Wildlife Research Wildlife Research Society
Ecology, management and conservation in natural and modified habitats

A robust baseline for bottlenose dolphin abundance in coastal Moreton Bay: a large carnivore living in a region of escalating anthropogenic impacts

Vimoksalehi Lukoschek A C D and B. Louise Chilvers B
+ Author Affiliations
- Author Affiliations

A School of Earth and Environmental Sciences, James Cook University, Townsville, QLD 4811, Australia.

B Department of Conservation, PO Box 10-420, Wellington, New Zealand.

C Present address: Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.

D Corresponding author. Email: v.lukoschek@uci.edu

Wildlife Research 35(7) 593-605 https://doi.org/10.1071/WR07021
Submitted: 20 February 2007  Accepted: 10 June 2008   Published: 17 November 2008


Marine megafauna populations in coastal waters are increasingly threatened by anthropogenic impacts. Moreton Bay, a large embayment in south-east Queensland, lies adjacent to one of the fastest growing regions in Australia and has a resident population of bottlenose dolphins, Tursiops aduncus. Evaluation of the effectiveness of any proposed management strategy requires robust population abundance estimates. We estimated abundances of bottlenose dolphins in central eastern Moreton Bay (350 km2) using two commonly used abundance estimation methods for cetaceans: photo-identification mark–recapture and line-transect surveys. Mark–recapture data were analysed in CAPTURE using a model that allowed capture probabilities to vary between sampling events and between individuals. Based on an estimated 76% of the population identifiable photographically, total abundance estimates were 673 ± 130 s.e. (1997) and 818 ± 152 s.e. (1998). Line-transect data, analysed using DISTANCE, gave an abundance estimate of 407 ± 113.5 s.e. (2000). These abundance estimates are large compared with many other coastal bottlenose dolphin populations. The line-transect surveys comprised a pilot study, and the lower line-transect abundance estimate is probably best attributable to methodological issues. In particular, smaller mean group size was estimated for the line-transects surveys (2.85 ± 0.29 s.e.) than the mark–recapture surveys (4.87 ± 0.39 s.e., 1997; 5.78 ± 0.73 s.e., 1998), and line-transect group sizes were probably underestimated. In addition, the line-transect detection probability (g(o)) was assumed to be one but was almost certainly less than one. However, the possibility of an actual decline in population size cannot be ruled out. Coefficients of variation (CV) were lower for mark–recapture than for line-transect surveys, however, CVs of line-transect estimates could be lowered through improved survey design. We evaluated the power of these surveys to detect trends in potential population declines for bottlenose dolphins in Moreton Bay and make recommendations for ongoing monitoring strategies.


We would like to thank Helene Marsh, Peter Corkeron, Ivan Lawler and four anonymous reviewers for providing comments and advice that improved this manuscript. Funding for this research came from the Earthwatch Institute and the Australian Research Council. Thanks to Grant Shearwin for being an excellent skipper and dolphin spotter, and to Earthwatch Institute volunteers for field assistance. Research was conducted in accordance with James Cook University animal ethics permits A848 and A517.


Anon. (1997). ‘Marine Parks (Moreton Bay) Zoning Plan 1997.’ (Queensland Parliamentary Counsel: Brisbane.)

Bejder, L. , Samuels, A. , Whitehead, H. , Gales, N. J. , Mann, J. , Connor, R. C. , Heithaus, M. R. , Watson-Capps, J. , Flaherty, C. , and Kruetzen, M. (2006). Decline in relative abundance of bottlenose dolphins exposed to long-term disturbance. Conservation Biology 20, 1791–1798.
CrossRef | PubMed |

Buckland S. T. , Anderson D. R. , Burnham K. P. , and Laake J. L. (1993). ‘Distance Sampling: Estimating Abundance of Biological Populations.’ (Chapman and Hall: London.)

Buckland S. T. , Anderson D. R. , Burnham K. P. , Laake J. L. , Borchers D. L. , and Thomas L. (2001) ‘Introduction to Distance Sampling: Estimating Abundance of Biological Populations.’ (Oxford University Press: Oxford.)

Carretta, J. V. , Forney, K. A. , and Laake, J. L. (1998). Abundance of southern California coastal bottlenose dolphins estimated from tandem aerial surveys. Marine Mammal Science 14, 655–675.
CrossRef |

Center for International Earth Science Information Network and World Resources Institute (2000). ‘Gridded Population of the World, Version 2.’ (Columbia University: New York.)

Chilvers B. L. (2001). ‘Behavioural ecology of bottlenose dolphins, Tursiops aduncus, in S.E. Queensland, Australia: adaptations to ecological and anthropogenic influence.’ Ph.D. thesis. (James Cook University: Queensland.)

Chilvers, B. L. , and Corkeron, P. J. (2001). Trawling and bottlenose dolphins’ social structure. Proceedings of the Royal Society of London. Series B. Biological Sciences 268, 1901–1905.
CrossRef | CAS |

Chilvers, B. L. , and Corkeron, P. J. (2003). Abundance of Indo-Pacific bottlenose dolphins, Tursiops aduncus, off Point Lookout, Queensland, Australia. Marine Mammal Science 19, 85–95.
CrossRef |

Chilvers, B. L. , Lawler, I. , Macknight, F. , Marsh, H. , Noad, M. , and Paterson, R. (2005). Moreton Bay, Queensland, Australia: an example of the co-existence of significant marine mammal populations and large-scale coastal development. Biological Conservation 122, 559–571.
CrossRef |

Connor R. C. , Wells R. S. , Mann J. , and Read A. J. (2000). The Bottlenose Dolphin. In ‘Cetacean Societies: Field Studies of Dolphins and Whales.’ (Eds J. Mann, R. C. Connor, P. L. Tyack and H. Whitehead), pp. 91–126. (The University of Chicago Press: Chicago.)

Corkeron P. J. (1989). ‘Studies of inshore dolphins, Tursiops and Sousa, in the Moreton Bay region.’ Ph.D. thesis, University of Queensland.

Corkeron P. J. (1997). Bottlenose dolphins Tursiops truncatus in south-east Queensland waters: social structure and conservation biology. In ‘Marine Mammal Research in the Southern Hemisphere: Status, Ecology and Medicine.’ (Eds M. Hindell and C. Kemper.) pp. 1–10. (Surrey Beatty & Sons: Chipping Norton.)

Davie P. J. F. , and Hooper J. N. A. (1998). Patterns of biodiversity in marine invertebrate and fish communities in Moreton Bay. In ‘Moreton Bay and Catchment.’ (Eds R. Tibbetts, N. Hall and W. C. Dennison.) pp. 331–346. (School of Marine Science, University of Queensland: Brisbane.)

Dennison W. C. , and Abel E. G. (1999). ‘Moreton Bay Study: A scientific basis for the healthy waterways campaign.’ (South East Queensland Regional Water Quality Management Strategy: Brisbane.)

Evans, G. H. , and Hammond, P. S. (2004). Monitoring cetaceans in European waters. Mammal Review 34, 131–156.
CrossRef |

Evans G. H. , Baines M. E. , Shepherd B. , and Reichelt M. (2002). Studying bottlenose dolphin (Tursiops truncatus) abundance, distribution, habitat use and home range size in Cardigan Bay: implications for SAC management. Abstracts, European Cetacean Society 16th Annual Conference, 7–11 April, pp. 12. (Liege, Belgium.)

Forcada, J. , Gazo, M. , Aguilar, A. , Gonzalvo, J. , and Fernandez-Contreras, M. (2004). Bottlenose dolphin abundance in the NW Meditteranean: addressing heterogeneity in distribution. Marine Ecology Progress Series 275, 275–287.
CrossRef |

Gerrodette, T. (1987). A power analysis for detecting trends. Ecology 68, 1364–1372.
CrossRef |

Gerrodette, T. (1993). TRENDS: Software for a power analysis of linear regression. Wildlife Society Bulletin 21, 515–516.

Hale P. , Long S. , and Tapsall A. (1998). Distribution and conservation of delphinids in Moreton Bay. In ‘Moreton Bay and Catchment.’ (Eds R. Tibbetts, N. Hall and W. C. Dennison.) pp. 477–486. (School of Marine Science, University of Queensland: Brisbane.)

Hammond, P. S. (1987). Techniques for estimating the size of whale populations. Symposium of the Zoological Society of London 58, 225–245.

Hiby, A. R. , and Hammond, P. S. (1989). Survey techniques for estimating abundance of cetaceans. Report of the International Whaling Commission. Special Issue 11, 47–80.

Jackson, J. B. C. , Kirby, M. X. , Berger, W. H. , Bjorndal, K. A. , and Botsford, L. W. , et al. (2001). Historical overfishing and the recent collapse of coastal ecosystems. Science 293, 629–638.
CrossRef | CAS | PubMed |

Lanyon, J. M. (2003). Distribution and abundance of dugongs in Moreton Bay, Queensland. Australian Wildlife Research 30, 397–409.
CrossRef |

Lanyon J. M. , and Morrice M. G. (1997). The distribution and abundance of dugongs in Moreton Bay, southeast Queensland, p. 36. (Queensland Department of Environment and Heritage: Brisbane.)

Lear R. J. , and Bryden M. M. (1980). A study of the bottlenose dolphins, Tursiops truncatus, in Eastern Australian Waters. In ‘Occasional Paper’. (Australian National Parks and Wildlife Service: Canberra.)

LeDuc, R. G. , Perrin, W. F. , and Dizon, A. E. (1999). Phylogenetic relationships among the delphinid cetaceans based on full cytochrome B sequences. Marine Mammal Science 15, 619–648.
CrossRef |

Lukacs, P. M. , and Burnham, K. P. (2005). Review of capture-recapture methods applicable to noninvasive genetic sampling. Molecular Ecology 14, 3909–3919.
CrossRef | PubMed |

Marsh H. (1995). The limits of detectable change. In ‘Conservation Through Sustainable Use of Wildlife.’ (Eds G. C. Grigg, P. T. Hale and D. Lunney.) pp. 122–130. (Centre for Conservation Biology, University of Queensland: Brisbane.)

Marsh, H. , and Sinclair, D. F. (1989). Correcting for visibility bias in strip transect aerial surveys of aquatic fauna. The Journal of Wildlife Management 53, 1017–1024.
CrossRef |

Mead J. G. , and Potter C. W. (1990). Natural history of bottlenose dolphins along central Atlantic coast of the United States. In ‘The Bottlenose Dolphin’. (Eds S. Leatherwood and R. R. Reeves.) pp. 165–198. (Academic Press: San Diego.)

Menkens, G. E. , and Anderson, S. H. (1988). Estimation of small mammal population size. Ecology 69, 1952–1959.
CrossRef |

Möller, L. M. , Allen, S. J. , and Harcourt, R. G. (2002). Group characteristics, site fidelity and abundance of bottlenose dolphins (Tursiops aduncus) in Jervis Bay and Port Stephens, southeastern Australia. Australian Mammalogy 24, 11–21.

Natoli, A. , Peddemors, V. M. , and Hoelzel, A. R. (2004). Population structure and speciation in the genus Tursiops based on microsatellite and mitochondrial DNA analyses. Journal of Evolutionary Biology 17, 363–375.
CrossRef | CAS | PubMed |

Neil D. (1998). Moreton Bay and its catchment: seascape and landscape, development and degradation. In ‘Moreton Bay and Catchment.’ (Eds R. Tibbetts, N. Hall and W. C. Dennison.) pp. 3–54. (School of Marine Science, University of Queensland: Brisbane.)

Otis, D. L. , Burnham, K. P. , White, G. C. , and Anderson, D. R. (1978). Statistical inference from capture data on closed animal populations. Wildlife Monographs 62, 1–135.

Pandolfi, J. M. , Bradbury, R. H. , Sala, E. , Hughes, T. P. , and Bjorndal, K. A. , et al. (2003). Global trajectories of the long-term decline of coral reef ecosystems. Science 301, 955–958.
CrossRef | CAS | PubMed |

Read, A. J. , Urian, K. W. , Wilson, B. , and Waples, D. M. (2003). Abundance of bottlenose dolphins in the bays, sounds and estuaries of North Carolina. Marine Mammal Science 19, 59–73.
CrossRef |

Rexstad E. , and Burnham K. P. (1991). ‘Users guide for interactive program CAPTURE. Abundance estimation of closed animal populations.’ (Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University: Fort Collins, Colorado, USA.)

Rice D. W. (1998). ‘Marine mammals of the world: Systematics and distribution.’ (Society for Marine Mammalogy: Lawrence, KS.)

Ross G. J. B. , and Cockcroft V. G. (1990). Comments on Australian Bottlenose dolphins and the taxonomic status of Tursiops aduncus (Ehrenberg, 1832). In ‘The Bottlenose Dolphin.’ (Eds S. Leatherwood and R. R. Reeves.) pp. 101–128. (Academic Press, Inc.: San Diego, CA.)

Shane S. H. (1990). Behaviour and ecology of the bottlenose dolphin at Sanibel, Florida. In ‘The Bottlenose Dolphin’ (Eds S. Leatherwood and R. R. Reeves.) pp. 245–265. (Academic Press: San Diego, CA.)

Skinner J. L. , Gilliam E. , and Rohlin C. J. (1998). The demographic future of the Moreton Bay region. In ‘Moreton Bay and Catchment.’ (Eds R. Tibbetts, N. Hall and W. C. Dennison.) pp. 67–78. (School of Marine Science, University of Queensland: Brisbane.)

Smolker, R. A. , Richards, A. F. , Connor, R. C. , and Pepper, J. W. (1992). Sex differences in patterns of association among Indian Ocean bottlenose dolphins. Behaviour 123, 38–69.
CrossRef |

Stensland, E. , Carlen, I. , and Sarnblad, A. (2006). Population size, distribution, and behaviour of Indo-Pacific bottlenose (Tursiops aduncus) and humpback (Sousa chinensis) dolphins off the south coast of Zanzibar. Marine Mammal Science 22, 667–682.
CrossRef |

Taylor, B. L. , and Gerrodette, T. (1993). The uses of statistical power in conservation biology: the Vaquita and the Northern Spotted Owl. Conservation Biology 7, 489–500.
CrossRef |

Taylor, B. L. , Marinez, M. , Gerrodette, T. , Barlow, J. , and Hrovat, Y. N. (2007). Lessons from monitoring trends in abundance of marine mammals. Marine Mammal Science 23, 157–175.
CrossRef |

Thomas L. , Laake J. L. , Strindberg S. , Marques F. F. C. , Buckland S. T. , et al (2004). Distance 4.1 Release 2. (Research Unit for Wildlife Population Assessment, University of St. Andrews: UK.) http://www.ruwpa.st-and.ac.uk/distance/.

Tibbetts R. (1998). Preface. In ‘Moreton Bay and Catchment.’ (Eds R. Tibbetts, N. Hall and W. C. Dennison.) pp. i–ii. (School of Marine Science, University of Queensland: Brisbane.)

Wade P. , and DeMaster D. P. (1999). Determining the optimum interval for abundance surveys. In ‘Marine Mammal Survey and Assessment Methods’ (Eds G. W. Garner, S. C. Amstrup, J. L. Laake, et al.) pp. 53–66. (A.A. Balkema: Rotterdam.)

Wells R. S. , and Scott M. D. (1990). Estimating bottlenose dolphin population parameters from individual identification and capture-release techniques. pp. 407–415. (Rep. Int. Whal. Commn (Special Issue 12.))

Wells R. S. , Scott M. D. , and Irvine A. B. (1987). The social structure of free-ranging bottlenose dolphins. In ‘Current Mammalogy, Vol. 1’ (Ed. H. H. Genoways.) pp. 247–305. (Plenum Press: New York.)

Whitehead H. , Reeves R. R. , and Tyack P. L. (2000) Science and the Conservation, Protection, and Management of Wild Cetaceans. In ‘Cetacean Societies: Field Studies of Dolphins and Whales.’ (Eds J. Mann, R. C. Connor, P. L. Tyack and H. Whitehead.) pp. 308–332. (The University of Chicago Press: Chicago.)

Williams, J. A. , Dawson, S. M. , and Slooten, E. (1993). The abundance and distribution of bottlenose dolphins (Tursiops truncatus) in Doubtful Sound, New Zealand. Canadian Journal of Zoology 71, 2080–2088.
CrossRef |

Wilson, B. , Hammond, P. S. , and Thompson, P. M. (1999). Estimating size and assessing trends in a coastal bottlenose dolphin population. Ecological Applications 9, 288–300.
CrossRef |

Wursig, B. , and Jefferson, T. A. (1990). Methodology of photo-identification for small cetaceans. Report of the International Whaling Commission. Special Issue 12, 43–53.

Rent Article (via Deepdyve) Export Citation Cited By (13)