[MARMAM] New paper: Linking organochlorine contaminants with demographic parameters in free-ranging common bottlenose dolphins from the northern Adriatic Sea

Tilen Genov tilen.genov at gmail.com
Sun Dec 9 15:02:21 PST 2018

Dear MARMAM colleagues

My co-authors and I are pleased to announce the publication of the
following paper:

Genov T., Jepson P.D., Barber J.L., Hace A., Gaspari S., Centrih T., Lesjak
J., Kotnjek P. (2019) *Linking organochlorine contaminants with demographic
parameters in free-ranging common bottlenose dolphins from the northern
Adriatic Sea*. *Science of the Total Environment* 657: 200-212.

Marine top predators, including marine mammals, are known to bio-accumulate
persistent pollutants such as polychlorinated biphenyls (PCBs), a serious
conservation concern for these species. Although PCBs declined in European
seas since the 1970s–1980s ban, considerable levels still persist in
European and Mediterranean waters. In cetaceans, stranded animals are a
valuable source of samples for pollutant studies, but may introduce both
known and unknown biases. Biopsy samples from live, free-ranging cetaceans
offer a better alternative for evaluating toxicological burdens of
populations, especially when linked to known histories of identified
individuals. We evaluated PCB and other organochlorine contaminants in
free-ranging common bottlenose dolphins (*Tursiops truncatus*) from the
Gulf of Trieste (northern Adriatic Sea), one of the most human-impacted
areas in the Mediterranean Sea. Biopsies were collected from 32 male and
female dolphins during 2011–2017. All animals were photo-identified and are
part of a well-known population of about 150 individuals monitored since
2002. We tested for the effects of sex, parity and social group membership
on contaminant concentrations. Males had significantly higher
organochlorine concentrations than females, suggesting offloading from
reproducing females to their offspring via gestation and/or lactation.
Furthermore, nulliparous females had substantially higher concentrations
than parous ones, providing further support for maternal offloading of
contaminants. Overall, 87.5% of dolphins had PCB concentrations above the
toxicity threshold for physiological effects in experimental marine mammal
studies (9 mg/kg lw), while 65.6% had concentrations above the highest
threshold published for marine mammals based on reproductive impairment in
ringed seals (41 mg/kg lw). The potential population-level effects of such
high contaminant levels are of concern particularly in combination with
other known or suspected threats to this population. We demonstrate the
utility of combining contaminant data with demographic parameters such as
sex, reproductive output, etc., resulting from long-term studies.

The paper is freely available for the next 50 days at:
Alternatively, please email me at tilen.genov at gmail.com for a PDF copy.

Best regards,

Tilen Genov

Tilen Genov

Morigenos - Slovenian Marine Mammal Society
Kidricevo nabrezje 4
6330 Piran

PhD student
Sea Mammal Research Unit
Scottish Oceans Institute
University of St Andrews
United Kingdom
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