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240 Endang Species Res 27: 233–241, 2015
If further analysis of historical Mediterranean white
shark material, for both mtDNA and nuclear markers,
does not refute the conjecture of a potentially small,
genetically isolated, and highly inbred population,
then concerns should be raised about its ability to
cope with rapid environmental and ecological change
(Cheptou & Donohue 2011). As a result of current de-
clines (Cavanagh & Gibson 2007, Storai et al. 2011)
and the rarity of contemporary material, it is impera-
tive that museum and trophy specimens found through-
out the Mediterranean region and Europe are utilized
to refine estimates of connectivity, decline of genetic
diversity, and contemporary gene flow to assess the
viability of Mediterranean white shark stocks.
Recourse to historical Mediterranean material may
be the only way to study the genetic diversity of this
threatened population, as artisanal fisheries through-
out the region complicate management strategies,
and contemporary captures are probably sold at mar-
ket before they can be sampled (S. Canese pers. obs.).
Yet reports of pregnant females off Tunisia and of
neonates in the Aegean Sea suggest key nursery sites
for this species are located within highly overexploited
and data-deficient regions (Saïdi et al. 2005, Kaba-
sakal 2008). In support, as a response to large declines
in predatory sharks (Ferretti et al. 2008) and rapidly
shifting trophic systems, increased pressure has been
placed on regional fisheries management organiza-
tions throughout the Mediterranean to improve spe-
cies-specific catch and landings data, prohibit finning
and encourage full utilization, and assess manage-
ment needs for elasmobranch conservation (Camhi et
al. 2009).
Three out of 5 Mediterranean historical samples
were of the contemporary haplotype, suggesting hap-
lotypes of the 2 oldest samples have not been seen in
the contemporary population sampled to date. Hence,
this retrospective analysis of tissue archives, with the
caveat of very small sample sizes and partial se-
quences, confirms the lack of haplotype diversity in
contemporary sharks and tentatively suggests a loss
of genetic diversity (Table 3) in the last 100 yr — a pe- ® Alter SE, Newsome SD, Palumbi SR (2012) Pre-whaling
riod during which white shark stocks and habitats
have suffered degradation. Necessarily, the ecological
implications of a lack, possibly as a result of recent
loss, of genetic diversity in an apex predator extend
beyond the demise of a single species.
CONCLUSIONS
This study demonstrates the validity of our ap-
proach for extraction, amplification, and sequencing
of genomic DNA from white shark teeth and histori-
cal material. Historical DNA sequences can be com-
bined with contemporary samples to increase sample
size for rare species, affording estimates of changes
in population and demographic parameters across
centuries. Data from this approach are particularly
relevant to conservation management of an endan-
gered K-selected species exhibiting philopatric be-
haviour. Our findings give no cause for complacency,
suggesting haplotype diversity of contemporary
Mediterranean individuals is depauperate compared
with that of other populations.
Acknowledgements. This work was supported by Aberdeen
University, the Marine Biological Association and Save Our
Seas Foundation (SOSF). We thank Mr Oliver Crimmen, Dr
Colin MacLeod, Dr Sharon Mitchell, and Patricia Crombie
for their support, Dr Takashi Sawada for valuable comments
on elasmobranch tooth formation, and Professor Richard
Aspden for use of the freezer mill for grinding osteodentine.
Thanks to Steffano Vanni, Giuseppe Guarrasi, Enrico Bellia,
Helmut Wellendorf, Radek Šanda, Peter Adamik, and
Georges Lenglet for allowing access to material from
museum and private collections.
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