Andrej Gajić usually dives alone. At night. In shallow, murky water. He dives in this setting because that’s where and when he’ll find sharks. And Gajić needs to find sharks.
Gajić is more than just a diver. He’s a National Geographic Explorer and a marine biologist. His goal is to understand the effects of pollution on sharks and skates and rays (flat fish closely related to sharks). To do this he needs to work both in a lab and in the water.
Many of Gajić’s dives take place at Neum Bay on the Adriatic Sea. It’s a hotspot for sharks, rays, and skates. It’s also a good place to observe these nocturnal creatures.
The bottom of Neum Bay is only about 30 meters (98 feet) below the surface. The water here is thick with sediment and colonies of plankton—small organisms that float in the sea. Gajic can’t see his hands in front of his face. He lets his eyes adjust. Then, he can make out some shapes.
His video camera carries a powerful light. He switches it on. Then he sees them. Smoothhound sharks swim in circles near the seabed. He knows he must avoid sudden movements.
Gajic examines an unborn smoothound shark, searching for signs of deformities.
A lesser spotted dogfish rests on the seabed.
Be watchful! That’s Gajić’s advice. Most of the marine animals Gajić encounters have no interest in people. They are not likely to attack. But his presence must
not cause stress to the animals. He pays close attention to the body language of the sharks. Is he seeing any sudden movements toward him? No. The sharks appear curious but not threatened by him.
As they swim around him, he looks closely at their jaws and teeth. He studies their gills, skin, and muscles. He’s looking for any signs of disease.
Gajić spends close to an hour in this silent world. To his eye, the sharks appear healthy. But to truly know, he needs to look much deeper.
Sharks in the Adriatic
There are 33 species of sharks in the Adriatic Sea. Catsharks, dogfish, and smoothhounds are the most abundant. These sharks are fairly small and like to stay near the ocean floor.
In the open water, Gajić’s team has encountered elegant blue sharks, as well as lightning-quick mako sharks. Makos may have bursts of speed up to 18.8 meters a second (68 kilometers or 42 miles an hour).
The thresher shark has a tail fin that grows up to 3 meters (almost 10 feet). It stuns its prey with its tail.