Biological invasions are a population-level rather than a species-level phenomenon.

Biological invasions pose a rapidly expanding threat to the persistence, functioning and service provisioning of ecosystems globally, and to socio-economic interests. The stages of successful invasions are driven by the same mechanism that underlies adaptive changes across species in general-via natural selection on intraspecific variation in traits that influence survival and reproductive performance (i.e., fitness). Surprisingly, however, the rapid progress in the field of invasion science has resulted in a predominance of species-level approaches (such as deny lists), often irrespective of natural selection theory, local adaptation and other population-level processes that govern successful invasions. To address these issues, we analyse non-native species dynamics at the population level by employing a database of European freshwater macroinvertebrate time series, to investigate spreading speed, abundance dynamics and impact assessments among populations. Our findings reveal substantial variability in spreading speed and abundance trends within and between macroinvertebrate species across biogeographic regions, indicating that levels of invasiveness and impact differ markedly. Discrepancies and inconsistencies among species-level risk screenings and real population-level data were also identified, highlighting the inherent challenges in accurately assessing population-level effects through species-level assessments. In recognition of the importance of population-level assessments, we urge a shift in invasive species management frameworks, which should account for the dynamics of different populations and their environmental context. Adopting an adaptive, region-specific and population-focused approach is imperative, considering the diverse ecological contexts and varying degrees of susceptibility. Such an approach could improve and refine risk assessments while promoting mechanistic understandings of risks and impacts, thereby enabling the development of more effective conservation and management strategies.

Economic costs of non-native species in Türkiye: A first national synthesis.

Biological invasions are increasingly recognised as a major global change that erodes ecosystems, societal well-being, and economies. However, comprehensive analyses of their economic ramifications are missing for most national economies, despite rapidly escalating costs globally. Türkiye is highly vulnerable to biological invasions owing to its extensive transport network and trade connections as well as its unique transcontinental position at the interface of Europe and Asia. This study presents the first analysis of the reported economic costs caused by biological invasions in Türkiye. The InvaCost database which compiles invasive non-native species' monetary costs was used, complemented with cost searches specific to Türkiye, to describe the spatial and taxonomic attributes of costly invasive non-native species, the types of costs, and their temporal trends. The total economic cost attributed to invasive non-native species in Türkiye (from 202 cost reporting documents) amounted to US$ 4.1 billion from 1960 to 2022. However, cost data were only available for 87 out of 872 (10%) non-native species known for Türkiye. Costs were biased towards a few hyper-costly non-native taxa, such as jellyfish, stink bugs, and locusts. Among impacted sectors, agriculture bore the highest total cost, reaching US$ 2.85 billion, followed by the fishery sector with a total cost of US$ 1.20 billion. Management (i.e., control and eradication) costs were, against expectations, substantially higher than reported damage costs (US$ 2.89 billion vs. US$ 28.4 million). Yearly costs incurred by non-native species rose exponentially over time, reaching US$ 504 million per year in 2020-2022 and are predicted to increase further in the next 10 years. A large deficit of cost records compared to other countries was also shown, suggesting a larger monetary underestimate than is typically observed. These findings underscore the need for improved cost recording as well as preventative management strategies to reduce future post-invasion management costs and help inform decisions to manage the economic burdens posed by invasive non-native species. These insights further emphasise the crucial role of standardised data in accurately estimating the costs associated with invasive non-native species for prioritisation and communication purposes.

Turcinoemacheilus ekmekciae, a new dwarf loach from upper Tigris and Euphrates (Teleostei: Nemacheilidae).

Turcinoemacheilus ekmekciae, new species, from upper Euphrates and Tigris drainages is distinguished from other species of Turcinoemacheilus in Western Asia by having a dark stripe broader than the eye diameter along the lateral line, rarely possessing roundish blotches, 5-6 mandibular pores in mandibular canal, a comperatvely smaller head, a deeper body, and a greater pre-pelvic distance. Our specimens collected from the upper Great Zab, near the type locality of Turcinoemacheilus kosswigi, showed notable genetic divergence (a minimum K2P of 3.3%) from sequences reported as T. kosswigi in previous studies. Despite morphological similarities, this molecular difference suggests that the populations analysed in previous studies may represent a potential new species of Turcinoemacheilus, which we tentatively named as Turcinoemacheius cf. kosswigi. Molecular data also suggest that T. ekmekciae is characterized by a minimum K2P distance of 3.5% from Turcinoemacheilus minimus and T. cf. kosswigi. The three methods for species delimitation (assemble species by automatic partitioning [ASAP], Poisson tree processes [PTP], and multi-rate PTP [mPTP]) that were utilized for testing species assignments consistently identified our test group as a distinct species.

Barbus urmianus, a synonym of Barbus cyri (Teleostei: Cyprinidae).

Barbus urmianus, from the upper Mahabad River in Lake Urmia basin, was distinguished from B. cyri based on several morphological characters. Our analysis demonstrated very small molecular (COI) differences between both species and mostly overlapping or identic morphological character states. Therefore, Barbus urmianus is treated as a junior synonym of B. cyri.

Two new freshwater blennies from the Eastern Mediterranean basin (Teleostei: Blenniidae).

Two new species of Salariopsis are described from the Eastern Mediterranean basin. Salariopsis burcuae, new species, from the Bay of Antalya east to the Jordan, is characterised by having a short cirrus, usually not overlapping the 9th circum-orbital sensory pore, and many tiny black dots on the cheek not organised in rows or bands. The new species shows a 4.1% K2P sequence divergence on the cytochrome-c-oxidase subunit 1 (COI) barcoding region from its closest relative, S. fluviatilis. Salariopsis renatorum, new species, from the upper Ceyhan drainage and a coastal stream in Arsuz, is distinguished by having an unbranched supraocular tentacle, black lateral line pores, a short snout, and no black dots on the upper part of the flank and on the cheek. It is also distinguished from its geographically closest congener, S. burcuae, by a molecular distance of 8.8% K2P in its COI barcode region.

Plastics in an endemic fish species (Alburnus sellal) and its parasite (Ligula intestinalis) in the Upper Tigris River, Türkiye.

Occurrence of micro-, meso- and macroplastics in Alburnus sellal and its parasite Ligula intestinalis is reported for the first time in the Tigris River, one of the two large rivers that defines Mesopotamia. Plastic occurrence was assessed from museum fish materials collected in the upper Tigris River between 2007 and 2021. Plastics were found in 57 % of A. sellal specimens (536 individuals) and in 74 % of L. intestinalis specimens (57 individuals). Mean plastic ingestion was 1.27 ± 1.30 items. fish-1 and 1.77 ± 1.79 items. parasite-1 considering all the fish and parasites analysed. Fibres were the most common types of plastics, comprising 96.2 % and 81 % of plastics in A. sellal and L. intestinalis, respectively. Black was the most common colour of plastics found in both fish (37 %) and parasite specimens (58 %). Microplastics comprised 95.5 % and 100 % of plastics found in A. sellal and L. intestinalis, respectively. In both specimens acrylic (PAN) was the most common polymer as confirmed by FTIR spectroscopy. Differences in plastic ingestion were not significantly over time and among regions. No significant correlation was found between plastics ingestion by fish and by parasites. The present assessment shows that native fish species of the Tigris River have been contaminated by plastics by more than a decade. Our results contribute to a better understanding of the status of plastic pollution in fish and parasites, provide plastic pollution baseline data for the Tigris River and highlight the urgent need to elucidate on the distribution and fate of plastics in freshwater environments and their effects on the ecosystem and humans.

Diversity, phylogeny and intraspecific variability of Paradiplozoon species (Monogenea: Diplozoidae) parasitizing endemic cyprinoids in the Middle East.

Diplozoidae are common monogenean ectoparasites of cyprinoid fish, with the genus Paradiplozoon being the most diversified. Despite recent studies on Diplozoidae from Europe, Africa and Asia, the diversity, distribution and phylogeny of this parasite group appears to be still underestimated in the Middle East. The objective of this study was to investigate the diversity, endemism and host specificity of diplozoids parasitizing cyprinoid fish from the Middle East, considering this region as an important historical interchange of fish fauna, and to elucidate the phylogenetic position of Middle Eastern Paradiplozoon species within Diplozoidae. Four Paradiplozoon species were collected from 48 out of 94 investigated cyprinoid species. Three known species, Paradiplozoon homoion, Paradiplozoon bliccae and Paradiplozoon bingolensis, were recorded on new cyprinoid host species, and a new species, Paradiplozoon koubkovae n. sp., was recorded on Luciobarbus capito and Capoeta capoeta from the Caspian Sea basin in Iran and Turkey. Paradiplozoon bliccae, exhibiting a wide host range in the Middle East, expressed both morphological and genetic intraspecific variabilities. The four Paradiplozoon species collected in the Middle East were placed in divergent clades, showing the rich evolutionary history of diplozoid parasites in the Middle East. Our study also revealed that two lineages of African diplozoids have a Middle Eastern origin. We stress the importance of applying an integrative approach combining morphological, ecological and molecular methods to reveal the real diversity of diplozoids.

DNA barcoding and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae) in Anatolia.

The DNA barcoding approach was used for the determination of evolutionary relationships and species delimitation of the genus Oxynoemacheilus (Teleostei: Nemacheilidae). The COI barcode region (615 bp amplicon) was used to barcode 444 individuals from 64 morphologically identified species in the genus Oxynoemacheilus and 189 haplotypes were identified. The average of the interspecific p distance (9.59%) was about 21-fold higher than the average intraspecific distance (0.44%). A general genetic threshold of 1.46% sequence divergence was defined for species delimitation. The multiple species delimitation methods (BCM, GMYC, bPTP and TCS) revealed a total of 62 molecular operational taxonomic units for 64 morphospecies with a new loach species from the BuyukMelen River. Neighbour-joining, maximum likelihood and Bayesian inference analyses indicated that all haplotypes were clustered into 62 clades, which corresponded to Oxynoemacheilus species, with strong bootstrap support (≥95%). Furthermore, all samples grouped in concurrence with the taxonomic status of the species except for species groups (O. germencicus-O. cinicus-O. mesudae and O. leontinae-O. namiri) that were showed intraspecific overlap in genetic diversity for COI-based barcodes. In conclusion, our analyses indicate that COI-based barcodes provide reliable species discrimination. Therefore, we currently recommend COI barcodes as the suitable barcode for genus Oxynoemacheilus.

Garra rezai, a new species from two widely disjunct areas in the Tigris drainage (Teleostei: Cyprinidae).

Garra rezai, new species, is described from the Chooman, a tributary of the Lesser Zab in Iran, and from headwaters of the Yanarsu, a tributary of the upper Tigris in Turkey. It is distinguished from its congeners in the Garra variabilis species group by having two pairs of barbels, a well-developed mental disc, 35-40 total scales along the lateral line, 15-19 scales along the predorsal midline, and 15-18 circumpeduncular scales. It is further characterised by having ten diagnostic nucleotide substitutions and the K2P genetic distances with the closest species i.e. G. klatti, G. kemali and G. variabilis as 11.9, 12.0, and 13.7%, respectively in the mtDNA COI barcode region.

Oxynoemacheilus isauricus, a new nemacheilid loach from Central Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus isauricus, new species, from the Lakes Beysehir and Sugla basins in Central Anatolia is distinguished from all other species of the O. angorae group by having a very slender caudal peduncle (its depth 2.22.6 times in its length). The new species is further distinguished by having a short head (head length 2124% SL), and a midlateral series of irregularly shaped blotches on the flank. Oxynoemacheilus isauricus is also distinguished by a minimum K2P sequence divergence of 7.5% and 8.0% in the mtDNA-COI barcode region from O. eregliensis and O. atili, its closest relatives.

Oxynoemacheilus nasreddini, a new nemacheilid loach from Central Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus nasreddini, new species, from Lake Aksehir, Eber, Egirdir, and Ilgin basins in Central Anatolia is distinguished from other species of Oxynoemacheilus in Central Anatolia by having irregularly shaped blotches on flank; 24 dark-brown bands on caudal fin; a slender body, and an emarginate caudal fin in which the shortest middle caudal-fin ray is 7691% of the longest ray of the upper caudal-fin lobe. Molecular data suggest that the new species is closely related to O. mediterraneus from the Aksu and Köprüçay drainages. Although the two species are separated by only a minimum K2P distance of 1.2% in the mtDNA COI barcode region, they are well distinguished morphologically. The situation is complicated by loaches from Lake Egirdir basin that are identified as O. nasreddini by their morphological character states but are only distinguished from O. mediterraneus by a minimum K2P distance of 0.2% in the mtDNA COI barcode region.

The Glyptothorax catfishes of the Euphrates and Tigris with the description of a new species (Teleostei: Sisoridae).

The Glyptothorax species inhabiting the Euphrates and Tigris drainages are reviewed and six species are recognised, one of which is described herein as new species. Glyptothorax armeniacus is endemic to headwater streams in the Euphrates drainage. Glyptothorax kurdistanicus is endemic to the upper Tigris downstream to the Lesser Zab drainage. Glyptothorax cous and G. steindachneri are riverine species widespread in both the Euphrates and Tigris drainages. Glyptothorax silviae is endemic to Iran. Glyptothorax daemon, new species, from the Greater Zab and Yanarsu in the upper Tigris drainage, is distinguished by having the thoracic adhesive apparatus strongly elevated, 1.11.2 times longer than wide, without tubercles on the head, well developed anteromedial striae, the medial pit without striae, and a short adipose fin. Glyptothorax daemon is separated into two mitochondrial lineages, externally indistinguishable and separated by a minimum K2P distance of 2.0% in the DNA barcode region. These lineages are paraphyletic in our analysis indicating past introgressive hybridisation with G. cous. All six species are diagnosed and all, except unstudied G. steindachneri, form distinct mitochondrial clades with between 1.2% and 3.4% minimum K2P distance between them. Species from the Euphrates and Tigris form a monophyletic mitochondrial group separated from 53 other Glyptothorax species studied from India and areas further east.

Heavy metal concentration levels and biometric analysis of Liocarcinus depurator from different locations on the western Black Sea coast of Turkey.

The aim of the current work is to examine the concentrations of nine heavy metals such as chromium, nickel, copper, cadmium, zinc, cobalt, iron, lead, and metal (aluminium) in two body parts (carapace and walking legs) of Liocarcinus depurator from different stations (Ilyas bey, Cide koyu, Anadolu feneri, igneada) in the western Black Sea coast of Turkey. And this study was carried out to examine morphological properties of Liocarcinus depurator in the region. The sex ratio (female/male) of 387 samples was calculated as F/M = 1:0.945. The mean carapace length and width were measured as 20.41 ± 2.41 mm and 25.10 ± 2.78 mm for female and 25.49 ± 3.33 mm and 32.32 ± 4.50 mm for male individually. The mean weight of crabs was measured as 4.09 ± 1.37 g for females and 8.33 ± 3.35 g for males. The samples were investigated trace metals by inductively coupled plasma-optical emission spectrometry (ICP-OES). Ranges over trace metals in all samples of L. depurator as follows: Cr 0.6-1.5, Mn 21-130, Cu 8-37, Zn 6-40, Cd 0.2-1.5, Pb 0.1-3.6, Co 0.1-1.1, Fe 22-160, and Ni 0.6-1 mg/kg wet wt. The walking legs and carapace/exoskeleton of female and male crabs were analyzed and contained various concentrations of Pb, Co, Ni, Cr, Cd, Fe, Cu, Zn, and Mn elements. The order of the heavy metal in all samples of L. depurator is shown as Fe > Cu > Mn > Zn > Cr > Cr > Ni > Cd > Pb > Co. In this research, metal levels of the crab samples compared between female and male and found highest mean metal concentrations in the station number 3 (Anadolu feneri) that the Al concentration in the carapace of female was 295.0 mg/kg wet wt and in the walking legs was 306.67 mg/kg wet wt, in the carapace of male was 264.4 mg/kg wet wt, and in the walking legs was 162.61 mg/kg wet wt in station number 3 (Anadolu feneri). The purpose of this work is to analyze the metal composition of this type of crab, which is abundant in the Black Sea region and is not planned to be attached to fisherman's nets, to evaluate whether it will be useful or not.

emOxynoemacheilus/em emphasicus/em, a new nemacheilid loach from the eastern Black Sea basin with some remarks on other Caucasian emOxynoemacheilus/em (Teleostei: Nemacheilidae).

Oxynoemacheilus phasicus, new species, is described from the Rioni and Enguri River drainages in Georgia. It is distinguished from other Oxynoemacheilus species in the O. brandtii group by a mottled or marbled flank pattern in adults, a slightly emarginate caudal fin, and a deep caudal peduncle. Molecular data suggest that the new species is characterized by a minimum K2P distance of 7.5% from O. brandtii from the Kura drainage in the mtDNA COI barcode region. Oxynoemacheilus brandtii and O. elsae are re-diagnosed. A very slender Oxynoemacheilus from the Aras drainage clusters as sister to O. elsae in our molecular analysis and not with O. brandtii from the Kura River. However, it is identified as O. brandtii as it is indistinguishable from this species in morphological characters.

emGarra/em emorontesi/em, a new species from the Orontes River drainage (Teleostei: Cyprinidae).

Garra orontesi, new species, is described from the Orontes River drainage in the eastern Mediterranean Sea basin in Turkey and Syria. It is distinguished from its congeners in the Mediterranean Sea basin and adjacent Mesopotamia by possessing 17-21 gill rakers on the lower part of the first gill arch, the pelvic-fin origin usually below the second branched dorsal-fin ray, 8½ branched dorsal-fin rays, usually 2-3 scales between the tip of the pectoral and pelvic-fin origins, and no tubercles behind the upper posterior eye margin. It is also distinguished by a minimum K2P distance of 2.7% in its COI barcode region against G. rufa, and 3.9% against the geographically adjacent G. turcica.

Oxynoemacheilus sarus/, a new nemacheilid loach from the lower Ceyhan and Seyhan in southern Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus sarus, new species, is described from the lower Ceyhan and Seyhan drainages in southern Anatolia. It is distinguished from other Oxynoemacheilus species in Cilicia (including the Göksu, Seyhan and Ceyhan drainages) by possession of a series of irregularly shaped midlateral blotches, 3-5 dark-brown bands on the caudal fin, a complete lateral line, a forked caudal fin (shortest middle caudal-fin ray is 56-70% of longest ray of the upper caudal-fin lobe), the caudal peduncle depth 1.4-1.8 times in its length, and a suborbital groove in male individuals. The new species occurs in sympatry with superficially similar O. seyhanicola and O. evreni, and is distinguished by colour pattern as well as morphometric and molecular characters. Molecular data suggest that the closest relatives to the new species in our dataset are O. euphraticus and O. shehabi, which is characterised by a minimum K2P distance of 3.6% and 3.8%, respectively, in the COI mtDNA barcode region.

Oxynoemacheilus amanos, a new nemacheilid loach from the Orontes River drainage (Teleostei: Nemacheilidae).

Oxynoemacheilus amanos, new species, is described from Incesu spring in the upper Hupnik drainage, a northern tributary of the lower Orontes in Turkey. It is distinguished from the other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line with 23-45 pores, terminating between the vertical through the dorsal fin origin and the anus, 10-13 pores in the infraorbital canal, a deeply emarginate caudal fin, no suborbital groove in the male, and a series of irregularly shaped and set dark-brown bars on the flank, not connected to saddles on the back.

Alburnus nasreddini, a synonym of A. escherichii (Teleostei: Leuciscidae).

Alburnus nasreddini described from Lake Eber in Central Anatolia is a junior synonym of A. escherichii, a widespread species in adjacent Sakarya River drainage. We found no morphological characters to distinguish Alburnus nasreddini from A. escherichii and both are poorly distinguished on a molecular level also.

Oxynoemacheilus cilicicus, a new nemacheilid loach from the Göksu River in southern Anatolia (Teleostei: Nemacheilidae).

Oxynoemacheilus cilicicus, new species, is described from the Göksu, Seyhan and Ceyhan rivers in southern Turkey. It is distinguished from other Oxynoemacheilus species in the Eastern Mediterranean Sea basin by possession of an incomplete lateral line, terminating before the vertical of the dorsal-fin origin or slightly behind the dorsal-fin base, a deeply emarginate caudal fin, no suborbital groove in male individuals, and a series of dark-brown bars on the flank not interrupted along the lateral line. Molecular data suggest that Oxynoemacheilus cilicicus is characterised by 22 variable nucleotide substitutions and a minimum K2P distance of 4.09% with O. panthera in the mtDNA COI barcode region.

Revision of the genus Seminemacheilus, with the description of three new species (Teleostei: Nemacheilidae).

The nemacheilid genus Seminemacheilus is revised. Six species are recognised, three of them described herein as new. All species are endemic to Central Anatolia. Seminemacheilus lendlii from the Sakarya River drainage and the endorheic Lake Aksehir and Eber basins, S. ispartensis from Lake Egirdir basin and S. ahmeti from Sultan Sazligi are valid species. Although Seminemacheilus lendlii and S. ispartensis have almost identical COI sequences, they are distinguished by the shape of the caudal peduncle and the presence of scales on the caudal peduncle in S. ispartensis (vs. absent in S. lendlii). Seminemacheilus attalicus, new species, from Kirkgöz drainage, is distinguished by having a slightly emarginated caudal fin, a central pore in the supratemporal canal and a marbled flank pattern. Seminemacheilus ekmekciae, new species, from Lake Tuz basin is distinguished by having a roundish caudal fin, a short post-dorsal length and large brown blotches fused into stripes on the flank. Seminemacheilus tubae, new species, from Lake Beysehir basin, is distinguished by having a truncate caudal fin and 2-5 (6) supraorbital head pores. Seminemacheilus dursunavsari from the Göksu River drainage is not a valid name and this population is identified as S. tubae.