White Sharks May be Recovering: First Ever Look on Seasonal Distribution Patterns

White sharks are some of the largest predators of the deep, feasting on seals and fish as they journey the world's oceans. Yet these apex predators are also vulnerable and now, scientists have taken the first ever look on seasonal distribution patterns and historic trends in abundance of white sharks.

"White sharks possess life history traits that make them vulnerable to exploitation," said Nancy Kohler, one of the researchers, in a news release. "These sharks can live 70 years or more, mature late, and do not produce many young. Their status and highly valued jaws and fins have made them the target of recreational and trophy fisheries in areas where their populations are not protected."

In this case, the researchers compiled data to create a new database. They found that white sharks occur primarily between Massachusetts and New Jersey during the summer, and off of Florida during the winter. They also have a broad distribution along the East Coast during spring and fall. They're far more common along the coast than in offshore waters, and feed on gray seals there.

Yet more interesting was the fact that white sharks may be increasing. In the 1970s and 1980s, the sharks declined drastically, likely due to expanding shark fisheries. Yet in the early 1990s onward, abundances have increased once more.

"The increases in relative abundance is likely due, in part, to the implementation of management measures," said Cami McCandless, one of the researchers, in a news release. "The U.S. has managed its shark fisheries since 1993, and banned both commercial and recreational harvesting of white sharks in 1997."

The findings reveal that white sharks may be on the rebound, which is important. Sharks function as regulators of the oceanic ecosystem, and play an important role in its health.

"We have improved our understanding of white sharks in the Northwest Atlantic in recent years through field research and technology," said Kohler, one of the researchers, in a news release. "But we still have many questions about life history, population structure and size, behavior, habitat preferences, feeding habits, movements, and migration."

The findings are published in the journal PLOS One.