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Öğe Acoustic Estimates of Leaf Height and Biomass of Posidonia oceanica Meadow in Gulf of Antalya, the Eastern Mediterranean(Çanakkale Onsekiz Mart Üniversitesi, 2020) Mutlu, Erhan; Olguner, CansuVegetation cover on the sea floor plays an important role in marine health, and sonar systems can provide detailed observation and evaluation of sea floor vegetation under rapidly changing environmental conditions. Various acoustic techniques are available for this purpose. In this study, a split beam echo sounder operating at a frequency of 206 kHz was employed. Simultaneous dive expeditions were performed for direct acoustic observations. The aim of this study was to use the BioSonics EcoSAV software program to generate acoustic estimates of leaf height and create seasonal distribution maps in Posidonia oceanica meadows distributed between Lara and Manavgat in the Gulf of Antalya (Turkey). Calculation of program parameters by species and acoustic identification of P. oceanica were carried out with the aid of the PAST 3.05 (PAleontological STatistics) statistics program, enabling isolation of P. oceanica and other non-target species from the sea floor. The results revealed three major meadow beds in the study area. The maximum leaf height was observed in July (80–90 cm), followed by April/May (70–80 cm), with the shortest leaf height in January (40–50 cm). The biomass of the leaves varied seasonally between 100 and 1000 g/m2 and decreased by the seafloor depth in a year. This method proved effective for mapping and monitoring important seasonal habitat parameters such as the distribution of aquatic vegetation.Öğe Ecological Gradients of Epimegafaunal Distribution along The Sectors of Gulf of İzmir, Aegean Sea(Çanakkale Onsekiz Mart Üniversitesi, 2021) Mutlu, ErhanDuring 2009-2010 epifaunal materials were collected seasonally with a beam trawl from seven fixed stations in the infralittoral of Gulf of Izmir to study spatiotemporal distribution of megabenthic fauna and their ecology. A total 153 megafaunal species were identified belonging to nine phyla, comprised mostly of 54 molluscans, 43 chordates (mostly fish), 20 arthropods, and 18 echinoderms. Nine alien species were recorded. Four species (two fish species, one gastropod and one Asteroidea species) were constant species and 16 species were common species in the study area. Lesueurigobius friesii, Buglossidium luteum, Turritellinella tricarinata and Astropecten irregularis were the most frequently occurred, and Lesueurigobius friesii, Varicorbula gibba, Anomia ephippium, Turritellinella tricarinata and Dentalium sp were the most abundantly occurred species. Excluding the evenness index, faunistic characteristics tended to increase as a factor of depth. Seasonal density (abundance and biomass) was minimal in April and maximal in February, followed by November having 2-fold higher abundance than that inJuly. Faunal assemblages were correlated with regions of the gulf and habitat type. Buglossidium luteum overspread the entire gulf excluding the inner gulf. Varicorbula gibba and Fulvia fragilis, a pollution indicator predominated the inner gulf. Hydrographical parameters and depth were associated to dictate faunal assemblages with difference among the sectors and habitats.Öğe Keystone Porgy Species (Sparidae) Overcome the Alien Randall's Threadfin Bream (Nemipterus randalli) for Catch Balance in Space on An Oligotrophic Levant Shelf or Vice Versa?(Çanakkale Onsekiz Mart Üniversitesi, 2022) Mutlu, Erhan; Meo, Ilaria de; Miglietta, Claudia; Deval, Mehmet CengizSince 2008 spatiotemporal and ecological distributions of porgies (sparid, all indigenous fish) were examined in the presence or absence of Randall's threadfin bream, Nemipterus randalli in the present study area. Seasonal fish and environmental parameters samplings were conducted at three transects of the fishing (nMPA) or non-fishing (MPA) regions on an oligotrophic shelf (Levantine Sea) in 2014-2015 for understanding management and ecology of the porgies’ catches. Of 13 sparid fish determined during the present study, five species are rarely found. There were no seasonal significant differences in densities of the sparid fish with or without the alien nemipterid fish. However, there were differences in the densities by the bottom depths, the regions, and soft and hard bottoms vegetated by Caulerpa spp and meadow, respectively. Ecologically, fish assemblages and faunistic characters of the sparid fish were highly variable when excluding the N. randalli as highlighted and follows; i) seasonal variation occurred and ii) the depthwise community assemblages became irregular. N. randalli seemed to balance the sparid catch attributed to the biomass-abundance ratio in the ecosystem or vice versa in this trophically sensitive gulf (ultra-oligotrophic) of the eastern Mediterranean Sea.Öğe Recent Occurrence of Rare Echeneis naucrates from the Turkish Mediterranean Coast(Çanakkale Onsekiz Mart Üniversitesi, 2021) Mutlu, ErhanOne specimen of live sharksucker was caught with a bottom trammel net in Taşucu Bay, south-eastern coast of Turkey, at 1 m depth on May, 2021. Meristic parameters were determined by fin ray counts and metric parameters were measured from the photos of the specimen. Excluding the recent record in Antalya Gulf, previous records of this species occurred later than May, generally in July in the Mediterranean Sea as well as in the Aegean Sea. The biometrical measurements were different in Taşucu Bay compared to those caught from the Aegean Sea and the central Mediterranean Sea (Tunisian and Sicilian waters), but relatively similar to those reported from Croatia. Major discriminative variables, albeit less significant in individuals from the central Mediterranean, were the number of anal, pectoral and dorsal fin rays. Numbers of suction disc laminae were higher in individuals from the central Mediterranean Sea and New Zealand than those from the Turkish coasts (all 21 disc laminae). The statistical analyses (Principal Component and Discriminant analyses) affirmed successful use of meristic parameters to differentiate the biometric characteristics of the species from the Aegean Sea, the central and eastern Mediterranean Sea. The length-weight relationship showed that the species had a negative allometric growth.Öğe Recent Record of Oceania armata and Near-Past Records of Other Gelatinous Organisms in the Turkish Waters Presumably Derived by Basin-Scale Current(Çanakkale Onsekiz Mart Üniversitesi, 2022) Mutlu, Erhan; Özvarol, YaşarThe present study reports the occurrence of Oceania armata in the Turkish Levantine Sea, and presents evidence to support a hypothesis established to link an increased recent and near-past records of many gelatinous zooplankton species in the Turkish seas, and particularly in the Turkish Levantine Sea to specific Mediterranean basin-scale currents (Atlantic-Ionian Stream and the Mid-Ionian Jet). One worldwide-distributed oceanic cnidarian specimen was collected from the surface water of a location of 36.59002 N and 29.02471 E by a SCUBA diver on January 18, 2019 in the eastern Mediterranean Sea. The hydrozoan specimen was then identified as O. armata and recorded for the first time in the Turkish Mediterranean coast and only second time in the Levant coast after about 30 years. This is the second report of the species from the Turkish waters, and the first report was from the Turkish Aegean coast. Recently, new records of the gelatinous species have increased from the Turkish marine coasts; Sea of Marmara, Aegean Sea, and Levantine Sea. Most of them are distributed in the West Mediterranean Sea, but are also present in the Adriatic Sea (East Mediterranean Sea). In the Mediterranean Sea, one branch of the Atlantic current (Atlantic-Ionian Stream) enters the eastern basin via the Mid-Ionian Jet, linked with the southern Adriatic current. Therefore, it is possible that zooplankton could have entered East Mediterranean by the Atlantic current through West Mediterranean.
