If you were asked to name the world’s most popular fish, what would you guess? Atlantic cod? Yellowfin tuna? Or something else that ends up on dinner plates or in sushi rolls in New York, London and Tokyo?

It’s pretty safe to say you would not guess Peruvian anchovy, or anchoveta. But in fact, this small, silvery South American fish is far and away the world’s most popular catch, at least if measured by the tons reeled in and exported.

According to the United Nations Food and Agriculture Organization,
4.7 million tons

of Peruvian anchovy were caught in 2012, outpacing the second-highest catch Alaska pollock by more than a million tons. And that was a down year for the anchoveta, whose stock has seen sharp ebbs and flows over the years, due to environmental factors and overfishing. In 2011, fishermen netted 8.3 million tons of it. An El Niño weather pattern moving toward South America, however, could hit the fish hard again this year.

The reason you’ve probably never heard of the Peruvian anchovy, fished mainly off the Pacific coasts of Peru and Chile, is that most people consume it only in processed form. It’s used primarily to make fish oil and fish meal, much of which is used for animal feed. And it’s made the South American area the world’s biggest exporter of both products, which mostly end up in East Asia.

That economically important industry could be at risk if current patterns hold. Like many of the world’s fish species, the anchoveta is under assault, as climate change and the growing global fish consumption, particularly from China, have thinned the population. In recent years, the Peruvian government has stepped up regulations limiting the amount being caught, but has had trouble enforcing the laws.

Policymakers this month are trying to raise awareness about the shaky state of the world’s fisheries during World Oceans Month. The U.S. State Department is hosting a two-day conference this week to discuss policy solutions for this and other threats to the ocean ecosystem, one that billions of people rely on for food and employment.

Opening the conference on Monday, Secretary of State John Kerry noted, “The ocean today supports the livelihoods of up to 12 percent of the world’s population.

“No one should mistake that the protection of our oceans is a vital international security issue, Kerry continued. “It’s a vital security issue involving the movement of people, the livelihood of people, the capacity of people to exist and live where they live today.