International fishing authorities are cracking down on illegal drift-netting, an environmentally destructive method using nets that are more than 1.5 miles long and that indiscriminately catch all fish and marine mammals in their paths. Though driftnets — referred to by enviros as “walls of death” — were banned in international waters by the U.N. in 1991, rogue boats from Russia and several Asian countries continue to use them. Last month, the Canadian government — working with the U.S., Russia, and China — spotted and seized two boats that were using driftnets.