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Bottlenose dolphin abundance in coastal Moreton Bay 2000
Citation
Lukoschek, V. and B.L. Chilvers. 2008. A robust baseline for bottlenose dolphin abundance in coastal Moreton Bay: A large carnivore living in a region of escalating anthropogenic impacts. Wildlife Research. 35(7):593-605

Access data
Availability: Creative Commons License This dataset is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

Description
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. more

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 analyzed 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, analyzed 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. Effort data do not include date/time.

Scope
Themes:
Biology > Mammals
Keywords:
Marine, I, Pacific, ISEW, Australia, Queensland, Moreton Bay, Tursiops Gervais, 1855

Geographical coverage
I, Pacific [Marine Regions]
ISEW, Australia, Queensland, Moreton Bay [Marine Regions]

Temporal coverage
8 January 2000 - 8 November 2000

Taxonomic coverage
Tursiops Gervais, 1855 [WoRMS]

Contributors
University of California, Irvine, moredata owner

Related datasets
Published in:
OBIS-SEAMAP: Spatial Ecological Analysis of Megavertebrate Populations, more

Publication
Based on this dataset:
Lukoschek, V.; Chilvers, L. (2008). A robust baseline for bottlenose dolphin abundance in coastal Moreton Bay: a large carnivore living in a region of escalating anthropogenic impacts. Wildl. Res. 35(7): 593-605. hdl.handle.net/10.1071/WR07021, more

URLs

Dataset information:

Dataset status: Completed
Data type: Data
Data origin: Research
Metadatarecord created: 2012-11-28
Information last updated: 2012-11-28
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