Activists rescued a humpback whale on Friday that had been caught in illegal fishing nets in Mexico's upper Sea of Cortes.

The activists from the Sea Shepherd conservation organisation were patrolling an area that is a refuge for a near-extinct porpoise species, the vaquita marina, when they came across the whale in distress

The whale was caught in a gillnet, which are set up by poachers in an effort to catch totoaba, an endangered species of marine fish sought by Chinese buyers on the black market for its prized swim bladders.

Octavio Carranza, a captain of one of Sea Shepherd's ships said, "it's a sad reminder of why it's so important for us to protect the refuge against illegal fishing".