LISBON, Oct 19 — Juan Mayorga smiled as a stingray glided across his computer screen, moving gracefully over the seabed near Portugal’s Desertas Islands, part of the Madeira archipelago in the Atlantic Ocean.

“It’s a good day when we see animals like this,” said the Colombian environmental engineer, who is analysing underwater footage to measure the effects of marine protection.

“This is conservation in action,” said Mayorga, 36, who works for Pristine Seas, a marine conservation initiative run by the National Geographic Society.

“As we protect the place, year after year, fish get bigger and bigger and bigger, produce more and more babies, and that is protection working right there.”