The discovery in fishing nets of a species of giant prawn normally found in the Indian and Pacific oceans has led to fears among marine biologists of an invasion.
The distinctively striped Japanese tiger prawn was found by the shrimp fisher Coral Strand skippered by Tadgh Regan off the Galley Head in west Cork last week.
Its appearance means a new population has arrived to compete with native prawns, according to Department of the Marine officer and rare fish expert Kevin Flannery. "You are talking about an invasive species," he said. "They will compete with local prawns for food."
Mr Flannery and his colleagues are exploring theories how such a species could have been taken live in Irish waters. At first he was dumbfounded: had he not known where it came from, he would have thought it was thrown out by a Thai or Chinese restaurant, he said.
"We get the odd rare species wandering up from the Caribbean or the Mediterranean, but nothing as dramatic as this. This should not be in European waters."
Mr Flannery has appealed to fishermen to watch out for the prawns and to report any appearances to the Department of the Marine or to himself.