For a moment, let's imagine that 80,000 miles of Texas interstate and U.S. highways, state and local roads, and rural farm roads are the responsibility of the Texas Highway Patrol, and that the THP has one, single, lonely patrol car.That will give you an idea of what the Republic of Palau was up against, with its near-Texas-sized marine sanctuary and one patrol boat. Twenty percent of Palau's near-shore waters surrounding its 250 islands in the western Pacific are reserved for domestic fishing. The outlying 80 percent is a no-take zone for any fishermen. Eco-tourism, particularly diving on Palau's many coral reefs, is an economic staple, and is a major economic incentive for the sanctuary. Critics have said that well-heeled tourists, rather than Palauans, are the main beneficiaries of the sanctuary law.Contributions from non-government groups have bolstered the one-ship Palauan Navy's efforts to enforce the fishing ban. Satellite surveillance led to a spectacular, headline-grabbing bust of a 15-boat Vietnamese pirate fishing fleet in 2015. Palau torched four of the captured boats to send a "keep-out" message to other prospective pirates. It sent 77 sailors back to Vietnam on the boats they rode in on.The other areas, like Chagos and an Australian reserve in the Coral Sea, have faced similar charges of elitism. So did Yellowstone in the 1870's, and recently, as neighboring ranchers see the reintroduction of gray wolves and bison as a menace. A proposal for New Zealand's Kermadec Islands was shelved by prime Minister Jacinda Ardern after complaints from Maori natives over the loss of commercial fishing rights. Australia's vast Coral Sea Marine Park overcame harsh resistance by cutting deals with recreational fishing guides. The biggest U.S. triumph to date is the Papahānaumokuākea Marine National Monument, covering the chain of uninhabited islands that stretch a thousand miles to the northwest of Hawaii. While history will remember President George W. Bush as having a poor environmental track record, marine sanctuaries were an exception. He created Papahānaumokuākea in 2006, and President Obama enlarged its footprint in 2016. As conservation measures, marine reserves look good now. There's every chance that, a century from now, they'll look like we've added some wisdom to our oceans, and not just plastic, acid and icemelt. Editor's note: For two years prior to joining EHN/Daily Climate, Peter Dykstra worked for the Pew Charitable Trusts, which promotes and funds marine reserves.