Guest Blog By Demian D.F. Chapman
Tens of millions of sharks are killed each year to satisfy the demand for the Asian delicacy shark fin soup, a level of fishing that is not sustainable for most shark species given that they reproduce more like mammals than other fish. Upcoming decisions to monitor global trade in seven shark species that are staples of this vast and secretive trade provide an opportunity to make a crucial first step towards rebuilding severely depleted populations of these top predators.
TV show skin-divers always used to have a wicked-looking knife sheathed to their leg to fight off marauding sharks, yet as it turns out it is the spoon that has been a far more lethal instrument when it comes to killing sharks. The retail vale of the Chinese delicacy shark fin-soup, which fetches over $USD100 per bowl, drives a vast, global trade in shark fins that is emptying our oceans of these top predators.
In ancient Chinese culture the soup was the Emperor’s dish and is today served mainly at weddings and banquets- a seagoing status symbol as it were. The emergence of a Chinese middle class as the countries economy grew in the 1980s led to a rapid escalation in demand for the soup and the fins used to make it.
Fishermen all over the globe were pleased to oblige. Shark fins were easy to process-sun drying on the deck would suffice-and they did not take up any valuable freezer space that was reserved for the meat of other species like tuna or cod. The fins were easily shipped around the world and most ended up in mainland China after having been sorted, graded and traded in Hong Kong, the world’s largest shark fin trading post. Interestingly enough the fins themselves contribute virtually none of the taste to the soup. A shark’s fins are made up cartilaginous rods that fall apart when boiled to produce a thick mass of what become, for all intents and purposes, noodles.
Although the shark fin trade is extremely secretive, it has been estimated that somewhere between 22 and 73 million sharks are killed each year to supply this trade. While this figure is frighteningly large, we lack the year-by-year, species-by-species and region-by-region breakdowns necessary to assess sustainability and make informed, effective management decisions for shark species in the trade. However, probably a direct result of this neglect, there are numerous published studies and assessments showing that sharks around the globe are in serious decline.
This month, proposals from the United States, Palau and the European Union will seek to list seven sharks that are staples of the fin trade under a treaty called CITES (Convention on International Trade in Endangered Species). If these proposals for listings under Appendix II of the treaty are accepted, then all of the countries that are parties to the treaty would be required to carefully monitor the imports and exports of these sharks to ensure that the trade is not detrimental to the survival of the species.
Why do we need to be especially careful when it comes to monitoring and managing the impact of fishing on sharks? Most people don’t realize that when is comes to reproduction sharks are much more like us and other mammals than they are to other fish. Many of the large sharks that feature in the fin trade reach sexual maturity at the same age or later than we do. While bony fish release millions of eggs into the water column and these are fertilized to become vast numbers of fast-growing, planktonic larvae, females of many shark species are internally fertilized and most have a pregnancy that is nine months or longer. Relatively small numbers of young are produced (2-20 is normal for many species) and, like human babies, the young of some species are born with a belly button because they are nourished with a placenta.
Before the intensifying fishing pressure of the last several decades, many large sharks suffered very little natural mortality once they reached maturity and lived for 30-50 years or more. When fisheries turn their attention to sharks-especially when motivated by exorbitant prices paid for the fins-it is clear that sharks simply do not have the reproductive capacity to keep pace with anything but the most careful and sparing harvests.
One species up for listing under Appendix II of CITES is the scalloped hammerhead shark (Sphyrna lewini). This is the species that you may have seen on the Discovery Channel forming schools around Cocos or the Galapagos Islands, which generates substantial local dive-tourism revenue. Despite their vast and sustainable value alive, the fins of a dead scalloped hammerhead shark ultimately fetch about $USD 120/kg. With this kind of price on their head, it is not surprising that this species is targeted by fishermen nearly everywhere it occurs. Along the U.S. eastern seaboard and Gulf of Mexico several researchers have looked at the trajectory of this population have found declines of 75-90% over in the past 20 years, almost all of which can be attributed to the fin trade since the meat of this species is not commercially valuable. A recent study used DNA to trace scalloped hammerhead fins on sale in Asia back to their country of origin and found that 21% of them came from the Western Atlantic Ocean, including the U.S.A. and Gulf of Mexico. Other fins were traced to the Indian Ocean, while others were traced to the Pacific, showing that the trade in scalloped hammerhead fins is globally-sourced and as such requires the global monitoring network that CITES can provide.
Given the basics of shark biology it would seem that using CITES to keep a closer eye on the global fin trade—and obtaining the data needed to ensure that a complete trade ban does not become necessary—should be a no-brainer. To their credit, together with the proposing parties (U.S.A., EU and Palau) a number of countries have already come out in support of this measure and a panel of fisheries experts with the United Nations Food and Agriculture Organization (FAO) has also voiced its official support for most of the proposed listings.
Not too surprisingly the country that consumes the most fins and makes the most money from the trade-China-has voiced its opposition to the proposal. They will no doubt bring up arguments that CITES is the wrong venue, or that monitoring the trade is too expensive, all the while ignoring the fact that a future trade ban or collapse of large sharks—which are the certain outcomes of the current trajectory—will do far more damage to the industry and the traditional consumption of the soup than the current proposals will. After several decades of largely unrestrained hunting of sharks and unmonitored trade in their fins, it is imperative that the international community votes to lift the shroud of secrecy off the global shark fin trade.
Demian D.F. Chapman, Ph.D. is Assistant Professor, School of Marine and Atmospheric Science, and Assistant Director of Science, Institute for Ocean Conservation Science
Stony Brook University, Stony Brook, NY 11794, USA.
Phone (work) 631-632 8731
Phone (cell) 954-552 6595