However, agency enforcement officers said they would return to repeat the operation on Thursday night to try to deter the gangs, who can clear several thousand pounds worth of the shell fish in one night.
Friday night it gave foreign oil interests in Nigeria, especially Shell, which the main operator in Niger Delta, till midnight Friday to leave the area or face what one commander called total war.
The north west of England has been the worst hit region so far, with the Stanlow Shell Oil Refinery at Ellesmere Port in Cheshire blockaded since Thursday night.