White shark populations are growing in waters off the east coast of the United States and Canada, which is welcome news for the species. Population declines seen along the Atlantic coast of North America appear to have halted, and the species has started to make gains in some areas, according to a new study.
However, the presence of additional top predators could spell trouble for their favorite prey animals, including seals.
White sharks (often improperly, called "Great") experienced a period of stable populations, followed by declines along the American Atlantic coast.
National Oceanic and Atmospheric Administration (NOAA) officials undertook the task of compiling "largest white shark dataset yet compiled from this region."
"Despite recent advances in field research on white sharks (Carcharodon carcharias) in several regions around the world, opportunistic capture and sighting records remain the primary source of information on this species in the northwest Atlantic Ocean (NWA)," Toby Curtis of NOAA, and other researchers wrote in a journal article detailing their study.
The team examined 649 confirmed white shark sightings between 1800 and 2010. This wealth of data was compiled with information already held by NOAA. Together, they revealed new findings about the distribution of populations, and how they change over time. Usage of habitat was also detailed, and researchers discovered patterns in migratory paths.
White sharks were found to live all along the eastern coast of the United States year-round. However, most of the animals congregated in the northeast, between New Jersey and Massachusetts in the summer, and made their winter homes in Florida. White sharks were seen along the east coast of the U.S. during spring and fall months.
Jaws, a film from director Steven Spielberg about a man-hungry white shark, was released in 1975. It was in the 1970's and 80's the species started suffering population losses. This was welcome news to prey animals such as the gray seal, native to New England waters. Their numbers on the Massachusetts coast grew greatly during the shark decline.
Environmental laws were passed in the 1990's, a decade which saw the first resurgence for the ancient species. Researchers believe these environmental regulations contributed to the population increases. The sharks are feasting on gray seals and other animals along the seacoast.
White shark populations fell 73 percent between 1961 and the 1980's. Today, populations are now nearly 70 percent of record levels.
University of Florida researchers calculate there have been just 106 unprovoked attacks on humans by white sharks in American waters since 1916. Just 13 of these encounters have resulted in a fatality.
Study of white shark populations in North American regions of the Atlantic Ocean was published in the journal Plos One.
