Shark Conference 2000
Honolulu, Hawaii February 21-24
|SHARKS, FISHERIES AND BIODIVERSITY|
Shark Research Center
SRC report 2000-02-21
It is widely perceived at present that 'sharks' have major conservation problems from overexploitation by fisheries because of their biological peculiarities, although they are also beset by problems of habitat degradation. This perception of sharks as victims of progress is very new, and essentially a product of the last decade of the 20th Century. A stumbling block in dealing with the 'shark problem' is that the public, fisheries and research concepts of 'sharks' tends to focus on only a small fraction of the approximately 1165 species of sharklike fishes or 'sharks' in a broad sense (as adopted by the 1998 FAO shark action plan), the Class Chondrichthyes. These include at least 50 species of silver sharks (chimaeras), 627 species of winged sharks (batoids), and 488 species of 'non-batoid' sharks or ordinary sharks.
Most sharks are affected in various ways by the burgeoning human species, particularly as mostly utilized or non-utilized bycatch in fisheries, but the batoids and chimaeras tend to go under the perceptual radar in most places. The non-batoid sharks are mostly ignored or little-studied, except for some small but important fisheries 'bread and butter' species and a subset of large spectacular pelagic species with a high human profile. Most sharks of all kinds are relatively small, between 0.3 and 1.5 m long maximum, with few species over 2 m long. Of these, the relatively few large littoral and oceanic carcharhinoid and lamnoid sharks, the 'large pelagic sharks', get the most attention, primarily over the finning issue and catch declines in the North Atlantic and elsewhere. Many of the same species got the most attention when the focus was on 'shark attack' not so long ago and sharks were considered vermin and monsters. In addition there are 'supersharks', a few gigantic wide-ranging, non-batoid sharks and batoids (such as the white, whale and basking sharks and manta rays) with separate constituencies and major conservation problems from extreme limits in life-history parameters and very high values for fins, flesh, jaws and other products.
It is easy and tempting for fisheries managers and bureaucrats to see the problems with sharks as increasingly their problems, to be solved by sound fisheries management of important commercial species, and to limit their focus on the more important fisheries species of non-batoid sharks. It is equally easy for conservationists to see the problems of sharklike fishes through a fisheries filter. Bureaucracy and management of fisheries cannot escape politics, and some aspects of the current concern for sharks relates to political strife, in which nations compete for increasingly scarce marine resources. The fisheries problems with shark exploitation exist in a broader framework of human impact on the biodiversity of virtually the entire Class Chondrichthyes, and is exacerbated by the limited biological knowledge, including basic systematics, of the group. Although sound fisheries management is essential for many species including many that are not being managed at present, sound management of biodiversity with a broad focus on biology is necessary for the entire group. Many sharklike fishes are rare or have a limited habitat and geographic distribution, are largely ignored by fisheries managers, and may be under considerable risk of extinction from human factors. There are too many gaps in our knowledge of chondrichthyan faunas to manage this in many places, and basic knowledge of systematics, distribution, ecology, and behavior needs to investigated for many species and in many places. A proposal is made for a shark biodiversity center and a roving expedition to serve as a focus for wide-ranging biodiversity investigations in cooperation with fisheries researchers and other biologists.
It is widely perceived at present that sharks have major conservation problems from overexploitation by fisheries because of their biological peculiarities. These include an essentially mammalian or avian-like life history strategy with relatively slow growth, relatively long lives, and relatively low fecundity. It is becoming apparent, however that sharks vary considerably in life history, and that, although many of them are poorly known biologically, they vary a lot in life-history parameters, and, although all have limitations, some are much more limited than others as amongst birds and mammals. Litters or egg numbers range from one to 300 per year, although most have less than 50 young or eggs per year and many have less than 10. Some may mature in about a year while others mature at over 10 years old. Some have long gestation periods, nearly two years, while others have eggs that take a year to hatch. Sharks are also beset by problems of habitat degradation including pollution and habitat modification by human activities, which may be stark as poisoning river systems or destroying inshore breeding areas and reefs or as subtle as modifying climate.
The perception of sharks as victims of human progress (rather than the usual obsession of humans as victims of shark gustation) is very new, and essentially a product of the last decade of the 20th Century. Sharks were ignored or overlooked for various reasons by the expanding worldwide conservation movement from the 1960s onwards despite early warnings of the problems they faced from fisheries research during the 1940s and 1950s. These warnings stemmed from scattered work on directed or targeted fisheries on a live-bearing shark, the soupfin or school shark (Galeorhinus galeus) in California and Australia and on an egg-laying shark relative, the elephantfish (Callorhinchus milii), in New Zealand. The findings of this early work were that the low fecundity of sharks placed a strict limit on their exploitation. This was expanded and highlighted by the pioneering work of Michael Holden in the UK in the late 1960s and 1970s, who noted that targeted shark fisheries tended to rapidly decline after initial high catches and in some cases collapsed entirely. In many species long maturation times coupled with low fecundity allowed for little reproductive surplus and flexibility to compensate for increased mortality through fisheries (essentially increased predation through human agencies). Fisheries mortality caused the number of reproductive adults to decline, which in turn caused a decline in recruitment of young to the population, in a cycle that could result in collapse of the fisheries or even extinction. In contrast egg-laying bony fishes with high fecundity and small pelagic eggs a different pattern, in which recruitment rate is partly decoupled from adult population size because of vast surpluses in reproductive potential through broadcasting of enormous numbers of eggs. Some larger sharks with inshore nurseries face an additional problem as their young are fished alongside small species of sharks and other marine life and may be highly desirable as catches. Recruitment in such species is hit from both ends of the growth curve towards the middle, often by differing fisheries.
Holden's findings met with limited interest from shark researchers at the time, some of whom were preoccupied with narrow anthropocentric issues such as 'shark attack' on people and marine gear and 'anti-shark measures' to prevent 'attacks'. Also, during the early 1980s, a focus developed in a few places, most notably in the USA, on sharks as underutilized resources for human consumption following the 'Jaws' popularization phenomenon. Sharks in these areas were often regarded as trash fish of lower value than other fishes and were slated for disposal (discarded bycatch) or limited use as best. They were often regarded as pests or vermin that competed with fisheries for more valuable marine organisms and which damaged fishing gear. The bad reputation 'sharks' had or still have as 'man-eaters' did not help their conservation status.
The 'Jaws' motion pictures in the late 1970s helped to promote a greatly increased and ever-expanding public interest in sharks, particularly in the First World and ultimately world-wide, but also resulted in increased capture, killing, utilization and exploitation of sharks in certain countries. The 'Jaws' image of sharks as demonic man-eaters did not help the cause of shark conservation during this period, although a few researchers had pointed out in the early 1980s that 'shark attack' was a minuscule and unimportant issue compared to the vast problem of 'human attack' on sharks in the form of fisheries. At the time at least one researcher (the late Tom Thorson) noted that freshwater sharks were at high risk of extinction. The negative image of sharks also inhibited shark research, which did not develop the major support received by marine vertebrates with positive public images such as seabirds and marine mammals (particularly cetaceans). During the mid-1980s support for shark research hit a trough as funding on issues related to 'shark attack' (including basic and important research on sensory physiology) dried up as the US Navy, the main supporter of shark research in the USA, essentially solved its shark problems and downsized research support. Also, an important shark research program in South Africa collapsed as pragmatic solutions (extensive beach netting) to 'shark attack' were found. Funding for shark research, despite major publicity on the problems of shark conservation, hasn't quite recovered to this day.
A US-Japanese workshop on elasmobranchs as living resources was held in Hawaii in 1987, and a volume of its proceedings was published in 1990. This may have been pivotal in focusing on and legitimizing the conservation problems that sharklike fishes face from human activities. Considerable detailed information was presented on regional issues of shark fisheries and exploitation, with different national groups focusing on conflicting issues. However, an attempt was made to focus on conservation issues raised by world shark fisheries utilizing fisheries statistics published by the United Nations Food and Agriculture Organization (FAO) since 1947. World fisheries catches rose five-fold from the 1940s to the 1990s, but shark fisheries rose only about 3.5 times and declined from about 1.0% to 0.7% of the total catch in the same period. Although sharks were probably underexploited at the beginning of this period it wasn't the case forty years later as catches declined in many regions and some targeted fisheries collapsed. In the late-1990s reported catches of sharklike fishes were about 730 thousand metric tonnes worldwide, compared to about 100 million metric tonnes of all fisheries reported to FAO. Actual catches were estimated as being double the reported catch, which would be 146 million individuals caught per year on the assumption that each shark, ray, or chimaera caught weighed 10 kg. This seems large but isn't compared to the ultimate force driving these catches, the expanding human population: Over 6 billion large omnivorous mammals with a collective biomass of roughly 300 million metric tonnes assuming 50 kg per individual and a 28 year time for doubling its population. Such statistics are somewhat science-fictional and arbitrary, but the shark catch per year using such thumbsuck estimates is 0.5% of the human biomass and 2.3% of the number of humans, and equivalent to one person eating 0.25 kg of shark per year or roughly two 10 kg sharks every hundred years. If one billion people each ate one shark fin per year, and there are assumed to be 5 usable fins per average shark (pectorals, first dorsal 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.
PERCEPTIONS OF SHARKS. A stumbling block in dealing with the 'shark problem' is that the public, fisheries and research concepts of 'sharks' tends to focus on only a small fraction of the approximately 1165 KNOWN species of sharklike fishes or 'sharks' in a broad sense (as adopted by the 1998 FAO shark action plan), the Class Chondrichthyes. These include at least 50 species of silver sharks (chimaeras), 627 species of winged sharks (batoids or rays), and 488 species of 'non-batoid' sharks or ordinary sharks. The living cartilaginous fishes are divided into two groups with a long separate, pre-Devonian history, the silver sharks or chimaeroids, Holocephali, and the sharks and rays proper or Elasmobranchii with the surviving group Neoselachii comprising all the living species. There is a traditional bias in the taxonomic literature for dividing the living Neoselachii into sharks, Selachii or Pleurotremata, and rays or batoids, Batoidea or Hypotremata. Modern cladistic classifications rank the rays as a subset of the sharks, so it is useful as a conceptual exercise to consider them sharks, flat sharks, winged sharks (William King Gregory's concept, analogous to birds relative to theropod dinosaurs), or Sonny Gruber's 'pancake sharks', which tends to bring them out of the perceptual cold. The batoids and chimaeras tend to go under the radar in most places, and there was resistance to including the chimaeroids as 'sharks' from some quarters during the FAO debates in 1998. Much debate also continues on the origin of birds, with most scientists favoring descent of birds from theropod dinosaurs and some vociferously opposed to it; some researchers have ranked theropod dinosaurs that are not birds as 'non-avian theropods', as distinguished from avian theropods or birds. The evolution of batoids from sharks parallel the origin of birds; so I use the term 'non-batoid sharks' for all neoselachian sharks other than batoids, and rays, batoids, or batoid sharks for rays. Some of the batoid sharks at present are as important for fisheries or more so than non-batoid sharks, and some are under severe threat from overexploitation. The Japanese have a useful term, ginzame or silver shark, for chimaeroids, which may help to conceptually unite the neglected and obscure chimaeroids with the non-batoid sharks.
Most sharks are affected in various ways by the burgeoning human species, particularly as mostly utilized or non-utilized bycatch in fisheries but probably also from habitat modification or destruction. Fisheries are documented by statistics, however adequate, but habitat modification is harder to monitor. The non-batoid 'ordinary' sharks are little-studied, except for some small but important 'bread and butter' fisheries species and a subset of large spectacular species with a high human profile. Most sharks of all kinds are relatively small, between 0.3 and 1.5 m long maximum, with few species over 2 m long.
Compagno (1990) made an attempt to grade the living species of non-batoid sharks into four qualitative categories of importance to fisheries, which can be extended to other sharks:
Rare and unusual or uncommon species of sharks that are not known from fisheries or are occasionally taken in fishing operations. Included are most deepwater catsharks (Scyliorhinidae, Proscylliidae, Pseudotriakidae), many deepwater benthic and oceanic dogfish (Squaliformes), frilled sharks, megatooth sharks, bullhead sharks, some sawsharks (Pristiophoriformes), many skates (Rajoidei), some stingrays (Myliobatoidei), and many chimaeroids.
Species that are regularly caught in small numbers and utilized but are not important because of limited value and numbers. Many dogfish (Squaliformes), angelsharks (Squatiniformes), carpetsharks (Orectoloboids), and certain lamnoids (some odontaspidids, mitsukurinids, pseudocarchariids), some skates (Rajoidei), some guitarfish (Rhinobatidae, Platyrhinidae, Zanobatidae), some stingrays (Myliobatoidei), and some chimaeroids.
Species that are regularly caught in substantial amounts or are caught in small numbers but are disproportionally valuable because of products made from them. Some hexanchids, some dogfish (Squalidae), some angelsharks (Squatiniformes), some sawsharks (Pristiophoriformes), some carpetsharks (Orectolobiformes), some lamnoids, numerous carcharhinoids, some guitarfish (Rhinobatidae), wedgefish (Rhynchobatidae), shark-rays (Rhinidae), sawfish (Pristidae), some skates (Rajoidei), many stingrays (Myliobatoidei), and some chimaeroids (elephantfishes).
Important fisheries species that are caught in large numbers or are caught in lesser numbers but are of high value. Spiny dogfish (Squalus acanthias), some lamnoids (threshers, porbeagles, salmon sharks, shortfin makos), some carcharhinoids (some triakids, several carcharhinids and two hammerheads), possibly some skates, and certainly some stingrays (Myliobatoidei, particularly Dasyatidae).
By this classification, approximately 8% of the non-batoid shark species are major, 20% moderate, 18% minor and 54% minimal fisheries species. Batoids and chimaeroids are not included here at present due to inadequate time to generate the numbers, but it is predicted that adding their numbers to the non-batoid sharks will increase the minimal category slightly at the expense of the other categories. Most species, however, are impinged by fisheries at some level, if only as rare and discarded bycatch. A limited focus on some nonbatoid sharks reflects, however, human perceptions of relative importance, and some species are the focus of more attention, particularly the large pelagic sharks and the 'supersharks'. Other minor, moderate, and even major fisheries species are 'bread-and-butter' sharks, relatively small species which may be important components of the directed catch and marketed bycatch of sharks, but are often little-studied (particularly the batoids).
LARGE PELAGIC SHARKS
Of the non-batoid sharks, the relatively few large, abundant littoral and oceanic carcharhinoid and lamnoids, the 'large pelagic sharks' (eg., blue sharks, shortfin makos, silky sharks, dusky sharks, sandbar sharks, etc), get great attention, primarily over the shark-fin issue and declines in numbers in fisheries in the North Atlantic and elsewhere. Many of the same species were featured when the focus was on 'shark attack' not so long ago when sharks were considered as vermin and anthropophagous monsters. Large nonbatoid sharks that are major and moderate fisheries species have a high media appeal and high profile, while the far more numerous small nonbatoid sharks, batoids and silver sharks get little recognition. Political strife between the dominant nations may have an influence in directing and channeling the perception of 'sharks' in the media as revolving around the conservation problems of the few, large, moderate and pelagic fisheries species, and there seems polarization around large, high-technology offshore fisheries (including gillnetting and particularly longlining, but also purse-seining) with a shark bycatch or primary catch, and with 'finning' (the removal of fins from sharks and discarding of their bodies, sometimes alive) being raised as an emotional animal-cruelty issue in the Western media as well as an issue of wastage in fisheries circles. This sets up an arena for potential international conflict, with sharks a hot-button side issue between various nations with major interests in the diminishing schools of offshore pelagic bony fishes and radically different approaches to fisheries and to conservation: East vs. West, our sharks vs. our tuna. Unfortunately there are no heroes on the commons of the open ocean, no more than saints on the battlefield, and all the fishing nations are causing or have caused problems to varying extents with sharks and other reproductively limited species (including cetaceans and sea birds), and with sharks probably not just with the high-profile, abundant large species. There is considerable if variably limited information on trends of major and moderate pelagic fisheries species, but relatively little is known about trends in catches of minor or minimal fisheries species such as crocodile sharks, longfin makos, whitefinned velvet dogfish, and bigeyed sand tigers. Pelagic batoids such as some mobulids and pelagic stingrays may have been adversely affected by fishing gear, but little is known about them.
Rather than econowar and hegemonism over hot-button issues, what one needs is international agreements, ultimately leading to abandonment or severe modification of conventional fishing gear on all sides and substitution of more catch-specific gear and techniques allowing sustainable catches of high-fecundity teleosts, and very limited and sustainable catches of low-fecundity species. A tall order, hard even with everyone being nice to one another, which they certainly won't be.
Unfortunately, sharks, including the high-profile large, moderate and major fisheries species but also small minor and minimal species, are discarded, complementary and utilized bycatch of the fisheries for oceanic fishes such as scombroids. Although the meat of most pelagic sharks isn't landed the fins of nonbatoid sharks are increasingly valuable and are saved in partial compensation for gear damage by unwanted sharks and for increasingly large profits. Fins don't compete with tunas (or afford limited competition if frozen) for freezer and hold space, and can be nicely harvested alongside the far more numerous scombroids. Because of different reproductive strategies, the sharks can be fished out by these fisheries without substantially altering the catches of tunas in the short term although long-term effects are hard to predict. With directed oceanic fisheries for sharks, including such major and desirable fisheries species as threshers or shortfin makos, the rare and unusual, minor and minimal fisheries species in turn may be fished out without affecting the short-term success of the fisheries (eg., longfin makos, crocodile sharks, pelagic stingrays, bigeye sandtigers, whitefinned velvet dogfish, cookie-cutter sharks, and others), although the major fisheries species will also collapse with sufficient pressure despite their enormous and often circumglobal ranges and (formerly) high biomass.
A recent addition to the conservation roster is termed 'supersharks', analogous to supermodels, a few gigantic wide-ranging sharks (particularly the white shark, whale shark and basking shark) with extremely high media profiles as individual species, separate ecotouristic and conservation constituencies that antedate the recent interest in shark conservation, and major conservation problems from extreme limits in life-history parameters. These also have very high values set on their fins, flesh, jaws and other products and are subjected to targeted fisheries. All the 'supersharks' are or may be showing local declines, and are protected or being considered for protection in various countries. Basking sharks have a major conservation constituency in the United Kingdom, and the government with its help is proposing the basking shark for CITES II listing. Basking sharks have been long fished in the North Atlantic for liver oil and have declined, but recently fin values have become exorbitantly high and have sustained diminishing fisheries. The whale shark has a major ecotouristic constituency in the tropics through diving with 'gentle giants', and this collides with an increasingly lucrative fishery and Far Eastern market for flesh, fins and other products. The white shark was elevated into supersharkdom by Hollywood, and apart from having large, increasingly valuable fins, has immensely valuable jaws and teeth for collectors. It has a constituency with cage-dive operators, thrill-seekers, ecotouristic divers and film-makers in conflict with big-game anglers, the fin industry and the collector's market, and is being proposed for CITES I listing by the United States and Australia. Another candidate for supersharkdom is the manta ray (Manta birostris), another 'gentle giant' plankton-feeder with an increasing constituency for ecotouristic viewing and film-making, coupled with extremely low fecundity and an unknown impact from targeted and bycatch fisheries. 'Supersharks' have been easier to support conservation-wise than more obscure species because of their anthropocentric appeal, although it has been an uphill battle for at least the white shark because of its JAWS-image reputation and status as a macho focus for would-be 'shark hunters'.
BREAD AND BUTTER SHARKS
There are large numbers of species of mostly smaller sharks that feature in inshore and offshore, continental and insular fisheries, range from minor to major fisheries species, and range biologically from essentially unknown to amongst the best-known of fisheries species. For the most part they achieve little focus and recognition as 'sharks'. Some of the best-known 'bread and butter' sharks are certain squalids, triakids, scyliorhinids, carcharhinids, squatinids, and rajoids, with a broad base of biological and fisheries research. Many species, including various orectoloboids (particularly Chiloscyllium), stingrays (Myliobatoidei), guitarfish (Rhinobatidae), wedgefish (Rhynchobatidae), many rajoids, and shark-rays (Rhinidae), are sketchily to poorly known biologically but are the subject of moderate to heavy fisheries. As discovered by the recent study of shark biodiversity in Sabah, Indonesia funded by the U.K. Darwin Initiative program, there may be 'bread and butter' species that are being harvested daily but may comprise new geographic records or may be new to science.
The late Sid Cook and the present writer have treated freshwater sharks (which are mostly batoids) in detail in several papers elsewhere. These sharks comprise roughly 5% of the world shark fauna, and comprise minor fisheries at most. In addition to the biological factors constraining marine elasmobranchs, they suffer physically restricting environments that increase their vulnerability to natural and human-made problems including fisheries, pollution and habitat destruction. Freshwater carcharhinid sharks and sawfishes may be finned (and sawfishes de-sawed) as well as utilized for their flesh, but freshwater stingrays yield edible flesh but not fins. Many species of freshwater stingrays figure in the aquarium trade, but little is known of its impact upon them. Most species are poorly known biologically, and many are poorly known taxonomically, which increases their risk from human factors. Until recently freshwater sharks received little notice as having any conservation problems, yet some of them may be at greater risk of becoming extinct than other sharks, particularly obligate freshwater endemics in restricted river systems. They still tend to slip under the perceptual radar because they are not spectacular, for the most part, and live in the tropics away from the action in the First World or on the high seas.
THE REST OF THEM
Most sharks are minimal fisheries species, or are subjected to minor specialized fisheries including deep-water fisheries for squalene oil, flesh, etc. Diversity is high but international realization of the existence of 'none of the above' sharks is low, and there are areas such as the Indo-Australian Archipelago and the entire tropical Indian Ocean where the possibility of collecting new species and new records is very high, particularly on the outer shelves and on the slopes but even close inshore. The massive increase in knowledge of the shark fauna of Australia, summarized in Peter Last's and John Stevens' monumental 1994 book, showed the way forward to further exploration and discovery in the Indo-Australian Archipelago, as has Bernard Seret's work off New Caledonia. Australia has proved to have a very rich shark fauna, including numerous endemic species (many undescribed) that are of limited or no interest to fisheries, have limited geographic and bathymetric ranges, and are inherently vulnerable to conservation problems including habitat degradation, pollution and fisheries pressure. Many smaller inshore and offshore sharks (including scyliorhinid catsharks, some squaloids, guitarfishes, wedgefishes, skates, and torpedo rays) are localized in island groups or may be confined to the coasts of one country (national endemics) or to a group of contiguous nations (regional endemics). Deepwater sharks of the continental slopes are sketchily known, and few nations have had the means or opportunities to fully or even extensively explore their deep water shark faunas. Slope faunas are best known in the North Atlantic and North Pacific, and off Australia, New Zealand and South Africa, and sketchily to poorly known elsewhere. The advent of scuba diving and underwater photography, coupled with easy international travel, has allowed divers to penetrate little-known habitats and to photograph sharks that can be an embarrassment to systematists because they represent undescribed species. Some examples from the far edge of elasmobranch biodiversity include:
Order Hexanchiformes, cow and frilled sharks. An undescribed frilled shark is known from off southern Africa, which confounds the notion of the frilled shark being a world-wide species of a monotypic family.
Order Squaliformes, dogfish. There are many undescribed species of dogfish sharks, including members of the genera Etmopterus, Centrophorus, Somniosus, and Squalus.
Order Pristiophoriformes, sawsharks. There are four undescribed species known at present, from Australia, Philippines and the Western Indian Ocean.
Order Squatiniformes, angel sharks. There are at least three undescribed angel sharks from Australia and the Andaman Sea (the latter photographed by a diver but not collected).
Order Heterodontiformes, bullhead sharks. There is an undescribed bullhead shark from Oman, Arabian Sea.
Order Orectolobiformes, carpet sharks. There are undescribed species of collared carpet sharks and wobbegongs from Australia.
Order Lamniformes, mackerel sharks. There is a possibly undescribed thresher from the Eastern Pacific, confused with the bigeye thresher but separated by an electrophoretic study.
Order Carcharhiniformes, ground sharks. There are numerous undescribed species of catsharks (Scyliorhinidae, genera Apristurus, Asymbolus, Bythaelurus, Cephaloscyllium, Cephalurus, Galeus, Haploblepharus, Holohalaelurus, and Parmaturus), false catsharks (Pseudotriakidae, a new genus and species), houndsharks (Triakidae, genera Hemitriakis, Iago, and Mustelus), weasel sharks (Hemigaleus and possibly Paragaleus), and requiem sharks (Carcharhinus and Glyphis). Six new species of Asymbolus were recently (1999) described from Australia.
Order Rajiformes, batoids. Suborder Rhynchobatoidei, wedgefishes, with two undescribed species of Rhynchobatus. Suborder Rhinobatoidei, guitarfishes, with several undescribed species of Aptychotrema, Rhinobatos, and Trygonorrhina. Suborder Zanobatoidei, panrays, with undescribed species of Zanobatus. Suborder Torpedinoidei, electric rays, several species of Benthobatis, Narcine, Heteronarce, Narke, and Torpedo, including several species photographed by divers but not collected. Suborder Rajoidei, skates. Numerous undescribed species of softnose skates (Arhynchobatidae, Atlantoraja, Bathyraja, Irolita, Notoraja, and Pavoraja), hardnose skates (Rajidae, including Amblyraja, Breviraja, Dipturus, Leucoraja, Okamejei, possibly Raja, Rajella, and two undescribed genera), and legskates (undescribed species of Anacanthobatis). Suborder Myliobatoidei, stingrays, including several undescribed species of stingarees (Trygonoptera and Urolophus), river stingrays (Potamotrygonidae, including Potamotrygon and Paratrygon), and whiptailed stingrays (Dasyatis, Himantura and Pastinachus).
Order Chimaeriformes, silver sharks or chimaeras: Several undescribed species of shortnose chimaeras (Chimaera and Hydrolagus).
POSSIBLE OVERFOCUS ON FINS
The fin issue pits East with West, and is the potential focus of much misunderstanding and enmity, as well as heavy-handed geopolitics and even econowar. The burgeoning of world fisheries, the vast array of gear that can catch sharks even as bycatch, and widespread use of sharks for products other than fins, suggest that the fin issue aggravates the basic problems of shark fisheries, but is not the central problem. The problem is overfishing of sharks regardless of usage or non-usage and would continue if the fin trade vanished overnight. Although large pelagic nonbatoid sharks are often finned and the carcasses dumped by high-technology oceanic fisheries, and finned sharks may survive for a while if they're not killed outright, the problem remains of capture trauma and mortality of such sharks even if they're not finned, much less deliberate killing by fishers to eliminate sharks they consider vermin, as well as retention of more desirable species such as shortfin makos and threshers for their flesh as well as fins. Sharks that are caught in offshore and inshore waters and landed in markets may be finned if they have usable fins (including small non-batoid sharks, guitarfishes, wedgefishes, shark-rays and sawfishes), but their carcasses are generally used for human consumption or for fertilizer if spoiled. Even small nonbatoid sharks, wedgefishes and guitarfishes less than a meter long may be finned, but the fins form a profitable byproduct of animals that will be used regardless of finning. Most batoid sharks do not form a part of the fin trade even though myliobatoids are of major importance in tropical fisheries and are often landed in greater quantities than nonbatoid sharks. In the future it may be possible to offload the demand for fins from wild-caught sharks by synthetics and small fins from fast-growing small species that are cultured commercially, as well as education on the conservation problems inherent in the massive fin trade as it currently exists to lessen catches and utilization. There remains the difficulty convincing a large part of the human population to abandon or strictly limit their consumption fins as a 'soul food' for special occasions, which may resist all the economic and political pressure in the world. The emotive issue of finning, analogous to the clubbing of baby seals, collides with the equally emotive issue of a 'feel-good' food with a hoary tradition and far greater historical depth than a U.S. citizen's Thanksgiving turkey. It may also be noted that other shark-consumption issues could be equally mooted as equivalent to finning but don't have the perceived impact: Overfishing of spiny dogfish for the European fast-food trade; overfishing of angel sharks and threshers for the California luxury food trade; extirpation of certain skates by North Sea trawl fisheries; extirpation of sawfishes generally; problems with freshwater elasmobranchs generally; and heavy tropical fisheries for myliobatoid rays. It may be necessary to offer compensation or a trade-off for reduced fin consumption, including strict regulation of EC, USA and Canadian fisheries that currently threaten sharks. Shifting blame to one side of the sinking shark fisheries boat doesn't save the boat. The ultimate problem that won't go away without continuing pain is the burgeoning human population, with an increasing demand for all fisheries products, not just shark fins or other shark products. The entire fisheries boat is slowly sinking, not just the minor shark end and the even more minor fin trade. In addition, there are the issues of environmental degradation and pollution, which may also be affecting sharks more massively and more generally than just in critical, restricted environments such as tropical rivers and lakes.
MANAGEMENT OF FISHERIES AND BIODIVERSITY
It is easy and tempting for fisheries managers and bureaucrats to see the problems with shark conservation as increasingly their problems, to be solved by sound fisheries management of important commercial species, and to limit their focus to the more important fisheries species of non-batoid sharks and to certain well-established commercial batoids. It is equally easy for conservationists to see the problems of sharklike fishes through a fisheries and First World or even North Atlantic filter. Bureaucracy and management of fisheries cannot escape national and international politics, and some aspects of the current concern for sharks embraces political strife, in which dominant fishing nations compete for increasingly scarce marine resources. The fisheries problems with shark exploitation exists in a broader framework of human impact on the biodiversity of virtually the entire Class Chondrichthyes, and is exacerbated by the limited biological knowledge of the group, including the frontier view of systematics. Although sound fisheries management is essential for many species including many that are not being managed at present and sorely need to be managed, sound management of biodiversity with a broad focus on biological research is necessary for the entire group. Many sharklike fishes are rare or have a limited habitat and geographic distribution, are largely ignored by fisheries managers, and may be under considerable risk of extinction. Some are undoubtedly unknown to science, which doesn't protect them from the adverse affects of human activities. Fisheries and other forms of human impact are expanding faster then our perception of the biodiversity of sharklike fishes, and there are urgent needs to investigate little-known areas and habitats on a broader framework than management of existing fisheries. There are too many gaps in our knowledge of chondrichthyan faunas to manage their biodiversity in many places, and basic knowledge of systematics, distribution, ecology, and behavior needs to obtained for many species in many places.
Fisheries researchers can and do help with sound and thorough studies of biodiversity of Chondrichthyes, including extensive faunal and market surveys to monitor potential fisheries resources, but relatively few areas of the world have been adequately surveyed. Although the global nature of the shark conservation problem is now firmly established and recognized by most nations, the tasks that lie ahead are difficult. Most nations don't manage their sharks and don't report species-specific data, which will take a major effort to correct and which will be difficult to support through existing infrastructures and funding bodies which are often poorly subsidized and overtasked. Most national bycatch and targeted fisheries are essentially out of control, expanding, and driven by increasingly intensive, expansive and often sophisticated fisheries that are penetrating new and fragile deepwater habitats for diminishing resources as well as exhausting easily accessible ones and by the ever-expanding world-wide demand for fisheries products. Other problems sharks face include modification and destruction of habitats critical for them, particularly easily accessible rivers, estuaries, coasts and bays that form nursery grounds, reefs, as well as spatially restricted deepwater habitats including continental and insular slopes, submarine ridges, canyons and sea mounts.
A necessity for management and preservation of shark biodiversity is long-term and broad-based species-specific monitoring of chondrichthyan catches and exploratory survey work beyond what is possible from monitoring catches. This is properly a function of fisheries agencies in cooperation with systematists, museums and universities but which is not occurring in most of the world. Systematics is the cornerstone of biological research including fisheries biology, yet fish systematists in general and shark systematists in particular are relatively few and declining in numbers while the need for systematic research including alpha taxonomy has increased markedly over the past few decades with the expanding human population and commensurate impact on terrestrial and marine environments as well as discoveries of numerous undescribed species in many parts of the world. Systematics has become unfashionable in many universities, well-established university systematics institutions that trained systematic ichthyologists have disappeared, and recruitment of new systematists and employment of young postdoctoral systematists is not tracking the increased need for such researchers. There is often no incentive for the present generation of established systematic researchers to train replacements in the form of graduate students, and no incentives for graduate students to become systematists (particularly shark systematists) if they face long-term joblessness and an uncertain career as postdoctoral drifters dependent on soft money. Shark researchers, including systematists, are confronted with an exponentially increasing demand for knowledge on all aspects of sharks and their biology as their conservation status deteriorates. However, shark researchers including systematists are ridiculously few and are generally overcommitted and poorly subsidized. Many work in inadequate facilities and are deflected by other duties including fundraising and bureaucratic justification of their existence. Many researchers have little opportunity to develop critical mass with research teams at their facilities. Some researchers have to generate 'soft' money for salaries in addition to research funding, while others must work in professions that at best are only obliquely relevant to their research interests. The current popularity of sharks tempts many students to attempt careers in shark research, but poor support and other hardships, limited opportunities for study, and dead-end job prospects tends to weed out all but the thoroughly dedicated.
Sampling at markets or landing sites (as with the Sabah study, but known by systematic ichthyologists for at least three centuries) can be an extremely valuable tool for estimating the biodiversity of sharks and other chondrichthyans in some places, including determining the relative abundance of various fisheries species over time as fisheries take their toll. This can be tricky, and demands quick knowledge of the kinds of sharks being landed including difficult groups such as carcharhinid sharks and dasyatid stingrays. Although many fisheries agencies do not support systematics there is a need for parataxonomists or full-fledged systematists working in house or in cooperation with these agencies to sort out taxonomic problems of landings in poorly-known areas. It should be noted, however, that market and on-board sampling cannot substitute for wide-ranging faunal surveys, as the landings, catches and markets often reflect the activities of local fishers who can be relatively conservative and selective in optimizing the best catches on well-known inshore grounds. They also don't necessarily reflect what may be happen in the near future, when fishers may have to move to deeper waters as inshore catches decrease and start catching species not represented in current surveys, or the fleets of economically powerful fishing nations muscle in to exploit their deepwater resources. In many places fishers tend to land most things that they catch, but in places where catches are more selective and bycatch discarded on-board monitoring may be necessary. Markets in many parts of the world are not being monitored in detail for species-specific data on chondrichthyan catches including intraspecific composition by sex, size and age class, and this is partly reflected by the datasets on cartilaginous fishes provided to FAO by most of the countries in the Region, which combine chondrichthyan catches for various species or provide separate statistics only for non-batoid sharks and for batoids. At present only New Zealand provides comprehensive fisheries catch data for an endemic species, the rig or estuary smoothhound.
In the postmodern world of instant information publicity often equates to reality, but in addition to needed public relations a vast amount of unglamorous, hard work, including basic research, is required to achieve even modest goals in shark conservation and preservation of biodiversity. Moreover, our basic biological knowledge of most species is sketchy at best and zero at worst, and a lot of basic research is necessary to address questions of shark conservation. Also, shark conservation is in some instances in direct opposition to fisheries interests that have enormous sums invested in doing business as usual however short-sighted this may be. Well-intentioned conservation measures can be nullified by poor enforcement in the face of growing and ever-lucrative markets for shark products. The rise of shark-based ecotourism and the realization that sharks alive may be more valuable than dead as fisheries products is one hopeful counter to the relentless march of the fisheries, despite their problems, as are occasional changing attitudes to sharks in the media that portray them as complex and interesting creatures and not one-dimensional 'Jaws' demons or conceptual non-beings.
AN IMMODEST PROPOSAL:
As conventional institutions that study shark biodiversity are limited and increasingly inviable or focused on other subjects there is a need for a concrete initiative to promote and focus research on shark biodiversity and conservation. It is recognized that museums, universities, and fisheries organizations aren't quite doing the job because of various problems. The proposed Shark Biodiversity Center would provide a central nexus to interlink with existing organizations, and to develop a center of expertise and sufficient critical mass to carry forth its own investigations and interlink with and support existing organizations and researchers. It is all too simple nowadays to hang out a shark Web site and affect expertise or hoopla, but even with those that are legitimate and serious there is often little support behind them, and often these are one-person operations or small groups of genuine enthusiasts with little support. The Shark Biodiversity Center would:
1. Focus biodiversity research on sharklike fishes in one place, with several labs or subscribing research units worldwide.
2. Coordinate shark biodiversity research with fisheries research, to avoid wheel-reinvention, wasting money, and losing research opportunities on animals that may not be accessible or even extant in a few decades.
3. Develop tools for practical systematics, at a country, regional, and international focus, eg. field guides, regional guides, world guides, eg. the FAO (or non-FAO) batoid catalog.
4. Train parataxonomists in fisheries organizations and elsewhere where they are needed. Train and support systematists in the small numbers needed and viable.
5. Support research in basic systematics, higher classification and biodiversity.
6. Support local museums, to synergize them and coordinate their efforts with fisheries organizations and universities.
7. Conduct an International Shark Biodiversity Expedition, based around a capable research trawler with multi-gear capacity and long range, to investigate poorly known areas with cooperation with local ichthyologists, fisheries researchers, shark biologists, etc. It would involve major media participation, would serve as a floating base for inshore, riverine and land work, and would capable of deep-trawling with demersal and pelagic gear down to 2000 m, use deep-set longlines, traps, pelagic longlines, pelagic gillnets, deep-set gillnets, and other gear. It would not try to duplicate, exactly, existing and ongoing fisheries surveys, but to supplement them wherever and whenever possible. It's five-year mission, to seek out new faunas, to discover new sharks, to boldly go where no research vessel has gone before.
This last statement may sound familiar and facetious, but the unfacetious reality behind it is that chondrichthyan biodiversity is in part an undiscovered country; it has wilderlands with poorly known faunas, including poorly known and undescribed species, but which are not immune from decimation and destruction. It needs urgent exploration, before anthropogenic ecodestruction proceeds further apace and extirpates it. The 'bycatch' of other animals, from bony fishes to sponges, gathered by the expedition would also be fully utilized, but the focus would be, for the first time ever, on sharks in the broadest sense.
The writer refers to various papers, books and reports over the years that have in part inspired some of the ideas in the above essay, from basic classification of sharklike fishes to biodiversity, fisheries and conservation, but not more specific works of chondrichthyan systematics or regional FAO species sheets. A lot of the inspiration was gathered inside systematic collections in museums and universities worldwide, and in the field, often in fish markets and at landing sites. An inspiration and foil for some of the ideas presented here was the late Sid Cook, a close friend and colleague who put his life on the line for his research on rational utilization of sharks and paid the ultimate price.
Compagno, L.J.V. 1973. Interrelationships of living elasmobranchs. In P.H. Greenwood, R. Miles, and C. Patterson, eds., Interrelationships of fishes. London, Academic Press: 15-61.
Compagno, L.J.V. 1977. Phyletic relationships of living sharks and rays. In R.G. Northcutt, ed. Recent advances in the biology of sharks. Amer. Zool. 17(2): 303-322.
Compagno, L.J.V. 1981. Legend versus reality: the Jaws image and shark diversity. Oceanus, 24(4): 5-16.
Compagno, L.J.V. 1984. FAO Species Catalogue. Vol. 4, Sharks of the World. An annotated and illustrated catalogue of shark species known to date. FAO Fisheries Synopsis No. 125. vol. 4, pt. 1: viii, 1-250; pt. 2: x, 251-655.
Compagno, L.J.V. 1988. Sharks of the Order Carcharhiniformes. Princeton University Press, xii + 572+ pp., 157 figs., 35 plates.
Compagno, L.J.V. 1988. Shark diversity in southern Africa. The Naturalist, 32(3): 20-29, fig. 1-11. 1988E
Compagno, L.J.V. 1990. Alternate life history styles of cartilaginous fishes in time and space. In M. Bruton & E. Balon, eds. Alternative life history styles of fishes (Proceedings of the Zoological Society of South Africa symposium held in Grahamstown, 1987), Environm. Biol. Fishes, 28(1-4): 33-75, figs. 1-36.
Compagno, L.J.V. 1990. Shark exploitation and conservation. In H.L. Pratt, Jr., S. H. Gruber, & T. Taniuchi, eds.. Elasmobranchs as living resources: Advances in the biology, ecology, systematics, and the status of the fisheries: 397-420, fig. 1-16.
Compagno, L.J.V. 1990. Evolution and diversity of sharks. In S. H. Gruber, ed., Discovering sharks. A volume honoring the work of Stewart Springer. Underw. Nat., Bull. American Littor. Soc. 19-20(4/1): 15-22, figs.
Compagno, L.J.V. 1991. A review of the general biology and conservation of the white shark (Carcharodon carcharias). In T. Condon, ed. Great white sharks-Carcharodon carcharias. A perspective. Under Water (17) Durban, May-June 1991, 27 pp., ill.
Compagno, L.J.V. 1991. Government protection for the great white shark (Carcharodon carcharias) in South Africa. S. African J. Sci. July 1991, 87: 284-285.
Compagno, L.J.V. 1995. Book review: Sharks and rays of Australia, Peter R. Last and John D. Stevens. Rev. Fish Biol. Fisher. 5(1): 55-57.
Compagno, L.J.V. 1997. Threatened fishes of the world: Glyphis gangeticus (Müller & Henle, 1839)(Carcharhinidae). Environmental Biology of Fishes 49: 400, ill.
Compagno, L.J.V. 1998. Red List species assessments. In N.A. Gibble, G. McPherson, & B. Lane, eds., Shark management and conservation. Proceedings from the Sharks and Man workshop of the Second World Fisheries Congress, Brisbane, Australia, 2 August 1996, Dept. Primary Industries, Queensland, Aust: 72-73.
Compagno, L.J.V. 1998. Status of freshwater elasmobranchs. In N.A. Gibble, G. McPherson, & B. Lane, eds., Shark management and conservation. Proceedings from the Sharks and Man workshop of the Second World Fisheries Congress, Brisbane, Australia, 2 August 1996, Dept. Primary Industries, Queensland, Aust: 76-77.
Compagno, L.J.V. 1999. Chapter 1. Systematics and body form. In W. C. Hamlett, ed.. Sharks, skates and rays. The biology of elasmobranch fishes. Johns Hopkins Press, pp. 1-42, fig. 1.1-1.15.
Compagno, L.J.V. 1999. Appendix. Checklist of living elasmobranchs. In W. C. Hamlett, ed.. Sharks, skates and rays. The biology of elasmobranch fishes. Johns Hopkins Press, pp. 471 to 498.
Compagno, L.J.V. 1999. `Kinds of sharks' (pp. 20-35), `Sharks and their relatives' (pp. 36-37), `Shark encounters in South Africa' (pp. 134-147), 'Conserving sharks (pp. 214-218)', and `Checklist of living sharks' (pp. 230-233), in Stevens, J. D., consulting ed., Sharks. Revised edition. Weldon Owen publishers, Australia, 1-240 pp, ill.
Compagno, L.J.V., & S. F. Cook. 1995. Freshwater elasmobranchs: A questionable future. Shark News, 4-6, fig. 1.
Compagno, L.J.V., & S. F. Cook. 1995. Through the glass darkly: a troubled future for freshwater elasmobranchs. Chondros 6(1): 7-9.
Compagno, L.J.V., & S. F. Cook. 1995. The exploitation and conservation of freshwater elasmobranchs: Status of taxa and prospects for the future. In: Volume VII: The biology of freshwater elasmobranchs (Eds. M.I. Oetinger and G.D. Zorzi). Journal of Aquariculture and Aquatic Sciences: 62-90, figs. 1-5
Compagno, L.J.V., & S. F. Cook. 1995. Status of the giant freshwater stingray (whipray) Himantura chaophraya (Monkolprasit and Roberts, 1990). Shark News (Newsl. IUCN SSG) (5): 5, ill.
Compagno, L.J.V., D.A. Ebert, & P.D. Cowley. 1991. Distribution of offshore demersal cartilaginous fishes (Class Chondrichthyes) of the west coast of southern Africa, with notes on their systematics. S. Afr. J. Mar. Sci. 11: 43-139, figs. 1-24.
Compagno, L.J.V., D. A. Ebert, & M. J. Smale. 1989. Guide to the sharks and rays of southern Africa. Struik Pub., Cape Town, 160 pp., ill.
Compagno, L.J.V., Mark A. Marks, & Ian K. Fergusson. 1997. Threatened fishes of the world: Carcharodon carcharias. Environmental Biology of Fishes 50: 61-62, ill.
Compagno, L.J.V., & T.R. Roberts. 1982. Freshwater stingrays (Dasyatidae) of Southeast Asia and New Guinea, with description of a new species of Himantura and reports of unidentified species. Environ. Biol. Fish. 7(4):321-339.
Compagno, L.J.V., & T.R. Roberts. 1984. Marine and freshwater stingrays (Dasyatidae) of West Africa, with description of a new species. Proc. Calif. Acad. Sci. ser. 4, 43: 283-300, fig. 1-10.
Compagno, L.J.V., G. Zorzi, H. Ishihara, & J. Caira. 1990. Recommendations for future research in systematics, geographic distribution, and evolutionary biology of chondrichthyan fishes. In H.L. Pratt, Jr., S. H. Gruber, & T. Taniuchi, eds.. Elasmobranchs as living resources: Advances in the biology, ecology, systematics, and the status of the fisheries. NOAA Tech. Rept. (90): 519-521.
Cook, Sid F., & L.J.V. Compagno. 1994. Preliminary Thailand field trip notes: November-December 1993. Chondros 5(1): 8-13, fig. 1-2.
Cook, Sid F., L.J.V. Compagno & M. Oetinger. 1995. Status of the largetooth sawfish Pristis perottetti Müller & Henle, 1841. Shark News (Newsl. IUCN SSG), (4): 5, ill.
Fowler, Sarah L., Mabel B. Manjaji, Rachel D. Cavanagh, L.J.V. Compagno, Scott G. Mycock & Peter R. Last. 1999. Elasmobranch biodiversity, conservation and management in Sabah (Malaysia). Proc. 5th Indo-Pac.Fish Conf. Nouméa, ed. B. Seret & J.-Y. Sire, Soc. Fr. Ichthyol.: 257-269, fig. 1-4.
Compagno, L.J.V. 1990. A review of the general biology and conservation of the white shark (Carcharodon carcharias). Shark Research Center, South African Museum, SRC Report 19901202: 1-27.
Compagno, L.J.V. Diversity of cartilaginous fishes in the Western Cape and southwestern part of the Eastern Cape. Shark Research Center, South African Museum, SRC Report 19990318: 1-16, fig. 1-2.
Compagno, L. J. V., M. J. Smale, S.F.J. Dudley, & S.F. Cook. 1994. International Union for the Conservation of Nature. Shark Specialist Group. Preliminary report for The Subequatorial African Region, Atlantic, Indian, and Antarctic Oceans (Jan. 11, 1994). Submitted to IUCN. Shark Research Center, South African Museum, SRC Report 19940111: 1-57, 17 figs., 12 tables.
Compagno, L.J.V. 1999. Conservation status of the basking shark, Cetorhinus maximus, in southern Africa. SRC Report 19990920A, 10 pp. Prepared for the Chondrichthyian Working Group, Marine and Coastal Management (Sea Fisheries Research Institute).
Compagno, L.J.V. 1999. Conservation status of the whale shark, Rhincodon typus, in southern Africa. SRC Report 19990920B, 13 pp. Prepared for the Chondrichthyian Working Group, Marine and Coastal Management (Sea Fisheries Research Institute).
Cook, S.F., & Compagno, L.J.V. 1996. Preliminary field report and recommendations for structuring the freshwater and marine inshore elasmobranch project in Sabah, east Malaysia. Chondros res. rept. 9602A, 13 pp.
ITEMS IN PRESS, 2000:
Compagno, L.J.V. Review of the biodiversity of sharks and chimaeras in the region (South China Sea and adjacent areas). In International Seminar and Workshop on Shark and Ray Biodiversity, ed. S. Fowler. Darwin Initiative Sabah Project, IUCN Shark Specialist Group. Ms. ca. 25 pp. Galleys received, March 30, 1999, in press, 2000.
Compagno, L.J.V. Freshwater and estuarine elasmobranch surveys in the Indo-Pacific region: Threats, distribution and speciation. In International Seminar and Workshop on Shark and Ray Biodiversity, ed. S. Fowler. Darwin Initiative Sabah Project, IUCN Shark Specialist Group. Ms. ca. 26 pp. Galleys received, March 30, 1999, in press, 2000.
Compagno, L.J.V. An overview of chondrichthyan systematics and biodiversity in southern Africa. Trans. Roy. Soc. South Africa, 63 MS pages. In press, 2000.
Last, P. R., & L.J.V. Compagno. Review of the biodiversity of rays in the South China Sea and adjacent areas. In International Seminar and Workshop on Shark and Ray Biodiversity, ed. S. Fowler. Darwin Initiative Sabah Project, IUCN Shark Specialist Group. Ms. ca. 9 pp. Galleys received, March 30, 1999, in press, 2000.
Last, P. R., & L.J.V. Compagno. Importance of biological collections for future taxonomic research in the Indo-West Pacific. In International Seminar and Workshop on Shark and Ray Biodiversity, ed. S. Fowler. Darwin Initiative Sabah Project, IUCN Shark Specialist Group. Ms. ca. 7 pp. Galleys received 1999, in press, 2000.
top of page