Posted on 12/17/2021 8:20:55 AM PST by Capt. Tom
SHARK’S-EYE POINT OF VIEW
New video tags allow researchers to hitch a ride with massive predators off Cape
CHATHAM – If a picture is worth 1,000 words, shark researchers have found that a video can answer 1,000 questions.
Atlantic White Shark Conservancy scientist Megan Winton was reviewing footage from the first year of video tagging when she came across a newly tagged great white shark that had just eaten a seal — telltale sign: seal intestines hanging from its gills — and was resting on the bottom of the ocean.
Winton was initially disappointed they had missed the actual predation, something they have only rarely seen, but fascinated at witnessing the fairly unusual behavior of a shark taking a postmeal lie-down to rest and digest. The instruments on board the tag confirmed what they were witnessing, that the big animal wasn’t moving and had pointed itself into the current so that oxygenrich water could flow over its gills.
“The whole goal (of the grant-funded project) was to characterize predatory behavior,” Winton said. But this resting behavior was something entirely unexpected. She said her mind started racing to other datasets collected during conventional acoustic tagging and adding this observed behavior to explain some of the anomalies and unknowns.
It’s like looking over their shoulder as they do what sharks do. While there is the occasional attack on a seal or dogfish, mostly they’re just cruising, looking for that next meal.
“We don’t actually get to spend a lot of time watching what sharks do,” Winton said. “It makes me very excited to be a scientist right now because (the technology) is going to keep getting better.”
In 2019, the conservancy and state Division of Marine Fisheries shark researcher Gregory Skomal used a grant from Save Our Seas Foundation to purchase two video tags. Costing around $10,000 each, the tags are football-sized, look like a hot pink version of the snack cracker Goldfish, and are tethered to a great white shark by a thin steel cable attached to a surgical steel tip embedded at the base of a shark’s dorsal fin using a harpoon.
It’s the same method Skomal has used for years to put acoustic tags on
hundreds of great whites.
Since the Atlantic White Shark Conservancy began funding the effort in 2013, Skomal, working with volunteers and staff from the conservancy, has tagged 250 white sharks. This past tagging season, which runs from spring to late fall, they put acoustic tags on 39 sharks.
See SHARKS, Page 5A
RIGHT: This $10,000 CATS tag, attached temporarily to a dorsal fin, went missing during the nor’easter that slammed into the Cape.
TOP: Neptune was one of eight great white sharks tagged last season with a hot-pink device called a CATS, which includes a camera to record the shark swimming and sensors to collect data such as light, pressure and acceleration. The tags pop off the sharks, usually after 48-72 hours, and are recovered by the research team.
Sharks
Continued from Page 1A
Skomal also attached the new video tags to 10 of those sharks in 2021. While the acoustic tags just broadcast a unique identifying signal picked up by nearshore receivers mounted on buoys all along the Cape and Atlantic coastline, the video tag does much more than film the shark.
These pink footballs contain an accelerometer that can measure and record changes in speed and a gyro that can discern body orientation — whether a shark is nose-down diving, or nose-up ascending, for instance.
Other instruments record location, depth, water temperature and light. It’s like a Fitbit for sharks, Winton said.
Altogether, the tag records a million data points, including 11 hours of video and 48-72 hours of information from the other instruments before the cable is automatically severed and the tag floats to the surface. That’s an information bonanza, but it comes with a downside.
Much like they did with the video information they record using underwater cameras on long poles, which help Skomal’s team identify the sharks they encounter, the huge volume of data coming from the video tags has to be processed, entered and analyzed.
Processing video data taken during the five-year tagging portion of Winton’s white shark population study, completed in 2018, has been the biggest hurdle to getting the study completed and published.
“We have our work cut out for us this winter,” Winton said. “It’s the way it goes.”
But the first project to tackle now that tagging season has ended is the completion of a Woods Hole Sea Grant-funded study that matches tagging data with environmental data to see how conditions like water temperature, currents and water clarity affect whether a shark will be at a certain location. That analysis will be used to build a predictive model that could help educate water users on when a shark is more likely to be at a specific beach.
Then comes the completion of the long-awaited five-year population study that is attempting to put some numbers on how many great whites come to Cape waters — and maybe
a sense of the greater white shark population.
Winton said the research the Atlantic White Shark Conservancy and Skomal does involves collaborative studies with scientists from elsewhere.
“A lot of people don’t realize that our work here is informing research throughout the region,” Winton said.
The other issue with the video tags, known as CATS tags (the company name is Customized Animal Tracking Solutions), is that they have to be retrieved for the information to be downloaded. Sometime after the camera memory is filled, the tag severs the tether, floats to the surface and streams a locator signal via satellite.
Sharks can travel, and while most tags have been retrieved in local waters, this past summer Winton and Skomal had to travel to Rockland, Maine, and hitch a ride on a mail boat to pick one up. Retrieval is important not only because of the data they contain, but because these expensive little footballs get used over and over.
Skomal’s team lost one during the big nor’easter that hit the Cape region in late October. It popped up in bad weather and was blown to the southwest, hit the Gulf Stream and was gone, Winton said.
“We’re hoping someone will find it on the beach in Portugal,” she said.
The weather has closed them down even though a few white sharks remain in this area.
We will have to wait for late May or early June for white sharks to come back to Cape Cod. -Tom
Shark Cameras...The next best thing to lasers. ;)
There is just so much we can learn from Great White Sharks.
Their research on Covid is amazing.
The shark season is just about over, and the biologists will be working on the information gathered this winter.
Information gathering will start up again when the white sharks show up on Cape Cod in this coming end of May or June. -Tom
And my mind started racing about what fun Megan must be on a date. Imagine the conversation turning to her excitement about sharks resting on the ocean floor with seal guts hanging from their gills. I wouldn't be able to contain myself!
My only concern with this technology...
What’s to keep the Chinese shark fin soup fishermen from using the ping signal to track and capture the sharks?
IO’m not talking about the caps that pop off, but there is even a real time map (https://www.ocearch.org/tracker/) you can zoom into to find where these tagged sharks are.
Where do they go in the winter? Miami?...............
We have had a nice fat 15 footer show up here . Probably following calving Humpback whale pods. Knocked the two front teeth out of a surfer it rushed. How’s that for a close call? Dentist Whitey....
Thank you for the update, Capt. Tom...:)
Always appreciate the information.
There will be some pressure put on our local shark biologists on Cape Cod to come up with more information as to what white sharks are doing.
That pressure will come from “OSEARCH”, that has been trying for many years to get into Mass. waters to do some white shark research. The State has kept them out of Mass. waters for doing white shark research, but they are still trying to get in here.
You can read about the beef from the link below. -Tom
https://www.bostonmagazine.com/news/2021/09/29/shark-research-feud/
I recall that sharks do not get cancer.
It’s all that saltwater they drink.
Shark antibody-like proteins neutralize COVID-19 virus, help prepare for future coronaviruses
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