[MARMAM] New publication on abundance estimation of inshore dolphins

Alexander Brown Alex.Brown at murdoch.edu.au
Tue Feb 9 23:16:15 PST 2016

Dear colleagues,

My co-authors and I are pleased to bring to your attention the following open access publication:

Brown, A.M., Bejder, L., Pollock, K.H. and Allen, S.J. (2016). Site-specific assessments of the abundance of three inshore dolphin species to inform conservation and management. Frontiers in Marine Science 3:4. doi: 10.3389/fmars.2016.00004

The study provides estimates of abundance for Australian snubfin, Australian humpback and Indo-Pacific bottlenose dolphins in the Kimberley region of north-western Australia. The study also presents results on site fidelity and power analysis for trend detection. While the study has a regional-focus, the methods employed are broadly applicable to such studies elsewhere.

The full article pdf and supplementary material are available to download from the Frontiers in Marine Science website: http://dx.doi.org/10.3389/fmars.2016.00004

The abstract is pasted below, while an additional summary is provided on our research group's website: http://mucru.org/new-publication-inshore-dolphins/


Assessing the abundance of wildlife populations is essential to their effective conservation and management. Concerns have been raised over the vulnerability of tropical inshore dolphins in waters off northern Australia to anthropogenic impacts on local populations, yet a lack of abundance data precludes assessment of their conservation status and the management of threats. Using small vessels as cost-effective research platforms, photo-identification surveys and capture-recapture models were applied to provide the first quantitative abundance data for Australian snubfin (Orcaella heinsohni), Australian humpback (Sousa sahulensis), and Indo-Pacific bottlenose dolphins (Tursiops aduncus) at five sites in the Kimberley region of north-western Australia. The abundance of each species was highly variable between different sites, likely reflecting species-specific habitat preferences. Within the c. 130 km2 study sites, the estimated abundance of most species was ≤ 60 individuals (excluding calves), and fewer than 20 humpback dolphins were identified at each site in any one 3-5 week sampling period. However, larger estimates of c. 130 snubfin and c. 160 bottlenose dolphins were obtained at two different sites. Several local populations showed evidence of site fidelity, particularly snubfin dolphins. By implementing a standardized, multi-site approach, data on local populations were provided within a broader, regional context, and indicated that each species is patchily distributed in the region. This highlights the need for site-specific baseline data collection using appropriate survey techniques to quantitatively assess the potential impacts of threatening activities to local populations. These findings further illustrate the need to gain a greater understanding of known and potential threats to inshore dolphin populations, their relative impacts, and to mitigate where necessary. An ideal candidate site for a long-term study of snubfin dolphin population dynamics is identified, where trends in abundance and their influencing factors could be investigated. The methods employed herein provide an example of rigorous, site-specific population assessments of inshore dolphins that are broadly applicable to such studies elsewhere.

Keywords: baseline data, capture-recapture, abundance estimation, coastal delphinids, robust design, apparent survival, power analysis, trend detection

Best wishes,


Alexander Brown
Murdoch University Cetacean Research Unit (MUCRU)
School of Veterinary and Life Sciences, Murdoch University
Perth WA 6150 Australia
alex.brown at murdoch.edu.au<mailto:alex.brown at murdoch.edu.au>  |  +61(0)487399861  |  www.mucru.org<http://www.mucru.org/>  |  researchgate<https://www.researchgate.net/profile/Alexander_Brown4>

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