Types of Baby Sharks in Cape Cod Bay
It'southward not like nosotros didn't suspect information technology was true, but a new report past the country Sectionalization of Marine Fisheries, Atlantic White Shark Salvation and Arizona Land University researchers revealed that sharks visiting Cape Cod spend nearly half their time here in shallow waters that are also used past millions of waders, body surfers, swimmers and others each summer and fall.
"It's no secret that white sharks are shut to shore. It'southward one thing to say that, simply another to back it up," said DMF shark researcher Greg Skomal, ane of the co-authors of the study forth with conservancy scientist Megan Winton and Arizona State researcher James Sulikowski.
The report, published March 18 in the online journal "Wild animals Research," examined data generated past eight great white sharks that were fitted with a satellite tag that recorded water depth and temperature and an acoustic tag that broadcast an identifying signal that could exist recorded by over 80 receivers mounted to buoys beyond the surfline at beaches from the Rhode Isle to New Hampshire borders.
What is the shark population on Cape Cod?
The majority of the receivers are located on the Cape, which has become home to one of the largest concentrations of great white sharks in the world. The sharks come to feed mainly on gray seals that have recovered to number in the tens of thousands in Southeastern Massachusetts, particularly on Chatham'south Monomoy islands.
Although the sample size was small, the results were corroborated past a number of white shark studies on preferences in habitat, environmental conditions and predatory behavior conducted in other hot spots around the world.
"The big take-home is that they spend a lot of their time in shallow water," Winton said. "It's powerful to have a number."
Over a million information points analyzed from eight white sharks revealed that all but one stayed in the Cape Cod area for the entire 28-day period the tags remained fastened. They swam in water temperatures that ranged from 48-69 degrees Fahrenheit, and spent an boilerplate of 47% of their time in water less than 15 anxiety deep.
"We got so many pings (detections) off our buoys last summer information technology was ridiculous," said Suzanne Grout Thomas, Wellfleet customs services managing director and embankment ambassador.
The real-time buoys sent alerts to public condom personnel, beach administrators and lifeguards when a point from a tagged shark was detected. Thomas said lifeguards were endmost the beach to swimmers sometimes four or five times a twenty-four hours.
"I recall my perspective is not that of the average beachgoer, so I'one thousand not surprised (by study results)," Thomas said. "I would not be surprised if the average beachgoer was shocked."
Sharks take superior night vision
The written report also constitute that these nifty whites were less likely to be in shallow waters in twilight hours than during the 24-hour interval, but frequented shallow waters the most at night, especially during the new moon, when their superior night vision gave them an advantage over seals.
More:Sharks and seals: Here'due south what you lot need to know about the animals off Cape Cod
More:Corking white shark research consortium
Other studies showed that Cape seals tended to remain close to shore during the day, potentially drawing sharks into shallow waters, and ventured into the open sea under cover of darkness to feed.
The information indicated sharks were less probable to be close to shore at nighttime during a full moon, possibly considering they no longer had that visual border over their casualty.
Simply researchers cautioned that the pocket-sized sample size and short time span that animals were tagged meant that these results require more than enquiry to truly depict conclusions about white shark response to environmental atmospheric condition.
Skomal said the study told him that information technology must be worth information technology for big sharks to risk beaching to venture into shallow areas. Great whites do not hunt past sitting on the bottom waiting for prey to swim to a higher place them, though they do swim generally near the bottom, cruising slowly, looking to ambush casualty from below. Their hunting techniques are learned through experience, and in the Cape'due south shallow waters they have adjusted to attack seals laterally.
"You lot come in close to shore, that'due south a very dynamic environment," Skomal said. "You lot are at hazard if you are a big fish, but the benefits must outweigh the risks if there'due south i hell of a adept meal at that place. (A shark will) risk it, and chance it often, because the payoff is quite big."
Although they didn't have respective body of water state data, Skomal said that rough surf in the surf zone would tend to discourage neat whites because it would take too much energy to make the hunt worth it.
Winton and Skomal said the study was a outset step in what they hoped would exist the conclusion of a number of studies underway that could make full in pieces of the shark behavior study and contribute to public safety. Forest Hole Sea Grant has funded research that will merge existing data from over 200 tagged sharks with satellite temperature and water clarity data to determine the weather under which they prefer to hunt, in terms of the rest between their visual ability to see prey only not exist seen.
What practice white sharks practise in the shallows?
Another study washed in collaboration with the Center for Coastal Studies will continue this summer. While the recently published research paper speaks to white sharks spending a lot of time in shallow h2o, this written report will wait at what they do there by using a grid of acoustic receivers set off Head of the Meadow Beach in Truro and one off Nauset Beach in Orleans to determine exact depth and position, forth with specialized tags that mensurate acceleration and trunk position equally the shark hunts seals.
All-encompassing mapping of the lesser at these locations volition tell researchers how the sharks use bottom features such as channels and sandbars to travel and hunt, which will help inform the public almost places where sharks are more likely to be hunting seals.
Winton said researchers were getting close to completing data assay on a long-awaited, five-year population written report.
"I was quite surprised" by the written report results, said James Papadonis, a longtime surfer and board member of the grass-roots Cape Cod Bounding main Community. The grouping advocates for more than study and funding leading to solutions and technologies that provide greater safety for those who apply the bounding main. Papadonis uses a shark deterrent system on his own surfboard that aggravates the white sharks' electronic navigation and casualty-detection organs.
He said the study supports a drone study conducted by Moosh Systems and local scientist Kris Sexton that showed great whites patrolling along the coast in shallow water.
Fatal shark attacks
Iv bang-up white shark attacks take occurred on Cape Cod since the first in 2012, including the fatal attack on bodyboarder Arthur Medici in Wellfleet in September 2018. Kayakers in Plymouth were also attacked in 2014, and Maine had its first fatal attack last summer.
"Given the magnitude of the trouble, we'd like to see more inquiry being done," said Papadonis, who lives in Brewster and wants investigation into deterrence technology. His own children, who are in their 30s, are also surfers who no longer want to surf on the Cape.
"Nosotros want to coexist, he said, "simply how do nosotros deter them from inbound recreational areas?"
Contact Doug Fraser at dfraser@capecodonline.com. Follow him on Twitter:@dougfrasercct.
Source: https://www.capecodtimes.com/story/news/2021/03/26/cape-cod-sharks-spend-half-their-time-in-shallow-water/7000271002/
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