In recent years there has been a revolution in aquarium technology. The use of new materials and techniques has
allowed the development of massive public display tanks.
This in turn has encouraged the holding and exhibition of sharks and rays.
Over 100 million people visit public aquariums each year in North America alone, and shark exhibits are consistently popular with visitors (Sabalones 1995). The key role of public aquariums is in education. If threatened elasmobranch species are to receive the management and conservation they need, public support is vital. The display of living elasmobranchs supported by appropriate educational materials goes a long way towards dispelling misconceptions about elasmobranchs in general and sharks in particular. The display of a diversity of small species demonstrates how inappropriate is the 'Jaws' image (Croft 1993). Sabalones (1995) suggests that displays and presentations should cover three main issues:
• The negative image of sharks should be countered, for example by discussing the relatively low incidence of shark attacks in comparison to other animals.
• The positive contributions and aspects should be stressed, for example by discussing their importance to environmental balance.
• Their conservation needs should be emphasised.
Large public aquariums are also sources of information for the media, and so their influence on the public's image of sharks can be spread far beyond those who walk in (Sabalones 1995). In addition to this primarily educational role, public aquariums can promote elasmobranch conservation through their research activities (Sabalones 1995). For example, studies of reproductive behaviour (Uchida et al. 1990), reproductive physiology (Rasmussen and Murru 1992) and growth (Van Dykhuizen and Mollet 1992) have been successfully carried out on captive individuals. There have also been considerable improvements in the understanding of physiological changes in elasmobranchs subject to live capture, transportation and maintenance, as a result of which captive mortality has been reduced (Murru 1990, Smith 1992).
In parallel with the developments in the major aquariums, there have also been improvements in domestic aquarium technology and practice. This too has led to increased interest in keeping elasmobranchs in captivity (Fenner 1996). The smaller, demersal, strikingly patterned sharks such as the epaulette shark Hemiscyllium ocellatum are favoured. The USA is the largest market, and many of the elasmobranch species favoured by aquarists there originate in South East Asian waters (Table 2). Rose (1996) notes that live catshark (Scyliorhinid) juveniles and eggcases are exported from Indonesia to the USA for sale to private aquarists.
A problem for domestic aquarists is that even small elasmobranchs are relatively large. Table 2 lists the approximate maximum sizes of sharks commonly kept in captivity in the USA. Most sharks are purchased by
Table 2. Some sharks commonly kept in captivity in the USA. Port Jackson shark Zebra bullhead shark Tasselled wobbegong Blacktip reef shark Lemon shark
SW Pacific and Australia W Pacific and Australia Indo-W Pacific Indo-W Pacific
SW Pacific and Australia Atlantic and E Pacific W Atlantic
NE Pacific Indo-W Pacific Atlantic and E Pacific
Size
Source: Fenner (1996), with additional data from Compagno (1984) and Last and Stevens (1994).
aquarists as juveniles or eggcases. If they lived long in captivity most would outgrow all but the largest tanks.
However, the difficulties associated with keeping such animals in domestic aquariums are such that most sharks survive for less than one month (Fenner 1996). Despite these losses, the growth of interest in elasmobranchs among the large aquarium hobbyist fraternity is creating a constituency of people who are aware of their conservation requirements.
The demand for living elasmobranchs from the aquarium trade is small compared to the demand for other elasmobranch fishery products. The impact of most aquarium fisheries on wild populations is therefore thought to be insignificant (Sabalones 1995). However, this might not be the case where wild populations are particularly small or already under threat from other causes. For example, there is trade in live freshwater stingrays and sawfish species, including species from Malaysia (Rose 1996), which may further endanger some threatened local populations.
Conclusions
Recreational utilisation is an increasingly important component of the overall utilisation of many elasmobranch resources. The growth of sport diving, the expansion of recreational elasmobranch fishing and the changing of attitudes among its practitioners, and the development of new aquarium displays are all helping to create a vast constituency of people with an interest in elasmobranch conservation. Furthermore, these people have considerable spending power, and this economic influence can be used to forward elasmobranch conservation.
Many elasmobranch species have no recreational value and, even for those that do, promotion of recreational utilisation over commercial fishing is unlikely to provide a cure for all problems. Nevertheless, elasmobranch resource managers, researchers and conservationists need
to be aware of the challenges and take advantage of the opportunities presented by the increasing recreational utilisation of elasmobranch resources.
Acknowledgements
I thank the organisers of the International Seminar and Workshop on Shark and Ray Biodiversity, Conservation and Management, and in particular Sarah Fowler, for inviting me to participate and providing the funds for me to do so.
References
Amsler, K. 1997. Sharks: look don't cook. Diver 42(1): 21, Eaton Publications, London.
Anderson, E.D. 1990. Estimates of large shark catches in the western Atlantic and Gulf of Mexico, 1960-1986. Pp.203-268. In: Pratt, H.L., Gruber, S.H. and Taniuchi, T. (eds).
Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status of the fisheries. NOAA Technical Report NMFS 90. Pp.443-454.
Anderson, R.C. 1994. Sport diving–a growing force for shark conservation. Chondros 5(3): 3–5.
Anderson, R.C. and Ahmed, H. 1993. Shark fisheries of the Maldives. Ministry of Fisheries and Agriculture, Maldives, and FAO, Rome. 73 pp.
Anon. 1991. White shark gains government protection in South Africa. Chondros 2(7): 2-3.
Casey, J.G. 1985. Transatlantic migrations of the blue shark:
a case history of co-operative shark tagging. Pp.253-268.
In: Strond, R.H. (ed.). World Angling Resources and challenges. Proceedings of the first world anglingconference, Cap d'Agde, France, September 1984.
Casey, J.G. and Kohler, N.E. 1992. Tagging studies on the shortfin mako shark (Isurus oxyrinchus) in the western North Atlantic. Aust. J. Mar. Freshwater Res. 43:45–60.
Caton, A.E. and Ward, P.J. 1996. Fisheries for tunas and tuna-like species in the western region of the Australian FishingZone. Pp.70–73.In:Anganuzzi,A.A.,Stobberup, K.A. and Webb, N.J. (eds). Proceedings of the sixth expert consultation on Indian Ocean tunas. Indo-Pacific Tuna Programme, Colombo, collective volume 9.
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. 125,4(1 and 2). 655 pp.
Cousteau, J.M. 1996. A manta in the hand ... Asian Diver 4(5): 15, Singapore.
Croft, G.S. 1993. Review of sharks and rays held at St Andrews Sea Life Centre. Chondros 4(1): 4-6.
Fenner, R. 1996. Shark attack! Tropical Fish Hobbyist 44(9): 46-57.
Grove, J.S. 1995. Ecuador moves to develop sport fisheries in the Galapagos. Chondros 6(1): 10.
Hall, H. 1994. Jewels in the Caribbean Sea. Ocean Realm January 1994: 51-54, San Antonio, USA.
Hanauer, E. 1995. Born to be wild. Action Asia 3(2): 35-39.
Hueter, R.E. 1996. Catch/tag-and-release: the conservation option for recreational fishermen. Shark News (Newsletter of the Shark Specialist Group), 7: 7.
King, A.E. and Cailliet, G.M. 1992. The Elkhom Slough Shark Derby: past and present. Chondros 3(2): 1-4.
Kohler, N. 1996. NMFS co-operative shark tagging program. Shark News (Newsletter of the Shark Specialist Group), 7: 1-2.
Last, P.R. and Stevens, J.D. 1994. Sharks and Rays of Australia. CSIRO, Australia. 513pp, 84 plates.
Manire, C.A. and Gruber, S.H. 1991. The effect of M-type dart tags on field growth of juvenile lemon sharks.
Trans. Amer. Fish. Soc. 120(6): 776-780.
Murphy, G. 1993. 26 great shark dives around the world.
Skin Diver, March 1993: 120-123.
Murru, F.L. 1990. The care and maintenance of elasmobranchs in controlled environments. Pp.203-209.
In: Pratt, H.L., Gruber, S.H. and Taniuchi, T. (eds).
Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status of the fisheries. NOAA Technical Report NMFS 90.
Newman, H. 1994. Shark's fin soup anyone? Asian Diver 2(5): 53-55, Singapore.
Newman, H.E., Medcraft, A.J. and Coleman, J.G. This volume. Whale Shark Tagging and Ecotourism. Pp.230-235. In: Fowler, S.L., Reed, T.M. and Dipper, F.A. (eds).
Elasmobranch biodiversity, conservation and management:
Proceedings of the International Seminar and Workshop in Sabah, July 1997. IUCN SSC Shark Specialist Group.
IUCN, Gland, Switzerland and Cambridge, UK.
Pepperell, J.G. 1992. Trends in the distribution, species composition and size of sharks caught by gamefish anglers off southeastern Australia, 1961-90. Aust. J.
Mar. Freshwater Res. 43: 213-225.
Perrine, D. 1994. Race against time. SCUBA Times 15(4):
36-39.
Rasmussen, L.E.L. and Murru, F.L. 1992. Long-term studies of serum concentration of reproductively related steroid hormones in individual captive carcharhinids. Aust. J.
Mar. Freshwater Res. 43: 273-81.
Radtke, R.L. and Cailliet, G.M. 1984. Age estimation and growth of the gray reef shark, Carcharhinus amblyrhynchos, from the northwestern Hawaiian Islands. Pp.121–127.
In: Proceedings of the 2nd Symposium on Resource Investigations of the Northwestern Hawaiian Islands.
Rose, D.A. 1996. An overview of world trade in sharks and other cartilaginous fishes. TRAFFIC International, Cambridge. 106 pp.
Sabalones, J. 1995. The role of aquariums in the conservation of sharks. Shark News (Newsletter of the Shark Specialist Group), 5: 9.
Saunders, B. 1995. A sure shark. Sportdiving Magazine 51:
26-31, Melbourne, Australia.
Sigel, R. 1996. Mission possible. Asian Diver 5(3): 4-7, Singapore.
Skomal, G. and Chase, B. 1996. Release mortality studies in Massachusetts. Shark News (Newsletter of the Shark Specialist Group), 7: 8-9.
Smith, M.F.L. 1992. Capture and transportation of elasmobranchs, with emphasis on the grey nurse shark (Carcharias taurus). Aust. J. Mar. Freshwater Res. 43:
325-343.
Stafford-Deitsch, J. 1996. ... until there were none. Dive International2(6): 16-19, London.
Stevens, J.D.I 984. Biological observations on sharks caught by sport fishermen off New South Wales. Aust. J. Mar.
Freshwater. Res. 35: 573-90.
Stevens, J.D. 1994. Whale sharks at Ningaloo Reef, northern Western Australia. Chondros 5(3): 1-3.
Strickland, M. 1994. Interactions with big marine life:
suggestions for diver etiquette. Ocean Realm January 1994: 21-22, San Antonio, USA.
Uchida, S., Toda, M. and Kamei, Y. 1990. Reproduction of elasmobranchs in captivity. Pp.211-237. In: Pratt, H.L., Gruber, S.H. and Taniuchi, T. (eds). Elasmobranchs as living resources: advances in the biology, ecology, systematics, and the status of the fisheries. NOAA Technical Report NMFS 90.
Van Dykhuizen, G. and Mollet, H.F. 1992. Growth, age estimation and feeding of captive sevengill sharks, Notorynchus cepedianus, at the Monterey Bay Aquarium.
Aust. J. Mar. Freshwater Res. 43: 297-318.
Vas, P. 1997. A case of the blues. Marine Conservation 3(11): 8-9, Marine Conservation Society, UK.
Walker, T. 1996. Localised stock depletion: does it occur for sharks? Shark News (Newsletter of the Shark Specialist Group), 6: 1-2.
Watkins, P. 1996. Fishin' folk: the shark hunter. S.E.A.
Fishing World 1(6): 41-43, Singapore.