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Seasonal cycles and long-term trends in abundance and species composition of sharks associated with cage diving ecotourism activities in Hawaii


Shark cage diving is both popular and controversial, with proponents citing educational value and non-extractive use of natural resources and opponents raising concerns about public safety and ecological impacts. Logbook data collected 2004–2008 from two Oahu (Hawaii) shark cage diving operations were analysed to determine whether such voluntary records provide useful insights into shark ecology or ecotourism impacts. Operators correctly identified common shark species and documented gross seasonal cycles and long-term trends in abundance of Galapagos (Carcharhinus galapagensis), sandbar (Carcharhinus plumbeus) and tiger sharks (Galeorcerdo cuvier). Annual cycles in shark abundance may indicate seasonal migrations, whereas long-term trends suggest gradual exclusion of smaller sandbar sharks from cage diving sites. Numerically dominant (> 98%) Galapagos and sandbar sharks are rarely implicated in attacks on humans. Negligible impact on public safety is supported by other factors such as: (1) remoteness of the sites, (2) conditioning stimuli that are specific to the tour operations and different from inshore recreational stimuli and (3) no increase in shark attacks on the north coast of Oahu since cage diving started. Tracking studies are required to validate logbook data and to determine whether sharks associated with offshore cage diving travel into inshore areas used for in-water recreation.

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*Correspondence: Dr Carl Meyer e-mail:
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Akama, J.S. & Kieti, D.M. (2003) Measuring tourist satisfaction with Kenya's wildlife safari: a case study of Tsavo West National Park. Tourism Management 24: 7381.
Bascompte, J., Melia, C.J. & Sala, E. (2005) Interaction strength combinations and the overfishing of a marine food web. Proceedings of the National Academy of Sciences 102: 54435447.
Bruce, B.D. (1995) The protection of the white shark. A research perspective. Southern Fisheries 3: 1115.
Burgess, G.H. (1998) Diving with elasmobranchs: a call for restraint. IUCN Shark Specialist Group. Shark News 11: 14.
Carwardine, M. & Watterson, K. (2002) The Shark-Watcher's Handbook: A Guide to Sharks and Where to See Them. Princeton, NJ, USA: Princeton University Press: 232 pp.
Castro, J.I. (1983) The Sharks of North American Waters. College Station, TX, USA: Texas A & M University Press: 179 pp.
Clarke, S.C., McAllister, M.K., Milner-Gulland, E.J., Kirkwood, G.P., Michielsens, C.G.J., Agnew, D.J., Pikitch, E.K., Nakano, H. & Shivji, M.S. (2006) Global estimates of shark catches using trade records from commercial markets. Ecology Letters 9: 11151126.
Compagno, L., Dando, M. & Fowler, S. (2005) Sharks of the World. Princeton, NJ, USA: Princeton University Press: 480 pp.
Compagno, L.J.V. (1984) FAO species catalogue, volume 4. Sharks of the world: an annotated and illustrated catalogue of shark species known to date. Part 2. Carcharhiniformes. FAO Fisheries Synopsis 125: 251655.
Conrath, C.L. & Musick, J.A. (2008) Investigations into depth and temperature habitat utilization and overwintering grounds of juvenile sandbar sharks, Carcharhinus plumbeus: the importance of near shore North Carolina waters. Environmental Biology of Fishes 82: 123131.
Durbin, J. & Watson, G.S. (1951) Testing for serial correlation in least squares regression. II. Biometrika 38: 159178.
Global Shark Attack File (2009) Incident log [www document]. URL
Grubbs, R.D., Musick, J.A., Conrath, C.L. & Romine, J.G. (2007) Long-term movements, migration, and temporal delineation of summer nurseries for juvenile sandbar sharks in the Chesapeake Bay region. In: Shark Nursery Grounds of the Gulf of Mexico and the East Coast Waters of the United States, ed. McCandless, C.T., Kohler, N.E. & , H.L. Pratt Jr, pp. 87107. Bethesda, MD, USA: American Fisheries Society Symposium Volume 50.
Hawaii Division of Aquatic Resources (2009) Most recent shark incidents [www document]. URL
Heupel, M.R., Simpendorfer, C.A., Collins, A.B. & Tyminski, J.P. (2006). Residence and movement patterns of bonnethead sharks, Sphyrna tiburo, in a large Florida estuary. Environmental Biology of Fishes 76: 4767.
Hoyt, E. (2001) Whale Watching 2001: Worldwide Tourism Numbers, Expenditures, and Expanding Socioeconomic Benefits. Yarmouth Port, MA, USA: International Fund for Animal Welfare: 158 pp.
Johnson, R. & Kock, A. (2006) South Africa's white shark cage-diving industry: is there cause for concern? In: Finding a Balance: White Shark Conservation and Recreational Safety in the Inshore Waters of Cape Town, South Africa; Proceedings of a Specialist Workshop, ed. Nel, D.C. & Peschak, T.P., pp. 4059. Capetown, South Africa: WWF South Africa Report Series – 2006/Marine/001.
Laroche, R.K., Kock, A.A., Dill, L.M. & Oosthuizen, W.H. (2007) Effects of provisioning ecotourism activity on the behaviour of white sharks Carcharodon carcharias. Marine Ecology Progress Series 338: 199209.
Malcolm, H., Bruce, B.D. & Stevens, J.D. (2001) A review of the biology and status of white shark in Australian waters. CSIRO Marine Research, Hobart, Australia: 113 pp.
Meyer, C.G., Clark, T.B., Papastamatiou, Y.P., Whitney, N.M. & Holland, K.N. (2009) Long-term movements of tiger sharks (Galeocerdo cuvier) in Hawaii. Marine Ecology Progress Series 381: 223235.
Myers, R.A., Baum, J.K., Shepherd, T.D., Powers, S.P. & Peterson, C.H. (2007) Cascading effects of the loss of apex predatory sharks from a coastal ocean. Science 30: 18461850.
Orams, M.B. (2000) Feeding wildlife as a tourism attraction: a review of issues and impacts. Tourism Management 23: 281293.
Papastamatiou, Y.P., Wetherbee, B.M., Lowe, C.G. & Crow, G.L. (2006) Distribution and diet of four species of Carcharhinid shark in the Hawaiian Islands: evidence for resource partitioning and competitive exclusion. Marine Ecology Progress Series 320: 239251.
Papastamatiou, Y.P., Meyer, C.G. & Holland, K.N. (2008) A new acoustic pH transmitter for studying the feeding habits of free-ranging sharks. Aquatic Living Resources 20: 287290.
Pyper, B.J. & Peterman, R.M. (1998) Comparison of methods to account for autocorrelation in correlation analysis of fish data. Canadian Journal of Fisheries and Aquatic Sciences 55: 21272140.
Stevens, J.D., Bonfil, R., Dulvy, N.K. & Walker, P.A. (2000) The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. ICES Journal of Marine Science 57: 476494.
Theberge, M.M. & Dearden, P. (2006) Detecting a decline in whale shark Rhincodon typus sightings in the Andaman Sea, Thailand, using ecotourist operator-collected data. Oryx 40: 337342.
Thompson, K.R. & Page, F.H. (1989) Detecting synchrony of recruitment using short, autocorrelated time series. Canadian Journal of Fisheries and Aquatic Sciences 46: 18311838.
Topelko, K.N. & Dearden, P. (2005) The shark watching industry and its potential contribution to shark conservation. Journal of Ecotourism 4: 108128.
Walsh, W.A., Kleiber, P. & McCracken, M. (2002) Comparison of logbook reports of incidental blue shark catch rates by Hawaii-based longline vessels to fishery observer data by application of a generalized additive model. Fisheries Research 58: 7994.
Wass, R.C. (1971) A comparative study of the life history, distribution, and ecology of the sandbar shark and gray reef shark in Hawaii. Doctoral dissertation, University of Hawaii, Honolulu, Hawaii, USA.
Wass, R.C. (1973) Size, growth, and reproduction of the sandbar shark, Carcharhinus milberti, in Hawaii. Pacific Science 27: 305318.
Wetherbee, B.M., Crow, G.L. & Lowe, C.G. (1996) The biology of the Galapagos shark, Carcharhinus galapagensis, in Hawaii. Environmental Biology of Fishes 45: 299310.
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