The Gulf of California

One hundred and thirty million years ago, what we now know as Baja California Peninsula began drifting away from mainland Mexico.  As the two land masses separated, they created a large interior sea.  Five million years ago, the mouth of this sea began to open, allowing the cold waters coming from the North Pole (now known as the California Current) to mix in with the warm waters coming from the tropics (the Equatorial Current).  This mixing bowl created one of the most productive seas in the world: the Gulf of California, or Sea of Cortes, named after the famous Spanish conquistador.

Forage fish such as sardines, anchovies, and herrings are small species that sustain larger predators higher up in the marine food chain.  These forage fish comprise around ten species in the Gulf of California, forming immense shoals that move along coastlines and migrate across pelagic waters as they efficiently filter plankton.  Despite their small size, they number in the millions, and they feed all the top predator fish, seabirds, and marine mammals.  Sea lions, whales, and dolphins are some of the species that take advantage of these fish.  Their abundance is what makes it possible for this sea to be home of the highest concentration of cetacean diversity in the world.

Like no other region in the world, the Gulf of California supports a remarkable and singular diversity of species.  From rhodoliths—purple-pink spheres of seaweed the size of golf balls—to the largest animal that ever lived on Earth, the blue whale, the Gulf’s rich waters are home to more than 8,000 marine species.

This is an excerpt from the CEMEX Conservation Series Book Oceans: Heart of Our Blue Planet (2011)