Hydroides dianthus
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).
Distribution
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
Unknown.
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.
Comments
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).
References
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.