
Great white sharks like this one (seen at Isla de Guadalupe) typically spend their time in water temperatures between 60-75 ° F, although evidence has shown that they occasionally venture into colder waters.
UPDATED: Thanks to reader Kevin Polk for the link in the comment section to a CapeLinks Blog article that sheds a lot more light on this story. Most notably that the shark was dead when it was found entangled in the fishing gear, and that the story was kept quiet due to legal concerns due to white sharks being legally protected species.
According to a Cape Cod Times article, a fishing vessel reportedly caught a 20′ (6m) great white shark a few miles off of Chatham, Massachusetts, last month. The capture was reported to Division of Marine Fisheries senior biologist Greg Skomal, who was caught “off-guard” by the news.
Data collected from tagging efforts by Skomal have shown that the tagged great white sharks tended to leave the Chatham area around October or November and spent winter months in the waters off of Florida. Skomal theorized that the bulk of a white shark that large would probably have provided insulation to allow the shark to tolerate the lower water temperatures in the area, which were reported to be in the lower 40s (° F).
The Cape Code Times article does not go into much detail about the capture of the great white shark. There is no mention, in the report, of whether the white shark (a protected species) was released after being caught. There is also no mention of any photographic documentation of the white shark. A 20′ (6m) specimen would be considered very large for the species.