Shark fishing is mainly carried out with drift gill nets measuring close to
two kilometers long, as well as long lines of up to 70 kilometers in length with
thousands of hooks. The drift gill nets have been called walls of death because
they catch all marine organisms.
These nets are the main threat to cetaceans. Most of the captures around the
world occur in gill and drift nets, in the case of whales, dolphins and
porpoises (84% of captures), for seals and sea lions (98% of catches).