[MARMAM] Unusual mass mortality of cetaceans in the western Black Sea

Arda M. Tonay atonay at istanbul.edu.tr
Mon Aug 1 02:34:19 PDT 2016

Dear All,

Apologies for cross posting.

In the last two months, there have been mass mortality of cetaceans on the
Black Sea coast of Bulgaria and Turkey. Most of them are newborn or juvenile
harbour porpoises, body length less than 70cm and usually at an advanced
stage of decomposition. A similar phenomenon was observed last years but
this year stranding rate (actually July) was at the highest (7.2ind./km) on
the western Black Sea coast of Turkey, where we found more than 150
individuals (97% harbour porpoise, 91% neonate) on a 22 km coast. In June
the stranding rate was also high but not too much as to call it mass
stranding (1 ind./km).

In 2003 and 2009 unusual mass mortality (Tonay et al. 2012) and high neonate
mortality was reported presumably as a secondary effect of bottom gillnet
turbot fishery in summers (Öztürk et al. 2012). Because of the death of
lactating and nursing mothers in turbot nets, neonates might starve to death
and get stranded ashore in this season. But this year and last year's events
seem different.


We are working to understand the reason for this mortality. Does anybody
have any experience similar, with many newborn or juveniles dead (almost no
adult animals)? There can be various scenarios, such as disease, acoustic
trauma, biotoxins, bycatch, suppression of immune system due to chemical


Please send us directly your comments or your observation of these
strandings: Ayaka Amaha Ozturk (ayakamaha at gmail.com) and Arda M. Tonay
(tonay at istanbul.edu.tr).


Turkish Marine Research Foundation (TUDAV)




Öztürk A.A., Tonay M.A., Raykov V., Dede A. 2012. High mortality of harbour
porpoise neonates in the southwestern Black Sea in 2010 and 2011. 26th
Annual Conf. European Cetacean Society, Galway, 90p.

Tonay, A.M., Dede, A., Öztürk, A.A., Ercan, D., Fernández, A. 2012. Unusual
mass mortality of cetaceans on the coast of the Turkish Western Black Sea in
summer 2009. J. Black Sea/Mediterr. Environ. 18:65-75


Arda M. TONAY Ph.D

Faculty of Fisheries, İstanbul University

Marine Biology Dep.

Ordu Cad. No:200 Laleli, 34480 İstanbul, Turkey

Tel: ­+90 212 455 5700/16459   Fax: +90 212 514 0379

atonay at istanbul.edu.tr   http://suurunleri.istanbul.edu.tr/


Turkish Marine Research Foundation (TUDAV)

P.O. Box 10 Beykoz, İstanbul, Turkey

Tel: +90 216 424 0772   Fax: +90 216 424 0771


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