Conservation group Sea Shepherd has revealed details of a violent attack on one of its ships by poachers in the Gulf of California off Mexico.

The society said its 168-gt former US Coast Guard cutter Farley Mowat was target by more than 50 assailants "posing as fishermen on board 20 high-speed boats while conducting maritime conservation patrols inside the Vaquita Refuge."

A total of 52 skiffs were counted. The others attacked Mexican navy boats in the area.

Molotov cocktails and projectiles, including lead weights and large stones, were hurled by the poachers, shattering windows and setting the side of the vessel on fire.

Crew fended the attackers off using emergency fire hoses while navy and federal police stationed on board opened fire into the air and sea to deter the attackers.

The master carried out anti-piracy procedures such as varying the vessel’s speed and other anti-boarding techniques.

When hailed by radio by the Mexican naval frigate Barrera, Farley Mowat set course towards the vessel stationed inside the refuge for increased safety.

No injuries were reported.

A similar attack took place on 9 January, Sea Shepherd said.