[MARMAM] New paper using passive acoustics: Spatio-temporal occurrence variability of coastal dolphins in Zanzibar, Tanzania

Andrew Temple (PGR) andrew.temple at newcastle.ac.uk
Fri Mar 4 06:49:11 PST 2016

Dear MARMAM colleagues,

On behalf of my co-authors and myself I wish to announce the publication of our new paper on the spatio-temporal variability of Indo-Pacific bottlenose and Indian Ocean humpback dolphins in Zanzibar, Tanzania. 

Temple AJ, Tregenza N, Amir OA, Jiddawi N, Berggren P (2016) Spatial and Temporal Variations in the Occurrence and Foraging Activity of Coastal Dolphins in Menai Bay, Zanzibar, Tanzania. PLoS ONE 11(3): e0148995. doi:10.1371/journal.pone.0148995

Understanding temporal patterns in distribution, occurrence and behaviour is vital for the effective conservation of cetaceans. This study used cetacean click detectors (C-PODs) to investigate spatial and temporal variation in occurrence and foraging activity of the Indo- Pacific bottlenose (Tursiops aduncus) and Indian Ocean humpback (Sousa plumbea) dolphins resident in the Menai Bay Conservation Area (MBCA), Zanzibar, Tanzania. Occurrence was measured using detection positive minutes. Inter-click intervals were used to identify terminal buzz vocalisations, allowing for analysis of foraging activity. Data were analysed in relation to spatial (location) and temporal (monsoon season, diel phase and tidal phase) variables. Results showed significantly increased occurrence and foraging activity of dolphins in southern areas and during hours of darkness. Higher occurrence at night was not explained by diel variation in echolocation rate and so were considered representative of occurrence patterns. Both tidal phase and monsoon season influenced occurrence but results varied among sites, with no general patterns found. Foraging activity was greatest during hours of darkness, High water and Flood tidal phases. Comparisons of echolocation data among sites suggested differences in the broadband click spectra of MBCA dolphins, possibly indicative of species differences. These dolphin populations are threatened by unsustainable fisheries bycatch and tourism activities. The spatial and temporal patterns identified in this study have implications for future conservation and management actions with regards to these two threats. Further, the results indicate future potential for using passive acoustics to identify and monitor the occurrence of these two species in areas where
they co-exist.

The paper is open access and is available at the following link: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148995 

Many Thanks,

Andrew Temple

Andrew Temple, PhD Candidate
Marine Science and Technology
Newcastle University
Office: 0191 222 5607
E-Mail: andrew.temple at ncl.ac.uk
Co-Investigator in the BYCAM project: http://www.wiomsa.org/ongoing-project/by-catch-assessment-and-mitigation-in-western-indian-ocean-fisheries-bycam/ 

More information about the MARMAM mailing list