Why should we be concerned about shark conservation?
Sharks tend to be at or near the top of the food chain. As apex predators, they are believed to play an important role in regulating numbers of the prey animals on which they feed. Their removal from the ecosystem can have drastic and unpredictable consequences! A good example is provided by a study from America, which found that as the abundance of large sharks had fallen (due to overfishing) the population of cownose rays (a favorite prey of sharks) had increased. As the population of rays increased they decimated the population of scallops (a favorite food of rays), which led to the eventual collapse of a century long scallop fishery and the loss of thousands of jobs.
Sharks have survived largely unchanged for some 400 millions years and form a unique and fascinating group of animals. They have the potential to be important in fields such as human medicine, and, when fished responsibly, can provide a valuable source of food.
The life history of sharks is such that they are very vulnerable to overfishing. Typically, sharks grow slowly, mature late and give birth to few young. These characteristics mean that only a small proportion of a given shark stock can be caught on a sustainable basis. Also, if a shark stock has been overfished, it takes a long time to recover.
Threats to sharks
Historically, shark fisheries tended to be small-scale. Since the 1980s, however, sharks have been targeted increasingly. Declining catches of traditional food fish led to a search for alternative resources with which to feed the world's growing human population. Sharks were obvious candidates. One estimate in the 1990s was that the global shark and ray catch may exceed 1.3 million tons, or more than 100 million individuals. Although this is a small percentage of the world's total fish catch, there is concern that catches may be unsustainable in the case of some shark populations.
About half of the world's total shark and ray catch is taken as bycatch. This means that the catch is unintentional, and is taken in fishing operations which are actually targeting other species. For example, as many as six million blue sharks may have been caught annually in recent years, mostly as bycatch. This kind of catch is very difficult for the fishing industry and the authorities to control.
One of the reasons for the increased targeting of sharks has been the growing trade in shark fins. Shark fin soup is an expensive delicacy and fishermen are able to sell fins for a much higher price than they are able to sell shark meat. This has led to the wasteful and inhumane practice of finning, in which the fins are cut off the sharks, which are often still alive, and the bodies are then dumped back in the ocean. Some countries, including South Africa, have now banned finning.
Fisheries for high value fish are often well regulated by national authorities. Historically, however, fisheries managers have neglected shark fisheries because of their low value. This means that accurate information on catches and detailed understanding about the life history of commercial shark species has been lacking. Also, it means that few fishing nations have adequate management plans for their shark stocks.
International conservation efforts
The Shark Specialist Group of the IUCN (World Conservation Union) is assessing the conservation status of many species of sharks and rays, thus identifying those which require urgent attention (www.redlist.org). At the urging of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora), the United Nations Food and Agriculture Organisation (FAO) has asked all states which have shark fisheries to draw up management plans to ensure their sustainability. South Africa has drafted a plan in response.
Legislation protecting sharks in South Africa
The Marine Living Resources Act (Act 18 of 1998) controls the exploitation of marine plants and animals in South African waters. There are a small number of regulations that pertain to sharks, most but not all of which are summarised below. The great white shark is totally protected; in 1991 South Africa being the first country in the world to do so. If caught or killed unintentionally, a white shark must be kept in a whole state and handed over to a fisheries officer. No white shark, part or product thereof may be sold. In 2005, the whale shark and the basking shark were added to the prohibited species list (pdf download).
Other shark species may be caught for recreational and commercial purposes. An important item of the legislation states that finning - the process of removing the fins and then discarding the carcass - is prohibited. Fins may be separated from carcasses but must be landed together with a fin-to-carcass (dressed-weight) ratio of 8% for domestic vessels and 5% for foreign vessels.
Four shark species are classified as recreational species in that they can be caught in the recreational fishery but they or parts thereof may not be sold. They are the raggedtooth shark Carcharias taurus, the spotted gully shark Triakis megalopterus and two species of small catsharks, the leopard catshark Poroderma pantherinum and the striped catshark P. africanum. There is a daily bag limit of one per species, but a total bag limit of 10 sharks of any species. Commercial fishermen are not restricted by these bag limits, but limiting the number of licences allocated within a particular sector controls the total fishing effort.
There have been complaints of sharks hooked on rod and line being maimed because they prevent the anglers from landing their target fish, either by taking the bait directly or by eating the fish once they are hooked. The regulations state that there may be no dumping or discard at sea of any fish species for which there are restrictions. This implies that the maiming of sharks is illegal, albeit that the legislation is aimed at resource management rather than preventing cruelty.