Greenpeace activists prevented four pirate fishing trawlers from leaving Rostock harbour with chains and oil drums. One vessel was chained to the harbour wall and hung with a banner reading 'Stop pirate fishing'. A fifth trawler left Rostock last night - all five are on the EU blacklist for having been engaged in illegal, unregulated and unreported fishing - also know as pirate fishing - in the Atlantic. All have recently changed names and flags and were trying to leave port to plunder the high seas again.