Queen Elizabeth National Park is a place of outstanding beauty and extreme biodiversity. On a previous underwater assignment with my wife and photographic partner, Jennifer Hayes, we'd documented healthy coral reefs surrounded with fish, sharks, and crocodiles. We knew that time, increased tourism and climate change could make the park different—so 15 years later, we returned to see how it was going.

We were photographing some jellyfish. Jennifer, her back to me, was focused on something above her. Out of the corner of my viewfinder, I saw a sizable crocodile coming. As I began to take its photograph, I realized that the crocodile was going to swim directly between Jennifer and me. I started to make loud noises through my regulator and moved towards Jen, firing a burst of flash-lit shots to warn her that we had company. She quickly detected my signal and turned to meet our visitor. 

She gave me a quick thumbs-up, nodded OK, and said "Hello, handsome" as she bent closer to take its photos. I admired her for treating the crocodile with respect, calm curiosity, and absolute joy. She didn't feel threatened. She was familiar with this kind of crocodile in this particular place—and she had a big underwater camera housing that could double as a mighty shield (盾牌) if needed. After a few pictures the crocodile, unimpressed with us, swam downstream on its way to do other crocodile things. We continued our search for jellyfish.

There is always risk in our line of work. But this encounter highlighted the good news that we saw all around us here. The crocodile is an indicator animal, a symbol of a healthy ecosystem that can support top predators (捕食性动物). The easing of travel restrictions is bound to bring more tourists—so it's vital to maintain a balance among ecotourism, exploration, and conservation. That's possible if visitors adopt the same philosophy that we hold toward that curious crocodile. We enter Earth's oceans on their terms, not our own.