Invasive marine species loses its grip during recent storms
AN invasive species that poses a serious threat to the local marine environment is being washed up in its hundreds on the Island’s south coast.
A trail of common, or American, slipper limpets has appeared along the high tide line stretching from Millbrook to La Haule, littering the beach with shells.
Environment’s marine resources department says the limpets were most likely dislodged from their usual habitat on the sea bed and swept ashore by the rough seas and high winds that hit the Island over Christmas and new year.
Slipper limpets (Latin name crepidula fornicata) originate from the west coast of America. The species is believed to have spread to the Island in the mid-1970s from France, having been carried across the Atlantic in the ballast tanks of cargo ships.
Rather than lamenting the loss of such a high number of shellfish, the loss of this species is welcome news for the department because of the limpets’ destructive effect on the sea bed and other species.
Once established in an area it spreads rapidly over the sea bed, destroying the habitats that local species and oyster farmers rely on.
Environment is currently drawing up a strategy to help the Island deal with the invasion of limpets and other species that pose a risk to local waters.
Dr Paul Chambers, marine and coastal manager who recently published a report on the non-native marine species in the Channel Islands, said: ‘This is a global problem and not unique to us, and one we can’t solve on our own in any effective way.
‘We can’t prevent a species getting into our marine environment in the first place, so part of the job is to conduct research so we are aware of any potential threats coming our way.
‘The islands are in an unusual situation because of our geography, as we are at a crossroads between the colder waters of the North Sea and sub-Arctic areas, and the warmer waters of the Bay of Biscay and the Mediterranean, which means we receive an unusually wide range of invasive species.’
Many invasive species migrate across the globe on huge cargo ships. These vessels take on ballast water in their home port to keep them stable while they travel across the oceans. Before docking in port to discharge their load they release the water as well as any organisms sucked in at the beginning of the journey.
Marine scientist Francis Binney says the slipper limpets washed up in St Aubin’s Bay will die off on the beach or be eaten by seagulls and that their shells will break down and be washed back out to sea.