Press Releases

Tropical shellfish could threaten British wildlife

Experts from Amgueddfa Cymru – National Museum Wales are warning that marine bivalve species (such as scallops and oysters), which have recently been found on the British and Irish shores, could have a negative impact on our marine life.


The six particular species of bivalve found, which require a warm sea temperature of 22 - 26°C to reproduce, all originate from the southeast coast of the United States and have been washed up on the shores attached to plastic litter.


For the last year and a half, since the winter storms of 2013-14, an unusually large amount of plastic waste has been washing up on the British and Irish coast. Plastic litter is not only harmful to marine life, it can also carry alien species to our shores.


Museum scientists are concerned that these incomers could out-compete native species such as the edible oyster for habitat and food. One of the hitch-hiking species Isognomon bicolor (the two-coloured purse oyster) originates from Florida but has spread throughout the Caribbean and invaded Brazil, outcompeting their native oyster.


Anna Holmes, from Amgueddfa Cymru said:


“Last July the UK recorded a sea temperature of 20°C in Cornwall. If the temperature  continues to rise, some of these and other tropical visitors could become established in British seas and threaten our native wildlife.”


People can help by reporting any live bivalves, crabs or barnacles that they find attached to plastic litter to


Entry to the Museum is free, thanks to the support of the Welsh Government. 

Amgueddfa Cymru – National Museum Wales operates seven museums across Wales: National Museum Cardiff, St Fagans National History Museum, National Roman Legion Museum, Caerleon, Big Pit National Coal Museum, Blaenafon, National Wool Museum, Drefach Felindre, National Slate Museum, Llanberis and the National Waterfront Museum, Swansea.