Marenzelleria viridis

Phylum: Annelida
Class: Polychaeta
Order: Spionida (Spionidae; spionid)
Species name: Marenzelleria viridis (Verrill 1873)
Synonyms: Scolecolepis viridis Verrill 1873, Scolecolepides viridis (Verrill 1873)
Common name: None
Date of introduction and origin
Marenzelleria viridis was found in 1982 in the Firth of Forth (McLusky, Hull & Elliott 1993) and the Firth of Tay in 1984 (Atkins, Jones & Garwood 1987). It was first recorded on the European mainland coast in the Ems estuary (lying between Germany and The Netherlands) in 1983 (Essink & Kleef 1988). This species occurs naturally on the east coast of North America from where it was probably introduced.
Method of introduction
The species was probably transported as larvae and/or adults in ballast water. This theory is supported by collection of specimens in a plankton tow in a North American estuary (Maciolek 1984).
Reasons for success
Although the species has an exceptionally large reproductive potential (Sarda, Valiela & Foreman 1995) Atkins, Jones, & Garwood (1987) reported that in the period 1984-1986 recruitment occurred only once. There appear to be no recent data on reproduction in Britain.
Rate of spread and methods involved
In the UK it has been found in the Firth of Forth, Firth of Tay and Humber estuary. It is also found in estuaries on the European side of the North Sea and in the Baltic (Essink & Kleef 1993; Bastrop, Röhner & Jürss 1995).
Factors likely to influence spread and distribution
Shipping may influence its spread
Effects on the environment
In the Tay, M. viridis occurred at greater sediment depths than other species in an intertidal mudflat, yet its distribution and population densities were negatively correlated with all other species (Atkins, Jones & Garwood 1987). In the Ems estuary in The Netherlands, increasing densities of Marenzelleria viridis in a sandy habitat coincided with a reduced abundance of the polychaete Hediste diversicolor, and density fluctuations of M. viridis and the amphipod Corophium volutator showed a significant positive relationship (Essink & Kleef 1993). However, the cause of these effects is not understood, and may be environmental factors rather than species interactions. Recent studies in the Ems estuary by Essink, Eppinga & Dekker (in prep.) demonstrated an inverse abundance and biomass relationship between the introduced spionid polychaete M. viridis and the previously most abundant native polychaete Hediste diversicolor, indicating that competition occurs between the two species.
Effects on commercial interests
Control methods used and effectiveness
None used.
Beneficial effects
None known in Britain. In the Ems, M. viridis is preyed upon by plaice Pleuronectes platessa and flounder Platichthys flesus (Essink & Kleef 1993).
The biology of this species has been studied in the Tay estuary in Britain (Atkins, Jones & Garwood 1987) and various sites in mainland Europe, including the Ems estuary (Essink & Kleef 1993). There are also extensive studies (on the ecology, physiology, genetics, larval ecology and reproduction) of the species underway in German Baltic waters at the University of Rostock, Institute of Baltic Sea Research (K. Essink pers. comm.).
Atkins, S.M., Jones, A.M., & Garwood, P.R. 1987. The ecology and reproductive cycle of a population of Marenzelleria viridis (Annelida: Polychaeta: Spionidae) in the Tay Estuary. Proceedings of the Royal Society of Edinburgh, 92B: 311-322.
Bastrop, R., Röhner, M., & Jürss K. 1995. Are there two species of the polychaete genus Marenzelleria in Europe? Marine Biology, 121: 509.
Bick, A. 1995. Entwicklungsbedingte Veränderungen von morphologischen Merkmalen bei Marenzelleria viridis (Verill), (Spionidae) und Manayunkia aestuarina (Bourne), (Sabellidae). Mitteilungen hamburgischen zoologischen Museum und Institut: 92\: 41-53.
Essink, K., & Kleef, H.L. 1988. Marenzelleria viridis (Verrill, 1873) (Polychaeta: Spionidae): a new record from the Ems estuary (The Netherlands/Federal Republic of Germany). Zoologische Bijdragen, 38: 1-13.
Essink, K., & Kleef, H.L. 1993. Distribution and life cycle of the North American spionid polychaete Marenzelleria viridis in the Ems estuary. In: Proceedings of the 21st Symposium of the Estuarine and Coastal Sciences Association held in Ghent, 9-14 September 1991. Marine and estuarine gradients (ECSA 21), ed. by P. Meire & M. Vincx. Netherlands Journal of Aquatic Ecology, 27: 237-246.
Essink, K., Eppinga, J., & Dekker, R. In prep. Long-term changes (1977-1994) in intertidal macrozoobenthos of the dollard (Ems estuary) and effects of introductions of the North American spionid polychaete Marenzelleria viridis (Verrill, 1873).
Maciolek, N.J. 1984. New records and species of Marenzelleria Mesnil and Scolecolepides Ehlers (Polychaeta: Spionidae) from north-eastern North America. Proceedings of the first international Polychaete Conference, Sydney, ed. by P.A. Hutchings, 48-62. The Linnean Society of New South Wales.
McLusky, D.S., Hull, S.C., & Elliott, M. 1993. Variations in the intertidal and subtidal macrofauna and sediments along a salinity gradient in the upper Forth estuary. Netherlands Journal of Aquatic Ecology, 27: 101-109.
Sarda , R., Valiela, I., & Foreman, K. 1995. Life cycle, demography, and production of Marenzelleria viridis in a salt marsh of southern New England. Journal of the Marine Biological Association of the United Kingdom,75: 725-739.
Acknowledgements (contributions from questionnaire)
Dr S. Atkins, Scottish Natural Heritage.
Dr K. Essink, National Institute for Coastal and Marine Management, The Netherlands