Fishy Find: The Shark-Tracking Device That Washed Up on the 25th Street Beach

This device was attached for 28 days to a sandbar shark.

It was intended to be a casual walk on the beach on a beautiful late summer day. Or at least that was what Robin Schall assumed when she left her Avalon home on Sept. 21 and headed for the beach. She was around 25th Street when she spotted something unusual along the surf line.

“I picked it up because I was concerned that someone may step on it,” Schall says. “I was taking it to a trash receptacle but first showed it to my husband, Steve, who noticed Dr. Dunton’s contact information on it. So, obviously we contacted him.”

Robin Schall displays the S-PAT she found on 25th Street Beach.

It might look like a lightbulb or even an old radio tube, but what Schall found was part of a scientific experiment at Monmouth University. It is what is referred to as an S-PAT, which was attached to the dorsal fin of a shark. The device is intended to stay attached to the shark for 30 days and then pop up to the surface so that it can be returned with a full 30 days’ worth of data. The tags are intended to record demographics, survivorship, and post-release behavior of sharks captured in a land-based recreational shark fishery.

It turned out that this S-PAT had been attached for about 28 days before it released in the Delaware Bay and then floated around the cape to Avalon’s 25th Street beach. It was attached to a 112-centimeter sandbar shark (Carcharhinus plumbeus) on July 21. After the S-PAT popped off, it floated until it stopped transmitting on Aug. 21, and it was found by Schall a month later. This was one of two such devices found on a Seven Mile Beach this summer. It’s important to report the finding of any of these devices.

Dr. Keith Dunton is a sturgeon biologist at Monmouth University and its Urban Coast Institute. He and a group of his students have spent the past three years working on getting a better understanding of the migration and movement of the sharks that are native to New Jersey. Over the last two years, they have tagged nearly 100 sandbar and tiger sharks. Once tagged, they can follow the habits of the shark along the Atlantic Coast for up to a decade. They have already learned that these “local” sharks often head south for the winter and can travel up and down the East Coast.

Tagging is a highly coordinated process that takes only about four or five minutes. Once the shark is caught along the beach using traditional surf tackle, it is quickly cradled into a water-type stretcher and brought to the beach. Once ashore, the shark is examined, and any visible parasites are removed. Then, a 2-centimeter suture is made, and an acoustic transmitter is inserted in the shark’s abdominal cavity. The incision is then closed using medical-grade sutures. The shark is given a final brief medical exam before it is released back into the surf.

Tagged sharks have been tracked from Cape Cod to North Carolina. Receivers along the shore allow sharks to be tracked from Nova Scotia to the Gulf of Mexico. Data collected helps Dunton and the Urban Coast Institute understand more about the species of shark along the New Jersey coast, which have rarely been studied and which Dunton wants to work with local fishers to protect and conserve.

Dunton’s research is interesting and especially relevant to sport and surf fishers on our barrier island. To learn more about his work, visit monmouth.edu.