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    Description of Bithynia gonensis sp. nov. (Gastropoda: Bithyniidae) from Gönen Çayı, north-western Türkiye
    (E Schweizerbartsche Verlagsbuchhandlung, 2024) Odabasi, Deniz Anil; Odabasi, Serpil; Ergul, Halim Aytekin; Zilifli, Aytug
    This study aims to reveal the freshwater mollusc assemblages from 6 sites sampled along Gonen cayi, a stream which flows into the southern Marmara Sea in north-western Turkiye. The stream was sampled using the multi-habitat sampling method with a hand net. Ten species of freshwater molluscs, most of which are widely distributed in Turkiye, were found in the study area. Among these taxa was an unidentified species of Bithynia, which was only present at 1 site. Its shell and anatomy were compared with other Bithynia species from Turkiye and neighbouring countries and found to differ, which revealed that it is a new species. The discovery of the new species increases the diversity of Bithynia in northern Turkiye to 4 species, and to 11 species for Turkiye. This paper highlights the diversity and endemism of freshwater molluscs in Turkiye and emphasizes the need for further research on the distribution of bithyniid species in the country.
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    Development of a macroinvertebrate-based multimetric index for biological assessment of streams in the Sakarya River Basin, Turkey
    (Springer, 2022) Odabasi, Deniz Anil; Odabasi, Serpil; Ergul, Halim Aytekin; Ozkan, Nurcan; Boyaci, Yunus Omer; Baykose, Ahmet; Kayal, Melih
    The present study aimed to develop a multimetric index as a biological indication method of water quality using benthic macroinvertebrates for Turkey. A total of 207 operational taxa units were identified from 26 sampling sites through the employment of the multi-habitat method. Water was simultaneously sampled for both in-situ measurements and laboratory analysis in order to obtain the data on water chemistry. Ineligible metrics were excluded from the calculation process together with box-whisker plots and Kruskal-Wallis test (p < 0.05), considering the degree of overlap in the quartile limits (1 degrees-3 degrees). Among ten candidate metrics, four were considered suitable to form a multimetric index through Spearman correlation analysis. The core metrics were standardized with the 3(rd) quartile to obtain the index value. The index responded to a set of environmental variables, and split the ecological conditions into four categories as high, moderate, poor, and bad for the study area. Our results indicate that the multimetric index of the Sakarya River (MMIS) is an effective biological monitoring tool employing macroinvertebrates for biological monitoring in Turkey.
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    Sightings of cetaceans in the Western Antarctic Peninsula during the first joint Turkish-Ukrainian Antarctic Research Expedition, 2016
    (Tubitak Scientific & Technological Research Council Turkey, 2017) Ozturk, Bayram; Tonay, Mehmet Arda; Oz, Melike Idil; Yilmaz, Izzet Noyan; Ergul, Halim Aytekin; Ozturk, Ayaka Amaha
    During the cetacean surveys of the first Turkish-Ukrainian Antarctic Research Expedition conducted on 5-8 April 2016 in Lemaire Channel, Penola Strait, Flanders Bay, southern Gerlache Strait, and southern Neumayer Channel in the Western Antarctic Peninsula, 74 humpback whales (Megaptera novaeangliae) in 24 sightings and 11 Antarctic minke whales (Balaenoptera bonaerensis) in 6 sightings were recorded. The overall encounter rate (number of sightings/survey effort in nautical miles) was 0.333 (0.266 for humpback whale, 0.066 for Antarctic minke whale). According to the sighting distribution, the Lemaire Channel and Penola Strait are important migration and feeding habitats for whales. Five humpback whales were photo-identified individually by natural features on their flukes; one of them had a match in the Antarctic Humpback Whale Catalogue. The matched individual was first recorded on 30 August 2007 at Salinas, Ecuador.