Three billion people depend on fishery products as their main source of protein. Fishing is also the principal means of subsistence for nearly 900 million people on the planet. While this activity appears to be a pillar of the world economy, it also affects the marine environment, particularly marine mammals.

Bycatch

Attracted by the same prey, it is not uncommon for cetaceans and humans to find themselves around schools of fish. Thus, while hunting herring alongside tuna, dolphins, for example, can get caught in the nets of tuna seiners.

Overfishing

More than 90% of fish stocks are fully exploited or overexploited. Some of these stocks are the main source of food for several cetacean species. The reduction in their food resources can lead to the displacement of populations to more food-rich areas, or even the local disappearance of certain populations.

Cohabitation between cetaceans and fishermen can be difficult...

Competition for resources has exacerbated tensions in many regions of the world. Indeed, cetaceans sometimes take fish directly from fishermen's nets or lines, causing a significant loss of income and deterioration of fishing equipment that is expensive to repair or renew. This is called depredation.

…but sometimes harmonious.

In several regions of the world, a voluntary collaboration has been established between dolphins, who bring the fish toward the shore as the artisanal fishers cast their nets. The fishers catch more fish, and the dolphins catch their disoriented and isolated prey more easily.