Date of introduction and origin
Pileolaria berkeleyana was first recorded from
Portsmouth Harbour in The Solent by the name P.
rosepigmentata in 1974 (Knight-Jones et al. 1975).
The date of the introduction is unknown but it is thought to have
been introduced from Japan. Outside Britain the known distribution
of P. rosepigmentata is around Japan and the Kamchatka
Peninsula. P. berkeleyana is known from all oceans except
Method of introduction
While it is possible that this species was introduced with the
Japanese seaweed Sargassum muticum, its noted preference
for a hard substratum for settlement (Gray 1978) suggests that it
is more likely to have arrived on ships' hulls as a fouling
organism (Zibrowius & Thorp 1989).
Reasons for success
Rate of spread and methods involved
Its spread has not been rapid. Its distribution at quite
widely separated sites, each of which is a port, suggests that
dispersal has been 'remote', probably as fouling on boat hulls. The
record of a single specimen on S. muticum at St. Helier,
Jersey, and its original record from S. muticum in
Portsmouth Harbour suggest that, despite its preference for hard
substrata, S. muticum could serve as an additional
Currently recorded from Falmouth (Cornwall), Plymouth (Devon)
and Portsmouth (Hampshire) in the UK (Thorp, Knight-Jones &
Knight-Jones 1986). It has not been recorded as established from
elsewhere in Europe with any certainty: a single specimen,
epiphytic on Sargassum muticum,was recorded from St.
Factors likely to influence spread and distribution
Its presence in ports, together with its preference for hard
substrata for settlement, furnish this species with the potential
to spread through the agency of ship fouling (Gray 1978). Studies
of its reproductive biology suggest that the adult worm has the
ability both to survive and reproduce in a wide range of
temperatures (Thorp 1991). Thus, this species should be able to
survive in northern European waters without the need for any
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
None warranted on such a small animal.
This species, like Janua brasiliensis, has been
recorded only through the monitoring of the non-native alga S.
muticum, and it is therefore likely that there are other sites
where this species is present but has not been recorded. In fact,
C.H. Thorp (pers. comm.) considers it is likely that this species
has spread more widely than J. brasiliensis.
Gray, P.W.G. 1978. An investigation of the fauna
associated with Sargassum muticum. Ph.D. Thesis, Portsmouth
Knight-Jones, P., Knight-Jones, E.W., Thorp, C.H., & Gray,
P.W.G. 1975. Immigrant spirorbids (Polychaeta: Sedentaria) on the
Japanese Sargassum at Portsmouth, England. Zoologica
Scripta, 4(4): 145-149.
Thorp, C.H. 1991. The effect of temperature on brooding in
Pileolaria berkeleyana (Rioja, 1942) (Polychaeta:
Spirorbidae). Ophelia, 5, Supplement:
Thorp, C.H., Knight-Jones, P., & Knight-Jones, E.W. 1986.
New records of tubeworms established in British harbours.
Journal of the Marine Biological Association of the United
Kingdom, 66: 881-888.
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.