

Environmental Tolerances

For SurvivalFor Reproduction
Minimum Maximum Minimum Maximum
Temperature (ºC) 9.0 26.0
Salinity (‰) 17.0 40.0
Oxygen
pH
Salinity Range meso-eu

Age and Growth

Male Female
Minimum Adult Size (mm) 0.7 0.7
Typical Adult Size (mm)
Maximum Adult Size (mm) 3.0 3.0
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

Clytia paulensis is sufficiently abundant that it could be a significant fouling organism in the Chesapeake region. However, it has not been reported specifically from ship or powerplant fouling, to our knowledge, though it grows epizoically on many significant fouling organisms (Calder 1971). Its overall contribution to fouling problems is probably small, but is not known

Economic Impacts Outside of Chesapeake Bay

Clytia paulensis is quite cosmopolitan in warm waters. However, it has not been reported specifically from ship or powerplant fouling, to our knowledge. It does grow epizoically on many significant fouling organisms (Calder 1971; Cornelius 1982). Its overall contribution to fouling problems is probably small, but is not known

Ecological Impacts on Chesapeake Native Species

Clytia paulensis is sufficiently abundant that it could have significant impacts on native organisms. in Chesapeake Bay. However, it does not appear to differ greatly from native Clytia spp. in its biology or potential impacts. In any case, its impacts are unstudied in the Chesapeake region and elsewhere.

Ecological Impacts on Other Chesapeake Non-Native Species

Impacts of Clytia paulensis on other introduced and cryptogenic fauna have not been studied.

References

Abbe, George R. (1987) Epifauna, In: Heck, Kenneth L.(Eds.) Ecological studies in the middle reach of Chesapeake Bay- Calvert Cliffs. , Berlin. Pp. 82-91

Calder, Dale R. (1971) Hydroids and hydromedusae of southern Chesapeake Bay., Virginia Institute of Marine Science, Special Papers in Marine Science 1: 1-125

Calder, Dale R. (1972) Phylum Cnidaria, Special Scientific Report, Virginia Institute of Marine Science 65: 97-102

Calder, Dale R. (1976) The zonation of hydroids along salinity gradients in South Carolina estuaries, In: (Eds.) Coelenterate Ecology and Behavior. , New York. Pp. 165-174

Calder, Dale R. (1992) Seasonal cycles of activity and inactivity in some hydroids from Virginia and South Carolina, U.S.A., Canadian Journal of Zoology 68: 442-450

Calder, Dale R. (1997) Introduced hydroids in Chesapeake Bay, email, Zoologische Verhandlingen Leiden :

Calder, Dale R.; Hester, Betty S. (1978) Phylum Cnidaria., In: Zingmark, Richard G.(Eds.) An Annotated Checklist of the Biota of the Coastal Zone of South Carolina. , Columbia. Pp. 87-93

Cornelius, P. F. S, (1982) Hydroids and medusae of the family Campanulariidae recorded from the eastern North Atlantic, with a world synopsis of genera., Bulletin of the British Museum, Natural History (Zoology) 42: 37-148

Cory, Robert L. (1967) Epifauna of the Patuxent River Estuary, Chesapeake Science 8: 71-89

Fraser, C. McLean (1937) Hydroids of the Pacific Coast of Canada and the United States., , Toronto,. Pp.

Fraser, C. McLean (1944) Hydroids of the Atlantic Coast of North America, In: (Eds.) . , Toronto. Pp. 1-441

Humphries, Edythe M.; Duedall, Iver W.; Jordan, Stephen J. (1985) Coal-waste blocks as a fouling substrate in estuarine water., In: (Eds.) Energy Wastes in the Ocean. , New York. Pp. 613-649

Mergner, H., Wedler, E. (1977) Uber die hydropolypenfauna des Roten Meeres und seiner Ausgange., 'Meteor' Forschungen-Ergebnisse 24: 1-32

Millard, N. A. H. (1959) Hydrozoa from ships' hulls and experimental plates in Cape Town docks., Annals of the South African Museum 45: 239-255

Millard, N. A. H. (1975) Monograph on the Hydroida of southern Africa, Annals of the South African Museum 68: 1-513

Watson, Jeanette E. (1995) New records and redescriptions of thecate hydroids from southern Australia, Proceedings of the Royal Society of Victoria 106: 147-162

Direct questions and comments to chesnemo@si.edu.

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