This SharkoFiles profile covers the white shark’s size, diet, lifespan, range and conservation status. It then follows the great white shark migration that carries Northwest Atlantic sharks south each fall. Satellite, acoustic and pop-up tags have let researchers such as OCEARCH and the Massachusetts Division of Marine Fisheries (DMF) track tagged sharks’ seasonal movements. That work helps explain why white sharks turn up off the Carolinas and Florida in the cooler months.
The white shark (Carcharodon carcharias) is one of the most studied sharks in the world. Even so, federal scientists say basic questions about its numbers, habits and movements are still open. Here is what the evidence supports so far.
Great white shark facts: size, diet and lifespan
The white shark is the largest member of the mackerel shark family, which also includes makos, porbeagles and salmon sharks, according to NOAA Fisheries’ white shark species profile. It is named for its pale belly. The back is dark gray to brown.
Pups are born at about 4 feet (1.2 meters) long. NOAA says adults can grow to roughly 20 feet (6.1 meters) and weigh more than 4,000 pounds (1,814 kilograms). The University of Florida’s Florida Museum white shark profile also puts the maximum at about 20 feet. It treats reports of 23-foot (7-meter) sharks as unconfirmed.
White sharks are regionally endothermic. That means they are partially warm-blooded and can hold their internal temperature above that of the surrounding water. NOAA says this lets them hunt more actively in cool seas than cold-blooded species can. For a look at body heat in an extinct giant, see our story on the thermal secrets of megalodon.
Diet shifts with age. NOAA says juveniles mostly eat bottom fish, smaller sharks and rays, schooling fish and squid. Larger white sharks gather near seal and sea lion colonies to feed and sometimes scavenge dead whales. Off Cape Cod, gray seals are the main summer prey, according to the Center for Coastal Studies.
This is a slow-growing animal. NOAA says males mature at about 26 and females at about 33. Estimates of maximum age run from 30 to more than 70 years. Bomb-dating research cited by the Florida Museum suggests white sharks may live 70 years or longer.
Where do great white sharks live?
NOAA says white sharks live in temperate and subtropical seas worldwide. They often move with the seasons to stay within a preferred temperature range of roughly 50 to 80 degrees Fahrenheit (10 to 27 degrees Celsius). They use both near-shore coastal waters and the open ocean.
In the western Atlantic, the Florida Museum lists a range from Newfoundland to Florida, the northern Gulf of Mexico, the Bahamas and Cuba. NOAA, which now calls that body of water the Gulf of America, identifies nursery areas off Long Island, New York, and in southern California. Pups and juveniles there favor warmer, shallow waters over the continental shelf.
Is the great white shark endangered?
The International Union for Conservation of Nature (IUCN) lists the white shark as Vulnerable on its Red List. The species grows slowly, matures late and has few young. NOAA says that makes it prone to declines caused by people. It is also one of the most widely protected sharks in the world.
In most U.S. waters, the white shark is a prohibited species. There is no commercial fishery, and sharks caught by accident must be released. Atlantic anglers with the right permits may target white sharks with rod and reel. They must release each shark immediately, without taking it out of the water. Internationally, the species is listed on CITES Appendix II. Accidental catch is a broader shark issue, too; see our story on shark mortality in longline fishing.
The trend in the Northwest Atlantic is mixed. NOAA research indicates numbers there have been rising since protections began in the 1990s. The IUCN assessment, however, says abundance is still below historic levels. NOAA adds that no stock assessment has been completed for U.S. white sharks, and none is planned in the Atlantic.
Great white shark migration: where they go in fall
Summer is feeding season in the north. Scientific American says white sharks are most concentrated off Cape Cod from about June through October, though sources differ on the exact window. The magazine calls Cape Cod one of the world’s largest seasonal white shark gatherings. Massachusetts shark scientist Greg Skomal didn’t see a white shark near Cape Cod until 2004.
As the water cools, the sharks head south. OCEARCH, a nonprofit research group, says falling water temperatures and changing daylight prompt the move away from Cape Cod and Atlantic Canada. Stephan Kajiura of Florida Atlantic University told Newsweek that the timing shifts with temperature. In warm years the sharks stay north longer, and in cold years they arrive south sooner.
The Massachusetts DMF’s shark movement research has tagged more than 120 white sharks off Cape Cod since 2009. It reports that sharks leaving in late fall spend the winter off the southeastern United States and in the Gulf of Mexico. Many return to Cape Cod year after year. Larger sharks, those over 9 feet (2.7 meters), also travel into the open Atlantic as far as the Azores.
Much of the winter activity centers on the continental shelf from North Carolina to Florida’s east coast. In a 2019 analysis, OCEARCH named this stretch the Northwest Atlantic Shared Foraging Area. Detections were highest off Charleston, South Carolina, and Cape Canaveral, Florida. Nearly all of the large white sharks the group had tagged visited the area, mostly in winter.
The Gulf matters too. A study in the journal Wildlife Research tracked 92 sharks tagged between Nova Scotia and Jacksonville, Florida. It found that 57 of them spent significant time in the Gulf of Mexico or the Straits of Florida, mostly from December to May, according to OCEARCH’s summary of the Gulf study. The tracked sharks were males and females at every life stage, from first-year pups to adults.
In spring, the movement reverses. OCEARCH data scientist John Tyminski said sharks usually travel from the Southeast to Cape Cod or Atlantic Canada between mid-May and late June.
Individual tracks show how far one shark can go. Phys.org reported on Freya, who was tagged off Wilmington, North Carolina, in March 2021. She spent that summer around Cape Cod and Nantucket, moved into the Gulf of Maine and went south to Florida that fall. By summer 2022 she was near the Cabot Strait. Her tag logged 7,568 miles (about 12,180 kilometers) in nearly two years.
How scientists track white sharks
The DMF uses several kinds of tags:
The Gulf study combined satellite-linked SPOT tags, pop-up archival tags and acoustic tags. OCEARCH says its tags can last up to about five years.
Field trips keep adding sharks to the sample. Sharkophile covered one in OCEARCH’s research expedition to Nova Scotia. We have also followed individual animals, including Miss Costa, the tweeting shark. Any one group’s tagged sharks are a sample, not a count of the whole population.
What scientists still don’t know about white sharks
Many basic questions about their abundance, life history, habitats, and movements remain unanswered.
NOAA Fisheries, white shark species profile
No one knows how many white sharks exist. The Florida Museum says global population size is unknown and regional estimates are unreliable. It names missing data on reproduction, age, growth and population numbers as the biggest obstacle for managers.
Population structure is another open question. OCEARCH says its tracking data suggest the Northwest Atlantic could hold more than one population or subpopulation, separated by where sharks gather in late summer. That remains a hypothesis, not a settled finding.
Researchers are also unsure exactly why sharks go where they do. University of Miami scientist Neil Hammerschlag said in a 2022 Phys.org report that the summer presence off Nova Scotia is likely tied to food, but “we don’t fully know all the answers.”
Researchers are only beginning to understand what large sharks do far offshore and how heavily they use the Gulf. The Atlantic White Shark Conservancy lists ongoing work on several open questions:
The group’s Cape Cod catalog topped 600 individually identified sharks in a 2023 update. Every name added gives scientists more data to work with on these questions.
Source: NOAA Fisheries, Florida Museum of Natural History, University of Florida, Massachusetts Division of Marine Fisheries / Study: IUCN via ResearchGate
