More than 25 percent of the world's fisheries are overfished, according to the United Nations.Many communities worldwide depend on the ocean for their livelihoods.Now, they are struggling to manage resources. A growing number are adopting programs called "catch shares".These programs try to make fishing more sustainable but critics say they put many fishermen out of business.The sun is setting fast in Chesapeake Beach, Virginia. Rachel Dean is navigating her family's boat ‘Roughwater' into the port there."The deck light."She and her family make a living by fishing. There are rules that all fishermen must follow.The old rules set by regional fishery officials' decided how many striped bass fish could be caught in the Chesapeake Bay each year. Rachel Dean explains."It was a fishing derby and it was, Green light, go.' Catch all you can and hope that you get your share of the pie."This would lead fishermen competing to catch fish as quickly as possible.It also led to overfishing, unsafe and destructive fishing, and other problems.But last year, officials launched a "catch shares" system for striped bass in the Chesapeake.