As shark populations decline, fish face less pressure from the top of the food chain. As a result, new research shows, fish are getting fatter.
Researchers from the University of Western Australia and the Australian Institute of Marine Science studied fish behavior in Rowley Shoals and Scott Reefs. The former, a marine preserve, hosts healthy shark populations. The latter, an atoll-like reef off the northern coast of Australia, is a popular location for shark fishermen from Indonesia.
The team of scientists observed reef fish spending more time hunting and feeding in the water column near Scott Reefs, where sharks are rare. Spending time in the water column puts fish at risk of ambush, but it’s also home to more energy-rich prey.
Fish living among Rowley Shoals were observed mostly hunting and feeding close to the coral reefs, where sharks are less abundant and escape routes are plentiful. Food here, however, is less calorie-dense.