Published: Fri, September 07, 2018
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Side of seagrass please: Scientists find omnivorous shark

Side of seagrass please: Scientists find omnivorous shark

"Bonnetheads are capable of digesting components of seagrass, with similar effectiveness to omnivores, making them the only shark species known to have the ability to digest plant material".

Scientists at the University of California in Irvine, and Florida International University in Miami, made a decision to investigate the sharks' dietary habits after reading reports of the fish chomping on seagrass, the flowering marine plant that forms subsea meadows in some coastal waters.

Samantha Leigh, who headed the four-year study at UCI's School of Biological Sciences, said she hopes the discovery will help protect seagrass ecosystems that are at risk from climate change. "We have never seen a shark consume this seagrass, let alone that's able to digest it".

By working with five sharks in captivity over three weeks, the researchers ran a test involving feeding the sharks a diet of 90 percent seagrass and 10 percent squid.

"Understanding how the consumption and digestion habits of bonnethead sharks impact seagrass ecosystems is important as these omnivores may stabilize food web dynamics and even play a role in nutrient redistribution and transport", the study reads.

"Finally, we determined which types of digestive enzymes (enzymes are used to break down food molecules) the bonnethead sharks possessed", Leigh told Gizmodo.

The bonnethead shark, a relative of the much larger hammerhead shark, munches on seagrass for about 60 percent of its diet and has a gut capable of digesting greens-similar to that of juvenile green sea turtles and even better than those of pandas, scientists say in a study published September 5 in Proceedings of The Royal Society B.


They have a fearsome reputation as bloodthirsty monsters of the deep, but some sharks are actually quite happy to munch on greens, U.S. scientists have discovered.

The bonnethead shark is commonly found in the shallow waters of the Western Atlantic, Eastern Pacific, and the Gulf of Mexico.

According to United States researchers, one of the most common sharks in the world, a relative of the hammerhead which patrols the shores of the Americas, is the first variety of shark to be outed as a bona fide omnivore.

The smallest of the ten hammerhead species, bonnetheads are typically about 2 to 3 feet long.

For one shark subspecies, this fictional scenario isn't actually too far from the truth, according to a new study published inProceedings of the Royal Society B. But not all sharks are so blood thirsty, and a new study reveals that at least one species actually eats lots and lots of leafy greens. Some, like the bonnethead shark, prefer to munch on seagrass.

We show that a coastal shark, previously thought to be exclusively carnivorous, is digesting seagrass with at least moderate efficiency, which has ecological implications.[within] fragile seagrass ecosystems.

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