Tagging sharks is an effective way to learn about their migration patterns, but attaching the tracking devices to sharp-toothed predators is no easy task.
Danielle Haulsee would know. The researcher in the University of Delaware’s College of Earth, Ocean, and Environment has spent the past several years tagging dozens of sand tiger sharks caught off Delaware’s coast and analyzing the data collected.
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Haulsee will discuss her shark-wrangling experiences and the scientific lessons learned at a public lecture in Lewes Thursday, May 22, to kick off the annual Ocean Currents Lecture Series. The lecture will be held at 7 p.m. in Room 104 of the Cannon Laboratory at UD’s Hugh R. Sharp Campus, 700 Pilottown Road in Lewes.
Haulsee studies habitat preferences of sand tiger sharks migrating along the Atlantic coast. The species has experienced population declines in recent decades, which could disrupt the region’s natural ecological balance.
In an innovative approach, Haulsee, CEOE faculty member Matthew Oliver and their colleagues are using underwater robots, tagging techniques and ocean information from satellites to uncover patterns in the sharks’ behavior. They are aggregating huge amounts of data to find out which water conditions sand tigers prefer and create models that can predict where the sharks are likely to be.
The scientists use an underwater robot to “listen” for transmissions from the tagged sharks, and then use the device to track the sharks down to determine the water temperature, salinity and other properties at that location. Preliminary results suggest that during migration times, the sharks like being closer to shore in less salty waters, possibly using the environmental cues to help them navigate down the coast. The findings could potentially help improve conservation efforts.
Crunching the numbers and analyzing the data is not simple, and neither is recruiting sharks to participate in the study. Haulsee spends long days on a boat, setting fishing lines with menhaden as bait. When the team gets a bite, they haul the shark in next to the boat and make sure it’s big enough to wear a tag.
When flipped on its back, the shark enters a docile, catatonic state that makes it easier to attach a transmitter in a quick procedure that Haulsee was specially trained to perform. The team inserted the tags two years ago, and last fall they tried to get some of them back: They dangled a receiver in the water to see if any tagged sharks were nearby, tried to follow them and then tried to catch them again.
“We set the line, hope that the shark swims over and is hungry,” Haulsee said.
The researchers’ work has captured the attention of the public, having been featured on ABC’s "Ocean Mysteries with Jeff Corwin" and causing a media sensation when Haulsee posted a Facebook photo of a sand tiger shark swallowing a dogfish shark, which went viral.
Haulsee, currently a doctoral student in CEOE, majored in environmental studies and minored in biology at Gettysburg College. She conducted her senior thesis on blue mussels and decided to join Oliver’s lab at UD because of the intersection of technology with biological oceanography.
“I never dreamed that I would be working with sharks,” she said.
Haulsee’s lecture is free and open to the public, but reservations are required due to limited seating. They can be made by contacting Marcia Pettay at email@example.com or 302-645-4346. Light refreshments will be served.
Additional Ocean Currents lectures scheduled for this summer are:
June: Jon Sharp, automated water-quality monitoring and sampling onboard the Cape May-Lewes Ferry
July: Bill Ullman, real-time water-quality measurements on Delmarva
August: Jim Corbett, shipping impacts and innovation in the marine environment.
Go to www.ceoe.udel.edu for updates on dates and times.