The U.S. Marine Mammal Protection Act requires the federal government to ban seafood imports from fisheries that kill marine mammals, like the Vaqui¬ta porpoise, in excess of U.S. standards for marine mammal bycatch (the accidental entanglement and deaths of marine mammals in fishing gear).
Illegal fishing with gillnets in Mexico's Gulf of California is rapidly causing the extinction of the Vaquita porpoise, with less than 30 porpoises left.
The porpoises are becoming extinct because the Mexican government won't enforce its laws. It is simply not a high priority and the poachers are able to easily bribe or threaten officials who do attempt to enforce.
A ban against Mexican seafood would compel the Mexican government to enforce its laws and ensure that gill nets are not used in the Vaquita's habitat.
Sea Shepherd is currently working with the Mexican government with their Operation Milagro IV to patrol the Vaquita habitat and keep poachers out. In their last campaign they removed 233 illegal fishing gear, 1195 entangled dead animals - including sharks, dolphins, whales, turtles and sea lions – and released 795 live ones. Five dead Vaquita were discovered by Sea Shepherd during this campaign, their deaths attributed to being caught in illegal gillnets.