National Park Service

ScienceShot: A Giant Fish's Enormous Appetite

Like the Biblical Goliath whose great size didn't protect him from tiny David's slingshot, the mighty Goliath grouper (Epinephelus itajara) proved no match for scrawny humans. In 1990, after overfishing nearly extinguished the Goliath from Florida waters, government officials outlawed killing the slow-growing fish, which can reach 40 years old and 450 kilograms. The Goliath has since made a notable recovery—and become a major draw for scuba divers eager to see it. Recreational and commercial anglers aren't so happy, however: They say the behemoths scarf up valuable lobster and table fish. They've been urging officials to lift the ban and allow some "culling" in order to protect lucrative catches. But that's a questionable argument, concludes a study of catch trends and the Goliath's diet published online this month in Oryx. The Goliath's "recovering population is not the cause of declining fish and lobster stocks," writes Sarah Frias-Torres, an independent marine biologist based in Florida. The near disappearance of the predator 2 decades ago didn't lead to big catch increases, she notes, and its reappearance hasn't made a difference either. Studies of the Goliath's diet help explain why: They snack mostly on shrimp, crabs, and nontable fish. And although Goliaths like the occasional lobster, they also chow down on predators that eat baby lobsters. "Lobster fishers should be happy to have Goliaths around," Frias-Torres argues, "since they allow more baby lobsters to reach market size." 

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