There is a group of young blacktip reef sharks that regularly visit the shallow waters off the tip of the Calumpon Peninsula, near Anilao, Batangas, Philippines.
Almost every day on the rising tide, up to a dozen small sharks come inshore and swim together in small circles where the water is so shallow that the tops of their dorsal and caudal fins are out of the water. They were missing for maybe a whole year; probably the sharks we see now are the next brood. So far they have escaped capture. I would like to think that the local fishers realize the presence of the sharks is important-with luck it will mean the gradual resurgence of the shark population in the area. In the 1960s, sharks were indeed plentiful along this coast.
However, soldiers from a military post at one end of the peninsula began to use them for target practice. Probably hunting with nets and spears was responsible for removing the rest. In the New Scientist magazine, an article reports that fishing has decimated the populations of some large sharks in the Gulf of Mexico The scientist authors say that the oceanic whitetip shark is down to 1% of its population size in the 1950s; the silky shark down to 10%, and the dusky shark to 20%. Ironically, the oceanic whitetip was once said to be “perhaps the most abundant large animal on the face of the earth.” The article is only one of hundreds of similar stories of declining shark populations, with finning, that is, taking the fins for soup and throwing back the rest, the latest threat.
A report in the old ScubaGlobe print edition a few years ago (Vol 2, no. 2, May 2004, p. 79) on the rising threat of shark finning said that in the Northwest Atlantic, hammerheads were down to about 10%, and threshers and white sharks down to 20% of population sizes in 1986. Official figures from the Food and Agriculture Organization of the United Nations or FAO, show global annual fisheries catches of sharks at over 800,000 metric tons, and that is undoubtedly an underestimate, given the high proportion of illegal fishing that occurs worldwide.
The only way to stop fining, conservationists agree, is for consumers to stop eating shark fin soup. In Asia, there have been some recent successes in anti-shark fin campaigns. The WildAid web site claims that in Thailand, consumption has dropped by 30%; in fact WildAid staff faced a multimillion-dollar harassment lawsuit from shark fin dealers who claimed their business had been cut by up to 50%. Consumption has dropped by 25% in Singapore, Taiwan and Hong Kong, according to media. The oldest chain of shark fin restaurants closed in Hong Kong, citing economic downturn and environmental campaigning. But bringing back the reef sharks by not catching or fining them, however, is unlikely to be very successful unless some other measures are taken—primarily, providing food for them!
The Anilao reefs, for example, are in good condition but there are virtually none but small fish, especially damsels and anthiids left as a result of constant fishing pressure. Big sharks don’t eat minnows. These reefs are probably fairly typical of reefs throughout much of Asia. So where will sharks around Asia get their food? Human populations are getting bigger. The fisheries are exerting more and more pressure on finite numbers of fish in the seas. In the days when fisheries were still able to expand—up to the mid-1970s mainly—there were always refuges where fish stocks could shelter, areas where it was too deep or too rough or too shallow or too far away to fish. Nowadays, sophisticated fishing boats roam all over the seas and there are almost no more refuges left.
It’s not only sharks, of course. All big fish, from groupers to tunas, are rapidly dwindling all over the world’s oceans. Most kinds are down to small percentages of what they once were – like the sharks. The world’s fisheries haven’t stopped to mourn their passing. The nets that once caught them have turned to smaller fish, the fish that the sharks and other top predators once ate. And as these become overfished, other smaller fish are sought to replace them in the world’s fish markets. If that situation continues, and there is no sign of it abating, the short-term picture is one in which big fish have fewer choices of prey, that is, food chains become short, making life much more unpredictable for big fish, so their populations will fluctuate widely. In the long term, relentless fishing pressure will finally mean the disappearance of all big fish because there will be no suitable prey food left for them. We have already begun on this downward spiral in some parts of the world (for more details, see In a Perfect Ocean by Daniel Pauly and Jay Maclean, Island Press, Washington DC. 2003, islandpress.org).
The increasingly loud call by virtually all fish conservation groups to establish more marine sanctuaries (no fishing) and reserves (limited fishing) reflects the need for large areas of reefs and other marine habitats to be set aside permanently for fish populations to recover to some extent—a new generation of refuges. And recovery is a bottom-up process; smaller fish will need to become more numerous to form prey for larger reef carnivores. Top predators like sharks will be last to become properly re-established.