The U.S. Trade Representative's Office has filed the first environmental complaint against Mexico for failing to protect the critically endangered vaquita marina, the world's smallest porpoise.

The office said Thursday it had asked for "environment consultations" with Mexico, the first such case it has filed under the U.S.-Mexico-Canada free trade pact. Consultations are the first step in the dispute resolution process under the agreement, which came into force in 2020.

Mexico's government has largely abandoned attempts to enforce a fishing-free zone around an area where the last few vaquitas are believed to live. Nets set illegally for another fish, the totoaba, drown vaquitas.

The complaint is meant to try and urgently push for tougher protections for the critically endangered vaquita porpoise, according to U.S. trade officials who spoke out on Thursday as Reuters reported.

In September of last year, the Center for Biological Diversity urged Mexico to respond to allegations that the government was not enforcing protections for the critically endangered porpoises. The decision was made by the Commission for Environmental Cooperation which is a part of the U.S. Trade Representative's Office and works under the United States-Mexico-Canada Agreement in this context.

In that report which was published on Sept. 9 2021, it stated that only 10 vaquita porpoises remained on planet Earth. The report said that the animal's extinction is imminent if Mexico doesn't start to enforce protections for the species.