Preliminary Report on Dolphin Deaths 2012
Preliminary Report on Dolphin Deaths
December 21, 2012
PRELIMINARY REPORT ON DOLPHIN DEATHS
According to the necropsy study conducted by experts from Istanbul University Faculty of Fisheries and the Turkish Marine Research Foundation (TÜDAV), the preliminary report on 4 common dolphins (Delphinus delphis) that washed ashore dead in the Zeytinburnu-Yenikapı region of Istanbul between December 16-18, 2012 is presented below.
No. Sample No. Date Found Gender Height (cm)
1 12074 16.12.2012 male 134
2 12075 16.12.2012 female 176
3 12076 17.12.2012 female 141
4 12077 18.12.2012 male 103
Cause of death: Drowning was determined.
External examination revealed tooth marks from other dolphins, friction marks, and possible net marks on the skin. Morphometric measurements of the animal were taken, all changes on the skin were examined and photographed.
During examination of the respiratory system, signs of drowning were observed. Initial examination of the necropsy suggests that the dolphins suffocated due to entrapment. Preliminary analysis of stomach contents revealed undigested horse mackerel and bluefish/yellowfin tuna. Common digestive parasites were found in these animals, and no abnormalities that would cause death were initially observed. Routine sampling was conducted for further investigations (genetics, age analysis, pathology, etc.). Milk was found in the mammary glands of female individual number 12075. Individual number 12077 is likely a juvenile born this year. Whether 12075 is a juvenile will be determined after genetic studies.
This case shows similarities to the incident that occurred in Kartal in April 2008. Due to the undigested fish in the stomach, marks on the body, and bleeding, it is estimated that the dolphins suffocated after becoming entangled in fishing nets following feeding. Intensive purse seine fishing is currently being carried out in the area where the incident occurred, targeting seasonal pelagic fish. To prevent such deaths from happening again, all fishermen in the region should be careful about dolphins that may enter their nets and, in such a case, should immediately help the dolphins to get out of the nets unharmed, as shown in the video below, filmed in Zonguldak. http://siz.net/hamsi-diye-cektiler-yunus-cikti-videosu/
The bottlenose dolphin, one of three dolphin species (the others being the bottlenose dolphin and the common dolphin) that can be observed in the Bosphorus, the Sea of ??Marmara, and the Black Sea, is a species that generally prefers the open sea. In Istanbul, it can be observed near the shores, especially during spring and autumn months, during fish migrations between the Sea of ??Marmara and the Black Sea. According to the International Union for Conservation of Nature (IUCN) criteria, the Mediterranean subpopulation of this species is listed as "endangered," and the Black Sea subpopulation as "vulnerable." Until 1983, dolphin stocks were severely depleted due to hunting in these lands for 2300 years. According to the Fisheries Law No. 1380, all marine mammals living in Turkish seas are protected and their killing is prohibited under all circumstances. Today, the factors threatening dolphin populations are: accidental entanglement in bottom trawls (especially for the common dolphin species), habitat loss due to food scarcity, marine pollution, and epidemic diseases causing mass deaths. It is known that thousands of dolphins, especially common dolphins, die each year in bottom trawls throughout the Black Sea. Scientific field studies conducted monthly on stranded dolphins in the western Black Sea revealed hundreds of dead dolphins in a single month during mass deaths in 2003 and 2009. In 2013, a joint project involving all Black Sea countries will be undertaken to investigate the distribution and size of dolphin populations.
Istanbul University Faculty of Fisheries and TUDAV, which have been conducting scientific studies on marine mammals as a team since 1993; Its research focuses on fishing interactions, stranded animals, population distribution and size, acoustic and visual migration tracking in the Istanbul Strait, photo-ID identification, genetic structure, skull collections, stomach contents, conservation strategies, diseases, etc. Please support the Istanbul University/TUDAV Stranded Marine Mammal Communication Network by reporting your observations of dead whales, dolphins, and seals to the coast guard (158), marine police, white desk (153), Istanbul University Faculty of Fisheries, or TUDAV. Do not touch dead animals without wearing protective gloves to avoid any risk of disease. The reports are important data sources for our scientific studies. We expect you to join us and support our efforts to protect our seas.
Istanbul University Turkish Marine Research Foundation (TUDAV)
Faculty of Fisheries PK:10 Beykoz, Istanbul
Ordu Cad. No:200 Laleli Tel: 216 424 0772
Tel: 212 455 5700 Fax: 216 424 07
December 21, 2012
PRELIMINARY REPORT ON DOLPHIN DEATHS
According to the necropsy study conducted by experts from Istanbul University Faculty of Fisheries and the Turkish Marine Research Foundation (TÜDAV), the preliminary report on 4 common dolphins (Delphinus delphis) that washed ashore dead in the Zeytinburnu-Yenikapı region of Istanbul between December 16-18, 2012 is presented below.
No. Sample No. Date Found Gender Height (cm)
1 12074 16.12.2012 male 134
2 12075 16.12.2012 female 176
3 12076 17.12.2012 female 141
4 12077 18.12.2012 male 103
Cause of death: Drowning was determined.
External examination revealed tooth marks from other dolphins, friction marks, and possible net marks on the skin. Morphometric measurements of the animal were taken, all changes on the skin were examined and photographed.
During examination of the respiratory system, signs of drowning were observed. Initial examination of the necropsy suggests that the dolphins suffocated due to entrapment. Preliminary analysis of stomach contents revealed undigested horse mackerel and bluefish/yellowfin tuna. Common digestive parasites were found in these animals, and no abnormalities that would cause death were initially observed. Routine sampling was conducted for further investigations (genetics, age analysis, pathology, etc.). Milk was found in the mammary glands of female individual number 12075. Individual number 12077 is likely a juvenile born this year. Whether 12075 is a juvenile will be determined after genetic studies.
This case shows similarities to the incident that occurred in Kartal in April 2008. Due to the undigested fish in the stomach, marks on the body, and bleeding, it is estimated that the dolphins suffocated after becoming entangled in fishing nets following feeding. Intensive purse seine fishing is currently being carried out in the area where the incident occurred, targeting seasonal pelagic fish. To prevent such deaths from happening again, all fishermen in the region should be careful about dolphins that may enter their nets and, in such a case, should immediately help the dolphins to get out of the nets unharmed, as shown in the video below, filmed in Zonguldak. http://siz.net/hamsi-diye-cektiler-yunus-cikti-videosu/
The bottlenose dolphin, one of three dolphin species (the others being the bottlenose dolphin and the common dolphin) that can be observed in the Bosphorus, the Sea of ??Marmara, and the Black Sea, is a species that generally prefers the open sea. In Istanbul, it can be observed near the shores, especially during spring and autumn months, during fish migrations between the Sea of ??Marmara and the Black Sea. According to the International Union for Conservation of Nature (IUCN) criteria, the Mediterranean subpopulation of this species is listed as "endangered," and the Black Sea subpopulation as "vulnerable." Until 1983, dolphin stocks were severely depleted due to hunting in these lands for 2300 years. According to the Fisheries Law No. 1380, all marine mammals living in Turkish seas are protected and their killing is prohibited under all circumstances. Today, the factors threatening dolphin populations are: accidental entanglement in bottom trawls (especially for the common dolphin species), habitat loss due to food scarcity, marine pollution, and epidemic diseases causing mass deaths. It is known that thousands of dolphins, especially common dolphins, die each year in bottom trawls throughout the Black Sea. Scientific field studies conducted monthly on stranded dolphins in the western Black Sea revealed hundreds of dead dolphins in a single month during mass deaths in 2003 and 2009. In 2013, a joint project involving all Black Sea countries will be undertaken to investigate the distribution and size of dolphin populations.
Istanbul University Faculty of Fisheries and TUDAV, which have been conducting scientific studies on marine mammals as a team since 1993; Its research focuses on fishing interactions, stranded animals, population distribution and size, acoustic and visual migration tracking in the Istanbul Strait, photo-ID identification, genetic structure, skull collections, stomach contents, conservation strategies, diseases, etc. Please support the Istanbul University/TUDAV Stranded Marine Mammal Communication Network by reporting your observations of dead whales, dolphins, and seals to the coast guard (158), marine police, white desk (153), Istanbul University Faculty of Fisheries, or TUDAV. Do not touch dead animals without wearing protective gloves to avoid any risk of disease. The reports are important data sources for our scientific studies. We expect you to join us and support our efforts to protect our seas.
Istanbul University Turkish Marine Research Foundation (TUDAV)
Faculty of Fisheries PK:10 Beykoz, Istanbul
Ordu Cad. No:200 Laleli Tel: 216 424 0772
Tel: 212 455 5700 Fax: 216 424 07
