Shark Read online

  Economic and social reforms in China from the 1980s, and the emergence of a new Chinese middle class, resulted in a great increase in demand for shark fins. Documented world production of fins jumped from 2670 tonnes in 1976 to 6300 tonnes in 199711 and by 2006 was some 10 000 tonnes.12 This represents a fourfold increase in shark slaughter over three decades, essentially for one product, soup. CITES, the Convention on International Trade in Endangered Species, lists the great white shark, basking shark and whale shark, all three of which are exploited by the fin trade, though it is possible that their huge fins are rated more for their visual advertising potential—‘trophies for display’—than their taste.13

  Sharks’ fins drying in Callao, Peru, April 2007. (Oceana/LX)

  It is very difficult to police the illegal taking of fins, whether from protected species or in protected waters. For example, some Ecuadorean fishermen illegally cut fins from protected Galápagos Island sharks and sell them in Ecuador, where it has been legal to sell fins from sharks caught accidentally—the loophole being that it is almost impossible to prove how the shark was caught. The fin trade is attractive there because it is much more lucrative and less labour-intensive than traditional tuna fishing.14

  In 2006, a first-time study into the shark fin trade based not on unreliable fisheries estimates but on auctions in Hong Kong, the world’s main shark fin market, was published. Its findings into the ‘secretive and wary’ shark fin trade were depressing but not surprising. It established that shark exploitation for the finning trade is up to four times greater than an FAO estimate, with a mean total of 38 million sharks being killed per year, this figure rising to a median of 62 million (depending on species and types of fins used in the rigorously controlled statistical methodology).15 But even that is not the full picture:

  In addition our trade-based biomass calculations may underestimate global shark catches. For example, due to the lack of data on domestic production and consumption of shark fins by major Asian fishing entities such as in Taiwan and Japan, unless exported for processing and then re-imported, these fins are not accounted for within our methodology . . . Furthermore, shark mortality which does not produce shark fins for the market, eg. fish mortality where the entire carcass is discarded, is also not included. These discrepancies suggest that world shark catches are considerably higher than reported, and thus shark stocks are facing much heavier fishing pressures than previously indicated.16

  Shark fins are not the only part of the animal reputed to have curative effects on human ailments. Shark liver oil contains high levels of squalene, which is used in cosmetics and as a health product. In Australia, as elsewhere in the world, squalene is marketed as having a range of benefits, namely the temporary relief of arthritic pain, improved appearance of skin and hair, reduction in joint inflammation and swelling associated with arthritis and increase in oxygen uptake capacity. It is also claimed to reduce blood lactate levels, boost stamina and endurance, possibly reduce joint swelling and inflammation associated with gout and act as an anti-oxidant.17

  Shark cartilage is wrongly touted as a cure for cancer. The theory is that because sharks have cartilage rather than bone and sharks do not get cancer, therefore cartilage must have anti-cancer properties. (Sharks are, in fact, susceptible to a range of cancers.) Cancers require a blood supply and cartilage has no blood vessels. If cartilage has properties that prevent the formation of blood vessels, then such properties might be able to combat the development of cancerous tumours. The United States is a major producer of shark cartilage products, exporting to some 35 countries as interest in its possibilities as an alternative health product increases. Blue shark cartilage is considered to be the finest. An FAO report on non-food uses of cartilage states that:

  Many claims, not scientifically proven, attribute to shark cartilage the role of being beneficial in cases of asthma, candidiasis, eczema, allergies, acne, phlebitis, peptic ulcers, haemorrhoids, arthritis, psoriasis, diabetic retinopathy, neovascular glaucoma, rheumatism, AIDS and above all cancer.18

  Sharks are also taken from the wild for the aquarium trade. Some small shark species such as the bamboo shark, epaulette shark (Hemiscyllium ocellatum) and coral catshark (Atelomyctus marmoratus) adapt reasonably well to captivity; others grow too large to be kept in any kind of contained environment. Some species, particularly the great white, have a history of dying when kept in captivity, although sharks are found in all major public aquaria. The Sydney Aquarium, one of the largest and most modern in the world, has numerous species including blacktip reef sharks, zebra sharks (Stegostoma fasciatum), lemon sharks (Negapriou acutideus), crested hornsharks (Heterodontus galeatus), Port Jackson sharks (Heterodontus portusjacksoni), wobbegongs, eastern fiddler rays (Trygonorrhina fasciata) and southern eagle rays (Myliolsatis australis). In 2007, for the second time, one of the aquarium’s critically endangered grey nurse sharks gave birth to a single live young. Not all aquaria are accredited research facilities, however. The black market trade in sharks for the private aquarium industry is thriving.

  Shark cartilage in capsules and a jaw in a shop window, Madrid, Spain, 2008. (Oceana/XL.)

  Sharks and rays are vulnerable to all forms of commercial fishing, by the logic of which their only intrinsic worth is their economic value:

  Fishers identified the time required to repair damaged and lost gear from shark interactions, and to remove sharks to be discarded from gear, as a substantial problem. Lost revenue from shark damage to target species can amount to several thousand U.S. dollars in a single set in some fisheries. In some of these fisheries, there is large interest in minimizing shark interactions. On the other extreme, there are pelagic longline fisheries where revenue from sharks exceeds costs from shark interactions, a large proportion of caught sharks are retained (> 99% in some fisheries), and sharks are either always an important target species, are targeted seasonally or at certain fishing grounds proximate to ports where there is demand for shark products, or are an important incidental catch species.19

  Some commercial fishers now avoid areas of high shark concentration, or move when sharks arrive in large numbers. Using fish rather than squid as bait seems to reduce shark interaction, as does deep-setting of hooks. A range of measures to minimise bycatch—bycatch reduction devices (BRDs)—have been introduced, including new net designs, new hook types and sorting grids, which can separate out catch by size and release the non-targeted fishes. Electromagnetic devices known as SharkPods may be set on longlines to repel sharks. Such innovations are, however, expensive, and the numbers of many species of sharks and rays still being caught are unsustainable.

  Bottom trawl netting scoops up untold numbers of rays and benthic sharks, in the process destroying fragile seabed ecosystems. It has been described as the fishing industry equivalent of native forest clearfell: ‘Trawling has a devastating effect, ripping apart delicate benthic communities and depleting fish stocks . . . Areas that are fished heavily have been reduced to bare rock, coral rubble or sand . . . Scientists are not sure how long the coral takes to recover, if at all’.20 Midwater longline fisheries are little better, hooking vast numbers of blue sharks, as well as other predators that follow the target shoals, particularly oceanic whitetips, porbeagles, makos and hammerheads.

  Recreational fishing takes its toll. Some large species of shark, such as threshers, makos and salmon sharks, are considered to be great sport to fight on rod and reel. There is a growing tendency to ‘catch and release’, but the ‘macho’ aspect of ‘beating’ a big shark, as immortalised by Ernest Hemingway and Zane Grey, means that the world will never be rid of photographs of proud fishermen standing next to huge, dead sharks. Then there is recreational fishing for the table. One of the longest state coastlines in the world is that of Western Australia. State government statistics indicate that some 34 per cent of WA’s population of two million indulges in recreational fishing, which in 2007 contributed AUD$570 million to the economy.21 Similar statistics apply across all other Austral
ian states. The commercial and recreational shark catch off Queensland’s coast increased by more than 300 per cent between 1988 and 2003, and yet ‘the extent of recreational shark fishing is unknown’.22

  Novelist Ernest Hemingway with trophy—a large tiger shark. (John F. Kennedy Presidential Library, Boston, Massachusetts)

  A landmark 2006 publication, Economically Important Sharks and Rays of Indonesia, resulting from collaborative studies by Indonesian and Australian institutions, marks an important point at which exploitation moves from being unchecked to managed, with the next logical step being conservation. The Indonesian experience is critical, given that it is the world’s fourth most populous country and, being a nation of islands, relies heavily on seafood. As noted at the beginning of this chapter, it also heads the FAO’s table of top twenty shark-catching countries. The introduction to the 2006 publication states: ‘Although Indonesia has the largest chondrichthyan fishery and is considered to have one of the richest chondrichthyan faunas in the world, there are almost no published biological data or size compositions of species landed’.23

  If we do not know what is being taken out of the water, we can only guess what remains—not just in Indonesian waters but globally. Ultimately, the economic benefits of harvesting sharks can never be greater than the economic benefits that will result from ensuring that they continue the role they have played for millions of years, that of keeping our seas healthy.

  8

  SHARK CONSERVATION

  Problems, Solutions

  Every September, one of the world’s largest and densest congregations of great white sharks assembles in the waters surrounding the Farallon Islands, a 211-acre archipelago of ten islets in the Pacific, twenty-seven miles due west of the Golden Gate Bridge. No one fully understands what this gathering represents, why great whites, the ocean’s most solitary hunters, choose to reside for a period of time in such close quarters . . . year after year, the same sharks return to exactly the same spot.1

  There is beauty in mystery, and part of the wonder of the natural world is that there is so much that we do not yet, and perhaps never will, know or understand about its inhabitants. Certainly, the great whites gather at these islands to feed off their seal colonies, but their associated socialising remains unexplained, as do their their long-distance movements, despite satellite tracking. Alas, our lack of respect for many of the species with which we share this planet means that it is now imperative for us to learn as much as possible, as quickly as possible, about shark behaviour, be it that of the great white or the humble skate. If we don’t, the planet’s seventh mass extinction event, the one we have set in motion, will see many elasmobranch species disappear.

  It is said that statistics do not lie. The following statements are taken from various conservation and government sources around the world. Their accuracy may not be uncontestable, but the picture they paint is bleak:

  The International Food Policy Research Institute in Washington has calculated that more than 20 million tonnes a year of fish and other marine organisms are discarded at sea. This is the equivalent of nearly 20 per cent of the world’s total annual consumption of fish.2

  [Asia] has the world’s largest fishing fleet, with 42 per cent of its registered tonnage. The Asian Development Bank says that these vessels have twice the capacity needed to extract what the oceans can sustainably produce. The result, according to the bank, is a vicious circle: as catches per vessel fall, profits plummet, and fishers overfish to maintain supplies, causing serious depletion of stocks and endangering long-term availability.3

  More than 125 countries around the world now trade in shark products contributing to an uncontrollable surge in the number of sharks taken from the oceans. In a little over 50 years the slaughter of sharks has risen 400 per cent to approximately 800,000 metric tons per year.4

  If one billion people each ate one shark fin per year, and there are assumed to be 5 usable fins per average shark (pectorals, dorsals and caudal fin), they would consume 200 million sharks per year. Clearly the capacity for the human populace to consume sharks, much less kill them deliberately or inadvertently or to ruin their habitats, is far more enormous than the shark’s ability to compensate for this by reproductive surplus, which is adjusted to natural vagaries and not an all-consuming ultrapredator.5

  A female spiny dogfish may give birth to about 20 pups, but these need 20 to 30 years to reach sexual maturity, and pregnancy itself lasts about 22 months . . . The probability is thus very high that an animal is caught even before it has had a chance to reproduce.6

  The great white shark, often referred to as the ‘maneater,’ with its bluish grey black and white belly remains the favourite of most shark fishermen here since it has large fins that fetch a high price. Other species of shark—hammerhead, dogfish, tiger, bluntnose sixgill and a host of others abound in Ghana’s waters. ‘At least we get paid between $30 and $40 for every kilogram of dried shark fins we supply, this is not bad,’ Kweku Essuman disclosed with a smile. But in Singapore, Taiwan and Hong Kong, the largest centres of the shark fin trade, middlemen are paid $265 to $300 for the same kilogram of dried shark fins.7

  Overexploitation of elasmobranchs (sharks, skates, and rays) is known to have already nearly eliminated two skate species from much of their ranges . . . Our results show that overfishing is threatening large coastal and oceanic sharks in the Northwest Atlantic . . . The trend in abundance is most striking for hammerhead sharks; we estimate a decline of 89% since 1986 . . . The trend for white sharks was an estimated 79% decline . . . Tiger shark catch rates declined by an estimated 65% since 1986 . . . The trends for oceanic sharks have also shown decline. We estimate that thresher sharks . . . have declined by 80% . . . Blue sharks declined by an estimated 60% . . . The oceanic whitetip shark declined by an estimated 70% . . .8

  Historically, due to their fierce appearance and being mistaken for other sharks that pose a danger to humans, large numbers of Grey Nurse Sharks were killed by recreational spear and line fishers and in shark control programs, particularly in south-eastern Australia . . . The number of Grey Nurse Sharks in NSW could be as low as 292 . . . There are concerns that this population has fallen to such critically low numbers that individual animals are now failing to find mates and successfully reproduce. In addition, fishing activity, particularly recreational line fishing, is thought to be impacting severely on the existing Grey Nurse Shark population.9

  The International Union for the Conservation of Nature’s (IUCN’s) Red List features many species of sharks in its various categories, along with many other species of marine life, mammals, amphibians, reptiles, birds and plants. Those in the categories Critically Endangered, Endangered, and Vulnerable are all considered to be threatened with extinction. ‘Critically Endangered’ means just that: as in the example above of the grey nurse shark, if a certain level of species reproduction is no longer certain then a life form may be considered to be biologically extinct. The grey nurse shark is without doubt faced with extinction in eastern Australian waters; elsewhere however its numbers are less imperilled and so the species as a whole is listed only as Vulnerable. At the other end of the list, numerous shark species are described as ‘Data Deficient’, meaning that their status cannot be defined. One such example is the salmon shark, which is accepted as being common in its ranges. But this counts for little in the exploitation–conservation war. The salmon shark is

  a broad-spectrum predator that occupies a very high trophic level in subarctic waters of the North Pacific, and thus probably plays an important role in stabilizing the marine ecology where it occurs; recently, there has been a major attempt to launch a commercial fishery for this species off Alaska, where it does not appear to be migratory yet the basic life history parameters (population size and structure, recruitment and natural mortality rates, etc.) necessary for intelligent management of its stocks are poorly known; this seems a recipe for ecologic and economic disaster.10

  Along with the salmon shark,
those considered most at risk by the IUCN include the great white, whale shark, megamouth, basking shark, thresher, bigeye thresher, pelagic thresher, silky shark and the shortfin mako shark, Ganges shark, Borneo shark, speartooth shark, blacktip reef shark, tope shark, porbeagle, hammerhead shark, blue skate, barndoor skate, bowmouth guitarfish and at least ten ray species, including the spotted eagle ray. There are many complexities involved in grading life forms according to their future chances of survival. In 2007, an IUCN workshop was unable to accord the blue shark a higher threat rating, despite it being possibly the most exploited of all pelagic sharks (through finning), because the experts ‘could not reach consensus that the species is threatened with extinction on a global scale’.11 Elsewhere it has been pointed out that most of the 1200-plus species of sharks, skates, rays and chimaeras are not listed. ‘Are any of them threatened? Of course they are.’12

  Inshore recreational fishing takes an additional toll of sharks. In most developed countries, the introduction of bag limits and total allowable catches has gone some way towards fish stock management, but the reality is that takes began to decline as long ago as the 1970s, indicating a considerable fall in shark numbers, so the continued practice represents unsustainable exploitation. Defenders of recreational fishing counter-argue that well-kept records stretching back decades and ‘tag and release’ programs provide accurate data on species distribution, population and migratory habits, and that researchers have obtained much biological information from sharks taken by anglers at gamefishing tournaments. It’s an advance on the notion that the best shark was a dead shark, but the survival rate of sharks caught and released is unknown, and the physical trauma associated with capture can’t be ignored: