A great example of how data crowd-sourced from Citizen Scientists is helping to improve understanding of shark populations and behavior.
Site fidelity – the tendency to return to a particular area – isn’t exactly new in a species of shark (e.g. reef sharks, lemon sharks, even great white sharks). But that place is usually some sort of habitat… not a over 100-feet (34 meter) deep shipwreck. However, that is exactly the case for female sand tiger sharks (Carcharias taurus) off the coast of North Carolina!
Sand tiger sharks, also known as grey nurse sharks or spotted ragged-tooth sharks, are found globally in subtropical and temperate waters. Despite looking quite scary due to their tooth grins that never quite close, they are a slow-moving shark that are listed as Vulnerable by the International Union for Conservation of Nature (IUCN). A grey colored shark with reddish-brown spots throughout its body, they feast on a variety of animals such as a fish, crustaceans, squid, skates and even other sharks!
In September 2016, a citizen scientist wasn’t surprised to see an individual female sand tiger shark while scuba diving on the Aeolus shipwreck.Sunk in 1988 as part of North Carolina’s artificial reef program, she used to be a USA Navy attack cargo ship named “Turandot” until the mid 1940’s. Measuring over 409 ft (125 m) long, it is known to be a prime site to spot these sharks that are known to be able to gulp air and effortlessly suspend themselves in the water column. The coastal waters of North Carolina are known as the ‘Graveyard of the Atlantic’ due to being a permanent resting grounds for hundreds of shipwrecks. “Sand tiger sharks are known to aggregate around these wrecks, but it was unknown whether the same individual sand tiger sharks returned to these wrecks over time,” said marine ecologist Dr. Avery Paxton who was a postdoctoral researcher with the South-East Zoo Alliance for Reproduction & Conservation during this research.
Snapping a picture of the shark, the citizen scientist submitted it to the Spot A Shark USA research program, established by North Carolina Aquariums in June of 2018 to study wild sand tigers. “Using the spot pattern on the side of each shark we can identify individual sharks. Identifying individuals over time helps us understand many aspects of their biology such as how fast they grow, how long they live and changes in the population size,” said Dr. Jennifer Wyffels, research scientist with the South-East Zoo Alliance for Reproduction & Conservation leading reproductive research on wild and aquarium sand tiger populations. “A consortium of aquariums and the South-East Zoo Alliance for Reproduction & Conservation have been working collaboratively for nearly four years to understand more about the life of sand tiger sharks.”
The photographer didn’t think of the individual shark until 10 months later. In July 2017, the same photographer returned to the same shipwreck and captured another photograph of the same shark! And she wasn’t the only one! The photos collected by citizen scientists for Spot A Shark USA documented six female sharks returning to the same or nearby shipwrecks. “Our team’s finding adds to a growing body of evidence that shipwrecks are important habitat for a variety of species, including large predators like sand tiger sharks,” Paxton reiterated. “We do not know the exact reason that female sand tigers are returning to the same shipwrecks over time, but our multi-institutional team is conducting additional research to hopefully solve this puzzle.”
A common misconception about the scientific field is that it is only for highly trained, professionals but that isn’t the case. Citizen scientists can have been incredible asset to the scientific community in a myriad of ways, from engaging in research to helping with data analysis. “Studying an entire population of animals is a monumental task, especially when that population lives underwater. Its only possible in this case because the diving community can become citizen scientists and collect data in the form of photographs,” said Hap Fatzinger, Director of the North Carolina Aquarium at Fort Fisher and Program Leader for Saving Animals From Extinction: Sharks and Rays Program for the Association of Zoos and Aquariums (AZA). “Spot A Shark USA formally connects scientists with professional and recreational divers in the local community and leverages information from something they enjoy, taking images of sharks on shipwrecks. Communicating the scientific findings of the work to the public closes the loop on the scientific process.”
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