Goniadella gracilis

Phylum: Annelida
Class: Polychaeta
Order: Phyllodocida (Glyceridae; glycerid)
Species name: Goniadella gracilis (Verrill 1873)
Synonyms: None
Common name: None
Date of introduction and origin
Goniadella gracilis was first recorded in 1970 in Liverpool Bay (Walker 1972). It was previously reported from North America (from where it was described) and South Africa. The species is likely to have been introduced from the east coast of the United States.
Method of introduction
The precise method of introductions is unknown, but is likely to have been ship-assisted. It is suspected that trans-Atlantic shipping carried it into Merseyside as ships frequently lie at anchor in Liverpool Bay before docking.
Reasons for success
Rate of spread and methods involved
Walker (1972) considered that it may have become quite common in Liverpool Bay only within the preceding 20 years. It has spread about 300 km (Mackie, Oliver & Rees 1995).
It is widespread in the southern Irish Sea (Mackie, Oliver & Rees 1995). No other known European populations are known.
Factors likely to influence spread and distribution
Effects on the environment
Effects on commercial interests
Control methods used and effectiveness
None used.
Beneficial effects
None known.
It appears that Goniadella gracilis has become quite common in Liverpool Bay in sandy gravel below 15 m water depth.
Hartman, O. 1944. New England Annelida, Part 2 (including the unpublished plates by Verrill with reconstructed captions). Bulletin of the American Museum of Natural History, 82: 327-343.
Mackie, A.S.Y., Oliver, P.G., & Rees, I.S. 1995. Benthic biodiversity in the southern Irish Sea. Studies in marine biodiversity and systematics from the National Museum of Wales. Biomôr Reports, 1: 263 pp.
Walker, A.J.M. 1972. Goniadella gracilis, a polychaete new to British seas. Marine Biology, 14: 85-87.
Acknowledgements (contributions from questionnaire)
Dr A.S.Y. Mackie, National Museums and Galleries of Wales, Cardiff.