Environmentalists are issuing dire warnings about the health of marine life on the high seas as a U.N. review of global fisheries opened today, according to AP. The review, held once every four years, is meant to address the declining numbers of fish stocks under a 1995 United Nations Fish Stocks Agreement. The legal framework among 77 nations that have joined is used to regulate tuna, swordfish and other migratory species that travel long distances. It also covers halibut, cod and other species that straddle the exclusive economic zones of coastal nations. A Pew Environmental Group study found that governments have been ineffective at stopping illegal fishing. Pew international policy director Susan Lieberman cited «the deplorable state of fisheries on the high seas» based on U.N. figures showing three-quarters of the world's fish stocks are overfished and said global fisheries could «crash» by mid-century.