More than 200 fishermen handed out free fish to passersby on O'Connell Bridge in Dublin in protest at what they say is the plight of the industry.
Spokesperson David Kirwan said that it is becoming increasingly difficult to make a living from fishing in Ireland.
The fishermen marched to Government Buildings this afternoon.
They say they wanted to send a clear signal to visiting French President Nicolas Sarkozy that fishermen were instrumental in securing a No vote in the Lisbon Reform Treaty.
They say that unless fishermen receive immediate aid, they will call for a No vote in any re-run of the referendum.
