Posted on 01/10/2020 12:28:08 PM PST by Capt. Tom
The sky was winter gray, but researchers took advantage Friday of a relatively rare day with calm seas and little wind to retrieve 18 acoustic shark detection buoys off the Outer Cape and another eight or nine in Cape Cod Bay. Although these buoys primarily record signals from sharks whose tags emit a unique identifying signal, they also record water temperature.
Shark researchers Gregory Skomal of the state Division of Marine Fisheries and Megan Winton, a doctoral candidate at the University of Massachusetts Dartmouth’s School of Marine Science and Technology, hope to use this temperature data to create a computer model that will act like a weather forecast in predicting the likelihood of sharks being at any particular beach on any given day. snip...….
Skomal and Winton have about a decade of buoy data to comb through. They hope to compare the readings on their buoys to satellite data that measures sea surface temperature. Once they discern a pattern for temperature, they plan to look at other potential environmental factors such as water clarity, which they also can check against satellite data that uses reflected wavelengths to estimate the amount of chlorophyll in sea water that is indicative of plankton blooms that diminish visibility. They hope to layer in other factors, such as time of day, angle of the sun and the tide cycle to tease out other patterns and build a model that can use environmental conditions in the ocean to predict where sharks are more or less likely to be present. If the models prove able to discern patterns in white shark movements in response to detectable environmental factors, Winton said they may be able to add real-time data loggers to the buoys and have mini-ocean weather stations at beaches. snip ….
(Excerpt) Read more at capecodtimes.com ...
Sensors don't detect food sources only Pings from TAGGED sharks.- Tom
In the water?
Not my reading of the article. I get the acoustic ‘pingers’. We sometimes use those as a navigational aid when we’re diving in murky waters off New Jersey. But the sensors they are referring to are gathering sub-surface water temperatures and currents. That’s 2nd and 3rd order data, not direct data. Direct data would be a survey of the harbor seal population — that’s GWS food!
A cold water upwelling *MIGHT* bring in phytoplankton which in turn might bring in small fish, then bigger fish and finally larger predators. But there’s no guarantee that a particular type of shark is going to hang around for any length of time unless the type of food they’re looking for is present. See what I mean?
But there’s no guarantee that a particular type of shark is going to hang around for any length of time unless the type of food they’re looking for is present. See what I mean?
There is friction, animosity, and territorialism between shark biologists and seal people.
So any seal studies would be done by different biologists. - Tom
“There is friction, animosity, and territorialism between shark biologists and seal people.
So any seal studies would be done by different biologists.”
Understandable. I tend to believe that if you want to find out what is going on in a particular body of water — ask a commercial fisherman. They know, but often don’t say. Like a trade secret. This is how a lot of shipwrecks get found. The fisherman know where they lost nets. You can bet they’ll punch that number into their GPS to prevent a repetition.
If the fishermen are getting a lot of interference from harbor seals, or seeing certain types of bi-catch (which they report) then that is pretty good evidence of the type of food that certain shark species would be interested in.
Sub-surface water temp and currents are indicators, but they are indirect. They may correlate, but they aren’t causal.
You got that right.
A person I knew well (Bobby Lavedere) years ago was one of the first to dive on the Andrea Doria.
They had 3 sets of Lat/Long, one from the Govt, one from the Insurance Co. and one from a dragger Capt.
They found the wreck and dove on it.
It was located at the Lat/Long of the dragger Capt. who had lost nets entangled in the Andrea Doria. -Tom
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