New Delhi, April 25 -- The single greatest threat to the diversity of life in our oceans over the past 50 years, more than climate change or plastic pollution, has been unsustainable fishing practices.

In much of the ocean, there is little to no regulation or oversight of commercial fishing or other human activities. That's part of the reason about a tenth of marine plant and animal species are considered threatened or at risk.

It's also why countries around the world have been creating marine protected areas.

These protected areas, covering over 11.6 million square miles (30 million square kilometers) in 16,000 locations, offer refuge away from human activities for a wide variety of living creatures, from corals to sea turtles and wha...