30 July 2023
This can be the final day of Shark Week at the Discovery Channel however on Cape Cod it runs all yr. A brand new learn about revealed this week in Marine Ecology Growth Collection tagged and counted nice white sharks (Carcharodon carcharias) off the coast of Cape Cod, Massachusetts and located that 800 folks visited the world from 2015 to 2018. That implies Cape Cod can have the best density of white sharks on the earth.
Thankfully the entire sharks weren’t there on the similar time. As lead writer Megan Winton of the Atlantic White Shark Conservancy (AWSC) explains, nice white sharks are extremely migratory. Their inhabitants peaks on the Cape from July to November when the water is heat, as proven on this screenshot from AWSC’s logbook for 2022. Particular person sharks spend a couple of hours or a couple of weeks within the space. (Click on right here to look AWSC’s shark information and obtain their shark app.)
The sharks are interested in the Cape by means of the abundance seals, considered one of their favourite meals. A Google Haul Out survey of southeastern Massachusetts estimated most counts of grey seals at 30,000 to 50,000 animals in 2012 to 2015. Harbor seals arrive within the fall and upload to the seal inhabitants. No marvel sharks display up. Grey seals supply numerous meat, weighing up to 800 kilos.
All over our contemporary travel to Cape Cod I noticed plenty of seals at Chatham Fish Pier. A number of swam by means of the fishing boats however the overwhelming majority have been hauled out on a sand bar around the harbor. See that lumpy line of grey blobs? The ones are grey seals.
Whilst on the Cape I didn’t see any sharks however I did see a No Swimming shark signal at Race Level. I used to be on the lookout for birds and, because it seems, diving seabirds give the trace {that a} shark could also be within reach. Each feed on faculties of fish, the birds from above, the sharks from under.
The abundance of sharks and seals at Cape Cod is an environmental luck tale. Grey seals have been virtually extinct in U.S. waters by means of the mid twentieth century on account of bounty looking in Maine and Massachusetts from the overdue 1800s to 1962. The seal inhabitants started to get well, slowly, when the bounties ended. Sharks made a comeback on account of the seals.
(pictures from Wikimedia Commons and by means of Richard St. John, graph is a screenshot of AWSC’ logbook site; click on at the hyperlinks to look the originals)