"We already have one of the largest white shark populations in the world. As the mammal population grows, it appears the shark population follows. And so will attacks on humans. I heartily endorse the Marine Mammal Protection Act, but that's the reason the great whites are increasing."
Sharks are predators at the top of the food chain, the awesome wolves and tigers of the ocean. They are critical in maintaining the ecological balance of the seas. If they disappear, it will affect many other species. California sea lions and seals are multiplying rapidly—the estimated current population of 90,000 sea lions is double that of 10 years ago—and scientists think that the great whites are needed to cull the sick and the slow in order to maintain a healthy gene pool. Sandbar sharks, blacktips, lemons and sharpnose sharks eat finfish that feed on shrimp; a multimillion-dollar shrimp fishery could be harmed should those species of sharks become depleted. Bull sharks and hammerheads are major predators of stingrays. If those sharks are fished out, will the venomous fiat fish that injure hundreds of bathers each year proliferate? Sandbar sharks feed on octopus, which in turn feed on stone crabs. If the sandbars are eliminated, will the stone crab fishery also come to an end?
At the same time that the commercial fishery for sharks has intensified, sport-fishing for the species has also become popular. In September 1988 we boarded the Mindi, one of 30 craft competing in the 13th annual Port Salerno, Fla., shark tournament.
The weather wasn't cooperating for the three-day event, and the 40-foot charter boat pounded in the waves. Spray blasted the windshield. Captain Yogi McIntosh clung to the wheel and throttles, slowing down and then speeding up the throbbing diesel as we worked our way offshore. Rick and Chuck Stillwell from Port Salerno had paid $1,200 to charter the Mindi for the tournament.
At last we stopped and dropped the outriggers. Out came the rods and reels, and McIntosh baited up with live mullet that he had caught earlier with a cast net. "The mullet are doing the chumming for us," said McIntosh. "A shark can smell them a mile away and here he'll come." Sharks can detect minute quantities of a substance in the water—as little as one part per billion—and home in on it.
The lines played out. If ever there were distressed fish giving off vibrations, these were. The mullet sped desperately into the depths. When a shark closes in, it is aided in locating a potential meal by being able to detect electrical fields of one hundred-millionth of a volt through their ampullae of Lorenzini, the little jelly-filled pits, which are electroreceptors, found on the undersides of their snouts. They sense the electrical fields generated by the muscle activity in other animals, which is why certain sharks can locate and seize flounder that lie completely buried beneath the sand.
Only minutes passed before one of the rods bent violently. "It's a hit," yelled McIntosh, dashing forward, grabbing the rod and whipping it backward to set the hook. Rick Stillwell jumped into the fighting chair, took the bending rod and began reeling madly. It wasn't a monstrous shark, but it took all his strength to keep it coming toward the boat.
In a few moments the shark surfaced. It was a hammerhead of barely 50 pounds. McIntosh slipped on his gloves, leaned over, taking a wave in the face, and grabbed the leader. "Hell, he ain't hardly hooked!" McIntosh cried out. He reached down and grabbed the shark by its airfoil-shaped head, and with all his might jerked it up. Everyone scattered as the fish pounded the deck with its tail, arcing its grotesque hammer about and snapping its semicircular mouth filled with small, sharp teeth. McIntosh suffered a good wallop from the tail. Shortly afterward, a larger hammerhead was hauled up. This time McIntosh subdued it with a snub-nosed .38. As abruptly as the action began, it stopped. There would be no more sharks caught by the Mindi this day. When we arrived back at the dock, an enormous bull shark was hanging from the crane at Port Salerno's Sandsprit Park. It weighed out at 384 pounds and was enough to earn the team of Mike Simonds and Robert Mostler the $2,500 first prize. Crowds of people milled around the nearly nine-foot-long fish, gazing up at it with expressions of awe and fear, and watching biologists who were examining the catch.
"We enjoy having the biologists come down," said Karen Worden, one of the organizers of the tournament. "I can't see doing something like this and killing for nothing. We don't take enough to hurt—over the years the tournament's had as few as 18 and as high as 56 sharks." Thinking of the mass slaughter we had recently witnessed on the long-liner, I couldn't totally disagree with Worden's view.
After the biologists measured the fish—recording such things as the size of the fins, the number of its teeth, the length of its body—they dissected it. Tissue samples, frozen on the spot in liquid nitrogen, were collected by Mote Marine Lab's Hueter and his research team for a study on the genetic differences among shark populations. The shark's gut was empty, and so was the uterus. "Looks like she recently pupped," Hueter said, holding up a flaccid oviduct.