Tiger sharks have a symbiotic connection with seagrass habitats, acting as the apex predator to prevent overgrazing by other species while patrolling the underwater meadows for food. Using cameras affixed to their backs, scientists investigating these species have used their free-roaming inclinations to map out the world’s largest seagrass system.
Viewing the ocean from the back of a tiger shark
The study was conducted by researchers at Saudi Arabia’s King Abdullah University of Science and Technology in partnership with the non-profit Beneath the Waves. The work originates from previous investigations on tiger shark conservation in The Bahamas. The scientists began attaching 360-degree cameras to the animals’ backs to learn about their behavior as part of their efforts to better understand the animal and guide future conservation approaches.
The scientists got some ideas after watching shark footage showing them skimming across enormous tracts of seagrass meadows in The Bahamas. These ecosystems are challenging to map since satellite observations might be affected by glare and diver surveys can only provide so much information. The observations collected by the wandering sharks, on the other hand, allowed the team to fill in the gaps left by these existing techniques, providing a more complete picture of seagrass coverage.
“The marine ecosystem in The Bahamas, which two decades ago I was able to admire in awe from a commercial plane, contains the largest sand banks in the world, which are shallow habitats perfectly suited to growing seagrass,” research co-author Professor Carlos Duarte said. “We thought that The Bahamas likely had an extensive seagrass ecosystem, but the true spatial estimate had never been properly quantified because surveying this vast area remains challenging.”
Discovering the world’s biggest plant
The team estimates the extent of the seagrass ecosystem to be between 66,000 and 92,000 square kilometers (25,000 to 35,000 square miles). The scientists were able to characterize the world’s largest seagrass ecosystem with the help of wild tiger sharks.
“Research led by Beneath The Waves had shown that tiger sharks spend about 72 percent of their time patrolling seagrass beds, which can be observed by the 360-degree cameras we deployed on the sharks, for the first time in marine animals,” Dr. Duarte added. “This provided an opportunity to expand ground-truthing across the vast, challenging depths of the Bahamas Banks, as tiger sharks cover about 70 kilometers (43 miles) in one day and are not constrained, as human divers are, to shallow depths.”
Seagrass meadows are key components of the larger marine ecosystem, fostering ocean biodiversity, protecting shorelines from storm damage, and acting as a significant source of carbon sequestration. They can also live for a very long time. Earlier this year, scientists discovered a unique 180-kilometer-long (112-mile) seagrass billed as the world’s biggest plant. That particular sample was assessed to be 4,500 years old, giving important genetic insights into how plants cope with long-term environmental changes.
The authors of this study feel that interacting with marine animals can help fill in the gaps in our understanding of the ocean ecosystem.
Source study: Nature Communications— Tiger sharks support the characterization of the world’s largest seagrass ecosystem