Alper Doğan

İzmir şehrinin gelişmiş sanayisi şehri çevreleyen İzmir Körfezi’nin; evsel ve endüstriyel atıklar sebebiyle kirlilik sorunlarıyla karşı karşıya kalmasına neden olmuştur. Bu nedenle 2000 yılında devreye giren Çiğli atık su arıtma tesisinin etkilerini gözlemlemek, körfezdeki kirliliğin etkisini azaltmak ve deniz ekosistemini korumak için körfezde izleme çalışmaları başlatılmıştır. Bu amaçla 2014-2016 yılları arasında gerçekleştirilen “İzmir Körfezi Rehabilitasyon Projesi” kapsamında ihtiyoplankton çalışmalarına da yer verilmiştir. Proje kapsamında İzmir iç körfezden 4 istasyon belirlenmiş olup bu istasyonlardan ilkbahar ve sonbahar mevsimlerinde 30 cm çapında 200 µm göz açıklığına sahip apstein zooplankton kepçesi kullanılarak vertikal plankton çekimleri yapılmıştır. Çalışmada toplam; 7 familya ve 9 türe ait toplam; 11467 birey/m² yumurta, 323 birey/m² prelarva ve 2541 birey/m² larva elde edilmiştir. Tespit edilen familya ve türler sırası ile; Engraulidae (Engraulis encrasicolus), Gobiidae (Gobius niger, Gobius paganellus), Callionymidae (Callionymus festivus), Blennidae (Lipophrys pavo), Mugilidae (Mugil cephalus, Liza saliens), Atherinidae (Atherina boyeri), Soleidae (Buglossidium luteum)’dir. Yumurta, prelarva ve postlarvalar incelendiğinde özellikle E. encrasicolus türünün dominant durumda olduğu görülmüştür. Tespit edilen türler açısından istasyonlar karşılaştırıldığında; tür çeşitliliği açısından 1 ve 2 nolu istasyonların kendi aralarında benzer özellik gösterdiği 4 nolu istasyonun ise daha farklı olduğu saptanmıştır. Ülkemiz balıkçılığının büyük bir kısmını oluşturan hamsi türüne ait yumurtaların iç körfezde yoğun olarak bulunması bu türün üreme alanı olarak körfezi tercih ettiğini göstermektedir.

In this work, combined efforts by Greek and Turkish scientists produced an updated validated NIS inventory of the Aegean ecoregion, covering 120 years of records up to August 2024. Of the 342 NIS currently present in the Aegean Sea, the majority (281 species) have invaded the South Aegean, followed by the North Aegean (128 species out of 206 NIS). A total of 73 species were added to the list, while 56 were removed. Overall, unaided spread of Lessepsian immigrants from the Levantine Sea and shipping are equally responsible for NIS reported at the regional level. An increase in publications addressing NIS matches the upward trend of NIS since the mid-1990s, which continues to the present day. While unaided introductions of Lessepsian species and/or direct introductions via the Suez Canal peaked in the South Aegean during 2000–2005, they peaked in 2012–2017 in the North Aegean—a decade later. The opposite pattern was observed in ship-transferred NIS. The spatial distribution of introduction hotspots largely reflects the following phenomena/processes: unaided introduction is witnessed initially in the southeastern Aegean Sea; monitoring efforts are concentrated in vulnerable and at-risk areas; and research efforts relate to the spatial allocation of institutions and marine experts working on marine NIS along the Aegean coasts.

Molluscs, especially bivalves, play an important role in food production and are the dominant group in mariculture worldwide. They are also an important component of the marine ecosystem, influencing the food web and nutrient cycling, as well as creating and modifying habitats. In the Mediterranean Sea, about 578 non-native species have been reported, including 230 taxa of non-native mollusc species. In most regional European seas, including the Mediterranean, the socioeconomic impacts of high-impact mollusc species have generally been poorly studied, and only a few well-documented cases have been reported. The present study collects scientific information on non-native molluscs in Croatian waters that are classified as high impact according to the European Alien Species Information Network EASIN: one Gastropoda—Rapana venosa—and seven Bivalvia species—Anadara kagoshimensis, Anadara transversa, Arcuatula senhousia, Brachidontes pharaonis, Magallana gigas, Pinctada radiata, and Ruditapes philippinarum. This study aims to fill the gap in the literature on high-impact non-native molluscs in the eastern Adriatic Sea through reviewing the literature on examples from other European seas, focusing on the possibility of commercialization and sustainable management of high-impact non-native molluscs. The invasion of non-native molluscs must be managed appropriately, especially if commercialisation is chosen as a management strategy. Additional management measures must be selected and objectively evaluated, taking into account the specificities, location and feasibility of the proposed measures. The study could help researchers, decision-makers, and the public to address the problems with high-impact species in the Adriatic countries, but also in other regions where the monitoring of high-impact non-native species is still inadequate. In addition to Croatia, the monitoring and management of these species is also important for other countries in the eastern Adriatic: Slovenia, Montenegro and Albania.

This study is on the relationships between the abundances, of cnidarians and echinoderms found in Çardak Lagoon and environmental variables. The benthos samples were collected in three replicates in October 2018, February, April, and June 2019, using a metal framed quadrat system of 100 x 100 cm and 393 cm3 sediment core by a SCUBA diver. Sediment material was collected at 7 sampling points of Çardak Lagoon in Çanakkale Strait. A total of 259 individuals belonging to phylum, Cnidaria and Echinodermata were found in the study area. Cnidarian, Actinia sp. and echinoderm, Asterina gibbosa were the most dominant species. The highest positive correlation value was between Cnidaria species number and organic matter (OM%) content in the sediment. The highest negative correlation value was between Echinodermata species number and NO2+NO3 in lagoon system.

This paper includes three exotic polychaeta species, Hydroides dianthus (Verrill, 1873), Polydora cornuta Bosc, 1802, and Pseudopolydora paucibranchiata (Okuda, 1937), found during benthic samplings in Çardak Lagoon (Turkish Straits). The sampling was collected from the sandy and silty bottoms known to be polluted by sewage discharges. A total of 45 specimens of exotic polychaetes (H. dianthus: 1; P. cornuta: 4; P. paucibranchiata: 40) were found. The correlation values between the annual average values of the nutrients and the polychaeta abundance showed that the highest positive relationships with the abundance were between sand content, total phosphate, and pH. P. cornuta was the most observed species with a frequency index value of 75%, while H. dianthus was represented with a single species in the study area. Albeit the previous studies, P. paucibranchiata was observed most abundantly in the sampling station having low organic matter amounts. The study showed that opportunistic polychaetes observed in Çardak Lagoon mostly preferred organically poor sediments.

The coralligenous habitat was studied at the large Mediterranean scale, by applying a standardized, non‐destructive photo‐sampling protocol, developed in the framework of the CIGESMED project. The results provided evidence to support the following statements: (a) the assemblage pattern is not homogeneously distributed across the four Mediterranean ecoregions studied (biotic gradients hypothesis); and (b) the assemblage pattern does not change significantly when the information is aggregated to higher taxonomic levels (taxonomic sufficiency hypothesis). Surrogate taxonomic categories higher than species, such as genus and family, can be used to reveal the multivariate pattern of the coralligenous assemblages. Although preliminary at the pan‐Mediterranean scale, these outcomes set the scene for future comparisons as more data sets become available but also for comparisons between taxonomic and functional patterns.

The invasive alien mytilid species, Brachidontes pharaonis, forms a biogenic habitat in the mediolittoral and upper-infralittoral zones of the Levantine Sea, hosting a number of alien and native species. Examinations of samples taken from dense, continuous mussel beds at seven stations along the coast of northern Levantine Sea yielded 187 macro-benthic invertebrate species belonging to 11 taxonomic groups. Polychaeta accounted for 46% and 37% of the total number of species and individuals, respectively. The top three dominant species in the mussel beds were Stenothoe gallensis, Spirobranchus kraussi and Mytilaster minimus. The species with the highest frequency values on the mussel beds were Pseudonereis anomala, Phascolosoma stephensoni and Elasmopus pocillimanus. The highest density and biomass of the associated fauna were estimated as 42,550 ind m⁻² and 1503 wwt g m⁻², respectively. The species number in samples varied between 14 and 47 species. The environmental variables best explaining variations in zoobenthic community structures were salinity, dissolved oxygen and total inorganic nitrogen in the water column. The biotic indices, TUBI and ALEX, classified the ecological status of one or two stations as moderate or poor, based on the relative abundances of ecological and zoogeographic groups, respectively. A total of 21 alien species were found to be associated with the mussel bed, of which Syllis ergeni is being newly considered as a new established alien species for the Mediterranean Sea. The maximum density of associated alien species was calculated as 30,300 ind m⁻². The alien species assemblages were greatly affected by salinity and total inorganic nitrogen.

The present study was performed to follow temporal variation of the soft-bottom molluscan fauna in north-western Iskenderun Bay. The benthic material was collected at a depth ranging from 3 to 37 m at 12 sampling locations by the van Veen grab sampler in the summer season of 2012, 2013 and 2014. A total of 133 species were identified in the study area through the examination of the collected material. Among the identified species, Corbula gibba (Olivi, 1792), Bittium reticulatum (da Costa, 1778), Nassarius pygmaeus (Lamarck, 1822), Cerithidium diplax (Watson, 1886) and Finella pupoides Adams, A., 1860 have the highest values of the frequency index. According to the Bray-Curtis similarity index, these species also have an important effect on the similarity between the stations. Furthermore, C. diplax and F. pupoides are alien species to the Mediterranean.