March 8, 2013

Beaches on the coast of southern Florida were closed to swimmers this week as thousands of sharks were spotted in the waters near shore. The sharks are migrating north for summer, heading from Florida to North Carolina. This migration  takes them past the shores of many beaches frequented by tourists, including Palm Beach. Scientists estimate that there are approximately 15,000 sharks migrating–mostly blacktips (which grow to be about 5 feet, or 1.5 meters, long) and spinners (which grow to be about 10 feet, or 3 meters, long). The sharks swim about 200 yards (180 meters) out from the beach, but lifeguards closed the beaches for swimming as a safety precaution. Florida had 25 unprovoked shark attacks in 2012, although none were fatal.

The body of a shark. Sharks rarely threaten humans, but authorities will often close down beaches where sharks are sited as a precaution. (World Book illustration by Marion Pahl)

The shark migration is normal and happens every year, but it is usually earlier and does not affect beach season in Florida.  In 2013, the migration is happening during spring break for many schools. Spring break is one of Florida’s heaviest tourist seasons. Scientists are not certain why the migration is happening so late in 2013.

Additional World Book articles:

• Migration

• Shark