Reef Sharks Have Remarkably Small Appetite
As some of the ocean's top predators, you would think sharks have a voracious appetite. But this is not the case for many reef sharks, who for the most part consume remarkably small prey.
In the latest study from James Cook University's ARC Centre of Excellence for Coral Reef Studies, researchers analyzed the stomach contents of reef sharks and conducted chemical analyses of their body tissue to find out what the animals had been eating.
"We were surprised to find a broad range of small prey items such as fish, mollusks, sea snakes, crabs, and more often than not, nothing at all," Dr. Ashley Frisch, lead author of the study, said in a news release. "These results suggest that reef sharks eat small meals infrequently and opportunistically."
After pumping the sharks' stomachs to identify their last meal, researchers were interested in what the animals were eating over longer periods of time. To answer this question they analyzed the sharks' body tissue.
"Although black-tip, white-tip and grey reef sharks have long been thought of as top predators, we found that the chemical structure of the sharks' body tissue actually matched closely with that of large reef fishes such as groupers, snappers and emperors," Dr. Frisch explained. "This result tells us that reef sharks and large fishes have a similar diet, but they don't eat each other. So rather than eating big fish, reef sharks are eating like big fish."
Their findings, recently published in the journal Coral Reefs, provide a better understanding of how changes in one marine population may impact another.
"We now know that reef sharks are an important link in the food chain, but they are not the last link in the food chain. In most cases, the top predators are tiger sharks, hammerhead sharks, or people," co-author Dr. Justin Rizzari added. "Coral reef ecosystems are very complex. The more we look, the more we realize that each and every species plays an important role. Sharks are no exception. They help to keep coral reefs healthy and should be managed wisely."
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