THE BAHAMAS-Tiger sharks are well known for their aggressiveness. These sharks are ferocious predators that may grow to be more than 16 ft long. Recent research revealed that although other shark species avoided coastal areas during big storms, tiger sharks "didn't even flinch."
However, they now have a new position that might help them improve their reputation and image: marine scientists. Researchers affixed cameras and trackers to the dorsal side of tiger sharks to obtain access to hours of ocean bottom footage to quantify the size of seagrass beds in the Bahamas.
The data they obtained revealed the world's biggest known seagrass ecosystem, ranging from 92,000 square kilometers (35,000 square miles) of Caribbean seafloor, following the researcher's report. Based on the research released in Nature Communications dated November 1st, this discovery increases the worldwide seagrass cover by more than 40%.
Millions of Square Kilometers of Seagrass
This discovery demonstrates how far we are from exploring the seas, not just in the depths but also in shallow places, according to the report's co-author, professor Carlos Duarte of Saudi Arabia's King Abdullah University of Science and Technology.
Seagrass meadows have long been understudied, with estimates ranging from 160,000 to 1.6 million square kilometers. Mapping is extremely difficult: meadows in deep or foggy water cannot usually be seen by aircraft or satellites, and smaller ones might be sparse or intertwined with other marine plants, making identification difficult. It thus implies that seagrass meadows must be "ground truthed," which means anyone must validate them - or anything - on the surface. However, deploying sentient divers to photograph broad swaths of the ocean floor is extremely expensive, logistically difficult, and time-consuming, as reported by The Byte.
Tiger sharks, on the other hand, are an entirely different story. The extremely active creatures have a wide range but also spend much time on seagrass meadows. They're also free of commonplace human restraints like the requirement for a boat, the need to surface regularly, and the dependence on calm ocean circulation. Researchers attached camera packages connected with satellites and radio tags to the dorsal fins of 7 sharks between 2016 and 2020. The animals were captured using circular hook drumlines that hooked into the animals' mouths.
Oliver Shipley, a senior researcher at Beneath The Waves, a marine scientific non-profit and co-author of the article, says it is the "safest approach to catch sharks" and produces no long-term damage. They enticed the animals to attach the cameras in an activity Shipley compared to a "Nascar pit crew." Each bright orange camera takes 10 minutes to attach using biodegradable wire ties and a dissolvable time-released hinge. The swivel decayed in the seawater after approximately six hours, and the entire package drifted to the water, whereupon scientists could retrieve it.
Seagrass Benefits in Marine Wildlife
In a statement from The Guardian, Richard Unsworth, an assistant professor at Swansea University and the creator of Project Seagrass Charity, using marine species like this creates a window into the aquatic environment and can assist in answering concerns about the climate and biodiversity problems. Unsworth, who was not engaged with the study, believes mapping seagrass is critical. He explained that we couldn't safeguard it if we don't know where it is.
Many marine species rely on seagrasses for nursery and feeding grounds, and they also sustain commercial fisheries and act as a barrier against coastal erosion. They are also a huge source of "blue carbon," capturing and storing massive amounts of carbon dioxide in the seafloor, making them an important instrument in climate change mitigation.
Nonetheless, they are under threat from several sources, notably boating but also shipping, coastal development, and more severe extreme weather. Every year, around 7% of the world's seagrasses are lost. Over the last few centuries, the United Kingdom has lost 90% of its seagrass meadows.
The researchers hope their discovery may lead to greater safeguards for seagrass not only in the Bahamas, where it is endangered by excavation for coastal development and a push to mining for aragonite but also globally. Shipley believes that seagrass and other coastlines are among the strongest allies and assets in organically attempting to alleviate the consequences of climate change.
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