by Lonny Lippsett
Photography by Nuno Sa
Like most fathers, Simon Thorrold plays tag with his young daughter. But Thorrold, a biologist at Woods Hole Oceanographic Institution, also plays tag with 30-foot-long whale sharks, like this one looking straight at you.
Give us a brief status report on sharks in the ocean.
There are about 500 species of sharks in the world’s oceans, and a number of them are in trouble, for many reasons, but the main reason is the increased demand for sharkfin soup in Asia.
What are the numbers?
Estimates are as high as 100 million caught and killed per year, but certainly tens of millions of sharks are killed annually—most of those just for fins, bodies simply tossed over the side and never used. A colossal waste. The finning is pretty indiscriminate: whale sharks, basking sharks, hammerheads, blue sharks. I’ve seen some of that in the Dubai fish market, for instance—literally hundreds of whole sharks lined up. This industrial level of fishing is unprecedented in human history, and shark populations simply can’t handle it.
Why are they particularly vulnerable?
It’s a function of their biology. Sharks are more like large mammals than like fish. Unlike cod, which might release three or four million eggs in a single spawning episode, many sharks have no more than ten pups per litter, with gestation periods of one to two years between giving birth. Sharks take years before they can even reproduce. That’s typically not a problem for animals at the top of the food chain, because they don’t get eaten and can live long lives. But industrial fishing has radically changed the situation.
What do we know about sharks or other large fish in the sea?
Even though the sharks, rays, tuna, and swordfish roaming our oceans are large, spectacular, and commercially important, we know remarkably little about them. That impedes our ability to conceive and implement effective conservation strategies for these species, and more generally, to understand how they function in ocean ecosystems, and how the removal of these apex predators would affect those ecosystems.