How Too Few Sharks Could Spoil the Soup

SYMPATHY for the shark may be asking too much, but marine biologists are warning that it may be time for a minor truce. Since 1986, the market demand for sharks has surged dramatically - so dramatically that federal fishery officials and shark experts are concerned that overfishing could soon render some species commercially extinct.

And sharks mature and reproduce so slowly that, once decimated, it takes decades for them to come back.

To some people, fewer sharks may merely signal that it is safe to go back in the water. The stuff of nightmares and exaggerated fears fanned by the ``Jaws'' movies, the shark is a favorite metaphor for ruthlessness.

But biologists are concerned about the unknown impact on ocean ecologies if the predator at the top of the food chain disappears.

The most flagrant excesses of the shark catchers have already aroused public indignation on the shark's behalf.

About half of a shark's market value is in the fins, which are packed off to Asia for shark-fin soup. Last summer, fishermen off Florida's Gulf Coast began noticing sharks without fins. In shallow coastal waters, some of them could swim well enough to survive. In the ocean, finless sharks plummet bottomward.

Public outcry over the cruelty of live finning, as well as the waste of killing the shark without using the rest of the animal, pushed the industry into largely weeding out the practices last fall.

But the pressure on sharks from fishing is at an all-time high, especially in the Gulf of Mexico. Florida's shark catch doubled from 1986 to 1987 and has remained at that high level. Federal officials held an emergency meeting last weekend to consider limiting how many sharks Gulf fishermen can capture. Shark-watchers on every United States coast are concerned about overfishing.

Sharks are unlike other fish because it takes most shark species about 12 years to first have pups. Gestation periods are sometimes as long as 22 months.

A fish that reproduces so slowly does not easily accommodate the whims of the marketplace. In recent years, shark has become widespread in restaurants and grocery stores. And fishermen have become more efficient in catching them.

ONE operation in Fort Pierce, Fla., sends out spotter planes to find schools of sharks that are scooped up in nets. A single trip in recent weeks netted about 1,000 blacktip sharks, flooding the market and causing a price drop, according to Robert Hueter, a shark biologist at Mote Marine Laboratory in Sarasota, Fla.

Sharks have been fished out before. Their liver oil was valuable through the 1940s, and caused the soup fin shark in San Francisco Bay and the porbeagle off the coast of Maine virtually to disappear by World War II.

The porbeagle has yet to make a strong reappearance. The soup fin shark was coming back when a market for sharks began developing in the 1970s, and it was promptly fished out again.

An unlikely scene here two weeks ago: The quarter-ton predators dangling from scale hooks were caught in a tournament to sponsor shark research. The fish were being sacrificed to help save their species. Without better research, says Samuel Gruber, the University of Miami shark expert who organized it, biologists cannot hope for better laws and regulations to protect them.

Although dangerous and impressive, sharks are not merely the feeding machines they are popularly thought to be. They have large brains, more like those of mammals and birds than those of fish. Some have social hierarchies like the pecking order of chickens. They are easily trained to swim mazes and perform simple tasks. But they are difficult to study. ``There are a lot of very simple questions that I can't answer with any sense of accuracy,'' Dr. Gruber says.