Bottlenose dolphin abundance in coastal Moreton Bay 2000
Citation
Lukoschek, V. 2010. Bottlenose dolphin abundance in coastal Moreton Bay 2000. Data downloaded from OBIS-SEAMAP (http://seamap.env.duke.edu/dataset/494) on yyyy-mm-dd. https://doi.org/10.15468/yc94df accessed via GBIF.org on 2024-12-15.Description
Original provider: University of California, Irvine Dataset credits: Vimoksalehi Lukoschek, University of California, Irvine Abstract: 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. Supplemental information: Effort data do not include date/time.Purpose
Not available
Sampling Description
Study Extent
NASampling
NAMethod steps
- NA
Additional info
marine, harvested by iOBISTaxonomic Coverages
Scientific names are based on the Integrated Taxonomic Information System (ITIS).
-
Tursiops aduncuscommon name: Indian Ocean bottlenose dolphin rank: species
Geographic Coverages
Moreton Bay,South East Queensland
Bibliographic Citations
Contacts
Vimoksalehi Lukoschekoriginator
position: Primary contact
University of California, Irvine
email: vlukosch@uci.edu
OBIS-SEAMAP
metadata author
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu
OBIS-SEAMAP
distributor
Marine Geospatial Ecology Lab, Duke University
A328 LSRC building
Durham
27708
NC
US
email: seamap-contact@duke.edu
homepage: http://seamap.env.duke.edu
Vimoksalehi Lukoschek
owner
position: Primary contact
University of California, Irvine
email: vlukosch@uci.edu
Vimoksalehi Lukoschek
administrative point of contact
position: Primary contact
University of California, Irvine
email: vlukosch@uci.edu