Hydroides dianthus

Phylum: Annelida
Class: Polychaeta
Order: Sabellida (Serpulidae, serpulid)
Species name: Hydroides dianthus (Verrill, 1873)
Synonyms: Eupomatus dianthus
Common name: A tubeworm
Date of introduction and origin
Hydroides dianthus was first recorded in 1970 at Hamble Spit, Southampton Water (Zibrowius 1978). This species originates from the east coast of North America and was probably introduced from there, or possibly from the Mediterranean, where it is widespread within harbours and lagoons (Zibrowius 1971).
Method of introduction
It was possibly introduced as a fouling organism, transported on ships hulls, and larvae could be transported in ballast water. There was possible additional introduction associated with the American oyster Crassostrea virginica (Zibrowius 1983; Zibrowius & Thorp 1989).
Reasons for success
While other species of the genus Hydroides together with Ficopomatus enigmaticus are likely to be limited in distribution by their temperature tolerances, there appears to be no similar restriction on H. dianthus. This species will experience similar conditions around British coasts to those prevailing throughout large parts of its native habitat along the eastern seaboard of North America. Accordingly, if it has not already done so, it is expected to spread widely (C.Thorp pers. comm.).
Rate of spread and methods involved
There has been no known spread of this species, despite predictions. The pattern of spread expected would be to mimic that within the Mediterranean, namely, to ports and lagoons through the vector of shipping (Zibrowius & Thorp 1989).
Its current British distribution is limited to Southampton Water. This species is widespread in the Mediterranean and has been recorded from the Atlantic coasts of France and Spain (Zibrowius 1983).
Factors likely to influence spread and distribution
It only survives where there are good planktotrophic waters. Competition with other filter-feeders, particularly H. ezoensis, may influence its spread within Southampton Water.
Effects on the environment
Effects on commercial interests
It is a fouling organism. Nelson & Stauber (1940) reported that Hydroides dianthus may kill young oysters (Crassostrea virginica) by overgrowing them in its native area of eastern North America. It is also the host of certain nematode stages in eastern North America.
Control methods used and effectiveness
It can be removed by scraping of buoys and ships' hulls.
Beneficial effects
Its effects are negligible but see under H. ezoensis and F. enigmaticus.
While it is possible that H. dianthus has been present in British waters for some considerable time (Zibrowius & Thorp 1989), it is known from only a few specimens collected from Southampton Water (Thorp, Pyne & West 1987; Zibrowius & Thorp 1989).
Bianchi, C.N. 1981. Guide per il riconoscimento delle specie animali delle acque lagunari e costiere Itliane. No. 5 Series: Policheti, Serpuloidei. Rome, Consigleo Nazionale delle Ricerche.
Nelson, T.C., & Stauber, L.A. 1940. Observations on some common polychaetes of New Jersey oyster beds with special reference to Polydora. Anatomical Records, 78: 102-103.
Thorp, C.H., Pyne, S., & West, S.A. 1987. Hydroides ezoensis Okuda, a fouling serpulid new to British coastal waters. Journal of Natural History, 21: 863-877.
Zibrowius, H. 1971. Les espèces méditerranéennes du genre Hydroides (Polychaeta: Serpulidae). Remarques sur le prétendu polymorphisme de Hydroides uncinata. Téthys, 2: 691-745.
Zibrowius, H. 1978. Introduction du polychète Serpulidae japonaise Hydroides ezoensis sur la côte atlantique Française et remarques sur la repartition d'autres espèces de Serpulidae. Téthys, 8:141-150.
Zibrowius, H. 1983. Extension de l'aire de répartition favorisée par l'homme chez les invertebres marins. Oceanis, 9: 337-353.
Zibrowius, H., & Thorp C.H. 1989. A review of the alien serpulid and spirorbid polychaetes in the British Isles. Cahiers de Biologie Marine, 30: 271-285.
Acknowledgements (contributions from questionnaire)
Dr C.H. Thorp, University of Portsmouth.