Current status (as of end of 2020) of marine alien species in Turkey.

The 2020's update of marine alien species list from Turkey yielded a total of 539 species belonging to 18 taxonomic groups, 404 of which have become established in the region and 135 species are casual. A total of 185 new alien species have been added to the list since the previous update of 2011. The present compilation includes reports of an ascidian species (Rhodosoma turcicum) new to the marine fauna of Turkey and range extensions of six species. Among the established species, 105 species have invasive characters at least in one zoogeographic region, comprising 19% of all alien species. Mollusca ranked first in terms of the number of species (123 species), followed by Foraminifera (91 species), Pisces (80 species) and Arthropoda (79 species). The number of alien species found in seas surrounding Turkey ranged from 28 (Black Sea) to 413 (Levantine Sea). The vectoral importance of the Suez Canal diminishes when moving from south to north, accounting for 72% of species introductions in the Levantine Sea vs. only 11% of species introductions in the Black Sea. Most alien species on the coasts of Turkey were originated from the Red Sea (58%), due to the proximity of the country to the Suez Canal. Shipping activities transported 39% of alien species, mainly from the Indo-Pacific area (20%) and the Atlantic Ocean (10%). Misidentified species (such as Pterois volitans, Trachurus declivis, etc.) and species those classified as questionable or cryptogenic were omitted from the list based on new data gathered in the last decade and expert judgements. The documented impacts of invasive species on socio-economy, biodiversity and human health in the last decade as well as the legislation and management backgrounds against alien species in Turkey are presented.

Levinsenia species (Annelida: Polychaeta: Paraonidae) from the Sea of Marmara with descriptions of two new species.

The present study deals with the diversity of the genus Levinsenia in the Sea of Marmara. The specimens of Levinsenia were collected on soft and hard substrata at depths ranging from 10 to 500 m at 98 stations in 2013. Among the material, two new species, namely Levinsenia longobranchiata n. sp. and L. vulgaris n. sp., and five already known species (L. demiri, L. kosswigi, L. materi, L. marmarensis, L. tribranchiata) were found. Levinsenia longobranchiata n. sp. is mainly characterized by having very long branchiae (longer than the body width) and five prebranchial chaetigers without notopodial postchaetal lobes. Levinsenia vulgaris n. sp. is mainly characterized by having short branchiae (shorter than the body width) and five prebranchial chaetigers with notopodial postchaetal lobes. The SEM images enabled us to define some previously neglected/indistinct characters in the taxonomy of Levinsenia such as the degree of the fusion of the branchiae with the notopodia; the morphology of dorso-lateral irregular pores, cheek organ, ciliated patches and lateral organs on the lateral sides of the prostomium; and the shape and distribution of the lateral sense organs along the body. All species found in the region were presented and described, by also taking these novel characters into account.

The diversity of the genus Aricidea (Polychaeta: Paraonidae) from the Sea of Marmara, with descriptions of two new species and two new records for the Mediterranean fauna.

This paper reports 13 Aricidea species from the Sea of Marmara. The Aricidea specimens were collected at 98 stations in the region in 2012 and 2013 from soft and hard substrata at depths ranging from 0 to 1200 m. Among the material, two new species, namely Aricidea (Acmira) katzmanni n. sp. and Aricidea (Acmira) pseudoassimilis n. sp., and 11 known species were discovered. Aricidea mirunekoa and A. bulbosa are new records for the Mediterranean fauna; A. (Acmira) annae and A. (Aricidea) wassi are new records for the Sea of Marmara. Aricidea (Acmira) katzmanni n. sp. is characterized by having a long, digitiform antenna; no notopodial papillae on the posterior part of the branchial region; and hook shaped modified neurochaetae with a strong hood and fragile arista. Aricidea (Acmira) pseudoassimilis n. sp. is characterized by having a short, digitiform antenna; interramal lobes between notopodia and neuropodia; hook-shaped modified neurochaeta that gets subterminally thinner with a rounded tip. As A. (Strelzovia) bulbosa has been only previously reported from the Gulf of Suez (Red Sea), it could be a new alien species for the Sea of Marmara and Mediterranean Sea. Based on the characters that have been overlooked so far, the subspecies A. suecica meridionalis and A. capensis bansei were raised to species level, A. meridionalis n. stat. and A. bansei n. stat. The present paper reports the usage of ciliary bands and slits on the prostomium and body, swellings/ridges in the branchial region, and the shape and distribution of sense organs in the taxonomy of Aricidea. All species were described and figured.

The genus Paradoneis (Annelida: Paraonidae) from the Sea of Marmara, with descriptions of two new species.

The present study deals with the diversity of the genus Paradoneis (Annelida: Paraonidae) from the Sea of Marmara. Examination of materials collected from various soft and hard substrata from depths between 10 and 1200 m in the region revealed the presence of four species, among which one was already known from the region (P. ilvana), one was a new record for the Sea of Marmara (P. armata) and other two (P. heterochaeta n. sp. and P. longifurcata n. sp.) were new to science. Paradoneis heterochaeta n. sp. is characterized mainly by having a proportionately large size, by its pigmentation on the body, by bearing minute notopodial postchaetal lobes and by possessing two types of lyrate chaetae. Paradoneis longifurcata n. sp. is mainly characterized by having weakly jointed notopodial postchaetal lobes and lyrate chaetae with the long branch being up to 4.5 times longer than the short branch. All species found in the area are described and discussed.

Cirrophorus species (Annelida: Polychaeta: Paraonidae) in the Sea of Marmara, with description of a new species.

This paper deals with specimens of Cirrophorus collected from the depths ranging from 3 to 500 m in 2012 and 2013 in the Sea of Marmara, Turkey. Among the material, one new species and two already known species were found. The new species is mainly characterized by having long and clavate notopodial postchaetal lobes in the branchial region; red speckles near nuchal organs; and a very long branch of lyrate chaetae (4 times longer than the shorter one). A recently described species, Cirrophorus nikebianchii, was found at the majority of soft-bottom stations. All species found in the area were described and discussed.

New records of five sponge species (Porifera) for the Black Sea.

The present study deals with five sponge species [Chalinula renieroides, Haliclona (Halichoclona) fulva, H. (Rhizoniera) rosea, Hymedesmia (Hymedesmia) pansa and Ircinia variabilis] belonging to 3 families (Chalinidae, Hymedesmiidae, and Irciniidae) found at one locality (near the opening of Kizilirmak River) on the Black Sea coast of Turkey. All these species are new records for the Black Sea. Three species (Chalinula renieroides, H. (R.) rosea and H. (H.) pansa] are also new records for the marine fauna of Turkey. All these species were previously reported from Mediterranean Sea and the eastern Atlantic Ocean. The morphological and distributional features of these species are presented.

The alien ascidian Styela clava now invading the Sea of Marmara (Tunicata: Ascidiacea).

During the implementation of a large project aimed to investigate the benthic community structures of the Sea of Marmara, specimens of the invasive ascidian species Styela clava were collected on natural substrata (rocks) at 10 m depth at one locality (Karamürsel) in Izmit Bay. The specimens were mature, containing gametes, indicating that the species had become established in the area. The Sea of Marmara seems to provide suitable conditions for this species to survive and form proliferating populations.

Occurrence of Diopatramarocensis (Annelida, Onuphidae) in the eastern Mediterranean.

The present study deals with the presence of Diopatramarocensis in the eastern Mediterranean. This species is small-sized and inhabited muddy bottom near the opening of rivers or lagoons [salinity range: 33-39‰] in the Aegean and Levantine Seas, and reached a maximum density of 90 ind.m(-2) in Mersin Bay. This species might be an alien species that was introduced from the East Atlantic (near Gibraltar) to the eastern Mediterranean via ballast water of ships, as it has never been reported from the western Mediterranean Sea.

ALien Biotic IndEX (ALEX) - a new index for assessing impacts of alien species on benthic communities.

Biotic indices are mainly aimed at assessing levels of deterioration caused by chemical or organic pollution. However, no biotic index to date has been developed to detect impacts of alien species on benthic communities. In this paper, a new biotic index, namely ALEX, is proposed to address the objectives of the Water Framework Directive and was tested in Mersin Bay (Levantine Sea, Turkey). Species were divided into four biogeographic groups, namely native species, casual species, established species and invasive species, and the metric considers the relative importance of these groups in samples. The index classified the ecological status of some stations which are shallow, and close to harbor and river mouths as bad or poor in February and October. The ALEX values were positively and significantly correlated with total nitrogen, silicate and silt percentage in sediment, and negatively correlated with depth and the distance from the harbor.

Ecoregion-based conservation planning in the Mediterranean: dealing with large-scale heterogeneity.

Spatial priorities for the conservation of three key Mediterranean habitats, i.e. seagrass Posidonia oceanica meadows, coralligenous formations, and marine caves, were determined through a systematic planning approach. Available information on the distribution of these habitats across the entire Mediterranean Sea was compiled to produce basin-scale distribution maps. Conservation targets for each habitat type were set according to European Union guidelines. Surrogates were used to estimate the spatial variation of opportunity cost for commercial, non-commercial fishing, and aquaculture. Marxan conservation planning software was used to evaluate the comparative utility of two planning scenarios: (a) a whole-basin scenario, referring to selection of priority areas across the whole Mediterranean Sea, and (b) an ecoregional scenario, in which priority areas were selected within eight predefined ecoregions. Although both scenarios required approximately the same total area to be protected in order to achieve conservation targets, the opportunity cost differed between them. The whole-basin scenario yielded a lower opportunity cost, but the Alboran Sea ecoregion was not represented and priority areas were predominantly located in the Ionian, Aegean, and Adriatic Seas. In comparison, the ecoregional scenario resulted in a higher representation of ecoregions and a more even distribution of priority areas, albeit with a higher opportunity cost. We suggest that planning at the ecoregional level ensures better representativeness of the selected conservation features and adequate protection of species, functional, and genetic diversity across the basin. While there are several initiatives that identify priority areas in the Mediterranean Sea, our approach is novel as it combines three issues: (a) it is based on the distribution of habitats and not species, which was rarely the case in previous efforts, (b) it considers spatial variability of cost throughout this socioeconomically heterogeneous basin, and (c) it adopts ecoregions as the most appropriate level for large-scale planning.