We’re killing all the fish

B O R I S WO R M
National Post

The high seas are a mystical place, a vast wilderness that envelops twothirds of our planet. It is where our ancestors suspected the world ended and sea monsters reigned. It is the least known, least understood part of the planet, above and beyond the political radar screen.
That is changing fast. We understand now that there has been a silent, slow-motion erosion of life in the oceans in recent decades, even in places that are thousands of miles from shore.

Since about the 1950s, industrialized fishing has increasingly moved from depleted coastal and continental waters to the deep sea, quietly plundering the remaining riches. Because of its low productivity, much of the open ocean gets overfished quickly, and is slow to recover. Deep sea fishes, such as Orange Roughy, become mature only after 30 years, and can live up to 150 years. They aggregate on underwater mountain peaks that are often covered by coldwater coral reefs. These havens harbour large numbers of species, second only to rainforests on land. Deep sea trawlers are right now eliminating these creatures before we even get a chance to properly study them.

In an article released last month in Science magazine, my fellow authors and I showed that fishing has not only depleted the total number of fish worldwide, but also their variety. Through a series of maps, we depicted what is normally hidden from our eyes: the draining of species from the world’s oceans.

We used global fishing data for large tuna, billfish and swordfish — all prime targets of high-seas fisheries. We cross-referenced these with scientific data for a large number of species, from tuna, sharks and billfish to turtles, mammals and seabirds, collected by U.S. and Australian government agencies. We even looked at the distribution of the smallest animals — tiny single-celled zooplankton — in order to check the results.

All sources showed clearly that ocean life often concentrates in a few special places, which we call hotspots. These hotspots harbour a much larger number of species than surrounding areas, like oases in a desert.
Tracking changes back into the 1950s, we discovered that today’s hotspots are only remnants of numerous larger areas that have been shrinking and disappearing over time. On average, only half as many species are found on a fishing line today in the Atlantic and Indian
Oceans as in the past. (The Pacific is a little better off.) This does not yet mean that species are going extinct en masse, but that they are missing from large areas where they were formerly thriving.

These changes are very serious, because loss of species diversity is a one-way road. Low numbers of a particular fish can sometimes be recovered, but a broad loss across multiple species is much harder to restore. Worse, once the variety of species drops too low, the entire food chain can become unstable.

There are still some places left that harbour close to their native portfolio of species. Protecting these places — off the east coast of Florida, south of Hawaii, in the south Pacific and Indian Ocean — may be a first step to restoring balance to our oceans.

Fortunately, awareness is building. Talking to the United Nations this summer, I was pleasantly surprised that many countries are signing on to the idea of high-seas reserves, areas that are off limits for fishing, dumping, and other harmful activities. Also, moratoria on highseas trawling and certain forms of longlining are being discussed, as it is recognized that not all forms of fishing are equal in their capacity to disrupt ocean life.

The Canadian government’s position on these issues is very weak, however. This is a global problem. Yet our government would like to see the issue referred to local management councils, which have been woefully incapable in the past of halting the downward trend of ocean life on the high seas.

Paul Martin said it all too well when he opened a recent conference on high seas governance in St. Johns: “I’m asking you to seize this historic occasion, and begin the process to stop the rape of our fisheries and oceans, once and for all. I’m asking you to come together — as a global community — to write the next chapter in the history of the world’s fisheries and oceans, and to restore their once-proud place in our cultures, in our nations, and in our lives.”

The official theme of that conference was: “Moving from Words to Action.” I really hope they mean it.
Boris Worm is a Professor of Biology at Dalhousie University bworm@dal.ca