Articles

A sand tiger shark—also known as a gray nurse or spotted ragged tooth shark—off the coast of North Carolina
 

Who doesn’t love a sand tiger shark? With their sleek silhouettes, rows of jagged teeth, but docile nature, sand tigers (Carcharias taurus) are a big draw for divers and underwater photographers along the east coast of the U.S. This is especially true off the coast of North Carolina, where sand tigers can be found lazily meandering among the many shipwrecks lining the Carolina coast.

Although sand tigers are a common sight in the waters of North Carolina, researchers actually know very little about them. Why do sand tigers congregate around wrecks? Why do we see so many females during the summer, but so few males? Where are sand tigers giving birth? What are their migration patterns? With so many unanswered questions, researchers have decided to enlist the public’s help with a new citizen science initiative: Enter Spot A Shark USA.
 

A sand tiger inside the wreck of the Aeolus. Scientists are trying to understand why sand tigers tend to aggregate around shipwrecks in the western mid-Atlantic
 

Spot A Shark USA was developed by North Carolina Aquariums, South-East Zoo Alliance for Reproduction & Conservation, and their affiliated research partners. The program is based on the fact that nearly every sand tiger has a unique spot pattern on its skin, akin to each human having unique fingerprints. And with so many divers taking photos of sand tigers every year, those photos can be used to identify individual sharks based on their spot patterns.

The premise is simple: A diver takes a photo of a sand tiger and uploads it to the Spot A Shark USA website, the software identifies the shark based on the spot pattern, and that specimen is then matched to a shark already in the database, or recorded as a new individual. This information can subsequently be used by researchers to study larger numbers of sand tigers than traditional methods, such as tagging and tracking, normally allow. But why study sand tigers in the first place?
 

Most sand tiger sharks have a unique spot pattern on their skin that can be used to identify individuals
 

Like many shark species, sand tigers play a vital role as apex predators that help keep the marine ecosystem in balance. Sadly, their numbers in the northwestern Atlantic had declined by an estimated 75% by the 1990s due to overfishing, being caught as bycatch, and habitat degradation.

Although sand tigers have been protected in U.S. Atlantic waters since 1997, their populations face challenges in recovery due to their having delayed sexual maturity (6 to 7 years for males, 9 to 10 years for females), long gestations (9 to 12 months), and the lowest reproductive rate of any shark species (giving birth to one or two pups every 2 to 3 years). By improving our understanding of sand tiger migration patterns and population distributions, conservation efforts can be better tailored to protect them.
 

Like many other shark species, sand tigers play a critical role in the health of marine ecosystems
 

So what do you need to do if you’d like to contribute photos of sand tiger sharks to Spot A Shark USA? First of all, don’t worry about taking magazine-quality photos. Photos taken with a DSLR, a compact camera, and even stills from a GoPro are all equally valuable. Most importantly, the photo needs to show the left or right side of the shark, taken at a 90-degree angle (in other words, straight-on from the side). The image should be properly exposed so that the spots on the shark are clearly visible in the image, with backscatter kept to a minimum, in high-resolution JPEG format, preferably no larger than 2MB.

Then just go to the Spot A Shark USA website, upload your image, and provide some basic information such as your name, contact information, and the date and location of the dive. Of course, the more details, the better, so if you’re a shark aficionado and know your males from your females, juveniles from adults, can identify pregnant females, or witness any interesting behaviors, there is room on the submission form to include this and any other information you think may be beneficial. Once your photos have been submitted, you can choose to be notified via email anytime the sharks you photographed have been spotted again. Submitted photos can also be viewed at any time on the website.
 

Photos submitted to the program should show either the right or left side of the sand tiger, with its spots clearly visible
 

Photos with multiple sand tigers may also be submitted as long as the image shows the spots on one or more of the sharks
 

If you would like to do even more to help sand tiger sharks, there is a link on the website to “adopt” a shark. Just select your shark from the online gallery of sand tiger image submissions, pay the adoption fee (which ranges from $2 a month to $1,500 per year), and then choose a name for your shark. The funds raised through shark adoptions are used to maintain the Spot A Shark USA website, along with its sister program Spot A Shark in Australia, and also support additional sand tiger shark research and conservation.

So what are you waiting for? Grab your camera and scuba gear, head out to North Carolina—the conditions this year have been outstanding!—enjoy some great shark and wreck diving, and save sand tiger sharks in the process. It’s a win for you, and a win for the sharks! 
 

A pregnant sand tiger shark. Researchers are hoping that information gathered through Spot A Shark USA can help them to understand where sand tigers mate and give birth
 

For more information, visit the Spot A Shark USA website at www.spotasharkusa.com.