[MARMAM] new publication on the use of dolphin carcasses for the analysis of cetacean population genetic structure

Kerstin Bilgmann kerstin.bilgmann at mq.edu.au
Fri Jun 17 01:00:36 PDT 2011

Dear MARMAM readers,

The following paper has recently been published in PLoS ONE:

Bilgmann K, Moller LM, Harcourt RG, Kemper CM, Beheregaray LB (2011) The Use
of Carcasses for the Analysis of Cetacean Population Genetic Structure: A
Comparative Study in Two Dolphin Species. PLoS ONE 6(5): e20103.


Advances in molecular techniques have enabled the study of genetic diversity
and population structure in many different contexts. Studies that assess the
genetic structure of cetacean populations often use biopsy samples from
free-ranging individuals and tissue samples from stranded animals or
individuals that became entangled in fishery or aquaculture equipment. This
leads to the question of how representative the location of a stranded or
entangled animal is with respect to its natural range, and whether similar
results would be obtained when comparing carcass samples with samples from
free-ranging individuals in studies of population structure. Here we use
tissue samples from carcasses of dolphins that stranded or died as a result
of bycatch in South Australia to investigate spatial population structure in
two species: coastal bottlenose (*Tursiops* sp.) and short-beaked common
dolphins (*Delphinus delphis*). We compare these results with those
previously obtained from biopsy sampled free-ranging dolphins in the same
area to test whether carcass samples yield similar patterns of genetic
variability and population structure. Data from dolphin carcasses were
gathered using seven microsatellite markers and a fragment of the
mitochondrial DNA control region. Analyses based on carcass samples alone
failed to detect genetic structure in *Tursiops* sp., a species previously
shown to exhibit restricted dispersal and moderate genetic differentiation
across a small spatial scale in this region. However, genetic structure was
correctly inferred in *D. delphis*, a species previously shown to have
reduced genetic structure over a similar geographic area. We propose that in
the absence of corroborating data, and when population structure is assessed
over relatively small spatial scales, the sole use of carcasses may lead to
an underestimate of genetic differentiation. This can lead to a failure in
identifying management units for conservation. Therefore, this risk should
be carefully assessed when planning population genetic studies of cetaceans.

The paper can be downloaded from

or you can request a copy by emailing kerstin.bilgmann at mq.edu.au.

Kind regards,



Dr Kerstin Bilgmann

Postdoctoral Research Fellow

School of Biological Sciences
Flinders University
GPO Box 2100 Adelaide   SA 5001 Australia


Honorary Associate
Marine Mammal Research Group
Graduate School of the Environment
Macquarie University
Email: kerstin.bilgmann at mq.edu.au
Ph: +61 (0) 409134460

Fax: +61 (0) 08 8201 3015
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