That pact ultimately formed the core of the bill that passed last week. The bill's environmentalist supporters argue that free trade makes environmental sense, an idea that has been gaining currency among some environmental groups. According to Nina Young, a marine mammalogist with the Center for Marine Conservation, one of the bill's supporters, fishing methods that spare dolphins endanger other marine creatures. When fishermen set their nets around dolphins, the tuna they catch are almost all big, mature yellowfin. If tuna fishermen aren't allowed to pursue and net dolphins, warns Young, the by-catch will go up and damage those other species, and perhaps even tuna stocks.
Critics dismiss the by-catch argument.
While virtually nothing is known about whether the tuna fishery is hurting by-catch species, some tuna stocks, at least, are thriving in spite of the large numbers of juvenile fish being caught. Critics of the bill also doubt that Latin American fishermen are really keeping their dead dolphin count as low as they claim. Many of the observers who are supposed to tally the dolphins killed are almost certainly under intense pressure from ship captains, and perhaps their governments, to fudge their reports. Two Venezuelan biologists recently fled the country after being charged with treason. Their crime was reporting that Venezuelan shark fishermen killed 3,000 to 5,000 dolphins a year for bait.