Tiostrea lutaria
Phylum: Mollusca
Class: Pelecypoda
Order: Ostreoida
Species name: Tiostrea lutaria (Hutton 1873)
Synonyms: Ostrea lutaria Hutton 1873
Common name: New Zealand flat oyster
Date of introduction and origin
Tiostrea lutaria was first introduced to Britain from New Zealand to the MAFF Fisheries Laboratory, Conwy, north Wales, for quarantine procedures. Individuals were introduced into the wild in 1963 but these died out in the severe winter. A subsequent introduction was made in 1970 into the Menai Strait from seed produced at Conwy in 1966 (Walne 1979; Utting 1987).
Method of introduction
Deliberate commercial introduction of brood stock oysters was made into quarantine.
Reasons for success
Rate of spread and methods involved
This species has spread less than 1 km in 25 years. This oyster broods its larvae to the stage of metamorphosis so that upon liberation from the parent, the larvae settle within a few hours in the vicinity of the parent.
It is found in the Menai Strait, North Wales.
Factors likely to influence spread and distribution
This species cannot survive severely cold winters (Utting & Spencer 1992) and can be preyed upon where no alternative prey items are present (Richardson et al. 1993).
Effects on the environment
Effects on commercial interests
It is a commercially important edible species.
Control methods used and effectiveness
None used.
Beneficial effects
It is of potential commercial importance but is susceptible to the disease of flat oysters caused by Bonamia sp. so it is not viable to cultivate them commercially in the UK (S.D. Utting pers. comm.).
Tiostrea lutaria is thought to be conspecific with the Chilean oyster Tiostrea chilensis with the latter name possibly taking priority (Buroker et al. 1983).
Buroker, N.E., Chanley, P., Cranfield, H.J., & Dinamani, P. 1983. Systematic status of two oyster populations of the genus Tiostrea from New Zealand and Peru. Marine Biology, 77: 191-200.
Richardson, C.A., Seed, R., Al-Roumaihi, E., & McDonald, L. 1993. Distribution, shell growth and predation of the New Zealand oyster Tiostrea (= Ostrea) lutaria Hutton, in the Menai Strait, North Wales. Journal of Shellfish Research, 12B: 207-214.
Utting, S.D. 1987. Fresh prospects for bivalve farming. Fish Farmer, 10: 17-18.
Utting, S.D., & Spencer, B.E. 1992. Introductions of bivalve molluscs into the United Kingdom for commercial culture - case histories. ICES Marine Science Symposium, 194: 84-91.
Walne, P.R. 1979. Culture of bivalve molluscs, 50 years experience at Conwy: 2nd ed. Farnham, Fishing News (Books).
Acknowledgements (contributions from questionnaire)
Dr S.D. Utting, MAFF Fisheries Laboratory, Conwy.