A commercial fishing boat.
Overfishing occurs when a specific type of fish is caught so often and in such large numbers that the population of that fish is severely depleted, resulting in danger and potential extinction. This is often the result of commercial, rather than recreational, fishing. Overfishing has implications far beyond marine life; affects the human food supply, the fishing industry and the environment.
Wild salmon are uncommon in rivers in many places due to overfishing.
The world’s fishing industry can use many different types of technology to locate and capture fish. Some fishing vessels can stay at sea for weeks and can freeze and process the fish they catch on board. This means they only need to arrive at the port when their stores are full. Fishermen on these vessels are able to catch more fish in less time. The fishing industry may experience higher catches in this way and, as a result, more species may be overfished.
Overfishing leads fishermen to catch younger fish, which can exacerbate the problem.
As the number of fish is reduced, fishermen can use smaller nets to catch smaller fish. The result is that younger fish are often caught. Catching young fish can be problematic if they are caught before they are able to reproduce and contribute to population replenishment. The use of nets can also lead to bycatch, which is the capture of non-target species. For example, porpoises can be caught in salmon nets and dolphins can be caught in tuna nets.
Overfishing can also affect species that fishermen never catch. If one type of fish is eliminated, the entire ecosystem can collapse. For example, cod feeds on herring. If a fisherman harvests all the herring from a certain area, the cod will starve to death. Overfishing can also affect other non-marine animals, such as birds, that rely on fish for food.
Overfishing can not only have an impact on marine life, but also on human life. An example of this is an incident that occurred in Newfoundland, Canada in 1992. At the beginning of the fishing season, the cod that used to frequent the water did not show up. Many of the people who depended on catching cod lost their livelihoods.
The problem of overfishing can have serious economic and environmental implications for the world at large. Governments around the world have conducted studies and enacted laws to reduce or prohibit overfishing. There are advocacy groups that encourage consumers to reduce demand for overfished species by purchasing fish that are fished sustainably.