Pileolaria berkeleyana

Phylum: Annelida
Class: Polychaeta
Order: Sabellida (spirorbid)
Species name: Pileolaria berkeleyana (Rioja 1942)
Synonyms: Currently the taxonomy of this genus is being reconsidered and it is likely that Pileolaria rosepigmentata (Uchida 1971) will be reinstated as a species separate from Pileolaria berkeleyana (Rioja 1942). Thus, the population present in British waters will revert to its previously cited name of P. rosepigmentata.
Common name: A tubeworm
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 the Arctic.
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 vector.
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. Helier, Jersey.
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 artificial warming.
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
None warranted on such a small animal.
Beneficial effects
None known.
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 Polytechnic.
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: 383-390.
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.