[MARMAM] New paper: Local decline in abundance of bottlenose dolphins

Gaby de Tezanos Pinto lapachamamanz at gmail.com
Sat Jan 26 14:36:01 PST 2013

Dear friends and collegues:
We are pleased to let you know that a new paper: Local decline in abundance
of bottlenose dolphins (Tursiops truncatus) in the Bay of Islands, New
Zealand is currently available through early online access in the Marine
Mammal Science website. Altenratively, I can email PDF's upon request.
Regional populations of bottlenose dolphins (Tursiops truncatus) around New
Zealand are genetically isolated from each other and the species was
recently classified as nationally endangered based on relatively small
population sizes and reports of high calf mortality. Here, we estimate the
abundance and trends in one of these regional populations, the Bay of
Islands, using a photo-identification database collected from 1997 to 1999
and from 2003 to 2006, containing a total of 3,841 records of 317 individual
dolphins. Estimates of abundance obtained with the robust design fluctuated
widely but showed a significant decline in the number of dolphins present in
the bay over time (7.5% annual rate of decline). Temporary emigration was
random and fluctuated considerably (c = 0.18, SE = 0.07 to c = 0.84, SE =
0.06). Apparent survival was estimated at 0.928 (CI = 0.911-0.942). Seasonal
estimates (26 seasons) obtained in POPAN also showed a significant decline
in abundance (5.8% annual rate of decline). Despite the decline observed in
local abundance, dolphins continue to be found regularly in the Bay of
Islands, suggesting that fewer dolphins use the bay on regular basis.
Consequently, it seems that a change in habitat use, mortality and possibly
low recruitment could underlie the apparent local decline.
Kind regards
Gabriela Tezanos-Pinto
BSc (hons), PhD
Adjunct Research Associate
Coastal-Marine Research Group
Institute of Mathematics and Natural sciences
Albany Campus, Massey University
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