A fishery is an area with an associated fish or aquatic population which is harvested for its commercial value. Fisheries can be marine (saltwater) or freshwater. They can also be wild or farmed. Wild fisheries are sometimes called capture fisheries. The aquatic life they support is not controlled in any meaningful way and needs to be "captured" or fished. Wild fisheries exist primarily in the oceans, and particularly around coasts and continental shelves. They also exist in lakes and rivers. Issues with wild fisheries are overfishing and pollution. Significant wild fisheries have collapsed or are in danger of collapsing, due to overfishing and pollution. Overall, production from the world's wild fisheries has levelled out, and may be starting to decline.