Great White Shark Migratory Patterns

    I recently saw a map of about 70 or 80 dots all skewed along the East Coast of North America, all the way up from Newfoundland to the middle of Florida, some of these dots went thousands of miles into the middle of the ocean and some stayed right along the shore. This led me to click on the image solely out of curiosity to find the reasoning behind the dots, come to find out these dots were pings off where two different sharks had come up to the surface for air. These two sharks had traveled thousands of miles in a matter of months, yet there is no visible pattern between the two animals yet they seemed to enjoy hanging around the continental shelf with one shark staying much closer to the coast and one shark staying further out in the ocean and being more mobile. 

    Greg Skomal a shark expert was included in a Wired article by Peter Brannen about the complexity and importance of tagging and researching Great White Sharks, in the article he is described assisting tag of 2 important sharks, Mary Lee and Lydia, two sharks pictured on the map above. In the months since Mary Lee and Lydia were tagged the biologists have learned lots about their behaviors and movements. For example the biologists have found that Lydia had been deep diving, off the Continental Shelf, thousands of feet down, topping off at 3,543 feet. This behavior seemed off in the beginning but overtime the biologists have hypothesized that Lydia has been feeding, on the deep-scattering layer. The deep-scattering layer is a school of fish and squid that rise hundreds of meters at night, yet in the day drop back down into the dark, deep ocean. The deep-scattering layer was discovered in World War 2 using Submarine sonar, yet scientists aren't all convinced, with some believing there is more than just these fish and squid in this deep unexplored region of the Ocean.

    In Australia there are similar shark patterns, with Great Whites staying close to shore yet also venturing out to the Continental Shelf and spending weeks diving and swimming the shelf. These Australian Great Whites tend to like the warmer coastal waters and spend lots of time in the surf zone, and area of 1-5 meters deep where they can easily come in contact with swimmers or surfers. These sharks tend to frequently move locations in Australia, similar to the East Coast, while they might stay in the same region of the world sharks will travel thousands of miles, yet come back to their original location, over a period of a few months to a year (White).

 

   These Great White Shark migratory patterns are confusing and something scientists still know little about yet it is important to keep tracking the animals as we learn new things about them everyday, which in turn will help us protect the shark species from over fishing and poaching, which is becoming more and more common in today's society with meals like shark fin soup, a popular Asian dish. This dish uses the fins on a shark, causing the fishermen to kill the animal and only take the fins while oftentimes dumping the rest of the animal overboard. 

Brannen, Peter. "Tracking the Secret Lives of Great White Sharks." Wired, Conde
     Nast, 2021, www.wired.com/2013/12/secret-lives-great-white-sharks/.
     Accessed 14 Jan. 2021.

Great White Shark Habitats. 29 July 2011. A to Z the USA, 2020,
     adventurebaycharters.com.au/habitat-great-white-shark/. Accessed 14 Jan.
     2021.

Souppouris, Aaron. Ocearch Global Tracker. 2021. A to Z Maps Online, 2020,
     www.theverge.com/2013/8/29/4671128/
     shark-tracking-in-real-time-ocearch-global-tracker. Accessed 14 Jan. 2021.

"White shark research findings." CSIRO, 2020, www.csiro.au/en/Research/
     Environment/Oceans-and-coasts/Sharks/
     White-shark-research-findings#:~:text=White%20sharks%20move%20between%20eastern,o
     f%20these%20movements%20are%20unknown. Accessed 14 Jan. 2021.