Arda M. Tonay

Stomach contents of by-caught striped dolphins ( Stenella coeruleoalba ) in the eastern Mediterranean Sea

Stomach contents of six striped dolphins taken as by-catch in the swordfish fishery in the eastern Mediterranean Sea off the Turkish coast were examined. In total, 29 taxa were identified to species or family and 1777 individual food items (1394 bony fishes, 289 cephalopods, 94 crustaceans) were counted. Diaphus spp. and Ceratoscopelus maderensis were the most remarkable ones, as they accounted for 70.45% of the total number of fishes. Onychoteuthis banksii , on the other hand, was the only cephalopod species found in all stomach content analyses and represented 38.06% of the total number of cephalopods. Bony fish species: Myctophum punctatum, Notoscopelus elongatus, Electrona risso, Sudis hyalina, Moridae sp., Phycidae sp., Sternoptychidae sp. and cephalopods: Pterygioteuthis giardi and Chtenopteryx sicula were reported the first time in the stomach contents of striped dolphin in the Mediterranean Sea.

Stranding of a Green Turtle, Chelonia mydas (Linnaeus, 1758), in the Turkish Black Sea

& SIMMONS 1980, GLUTZ VON BLOTZHEIM & BAUER 1989), and other parts of Transcaucasia. Georgia has an estimated 10-50 breeding pairs, where a small colony was discovered on Javakheti Plateau (GÁLVEZ et. al. 2005). No recent breeding record is known for Armenia (ANANIAN, pers. comm.), although ADAMIAN & KLEM (1999) listed the species as a rare breeding species. I assume that this breeding occurs irregularly in Azerbaijan and in low numbers, and may have been overlooked in the past because of the low density of observers.

The stomach content of a Mediterranean Monk Seal (Monachus monachus): finding of Green Turtle (Chelonia mydas) remains

The stomach contents of an adult Mediterranean Monk Seal (Monachus monachus) found stranded on the Turkish eastern Mediterranean coast near Antalya in May 2013 were analysed. In total, 69 individual food items were counted and nine taxa were identified to species or family level. Of the identified taxa, Sparidae was the most highly represented family of prey fish, and one cephalopod species, Octopus vulgaris, was found. Ariosoma balearicum and Argyrosomus regius were encountered for the first time in the diet of a Monk Seal in the Mediterranean. Several body parts (three heads, six forelimbs, neck bones and fractured upper forelimb bones) of Green Turtles (Chelonia mydas) were also identified, which is the first record of this species in the Monk Seal’s diet.

Is there a distinct harbor porpoise subpopulation in the Marmara Sea

Abstract Genetic population structure of geographically isolated endangered Black Sea harbor porpoise (Phocoena phocoena relicta) is little known in Turkish waters, especially in the Turkish Straits System (TSS- Marmara Sea, Bosphorus and Dardanelles), which connects the Black Sea and the Aegean Sea. Mitochondrial DNA sequences of 70 new individuals sampled in the Turkish Black Sea, TSS and Aegean Sea, revealed five new haplotypes from the Black Sea. The findings support the idea that harbor porpoises from the Black Sea dispersed into the Aegean through the TSS. Considering signatures of population expansion, all subpopulations showed a signature of population expansion. The network data and the Фst calculations indicated that the Marmara Sea subpopulation was significantly differentiated from all of the other subpopulations, and supports the notion of its isolated. The finding of a potential management unit (MU) within an already heavily impacted subpopulation as a whole suggests that the individuals of P. p. relicta inhabiting the Marmara Sea require a very rigorous conservation strategy to ensure the survival of this subpopulation, represented by its unique haplotype.

Estimates of cetacean by-catch in the turbot fishery on the Turkish Western Black Sea Coast in 2007 and 2008

This is the first study estimating cetacean by-catch in the Turkish western Black Sea turbot fishery. One turbot fishing boat was observed during two fishing seasons, from April through July 2007 and April through mid-September 2008. During this time, 24 harbour porpoises and one bottlenose dolphin were caught in turbot trammel nets. The by-catch rate was found to be 0.18 for harbour porpoise and 0.01 for bottlenose dolphin individuals per kilometre in 2007, and 0.19 for harbour porpoise individuals in 2008. It is estimated that the total numbers of harbour porpoises killed in the Turkish western Black Sea during the legal fishing period (April and July) were 167 ± 153 (CV: 0.92) in 2007 and 329 ± 220 (CV: 0.67) in 2008, and the number killed during both legal and illegal periods of turbot fishing were 2011 ± 742 (CV: 0.37) in 2007 and 2294 ± 806 (CV: 0.35) in 2008. The estimated range of harbour porpoise by-catch in the turbot fishery on the Turkish western Black Sea coast is between these two estimates. The by-caught harbour porpoises were between 1–8 years of age. About half of them were within the age range of 4 (26%) and 5 (21%) years old, and 78% were physically immature individuals. Turbot fishing carried out with bottom nets, especially in May and June, when turbot fishing is banned, is a threat to the sustainability of harbour porpoise stocks.

Preliminary study of acoustic identification of odontocetes in the Istanbul Strait, Turkey

In the Istanbul Strait, three odontocetes species are observed; the harbor porpoise which belongs to Phocoenidae and the common dolphin and the bottlenose dolphin which belong to Delphinidae. Previous visual observation conducted in the middle of this Strait showed, Phocoenidae appeared frequently in March and April, whereas Delphinidae appeared throughout the year. However, visual observation can only occur during daytime. On the other hand, acoustic observation can be used all day long, but is not suitable to identify and distinguish different species. In this study, we examined whether a two band acoustic comparison of biosonar sounds can identify family or species of odontocetes. We compared the sound intensity ratio of two frequency bands at 70 kHz and 130 kHz. Narrow-band sounds, with dominant frequency around 130 kHz, correspond to a large ratio of two band intensities, possibly originating from Phocoenidae. In contrast, broad-band sounds provide similar intensities at both frequencies, which possibly originating from Delphinidae. The results show Phocoenidae appeared frequently in March and April, whereas Delphinidae appeared during all months. These findings are consistent with previous visual observations and suggest that two band acoustic monitoring of small odontocetes could be useful for the identification of harbor porpoises from Delphinidae species in a long term study.

Study of cetaceans in Istanbul Strait using passive acoustic method

The Istanbul Strait connects to the Aegean Sea and the Black Sea. Three cetaceans appear in this Strait, harbor porpoise (Phocoena phocoena relicta), common dolphin (Delphinus delphis ponticus), bottlenose dolphin (Tursiops truncatus ponticus). We used stereo passive acoustic monitoring system (A-tag) to monitor the moving pattern of these cetaceans from July 2009 to September 2010. This system enables to record the sound source direction calculated by the sound arrival time difference between two hydrophones. They have different frequency sensitivity, which enable to distinguish Phocoenidae from Delphinidae. Phocoenidae and Delphinidae were detected most frequently in April. They stay near the A-tag in March and April than in August. Acoustic sensing distance, which is proportional to the inter-click-interval of the sonar signals, was short in the same months. This was more clear in Phocoenidae. Dominant behavior pattern of both species was staying rather than moving in all seasons. However, Phocoenidae ...