A fish farm company has said that around 25% of its total salmon stocks have been killed after being attacked by jellyfish in recent days.
20,000 fish were killed at Marine Harvest Ireland's Clare Island facility.
The attack wiped out 40% of the stock at the Co Mayo farm.
The company operates nine fish farms along the western seaboard, at locations from Donegal to Cork.
It has an annual output of 10,000 tonnes of farmed salmon.
Some "accelerated harvesting" took place in an effort to mitigate the effects of the jellyfish and restocking of the facilities is underway.