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The Sea of Cortez is a dazzling pageant of nature. Scientists say this narrow sea between the Mexican mainland and the Baja California peninsula is one of the most biologically diverse bodies of water on the planet, home to more than 900 species of fish, thousands of species of invertebrates, and a wide array of marine mammals like sea lions, dolphins and whales. The late French explorer Jacques Cousteau once called the Sea of Cortez the world’s aquarium.

But decades of overfishing and commercial development have taken their toll, dramatically reducing the number of fish in the sea and causing widespread devastation by pollution. The Sea of Cortez, also known as the Gulf of California, has been in the news recently because of a new report documenting the decline of the vaquita, a rare species of porpoise endemic to the northern part of the gulf. It is the world’s most endangered marine mammal, and its recent decline is staggering.

Fishing boats using gill nets to catch an endangered fish called the totoaba, whose bladder is considered an expensive delicacy in China, also trap the vaquita, often killing them. As a result, just 60 vaquitas remain in the gulf, down from 500 some 20 years ago. In April, 2015, the Mexican government passed a two year ban on the deadly nets, but three dead vaquitas were discovered, trapped in nets, in March.

Over the last decade, the Mexican government has tried to crack down on polluters and reduce overfishing. Numerous marine reserves and national parks have been created to heighten awareness and create some kind of government protection. But poaching remains a massive problem, as large portions of the Baja peninsula’s population depend on fishing for their livelihoods.

For now, dolphins and manta rays still leap majestically from the sparkling water. Beneath the surface, a kaleidoscope of colorful tropical fish like the rainbow wrasse and butterflyfish swarm around mounds of golden coral. But if the Sea of Cortez is going to remain a jewel of the North American continent, a much more serious effort to conserve this marine ecosystem will be needed. More rangers are needed to enforce laws already on the books, and new regulations should be put in place to expand marine protected areas and reduce fishing. Otherwise, the Sea of Cortez and its marine life face a perilous future.