Shark attacks are vanishingly rare. The chance that any given American swimmer will be bitten is just 1 in 11.5 million, according to the University of Florida’s International Shark Attack File, which tracks shark-bite statistics. The odds are even lower in Texas, where only 48 people have been bitten in the past 113 years. “Over the last ten years, if anything, there’s been a slight drop in the number of unprovoked bites,” said Gavin Naylor, director of the Florida Program for Shark Research, noting that about 60 to 80 people are bitten worldwide each year. Still, the seemingly random nature of attacks and pop-culture portrayals of horror beneath the waves instill a persistent fear—which Texans may be feeling more strongly than usual this summer.On July…