"If you're overfishing at the top of the food chain, and acidifying the ocean at the bottom, you're creating a squeeze that could conceivably collapse the whole system." ~ Carl Safina
Overfishing is a form of overexploitation where fish stocks are reduced to below acceptable levels. Overfishing occurs when more fish are caught than the population can replace through natural reproduction. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, for example the overfishing of sharks, has led to the upset of entire marine ecosystems.
For our children to have future income and food we need healthy oceans and a healthy fishing industry. We need to create ocean sanctuaries to improve the state of our oceans and our fish populations.
Overfishing has significantly affected many fisheries around the world. As much as 85% of the world's fisheries may be over-exploited, depleted, fully exploited or in recovery from exploitation. Fishing fleets are heading to new waters because they have exhausted their old hunting grounds.
Examples of overfishing exist in areas such as the North Sea, the Grand Banks of Newfoundland and the East China Sea. In these locations, overfishing has not only proved disastrous to fish stocks but also to the fishing communities relying on the harvest. Faced with the collapse of large-fish populations, commercial fleets are going deeper in the ocean and father down the food chain for viable catches.
Populations of top predators are disappearing at a frightening rate. We have lost 99 percent of European eels, and 95 percent of Southern bluefin and Pacific bluefin tunas. About 80 percent of all the top predatory fish have gone from coastal areas of the North Pacific and North Atlantic. The sole fisheries in the Irish Sea, the west English Channel, and other locations have become overfished to the point of virtual collapse, according to the UK government's official Biodiversity Action Plan. The collapse of the cod fishery off Newfoundland, and the 1992 decision by Canada to impose an indefinite moratorium on the Grand Banks, is a dramatic example of the consequences of overfishing.
According to a 2008 UN report, the world's fishing fleets are losing US$50 billion each year through depleted stocks and poor fisheries management. The report, produced jointly by the World Bank and the UN Food and Agriculture Organization (FAO), asserts that half the world's fishing fleet could be scrapped with no change in catch.
Many regulatory measures are available for controlling overfishing. These measures include fishing quotas, bag limits, licensing, closed seasons, size limits and the creation of marine reserves and other marine protected areas.