Dr. Callum Roberts, 39, a soft-spoken senior lecturer of marine environmental management at the University of York in England and one of
the world's leading conservation biologists, was sipping a cup of tea and waxing passionate about his favorite creature: the fish.
"For me, they are as individual as dogs," he said. "They are incredibly varied. And quite intelligent. People underestimate fish. If you go underwater with a tank or a snorkel, you get to know them as individuals. When you look at tropical groupers on a reef, for instance,they have these beautiful doleful eyes and they stare at you amid the coral. You can often go back to the same place again and again for weeksand see the same fish. After a while, you detect personalities." If Dr. Roberts has a remarkable love for fish, it is because they are the center of his work. In environmental circles, he is known as the Rachel Carson of the fish world -- an untiring advocate of marine life conservation. He wrote, with his wife, Julie Hawkins, 37, also a conservation biologist, "Fully-Protected Marine Reserves: A Guide" (World Wildlife Fund, free). Dr. Roberts's studies about fish species and preservation have appeared often in scientific journals.
He and Ms. Hawkins live in a sprawling house outside York with two land-based mammals, their cats. They do not keep tanked fishes. "We travel too much for that," he says, "and besides, it's much more wonderful to see them in the natural state, swimming about freely."

Q. Dr. Roberts, what exactly is your profession?

A. I suppose I'm a marine biologist who has turned to conservation. So I
am what is called a "conservation biologist." That means I study marine animals in their ecosystems to try to figure out how they can be protected. This is a whole new profession. When I was a student at university, there weren't any conservation biologists. Today, our professional organization, the Society for Conservation Biology, has 5,000 members.

Q. The particular type of marine animals you seek to protect at this moment are deep-sea fish. How did they become the subject of your crusade?

A. With deep-water fishing, I saw an emerging problem, which had a solution. If you could step in early enough, then perhaps you can stop this global rush to exploit the deep sea -- which, I feel, will lead to the destruction of fragile deep-sea habitats and fish stocks.
The history of the problem is this: in the 1970's and 1980's as shallow-water fish got into trouble from overexploitation, the fishing industry worldwide began looking to the deep sea as virgin territory to work. By going to sea mounts (undersea elevations) and canyons that had never been trawled before, people were able to take huge catches --thousands of pounds in only a few minutes.
Then, in the 1990's, after the cold war ended, military technology developed for underwater spying and sea floor imaging became available for civilian use. Thanks to multibeam sonars, sea floor mapping, and positioning systems, fishermen could suddenly exploit deep underwater terrains that previously had been unknown.

Q. What is the problem with having fishermen in the deep sea?

A. It led to the wholesale destruction of many deep-water environments and to a kind of fishing that was more like strip mining than harvesting. In the past, there was luck to deep-water fishing. If you can't really see the sea bed, it's like fishing with a blindfold on. While dragging your net into the unknown, you might lose it. And the nets are very expensive. But once you could see the sea floor, get pictures of sea mounts -- the feeding and spawning grounds for deep-water fish -- the guesswork was gone. Trawlers could go in and clean out one community after another.

The fate of the orange roughy, a meaty white fish found in the deep waters around New Zealand and Australia, is emblematic. Before the 1970's, it was not a fish that people ate or even knew about.Once it was discovered, it seemed you could catch an amazing 60 tons in a 20-minute trawl. Fisherman would find a spawning ground and strip it bare. After a few years of this, the catches collapsed and you had people moving around, searching out new aggregations to exploit. In New Zealand now, they figure they've got 20 percent of orange roughy they once had. The same thing has happened to the pelagic armorhead, which aggregates onto sea mounts in the Hawaiian chain. That fishery went from
35,000 tons to 3,500 tons per annum in only a few years. It never recovered.
Moreover, with deep-sea trawling, the nets often clear-cut the communities of life the fish existed in. In the sea mounts where the orange roughy is hunted, there were once sea fans, black corals, hydroids, invertebrates. Yet these centers of life have frequently been stripped down to the rock. So this is the kind of collateral damage being done to those places. On land, if we thought we would destroy an entire forest just to catch a few deer, there'd be an outcry. Yet, we are doing something like that in the deep sea.

Q. You mentioned that the deep-sea fish species don't seem to recover. Why is that? In shallow waters, near the seashore, if you stop exploiting an area the fish often come back.

A. Deep-water species are different -- older, slower growing, with lower
production levels. When the orange roughy fishery had been under way for
five or 10 years, they realized that the individuals being caught were 70 to 100 years old. You don't fish out individuals that old and expect to keep it up for very long.

Q. Are you a fish eater?

A. I am. I am. That may seem paradoxical. But we've fished for thousands
of years, and its part of our heritage as a species. I think, however, we shouldn't drive marine species to extinction in our search for food. There are now ways consumers can start choosing more rationally what kinds of fish to eat. For example, the Monterey Bay Aquarium has published wallet cards which list which fish are overexploited and which
are not.

Q. Except that modern technology facilitates it, what is really new about our activities in the deep sea?

A. Nothing. When it comes to fisheries, we've always been moving from one thing to another. If you look at the kinds of fishes that were in cookery books in the 19th century, many of them aren't even known now. For example, a large flatfish called brill was one of the most popular fish in Victorian England. It's gone. Turbot is much rarer than it used to be. The cod, which once defined the ecosystems of the North Atlantic,
is at the edge of disappearance.
The most important thing about deep-sea fisheries is that they are bailing us out from the problems we've created in shallow water by intense fishing. Governments are offering incentives to do it.

Q. One senses you really like fish as creatures?

A. I hate to remember this now, but as a graduate student, I studied the
pairing behavior of butterfly fish. In doing so, I'd spear one of a pair
to see what happened to the remaining one. And if you missed with your first shot, I quickly learned, you didn't get another chance. The fish learned immediately that you were lethal and to avoid you. When you dive into an area, where people regularly feed fish, they swiftly come to you. There's that level of intelligence! In a sense, they are like birds. But people wouldn't even credit fish with bird intelligence.

Q. Do you have any theories on why people can be so particularly callous
about fish? Is it that we are used to seeing them on the fishmonger's slab, dead, scowling, inert?

A. That may be some of it. I think fish don't express pain in the way mammals do. So when you cut fish up, they don't scream. It's hard for us to appreciate they are sentient beings and so you end up with these remarkably callous approaches to exploiting fish that you wouldn't dream of inflicting on land species.

Q. On the issue of deep-sea fishing, are there any solutions you can propose?

A. Well, I think we must set aside large areas of the deep sea and make them off limits to fishing. If we don't do that now, we are going to lose things that we haven't even described. There are fishing fleets out now trawling in sea mounts and canyons that scientists have never even been to. So we don't even know what we're losing.