An approach for regional threat assessment under IUCN Red List criteria that is robust to uncertainty: The Fiordland bottlenose dolphins are critically endangered

Currey, Rohan J. C.; Dawson, Stephen M.; Slooten, Elisabeth

doi:10.1016/j.biocon.2009.02.036

Cited by 78 publications

(104 citation statements)

References 26 publications

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“…We simulated future changes of abundance for the Yangtze finless porpoise population, N(t), at year t using an individual-based Leslie matrix model that also factors the effects of demographic stochasticity and parameter uncertainty (Slooten et al, 2000;Currey et al, 2009a;Huang et al, 2012b). In this approach, N(t) was modelled by the following process:…”

Section: Population Trend Modelling and Status Assessmentmentioning

confidence: 99%

“…The mean (±SD) for our PE and TE estimates was calculated from 200 replications. We then applied the five criteria of the IUCN Red List Categories and Criteria Version 3.1 (IUCN, 2001) to known (abundance and occurrence) and projected (rate of decline and PE) population information for the Yangtze finless porpoise (see Currey et al, 2009a).…”

Section: Population Trend Modelling and Status Assessmentmentioning

confidence: 99%

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Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

Mei

Huang

Hao

et al. 2012

Biological Conservation

106

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Section: Population Trend Modelling and Status Assessmentmentioning

confidence: 99%

Section: Population Trend Modelling and Status Assessmentmentioning

confidence: 99%

Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

Mei

Huang

Hao

et al. 2012

Biological Conservation

106

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“…Under the New Zealand Threat Classification System, the species was listed as 'Not Threatened' up until 2002 (Hitchmough 2002) and subsequently uplisted to 'Range Restricted' in 2005 (Hitchmough et al 2007). A further reclassification to 'Nationally Endangered' in 2009(Baker et al 2010) was based on apparent declines in abundance in 2 of the 3 coastal populations, coupled with reports of high calf mortality (Currey et al 2009, Tezanos-Pinto et al 2013.…”

Section: Introductionmentioning

confidence: 99%

Overlooking a potential hotspot at Great Barrier Island for the nationally endangered bottlenose dolphin of New Zealand

Dwyer¹,

Tezanos‐Pinto²,

Visser³

et al. 2014

Endang. Species. Res.

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Conservation initiatives are typically constrained by economic circumstances, a factor certainly true for marine mammal conservation in New Zealand. Most research in this field has been conducted following concerns over anthropogenic impacts on populations and has therefore been funded and/or driven by stakeholder interest. Bottlenose dolphins Tursiops truncatus are classified as 'Nationally Endangered' in New Zealand waters. Here, we present the first study on occurrence, site fidelity and abundance of this species off Great Barrier Island (GBI), a previously overlooked region within the home range of the North Island population. Dedicated boat-based photo-identification surveys were conducted monthly from 2011−2013, resulting in 1412 sighting records of 154 individuals. Dolphins were recorded during all months of the year, with a higher probability of encounter in deeper waters during summer and shallower waters during winter and spring. Group sizes (median = 35, mean = 36) were higher than previously reported for this population in other regions. Individual re-sighting patterns were variable; however, overall site fidelity was high (mean monthly sighting rate = 0.33). A Robust Design approach resulted in seasonal fluctuations in abundance and temporary emigration. Based on a super-population estimate, 171 dolphins (CI = 162−180) visited the area during 2011−2013. Our data suggest that GBI is a potential hotspot for bottlenose dolphins of the North Island population rather than a corridor to reach other destinations. We highlight the need for researchers, managers and funding agencies to consider the entire range of a population when conducting or funding research.

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“…The bottlenose dolphin population of Doubtful Sound has been the subject of ongoing research since 1990 (Williams et al 1993) and is currently classified as Critically Endangered (Currey et al 2009a). The long-term data set generated from decades of photo-identification mark-recapture sampling provides the opportunity to produce detailed reproductive histories for each of the females in the population.…”

Section: Introductionmentioning

confidence: 99%

Factors influencing heterogeneity in female reproductive success in a Critically Endangered population of bottlenose dolphins

Brough

Henderson²,

Guerra³

et al. 2016

Endang. Species. Res.

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For threatened species or populations, variation in reproductive success among females may be explicitly linked with vulnerability to extinction. Thus, an understanding of factors that may cause variability in reproductive success is important. The population of bottlenose dolphins in Doubtful Sound, New Zealand, has a recent history of rapid population decline and low calf survival rates. A previous study has shown high variability in calf survival among multiparous females. This study addresses the factors that seem most important in explaining variation in calf survival and thus reproductive success among females in this population. Reproductive data were sourced from a long-term photo-identification dataset, which allowed tracking the fate of 49 calves born into the population between 1995 and 2012. General linear mixed models combined with model averaging were used to assess how birth timing, maternal size, age and potential anthropogenic impacts contributed to variation in calf survival. Models show that a female's size and her ability to give birth at an optimum time in the calving season are significant predictors of calf survival to an age of 1 and 3 yr. This is the first study to demonstrate how birth timing and mother size are correlated with female reproductive success in a cetacean species. These results confirm the importance of demographic stochasticity and reproductive heterogeneity in small, threatened marine mammal populations.

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An approach for regional threat assessment under IUCN Red List criteria that is robust to uncertainty: The Fiordland bottlenose dolphins are critically endangered

Cited by 78 publications

References 26 publications

Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

Accelerating population decline of Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis)

Overlooking a potential hotspot at Great Barrier Island for the nationally endangered bottlenose dolphin of New Zealand

Factors influencing heterogeneity in female reproductive success in a Critically Endangered population of bottlenose dolphins

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