I looked up just as the water above me darkened. Within an arm’s length, a massive whale shark passed over my head, its tail methodically propelling it forward. I caught its improbably small eye looking intently at me as it glided past. Directly behind came a second whale shark and then another.
But I wasn’t swimming in the ocean – I was 30 feet below the surface, at the bottom of the 6.3 million gallon Ocean Voyager exhibit at the Georgia Aquarium. As a marine scientist, I’ve logged a lot of dives in places from tropical reefs to temperate kelp forests. But I’d never been this up close and personal with the world’s biggest fish. In the wild, whale sharks can grow to 40 feet and nearly 50,000 pounds; those at the Georgia Aquarium are a relatively “small” 25 feet in length.
In June of 2013 the international body that manages tuna fish in the Eastern Pacific Ocean drafted and approved a resolution to protect whale sharks. The resolution isn’t groundbreaking; the New York Times didn’t report, Anderson Cooper wasn’t on the scene, and Greenpeace didn’t raise the flag. In fact, in the year it took to make U.S. compliance official via rulemaking in September 2014, even the fish-heads and whale shark lovers here at Ocean Conservancy barely noticed. This is a good thing.
Too often fisheries management is mired in relatively small, but high-profile, fights. The fact that the Inter-American Tropical Tuna Commission (IATTC) quietly prohibited tuna fishermen, who hail from many nations around the Pacific, from using whale sharks as de facto Fish Aggregating Devices (FADs) marks another small but important step towards saving some of the world’s most iconic species and preserving a healthy ocean.
Dr. Hoffmayer and a whale shark in the Gulf of Mexico. [Photo: Jim Franks]
(This blog is part of a series of interviews with scientists who are championing marine research in the Gulf of Mexico.)
A preeminent whale shark expert and ecophysiologist, Dr. Eric R. Hoffmayer is a research fishery biologist with the National Marine Fisheries Service, Southeast Fisheries Science Center, Mississippi Laboratories. His interest in coastal shark species ranges from their reproduction and life history to their specific abundance, distribution and feeding ecology in nursery grounds. He has pursued a particular interest in the Gulf of Mexico’s whale sharks, the largest fish in the ocean, compiling information on their basic biology, habitat use and movement patterns.
Ocean Conservancy: How much is known generally about the whale sharks found in the Gulf of Mexico? What is the size of the population?
Dr. Hoffmayer: Ironically, even though whale sharks are the largest fish in the ocean, we still know so little about them, specifically here in the Gulf of Mexico. We know from our research efforts, as well as from research efforts of our colleagues in the southern Gulf, that whale sharks are relatively common in the Gulf. Unfortunately, due to their highly migratory nature and preference for offshore habitats, we still do not have a good population estimate for this region. However, colleagues working in the southern Gulf have estimated that between 500 and 900 individuals occur off the Yucatan Peninsula. In the northern Gulf, whale sharks occur along the continental shelf edge from Brownsville, Texas, to the Florida Keys and commonly occur off the mouth of the Mississippi River.
“SHARK!” Does the word conjure up images of a fin slicing toward you in the open ocean or on the edge of your seat completely absorbed in one of the year’s best television specials?
In preparation for Shark Week, which starts this Sunday, we’ve put together a roundup of some of our best shark blog posts from the past year:
What’s Your Shark IQ? How much do you think you know about sharks? Before taking a deep dive into the world of these complex creatures, test your basic knowledge with our short quiz. Do you know which shark swims the fastest?
Suddenly out of the deep blue water appears a whale shark directly beneath me. The gentle giant moved gracefully to the surface of the water and began feeding next to me. I had been snorkeling off the coast of Tofo in Mozambique and felt that this was a dream come true. Experiences like this make me appreciate the variety of nature’s feeding techniques. You see whale sharks and baleen whales are both filter feeders, animals that eat by straining tiny food, like plankton, from the water. But how they go about filter feeding is completely different.
In whale sharks, teeth don’t play a major role in feeding. In one of their filter-feeding methods, they suction water into their mouths at high velocities while remaining stationary. Food moves through filtering pads that cover the entrance of their throats. The filtering pads are broad mess pads full of millimeter-wide pores that act like a sieve, allowing water to pass through while capturing food particles. Continue reading »