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Abstract

The Aegean Sea is highly impacted by biological invasions with 209 alien species being reported until the end of 2019, of which 149 are considered as established. Among these, the most abundant group is Pisces, followed by Mollusca, Crustacea, Annelida, and Macrophyta. There is an increasing trend of new species introductions in the Aegean Sea, reaching 60 new introductions between 2010 and 2019. The most common pathway of introduction in the Aegean Sea is “unaided” introduction from neighboring ecoregions, i.e., natural dispersal across the Aegean borders, without human agency. Most of these species are Lessepsian immigrants, introduced through the Suez Canal, and initially recorded in the Levantine Sea. The second most common pathway in the Aegean is “transport-stowaway,” i.e., introduction through ballast waters, hull fouling, or with angling/fishing equipment. All other pathways are of much lower importance for the Aegean Sea. The most invasive species in the region are the fish Siganus rivulatus, Siganus luridus, Fistularia commersonii, Lagocephalus sceleratus, and Pterois miles; the macroalgae Caulerpa cylindracea, Codium fragile, Stypopodium schimperi, Asparagopsis taxiformis, and Womersleyella setacea; the crab Callinectes sapidus; and potentially the molluscs Conomurex persicus, Pinctada imbricata radiata, Dendostrea cf. folium, and Fulvia fragilis.

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... Located in the northeastern part of the Mediterranean Sea, the Aegean Sea is an ecoregion [36] that supports rich biodiversity but lacks effective conservation management of its marine resources [37]. By 2019, 209 alien species had been recorded in the Aegean, with 149 having established populations [38]. Among the latter, 48 are considered to be invasive [12]. ...
... Local climatic conditions, along with other human activities that enhance the introduction of alien species, their natural expansion and their impacts, render the Aegean an ecoregion under siege that urgently needs effective management measures to eliminate local biodiversity loss within a proactive and adaptive systematic conservation planning approach. Such an approach requires continuous monitoring of alien species distribution, introduction pathways, and assessment of their impacts [38,40]. Although the presence of alien species in the Aegean Sea has been monitored over the past two decades [41,42], through scientific networks [43,44], citizen science initiatives [45], and collections of unpublished records [46,47], and their introduction pathways have been assessed [33,48], there are no studies that address their cumulative impacts under a systematic framework. ...
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Biological invasions are a human-induced environmental disturbance that can cause major changes in ecosystem structure and functioning. Located in the northeastern Mediterranean basin, the Aegean Sea is a hotspot of biological invasions. Although the presence of alien species in the Aegean has been studied and monitored, no assessment has been conducted on their cumulative impacts on native biodiversity. To address this gap, we applied the CIMPAL index, a framework developed for mapping the cumulative impacts of invasive species, to identify the most affected areas and habitat types and determine the most invasive species in the region. Coastal areas showed stronger impacts than the open sea. The highest CIMPAL scores were four times more frequent in the South than in the North Aegean. Shallow (0-60 m) hard substrates were the most heavily impacted habitat type, followed by shallow soft substrates and seagrass meadows. We identified Caulerpa cylindracea, Lophocladia lallemandii, Siganus luridus, Siganus rivulatus, and Womersleyella setacea as the most impactful species across their range of occurrence in the Aegean but rankings varied depending on the habitat type and impact indicator applied. Our assessment can support marine managers in prioritizing decisions and actions to control biological invasions and mitigate their impacts.
... Of the 2352 records reporting habitat type, 58.0% referred to rocky substrata, 23.0% to mobile substrata (i.e., including mud, sand, and small pebbles), 8.6% to mixed substrata (combining rock with sand or seagrasses), 3.8% to marine caves, 3.2% to seagrasses, and 2.1% to artificial substrata, while the water column and coastal lagoons accounted for less than 1% of records each. The habitat types with the highest numbers of species were the mobile (37 species) and rocky substrata (35), followed by mixed substrata (24), artificial substrata and marine caves (17 species each), seagrasses (12), the water column (2), and coastal lagoons (2) (Figure 6a). Regarding the progress of records through time, 96.5% of the total records were accompanied by temporal information, covering a period between 1893 and 2020 ( Figure 6b). ...
... These are amongst the most widespread alien species within the Mediterranean [10,43] with well-documented negative impacts [5]. They have also been classified as invasive in the study area in previous assessments [35,39] and are included among the 22 marine species in the Greek national list of invasive alien species (HELLAS-ALIENS) [56] that has been compiled in accordance with the provisions of Article 12 of the EU Regulation on the management of invasive alien species [7]. ...
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The Greek Seas are greatly exposed to the proliferation of marine alien species. At least 242 alien species have been reported within Greek territorial waters, three-quarters of which are considered established, while their rate of introduction is increasing. Some of these species exhibit high invasiveness, imposing severe impacts on native ecosystems and ecosystem services. The spatiotemporal proliferation of these species outside their natural boundaries depends on several parameters, including their biological characteristics, native distribution range, introduction pathway, and time of initial introduction. Knowing the current and potential alien species distribution is essential for the implementation of effective management actions. To investigate the distribution of impactful cryptogenic and alien species (ICAS) in the Greek Seas, we combined all records available until the end of 2020 from eight types of data sources: (1) scientific literature, (2) grey literature, (3) offline databases, (4) online scientific databases, (5) personal observations of independent researchers, (6) communications with divers and diving centers, (7) in situ underwater sampling, and (8) social networks. The results of 5478 georeferenced records refer to 60 marine ICAS belonging to 16 taxonomic groups. The number of records and the overall number of ICAS present an increasing trend from the northern to the southern parts of our study area, and there is a clear distinction in community composition between the northern and southern subregions. This latitudinal gradient is mainly due to the large number of thermophilous Lessepsian species ofWest Indo-Pacific origin, which reach the southern parts of the study area through unaided dispersal. On the other hand, transport stowaways appear to be more prevalent in areas located near large ports, which show significant differences in ICAS numbers and community composition compared to sites located far from ports. Most records (>40% of the total) were associated with rocky reefs, partly reflecting the preference of divers for this habitat type but also the presence of conspicuous, reef-associated impactful fish. The number of published records, as well as the number of reported ICAS, shows a dramatic increase with time, highlighting the urgent need for immediate proactive management actions and scientifically informed control measures.
... This led to debates about its alien status, with some researchers considering it as a cryptoexpanding species or neonative, excluding it from national lists (e.g. Servello et al. 2019; and others still listing it as an alien species (Petović et al. 2019;Katsanevakis et al. 2020b;Zenetos and Galanidi 2020;Zenetos et al. 2020a). Notwithstanding such disputes, B. leachii is indeed one of the most successful recent colonizers of the Mediterranean Sea, with records from 19 out of 23 Mediterranean countries (Rizgalla and Crocetta 2020). ...
... The present study was supported by the Hellenic Foundation for Research and Innovation (H.F.R.I.) under the "First Call for H.F.R.I. Research Projects to support Faculty members and Researchers and the procurement of high-cost research equipment grant" (Project ALAS -"ALiens in the Aegean -a Sea under siege"; Project Number: HFRI-FM17-1597; Katsanevakis et al. 2020b). FaCr was partially funded by the project PO FEAMP CAMPANIA 2014-2020 (DRD n.35 of 15th March 2018). ...
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Biological invasions have become a defining feature of marine Mediterranean ecosystems with significant impacts on biodiversity, ecosystem services, and human health. We systematically reviewed the current knowledge on the impacts of marine biological invasions in the Mediterranean Sea. We screened relevant literature and applied a standardised framework that classifies mechanisms and magnitude of impacts and type of evidence. Overall, 103 alien and cryptogenic species were analysed, 59 of which were associated with both negative and positive impacts, 17 to only negative, and 13 to only positive; no impacts were found for 14 species. Evidence for most reported impacts (52%) was of medium strength, but for 32% of impact reports evidence was weak, based solely on expert judgement. Only 16% of the reported impacts were based on experimental studies. Our assessment allowed us to create an inventory of 88 alien and cryptogenic species from 16 different phyla with reported moderate to high impacts. The ten worst invasive species in terms of reported negative impacts on biodiversity include six algae, two fishes, and two molluscs, with the green alga Caulerpa cylindracea ranking first. Negative impacts on biodiversity prevailed over positive ones. Competition for resources, the creation of novel habitat through ecosystem engineering, and predation were the primary reported mechanisms of negative effects. Most cases of combined negative and positive impacts on biodiversity referred to community-level modifications. Overall, more positive than negative impacts were reported on ecosystem services, but this varied depending on the service. For human health, only negative impacts were recorded. Substantial variation was found among Mediterranean ecoregions in terms of mechanisms of impact and the taxonomic identity of impacting species. There was no evidence that the magnitude of impact increases with residence time. Holistic approaches and experimental research constitute the way forward to better understanding and managing biological invasions.
... Nevertheless, it should be emphasized that the successive enlargements of the Suez Canal could be associated with the increase of new introductions of tropical and subtropical species from the Red Sea (Galil et al. 2017) and that the warming of Mediterranean waters due to climate change facilitates their expansion (Zenetos and Galanidi 2020). Furthermore, the intensification all over the basin of research efforts and of underwater observations performed by citizen scientists during recent years has greatly contributed to the early detection of new or overlooked non-indigenous biota in many countries at a much faster pace than in the pre-citizen science era (Roy et al. 2018;Katsanevakis et al. 2020). ...
... The Mediterranean Sea is a hotspot of biological invasions and introduced species are one of the major threats to Mediterranean biodiversity (Coll et al. 2010), resulting in changes of composition, function, and service of marine biocommunities, mainly in the eastern part of the basin (Katsanevakis et al. 2014. More than 100 alien fish species of the Red Sea/Indo-Pacific Ocean origin have been introduced via the Suez Canal into the Mediterranean basin (Golani and Fricke 2018), the majority established and integrated within the native food webs; many of these species do not have a commercial value and they are discarded in fishery activities, while other species dominate the fish catches, often with socio-economic and ecological impacts (Galil et al. 2017;Katsanevakis et al. 2020). Monitoring the expansion and abundance of non-indigenous species in the Mediterranean waters is of huge importance at the national and international level in order to contribute to the assessment of the quality of the waters of the basin and to manage its resources and sustainability, under the pressure of biological invasions and other factors (Anonymous 2020). ...
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Citation: Al Mabruk SAA, Zava B, Abdulghani A, Corsini-Foka М, Deidun A (2021) The first record of the pharaoh cardinal fish, Apogonichthyoides pharaonis (Actinopterygii: Perciformes: Apogonidae), from Libyan waters. Acta Ichthyologica et Piscatoria 51(1): 113-118. https://doi. Abstract The occurrence of the pharaoh cardinalfish, Apogonichthyoides pharaonis (Bellotti, 1874), is documented for the first time from the Libyan waters, after two subsequent findings reported in September and November 2020 in the far eastern region of the country. The location of these findings represents the westernmost area of distribution in the southern Mediterranean for this species, which has the western Indian Ocean and Red Sea origin and which entered into the Mediterranean via the Suez Canal.
... The specimens illustrated by Batsch (1791) are believed to originate from recent sediments in the Adriatic Sea (Cushman, 1931) and were assigned to Spirolina hemprichii (Ehrenberg) or Spirolina cylindracea (see Cushman, 1931, p. 72). Modern Mediterranean records include material from the Adriatic Sea, Greece, Israel and Turkey (Cimerman & Langer, 1991;Hollaus & Hottinger, 1997;Hyams et al., 2002;Langer, 2008;Meriç et al., 2008b;Koukousioura et al., 2010). Fossil material of Coscinospira hemprichii from the Mediterranean was recently reported by Melis et al. (2015), Yümün et al. (2016) and Hyams-Kaphzan (unpublished) from the Adriatic Sea, Turkey and Israel, respectively. ...
... The vast majority of alien foraminifera recorded so far have become established in the Eastern Mediterranean Sea (41 species = 93.1 %; Tbl. 1, Fig. 1), primarily along the Levantine coasts (Langer & Hottinger, 2000;Hyams et al., 2002;Hyams-Kaphzan et al., 2008;Langer, 2008;Almogi-Labin & Hyams-Kaphzan, 2012;Langer et al., 2012;Mouanga & Langer, 2014;Langer & Mouanga, 2016;Guastella et al., 2019;Servello et al., 2019;Katsanevakis et al., 2020). The number of alien species decreases rapidly from east to west. ...
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The human-mediated translocation of marine alien species beyond their natural ranges started as early as people began navigating the sea and is of growing concern to nature conservation. The Mediterranean Sea is among the most severely affected areas by biological invasions, a phenomenon that has been fostered by the opening and recent extension of the Suez Canal, the transport and release of ballast water, aquaculture and aquarium trade, ichthyochory and other active or passive dispersal mechanisms. The increase of marine invasions has stimulated considerable research, but for some important groups, in particular microorganisms, data are still limited. In this paper we have reviewed the current status of marine alien foraminifera in the Mediterranean Sea. Our survey includes a comrephensive taxonomic revision of previously recognized alien taxa, and new information obtained from the fossil record and from molecular studies. Our survey and reexamination of alien benthic foraminifera yielded a total of 44 validly recognized species and two species of cryptogenic taxa and reduces the number of previous recordings. The revised list includes both larger symbiont-bearing and smaller benthic foraminifera, including 16 hyaline-perforate, 3 agglutinated and 25 porcelaneous taxa. The vast majority of alien foraminifera recorded so far have become established in the Eastern and Central Mediterranean Sea, indicative for translocation and introduction via the Suez Canal pathway. Only one species, Amphistegina lobifera, causes significant ecological impacts and fulfills the criteria to be considered as an invasive alien. This species is a prolific carbonate producer, and displays extreme forms of ecosystem invasibility with capabilities to reduce native diversity and species richness. The proliferation and rates of recently observed range extensions, track contemporary sea surface temperature increases, provide strong support for previous species distribution models, and corroborate findings that rising water temperatures, global climate change and the extension of climate belts are major drivers fueling the latitudinal range expansion of larger symbiont-bearing and smaller epiphytic foraminifera. Intensified efforts to study alien foraminifera on a molecular level, in dated cores and in ballast water are required to trace their source of origin, to identify vectors of introduction and to verify their status as true aliens.
... Major inter-ocean canal systems including the Suez and Panama have facilitated the spread of non-native marine species between the Indian Ocean and Mediterranean, and the Atlantic and Pacific oceans respectively. The Lessepsian invasion of the Mediterranean, by means of the Suez Canal opened in 1869, enabled a migration route for organisms by self-dispersal, as stowaways on international shipping (Katsanevakis et al., 2020), and via ichthyochory (ingestion and defecation of viable individuals; Guy-Haim et al., 2017). The Mediterranean marine record shows a widespread signature of such invasions, for example though the spread of benthic foraminifera (Weinmann et al., 2013). ...
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The "Great Acceleration" beginning in the mid-20th century provides the causal mechanism of the Anthro-pocene, which has been proposed as a new epoch of geological time beginning in 1952 CE. Here we identify key parameters and their diagnostic palaeontological signals of the Anthropocene, including the rapid breakdown of discrete biogeographical ranges for marine and terrestrial species, rapid changes to ecologies resulting from climate change and ecological degradation, the spread of exotic foodstuffs beyond their ecological range, and the accumulation of reconfigured forest materials such as medium density fibreboard (MDF) all being symptoms of the Great Acceleration. We show: 1) how Anthropocene successions in North America, South America, Africa, Oceania, Europe, and Asia can be correlated using palaeontological signatures of highly invasive species and changes to ecologies that demonstrate the growing interconnectivity of human systems; 2) how the unique depositional settings of landfills may concentrate the remains of organisms far beyond their geographical range of environmental tolerance; and 3) how a range of settings may preserve a long-lived, unique palaeontological 2 record within post-mid-20th century deposits. Collectively these changes provide a global palaeontological signature that is distinct from all past records of deep-time biotic change, including those of the Holocene.
... Mediterranean marine biodiversity is undergoing rapid alteration, driven by multiple stress factors, mostly due to anthropogenic activities (Bianchi et al., 2012;Katsanevakis et al., 2020). Among these factors, alien species (considered here as synonymous of non-indigenous, non-native, allochthonous, exotic, Lessepsian) are considered a major threat to the biodiversity of the basin, affecting community synthesis, habitats, ecosystem functioning and services (Katsanevakis et al., 2014;Mannino et al., 2017;Zenetos et al., 2018;Giakoumi et al., 2019). ...
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Trammel net and boat-seine experimental fishing samplings were carried out seasonally, over a rocky-sandy and a Posidonia oceanica habitat respectively, in the coastal waters of Rhodes, southeastern Aegean Sea, Greece, between 2019 and 2020. Fish catch composition, abundance and biomass were investigated as a contribution to the qualitative and quantitative monitoring of the fish assemblages in the artisanal fishery in this Greek marine region most affected by biological invasion. A total of 56 native and 11 alien fish species were captured. Five invasive species Fistularia commersonii, Pterois miles, Siganus rivulatus, Siganus luridus and Lagocephalus sceleratus were recorded using both fishing gear. In trammel nets, the alien to native fish species ratio was 1:2.87 with eight allochthonous species composing 43% of the total abundance and greatly exceeding native species biomass with the most dominant being F. commersonii, P. miles, S. rivulatus and S. luridus. Boat seine samples were dominated by Spicara smaris and Boops boops, which accounted for 84% and 56% of total abundance and biomass, respectively, while the alien to native fish species ratio was 1:5.1. The 10 Lessepsian fish, i.e., fish that have entered the Mediterranean Sea via the Suez Canal, identified on a Posidonia seabed represented a small proportion of the total abundance (3.4%), while their biomass reached 17% of the total catch, with a prevalence of F. commersonii. Among alien fish on P. oceanica, S. rivulatus exhibited the greatest abundance, followed by F. commersonii, Parupeneus forsskali and S. luridus, with small but not negligible densities of Pteragogus trispilus and Torquigener flavimaculosus. The abundance of Pterois miles over the rocky-sandy habitat was remarkable. Results indicate a transitional shift in fish catch composition with introduced species competing with natives for food and space (i.e. between introduced siganids and Sparisoma cretense, Sarpa salpa, between the recently introduced P. forsskali and mullids, and between introduced P. miles and scorpaenids), further influenced synergistically by environmental and anthropogenic factors. The Total-Standard length and Total weight-Total length relationships and their applications in fisheries data for the allochthonous fish are briefly discussed.
... In the Mediterranean Sea, risk assessments that mainly concern fish IAS are available in the literature, including Plotosus lineatus , Pterois miles (Filiz et al., 2017;Kleitou et al., 2021), Siganus rivulatus (Shapiro Goldberg et al., 2021), Siganus luridus (D'Amen and Azzurro, 2020), and Lagocephalus sceleratus (Filiz et al., 2017;. These species have well-established populations in the Greek waters, having great impacts on ecosystems, native species, and fisheries (Katsanevakis et al., 2020). ...
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Greek waters are the recipient of several alien species, mainly through natural dispersal following invasion and establishment of non-indigenous species (NIS) in neighboring areas, making their monitoring and mitigating their effects of paramount importance. The European Union legislation framework toward alien species invasions considers risk assessments as the top of the spear for a first assessment of NIS and their potential to become invasive or not. The Union List has already included top priority species, with very few marine species. Golani’s round herring (Etrumeus golanii) is a species of round herrings in the family Dussumieriidae, a Lessepsian migrant and belonging to a group of NIS in the Mediterranean basin that are less studied. Its distribution range is mainly limited in the southeastern Mediterranean Sea, while in the Greek seas, it has not yet been observed in the north Aegean and Ionian seas, probably due to temperature and oceanographical reasons. Its presence in the basin is recorded by commercial fisheries landings in several countries (especially purse-seiners), indicating a potentially positive effect on commercial fisheries. A risk assessment of E. golanii in Greek waters was carried out in this work, based on the Risk Assessment Scheme developed by the GB Non-Native Species Secretariat (GB Non-Native Risk Assessment—GBNNRA). An overall semi-quantitative summary of risk, in terms of likelihood of events and magnitude of impacts, was facilitated for several attributors, including confidence levels for each one. The assessment highlighted a very likely possibility of introduction in the Greek seas from neighboring countries, as well as successful establishments of populations with high confidence levels. A moderate magnitude of impact regarding its further spread was deemed, while a minor one was indicated in terms of native species pressure and a minimal one in terms of economic costs and public health. Overall, E. golanii was not characterized as an invasive alien species (IAS) and local communities could benefit from its presence (commercial fisheries); however, further studies focusing on its reproduction and spawning grounds should be implemented.
... MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. impacts (negative or positive) [36,38]. Although the presence of alien species in the Aegean Sea has been continuously monitored over the past two decades [39,40] through scientific networks [41,42], citizen science initiatives [43], collections of unpublished records [44,45], and their introduction pathways have been assessed [31,46], there are no studies that address their cumulative impacts under a systematic framework. ...
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Biological invasions are a human-induced environmental disturbance that can cause major changes in ecosystem structure and functioning. Located in the northeastern Mediterranean basin, the Aegean Sea is a hotspot of biological invasions. Although the presence of alien species in the Aegean has been studied and monitored, no assessment has been conducted on their cumulative impacts on native biodiversity. To address this gap and identify the most highly impacted areas and habitats and the most impactful invasive species in the Aegean, we applied the CIMPAL index, a framework developed for mapping the cumulative impacts of invasive species. Coastal habitats showed stronger impacts than the open sea. The highest CIMPAL scores were four times more frequent in the South than in the North Aegean. Shallow (0-60 m) hard substrate was the most heavily impacted habitat type, followed by soft substrates and seagrass meadows. We identified Caulerpa cylindracea, Lophocladia lallemandii, Siganus spp. and Womersleyella setacea as the most im-pactful species across their range of occurrence in the Aegean but, ranking varied depending on the habitat and impact indicator applied. Our assessment can support marine managers in prioritizing decisions and actions to control biological invasions and mitigate their impacts in the Aegean Sea.
... invasion, although at a lesser extent than the Levantine Sea (Katsanevakis et al., 2020). In the north, the inflow of nutrientrich and lower salinity waters originating from the Black Sea and large rivers (Lykousis et al., 2002) supports large biomasses of commercially important small and medium pelagic fishes. ...
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The aim of this work is to present the food web models developed using the Ecopath with Ecosim (EwE) software tool to describe structure and functioning of various European marine ecosystems (eastern, central and western Mediterranean Sea; Black Sea; Bay of Biscay, Celtic Sea and Iberian coast; Baltic Sea; North Sea; English Channel, Irish Sea and west Scottish Sea; and Norwegian and Barents Seas). A total of 195 Ecopath models based on 168 scientific publications, which report original, updated and modified versions, were reviewed. Seventy models included Ecosim temporal simulations while 28 implemented Ecospace spatiotemporal dynamics. Most of the models and publications referred to the western Mediterranean Sea followed by the English Channel, Irish Sea and west Scottish Sea sub-regions. In the Mediterranean Sea, the western region had the largest number of models and publications, followed by the central and eastern regions; similar trends were observed in previous literature reviews. Most models addressed ecosystem functioning and fisheries-related hypotheses while several investigated the impact of climate change, the presence of alien species, aquaculture, chemical pollution, infrastructure, and energy production. Model complexity (i.e., number of functional groups) increased over time. Main forcing factors considered to run spatial and temporal simulations were trophic interactions, fishery, and primary production. Average scores of ecosystem indicators derived from the Ecopath summary statistics were compared. Uncertainty was also investigated based on the use of the Ecosampler plug-in and the Monte Carlo routine; only one third of the reviewed publications incorporated uncertainty analysis. Only a limited number of the models included the use of the ECOIND plug-in which provides the user with quantitative output of ecological indicators. We assert that the EwE modelling approach is a successful tool which provides a quantitative framework to analyse the structure and dynamics of ecosystems, and to evaluate the potential impacts of different management scenarios.
... This crab is the prey of the invasive Randall's threadfin bream Nemipterus randalli Russell, 1986 in Israel waters (Gilaad et al. 2017). The presence of several digested specimens in the stomach of the invasive tetraodontid L. sceleratus suggests that M. (M.) indicus may be established and integrated into the local food web, similar to other crab NIS in the area (Corsini-Foka et al. 2015;Katsanevakis et al. 2020;Kondylatos et al. 2020). ...
Article
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The findings of the crabs Arcania brevifrons and Macrophthalmus (Macrophthalmus) indicus, native to the Indo-West Pacific Ocean and Red Sea, and to the Indian Ocean and Red Sea, respectively, in 2021 are described from Rhodes Island, Greece. This first record of the leucosiid A. brevifrons in Hellenic waters and the Aegean Sea documents the westward expansion of its Mediterranean distribution. Two individuals of the introduced macrophthalmid M. (M.) indicus were found in the stomachs of silver-cheeked toadfish (Lagocephalus sceleratus), a fish species that itself is invasive. For both species, DNA barcoding was performed using the standard mitochondrial marker cytochrome c oxidase subunit I (COI). While the identification of A. brevifrons was genetically confirmed, M. (M.) indicus individuals were morphologically identified. There were no M. (M.) indicus genetic samples available in the nucleotide database of GenBank, hindering the ability to genetically confirm species identification. However, M. (M.) indicus had previously been detected 12 years ago in the same area.
... The governance of fisheries in the era of climate change should support a flexible, adaptive, and well-informed ecosystem-based management aiming to face environmental change and provide long-term yields with reduced risks of stock collapse (Bastardie et al., 2022). (Katsanevakis, Zenetos, et al., 2020). Therefore, different areas of the Mediterranean basin would have to cope with different conflicts according to the particular pressures they face, thus, necessitating differing management measures. ...
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Rapid anthropogenic climate change is driving threatened biodiversity one step closer to extinction. Effects on native biodiversity are determined by an interplay between species' exposure to climate change and their specific ecological and life-history characteristics that render them even more susceptible. Impacts on biodiversity have already been reported, however, a systematic risk evaluation of threatened marine populations is lacking. Here, we employ a trait-based approach to assess the risk of 90 threatened marine Mediterranean species to climate change, combining species' exposure to increased sea temperature and intrinsic vulnerability. One-quarter of the threatened marine biodiversity of the Mediterranean Sea is predicted to be under elevated levels of climate risk, with various traits identified as key vulnerability traits. High-risk taxa including sea turtles, marine mammals, Anthozoa and Chondrichthyes are highlighted. Climate risk, vulnerability and exposure hotspots are distributed along the Western Mediterranean, Alboran, Aegean, and Adriatic Seas. At each Mediterranean marine ecoregion, 21% to 31% of their threatened species have high climate risk. All Mediterranean Marine Protected Areas host threatened species with high risk to climate change, with 90% having a minimum of 4 up to 19 species of high climate risk, making the objective of a climate-smart conservation strategy a crucial task for immediate planning and action. Our findings aspire to offer new insights for systematic, spatially strategic planning and prioritization of vulnerable marine life in the face of accelerating climate change.
... It is noteworthy that the Saronikos Gulf is the gateway for 11 alien species in the Mediterranean Sea [7], including Lophocladia lallemandii (Montagne) F. Schmitz that was first reported back in 1908 [172]. Moreover, out of a total of 209 marine NIS reported to date (2020) from the Greek Aegean Sea, Greek territorial waters [173], 40 alien species were first reported from the Saronikos Gulf. ...
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The Saronikos Gulf and the small emBayment of Elefsis Bay (Eastern Mediterranean, Greece) represent the seaward boundary of the metropolitan areas of Athens and Piraeus Port, hosting 1/3 of the current Greek population. It constitutes a complex ecosystem due to the topographical and hydrological differentiation of the area, as well as its trophic character. Maintenance of the good environmental status of the Saronikos Gulf marine ecosystem is very important due to the cumulating impacts coming from multiple human activities. In order to protect and improve the marine environment and implement effective policies to sustain its quality, it is necessary to monitor the spatial and temporal variation of the major ecosystem elements, the pollutant levels, and their effects on the ecosystem and marine organisms. Thus, in this chapter, we provide an overview of ecosystem elements, hazardous substances, and alien species that have undergone changes over the last 25 years because of the various pressures, emphasizing mainly the sewage treatment plant of Athens in Psittalia Island. The environmental status of the inner Saronikos Gulf is also examined. Summarizing, we highlight the gradual improvement of many parameters of the ecosystem. This trend of improvement has started since 2004, as a result of the secondary treatment of the wastewater and the decrease of the industrial activities following the economic crisis in Greece. Nevertheless, it is essential the maintenance of the monitoring of the Saronikos Gulf and Elefsis Bay in order to investigate any expected change due to cumulative impacts from multiple human activities which in combination with climate change may provoke new ecological balances. Possible changes and impacts on the Saronikos Gulf ecosystem must be recorded to optimize the protection and the management of the marine environment in the context of the implementation of the European Directives in our country.
... All recorded NIS have Indo-Pacific origin, having reached the Eastern Mediterranean basin through the Suez Canal [64]. Although in the relevant literature there are no data that indicate any direct impacts of NIS on the diversity of marine caves, at least three of the observed NIS (i.e., Pterois miles, Siganus luridus and S. rivulatus) are considered as invasive with high impact on the native biodiversity of the Aegean Sea and the Eastern Mediterranean, while the remaining NIS have low or unknown impact [28,65]. Only two NIS were reported exclusively in the semi-dark cave zone (Table S3), suggesting that this habitat type could be unfavourable, at least to a certain point, for impacts related to opportunistic NIS [28]. ...
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Although more than 600 marine caves have been recorded so far along the Greek coasts of the Aegean Sea (Eastern Mediterranean), only a few have been systematically studied for their biodiversity. In this study, the benthic communities of six marine caves within a Protected Area of South-Eastern Aegean were studied for the first time, both qualitatively and quantitatively. The association of different geomorphological and topographical factors of the caves with the benthic community structure was investigated. A total of 120 photographic quadrats covering the entrance and semi-dark cave zones were analysed, with regard to coverage and taxon abundance, while motile taxa were qualitatively recorded by visual census. The ecological quality status of the caves was also assessed under an ecosystem-based approach. In total, 81 sessile and 45 motile taxa were recorded, including 12 protected and 10 non-indigenous species. Multivariate community analysis demonstrated that the geomorphological and topographical variables of the caves are significantly associated with the observed biotic patterns. The ecological quality of the caves was assessed as poor or moderate according to the CavEBQI index, highlighting the necessity for systematic monitoring. This study paves the way for similar studies in marine cave habitats aiming at the development of management and conservation actions.
... This study considers 13 fish species originating from the Red Sea (ii) human health (e.g. toxicity; Bentur et al., 2008;Galanidi et al., 2019) or (iii) commercial exploitation (e.g. for human consumption; Katsanevakis et al., 2020;Morris, 2012;Streftaris & Zenetos, 2006). ...
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Biological invasions represent one of the main threats to marine biodiversity. From a conservation perspective, especially in the context of increasing sea warming, it is critical to examine the suitability potential of geographical areas for the arrival of Range Expanding Introduced and Native Species (REINS), and hence anticipate the risk of such species to become invasive in their new distribution areas. Here, we developed an empirical index, based on functional and bio‐ecological traits, that estimates the Invasive Potential (IP; i.e. the potential success in transport, introduction and population establishment) for a set of 13 fishes that are expanding their distributional range into the Mediterranean Sea, the most invaded sea in the world. The IP index showed significant correlation with the observed spreading of REINS. For the six species characterised by the highest IP, we calculated contemporary and future projections of their Environmental Suitability Index (ESI). By using an ensemble modelling approach, we estimated the geographical areas that are likely to be the most impacted by REINS spreading under climate change. Our results demonstrated the importance of functional traits related to reproduction for determining high invasion potential. For most species, we found high contemporary ESI values in the South‐eastern Mediterranean Sea and low to intermediate contemporary ESI values in the Adriatic Sea and North‐western Mediterranean sector. Moreover, we highlighted a major potential future expansion of high ESI values, and thus REINS invasive potential, towards the northern Mediterranean, especially in the northern Adriatic Sea. This potential future northward expansion highlights the risk associated with climate‐induced impacts on ecosystem conservation and fish stock management throughout the entire Mediterranean Sea.
... Lagocephalus sceleratus was first recorded in the Mediterranean in Turkish waters of the Aegean Sea in 2003 ( Figure 1A; Akyol et al., 2005), followed by Israel in 2004 (Golani and Levy, 2005), and next in Rhodes and Crete in Greece (Corsini et al., 2006;Kasapidis et al., 2007). Within a few years, L. sceleratus were abundant throughout Aegean and Levantine coasts (Katsanevakis et al., 2020c). Their range expanded throughout the Mediterranean Sea during the following decade and are now found from the Strait of Gibraltar to the Black Sea (Akyol and Ünal, 2017;Azzurro et al., 2020;Gücü et al., 2021). ...
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The silver-cheeked toadfish (Lagocephalus sceleratus, from the pufferfish family Tetraodontidae) and the Pacific red lionfish (Pterois miles, family Scorpaenidae) have recently invaded the Mediterranean Sea. Lagocephalus sceleratus has spread throughout this entire sea with the highest concentrations in the eastern basin, while more recently, Pterois miles has spread from the Eastern to the Central Mediterranean Sea. Their effects on local biodiversity and fisheries are cause for management concern. Here, a comprehensive review of predators of these two species from their native Indo-Pacific and invaded Mediterranean and Western Atlantic ranges is presented. Predators of Tetraodontidae in general were reviewed for their native Indo-Pacific and Western Atlantic ranges, as no records were found specifically for L. sceleratus in its native range. Tetraodontidae predators in their native ranges included mantis shrimp (Stomatopoda), lizardfish (Synodus spp.), tiger shark (Galeocerdo cuvier), lemon shark (Negaprion brevirostris), sea snakes (Enhydrina spp.), catfish (Arius spp.), cobia (Rachycentron canadum), skipjack tuna (Katsuwonus pelamis), and common octopus (Octopus vulgaris). The only reported predator of adult L. sceleratus in the Mediterranean was loggerhead turtle (Caretta caretta), whereas juvenile L. sceleratus were preyed by common dolphinfish (Coryphaena hippurus) and garfish (Belone belone). Conspecific cannibalism of L. sceleratus juveniles was also confirmed in the Mediterranean. Pufferfish predators in the Western Atlantic included common octopus, frogfish (Antennaridae), and several marine birds. Predators of all lionfish species in their native Indo-Pacific range included humpback scorpionfish (Scorpaenopsis spp.), bobbit worms (Eunice aphroditois), moray eels (Muraenidae), and bluespotted cornetfish (Fistularia commersonii). Lionfish predators in the Mediterranean included dusky grouper (Epinephelus marginatus), white grouper (Epinephelus aeneus), common octopus, and L. sceleratus, whereas in the Western Atlantic included the spotted moray (Gymnothorax moringa), multiple grouper species (tiger Mycteroperca tigris, Nassau Epinephelus striatus, black Mycteroperca bonaci, red Epinephelus morio, and gag Mycteroperca microleps; Epinephelidae), northern red snapper (Lutjanus campechanus), greater amberjack (Seriola dumerilli), and nurse shark (Ginglymostoma cirratum). The sparse data found on natural predation for these species suggest that population control via predation may be limited. Their population control may require proactive, targeted human removals, as is currently practiced with lionfish in the Western Atlantic.
... Concerning the non-indigenous fishes, more than 100 species of Red Sea/ Indo-Pacific Ocean origin entered into the Mediterranean basin through the Suez Canal (Golani and Fricke 2018). The majority have established and integrated into the native bio-communities and within food webs; many of these species dominate the fish catches, often with evident socio-economic and ecological impact, including danger for human health (Galil et al. 2017;Katsanevakis et al. 2020). ...
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An individual of the non-indigenous fish Terapon jarbua and one of Acanthopagrusbifasciatus were fished from the coastal waters off Alexandria, Egypt in November2020. The former was collected with shore jigging and the latter with a trammel net.The record of T. jarbua constitutes the first one for the Mediterranean Egyptian watersand the second one for the entire Mediterranean basin. The record of A. bifasciatusis the first one for the Mediterranean Egyptian waters and the fourth for theMediterranean. The morphometric and meristic characteristics of the recordedindividuals are hereby presented, along with different hypotheses explaining the entrywithin the Mediterranean of these non-indigenous species.
... This work reports on the first occurrence records of U. pulchella from Greek waters and the Aegean Sea (Zenetos et al. 2018(Zenetos et al. , 2020Katsanevakis et al. 2020c). The herein reported new records extend from Kastelorizo Island (very close to the type locality of the species description in southwestern Turkey by Yokeş and Galil 2006) to the Cyclades Islands in the South Aegean Sea. ...
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Urocaridella pulchella Yokeş & Galil, 2006 is a palaemonid cleaner-shrimp of Indo-Pacific origin that was first described from the Mediterranean Sea in 2006. However, limited information is available about its distribution and ecology due to the small size and cryptic habit of the species. We hereby report the first records of U. pulchella in marine caves and crevices of Greece, updating the species distribution that now spreads from the Levantine Sea to the South Aegean. Species identification was based on morphological examination and DNA barcoding of collected samples and in situ photographs. We also report on the fish cleaning behaviour of the species (based on observations of cleaning behaviour to the native Mediterranean moray eel, Muraena helena), the finding of an ovigerous-female and a wide distribution range, attesting to the establishment of the species in the area.
Preprint
Abstract: The “Great Acceleration” of the mid-20th century provides the causal mechanism of the Anthropocene, which has been proposed as a new epoch of geological time beginning in 1952 CE. Here we identify key parameters and their diagnostic palaeontological signals of the Anthropocene, including the rapid breakdown of discrete biogeographical ranges for marine and terrestrial species, rapid changes to ecologies resulting from climate change and ecological degradation, the spread of exotic foodstuffs beyond their ecological range, and the accumulation of reconfigured forest materials such as medium density fibreboard (MDF) all being symptoms of the Great Acceleration. We show: 1) how Anthropocene successions in North America, South America, Africa, Oceania, Europe, and Asia can be correlated using palaeontological signatures of highly invasive species and changes to ecologies that demonstrate the growing interconnectivity of human systems; 2) how the unique depositional settings of landfills may concentrate the remains of organisms far beyond their geographical range of environmental tolerance; and 3) how a range of settings may preserve a long-lived, unique palaeontological record within post-mid-20th century deposits. Collectively these changes provide a global palaeontological signature that is distinct from all past records of deep-time biotic change, including those of the Holocene. (The preproof-article is now open access: https://doi.org/10.1016/j.earscirev.2024.104844 )
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This chapter is a brief overview of 14 contributions to Book I titled The Aegean Sea Environment: The Geodiversity of the Natural System and 15 contributions to Book II titled The Aegean Sea Environment: The Biodiversity of the Natural System. These contributions summarize the current knowledge of the Aegean Sea environment as a natural system. The structure of the two books is designed in a way that navigates the reader from the geological processes – that have shaped the Aegean Sea – to the land–sea and the air–sea interactions, from the nature of the water masses and the sea bottom to life in the land–air–sea transition zones, life in the seawater masses, and benthic flora and fauna in the Aegean Sea. Furthermore, gaps in knowledge are highlighted, crucial questions about the function of the Aegean Sea system are raised, and new interesting research issues appear which require special attention in the future.
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The Aegean Sea stands as a unique Mediterranean ecoregion with intricate geomorphological attributes and diverse habitats. This article delves into the sea’s rich biodiversity and the challenges of managing its resources sustainably. The Aegean’s complex structure encompasses shallow shelves, deep basins, and a multitude of habitats, mirrored by a high species richness. However, cumulative impacts from human activities pose significant threats to marine biodiversity. Assessments of conservation status are limited, primarily due to data constraints. We argue for the need for an ecosystem-based management (EBM) approach as the cornerstone for integrated marine management in the Aegean, building upon previous research in the region. The framework of Drivers-Activities-Pressures-State-Impacts (to human Welfare)-Response (Measures) (DAPSI(W)R(M)) facilitates the understanding of interactions between human activities, ecosystem changes, and societal impacts. At the same time, a Social-Ecological System framework can inform on possible synergies and/or tradeoffs of decision-making for a more inclusive governance structure hence advancing the EBM approach. We underscore the need to transition from sectoral management to EBM and marine spatial planning, guided by a comprehensive governance structure, using tools and concepts of Social-Ecological systems for an advanced EBM. We propose an array of concrete actions spanning from enhanced scientific research and stakeholder involvement to adaptive governance structures and addressing global change impacts. This holistic approach, emphasizing interdependence and balance, aims to pave the way for the Aegean Sea’s preservation and prosperity in the face of mounting challenges.
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Biological invasions, resulting from human activities, exert substantial impacts on ecosystems worldwide. This review focuses on marine invasive alien species (IAS) in Europe, examining the current state, proposing strategies to address the problem, and offering recommendations for enhanced management. Effective management of biological invasions relies on accessible, accurate data to inform decision-making. Information systems such as the European Alien Species Information Network (EASIN), Aquatic Non-Indigenous and Cryptogenic Species (AquaNIS), and World Register of Introduced Marine Species (WriMS) provide comprehensive databases on IAS, but their sustainability requires long-term maintenance, continuous updates, and support. Most countries lack specific monitoring programs for marine IAS, and standardization and improvement of monitoring methods are needed. Port monitoring plays a vital role in the early detection of new arrivals, and recent advancements in molecular techniques show promise for effective IAS monitoring. Risk screening tools are commonly employed to rank taxa based on their invasiveness potential in European regions, but variations in protocols can yield inconsistent results. European impact assessments highlight resource competition, novel habitat creation, and predation as primary mechanisms for negative impacts on biodiversity, while the creation of novel habitats represents a key mechanism for positive impacts. Preventing IAS introductions is critical, and measures such as ballast water treatment systems are implemented to reduce the likelihood of marine introductions. However, understanding introduction pathways remains uncertain for many IAS. Eradication and control efforts for marine IAS have limited success, emphasizing the need for enhanced biosecurity measures. Climate change, especially ocean warming, can intensify IAS impacts on native species and ecosystems. In climate change hotspots, some tropical aliens may, however, compensate for the loss of thermally sensitive natives with similar traits. Therefore, it is imperative to consider the interactions between climate change and IAS in developing effective management and conservation strategies. Enhancing IAS management in Europe entails i) securing adequate funding, ii) expanding the list of IAS of Union Concern to adequately cover marine invasions, iii) learning from countries with successful biosecurity practices, iv) sustaining information systems, v) improving monitoring and early warning systems with innovative technologies, vi) enhancing prediction models, vii) conducting integrated impact assessments and mapping cumulative IAS impacts, and vii) considering the potential benefits of IAS in ecosystem functioning and services.
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The degradation of marine ecosystems is a growing concern worldwide, emphasizing the need for efficient tools to assess their ecological status. Herein, a novel ecosystem-based ecological evaluation index of shallow rocky reefs is introduced and tested in the Aegean and Ionian Seas (NE Mediterranean). The index focuses on a specific set of pre-selected species, including habitat-forming, key, commercially important, and non-indigenous species, across a wide range of trophic levels (1.00–4.53). Data acquisition is conducted through rapid non-destructive SCUBA diving surveys to assess all macroscopic food web components (macroalgae, invertebrates, and fish). Two versions of the index, ECOfast and ECOfast-NIS, were developed, each applying a different approach to account for the impact of non-indigenous species. In our case study, the correlations between the two versions of the index and sea surface temperature, protection status, occurrence of carnivorous fish, and non-indigenous herbivores were assessed through generalized additive models (GAMs). The assessment assigned 93% (ECOfast) or 96% (ECOfast-NIS) of the sites to a moderate to bad ecological status, indicating an alarming situation in the shallow rocky reefs of the NE Mediterranean. Sites evaluated as poor or bad were characterized by extensive coverage of ephemeral macroalgae, absence or minimal presence of large indigenous carnivorous fish, and complete absence of one to three out of five invertebrate functional trophic groups. The community composition of macroalgae, herbivorous species, and carnivorous fishes differed between the 5 m and 15 m depth zones. Surface temperature and carnivorous fish occurrence were the most important tested predictors of the ecological status of shallow rocky reefs. The best GAMs showed that the ECOfast score declined with sea surface temperature and increased with the occurrence of carnivorous fish; ECOfast-NIS declined with sea surface temperature and the occurrence of non-indigenous fish and increased with the occurrence of carnivorous fish. The nondestructive and integrative nature of this approach, its speed of data acquisition and analysis, and its capacity to account for highly mobile predatory fish and non-indigenous species render the ECOfast index a novel, robust, and valuable tool for assessing the ecological status of shallow rocky reefs.
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This chapter is an introduction to the book “The Aegean Sea Environment: The Natural System,” which is the first book of the two-volume issue with the second volume entitled “The Aegean Sea Environment: Anthropogenic Presence and Impact.” In the present volume, we aim to approach the Aegean Sea marine ecosystem as a “water-way” connecting the Black Sea with the Eastern Mediterranean Sea, as a natural system. We discuss specific features and geodynamic evolution of the Black Sea–Mediterranean Sea system. We briefly describe geomorphological characteristics, land–sea and air–sea interaction, water masses, hydrology, chemistry, suspended matter and fluxes, sediments at the bottom, as well as biological dynamic and evolution, and life separately for the Black Sea, Mediterranean Sea, and Aegean Sea systems. The structure of the book is presented at the end of the chapter.
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Based on the reanalysis MEDSEA_REANALYSIS_PHY_006_009 data, the interannual variability of temperature and salinity of the Aegean Sea at depths from 1.5 to 209 m was investigated for 1955–2015. An increase in the average temperature of the Aegean Sea during the study period was found at depth till approximately 100 m. At deeper levels, neutral and negative temperature trends were found. The average growth rate of sea temperature at the surface was approximately 0.01°С per year. Since the surface temperature has increased more strongly and more evenly in space than at depth, this increase may be associated with regional warming. At the same time, the salinity of the Aegean Sea did not change significantly during the study period. Against the background of an average increase in the temperature of the upper layer of the Aegean Sea, its fluctuations were found at various periods, the main of which is approximately 18.6 years. This period can be associated with the lunisolar nutation of the Earth’s axis of rotation, which affects the tides and mixing of waters, in particular, in the Aegean Sea. This is confirmed by the fact that the maximum energies of fluctuations in the salinity of the Aegean Sea on time scales from 1 to 30 years are located exactly on the period of 18.6 years. Teleconnections of temperature and salinity fluctuations in the Aegean Sea for a period of 18.6 years with the Pacific Decadal Oscillation (PDO), which are also significantly affected by the lunisolar nutation of the Earth’s rotation axis, have been found. Another reported period of temperature fluctuations in the Aegean Sea is approximately 11.5 years, and may be associated with an 11-year cycle of solar activity and with the internal dynamics of Eastern Mediterranean. The spectral peaks of the Aegean Sea temperature were found at periods of 8, 4, and 2 years also. They can be associated with the North Atlantic Oscillation (NAO), which has a period of 8 years. The spectral peaks at periods of 4 and 2 years can be 1:2 and 1:4 super-harmonics of the nonlinear effect of NAO on the Aegean Sea. Also, fluctuations in the temperature of the Aegean Sea were found for periods of 4.8, 3.6, and 2.4 years. These periods are characteristic of the El Niño – Southern Oscillation (ENSO), and they may be sub-harmonics of the Chandler wobble of the Earth’s poles over a period of about 1.2 years, which, through pole tides, can affect both El Niño and the Aegean Sea.
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Shipping is the greatest pathway of non-indigenous species (NIS) introductions, and port areas are considered as alien hotspots. In this study, we analyzed data covering a 112-year period and found that Saronikos Gulf in Greece, hosting one of the largest container port terminals in Europe, is a hotspot of NIS introductions. To date, 89 NIS have been recorded, of which 8 are characterized as invasive. Most species belong to the taxonomic group of Mollusca (33%), followed by Pisces (22%). For the first time in the Mediterranean Sea, we report the presence of the micromolluscs Sinezona plicata (Hedley, 1899) and Ringicula sp. Moreover, we provide evidence for the trend of NIS introduction in the Saronikos Gulf across the past 70 years, the pathways of introduction and their importance through time, as well as the distribution of the most invasive species in the Saronikos Gulf. The information provided herein can assist the implementation of the EU Marine Strategy Framework Directive and inform NIS management. As Transport-Stowaway remains the main pathway of NIS introduction in the Saronikos Gulf, our principal recommendation is to reinforce regulations for the adoption of better antifouling practices and more effective ballast water treatment and management.
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Shipping is the greatest pathway of non-indigenous species (NIS) introductions, and port areas are considered as alien hotspots. In this study, we analyzed data covering a 112-year period and found that Saronikos Gulf in Greece, hosting one of the largest container port terminals in Europe, is a hotspot of NIS introductions. To date, 89 NIS have been recorded, of which 8 are characterized as invasive. Most species belong to the taxonomic group of Mollusca (33%), followed by Pisces (22%). For the first time in the Mediterranean Sea, we report the presence of the micromolluscs Sinezona plicata (Hedley, 1899) and Ringicula sp. Moreover, we provide evidence for the trend of NIS introduction in the Saronikos Gulf across the past 70 years, the pathways of introduction and their importance through time, as well as the distribution of the most invasive species in the Saronikos Gulf. The information provided herein can assist the implementation of the EU Marine Strategy Framework Directive and inform NIS management. As Transport-Stowaway remains the main pathway of NIS introduction in the Saronikos Gulf, our principal recommendation is to reinforce regulations for the adoption of better antifouling practices and more effective ballast water treatment and management.
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The invasive species Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta) on Andalusian coasts (Southern Spain): reproductive stages, new records and invaded communities. The present study provides new records from Andalusian coasts of the exotic invasive seaweed Asparagopsis taxiformis (Delile) Trevisan. These records demonstrate that A. taxiformis has rapidly and widely expanded its distribution range in this region, from Almería to Cádiz (Strait of Gibraltar). The latter locality may represent the western geographical limit of the species in the Mediterranean Sea. Spermatangial heads and cystocarps were observed in the collected gametophytes. Additionally, we report the first record of the tetrasporophytic stage, Falkenbergia hillebrandii (Bornet) Falkenberg from the Andalusian coast, although tetraspores were not encountered in these samples. Consequently, information on the affected communities and arguments for considering A. taxiformis as an invasive species in the Andalusian coast are provided.Key words. Asparagopsis taxiformis, Bonnemaisoniales, distribution, Falkenbergia hillebrandii, invasive species, Mediterranean Sea, new record, reproductive stage, RhodophytaRESUMEN. La especie invasora Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta) en las costas andaluzas (Sur de España): fases reproductivas, nuevas citas y comunidades invadidas. El presente trabajo aporta nuevas citas para las costas andaluzas de la especie exótica invasora de macroalga Asparagopsis taxiformis (Delile) Trevisan. Estas citas muestran que la especie ha aumentado ampliamente su área de distribución de manera rápida en esta región, desde Almería hasta Cádiz (Estrecho de Gibraltar). Esta última localidad representaría el límite occidental de la especie en el mar Mediterráneo. En las muestras recogidas de gametofitos se pudieron observar ramas espermatangiales y cistocarpos. Se aporta la primera cita del estadio tetrasporofítico, Falkenbergia hillebrandii (Bornet) Falkenberg en las costas andaluzas, aunque no se observaron tetrásporas en estas muestras. Se informa sobre las comunidades afectadas y se dan argumentos para considerar a A. taxiformis invasora en las costas andaluzas.Palabras clave. Asparagopsis taxiformis, Bonnemaisoniales, distribución, especie invasora, estadio reproductivo, Falkenbergia hillebrandii, mar Mediterráneo, nueva cita, Rhodophyta
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Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta.
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Good datasets of geo-referenced records of alien species are a prerequisite for assessing the spatio-temporal dynamics of biological invasions, their invasive potential, and the magnitude of their impacts. However, with the exception of first records on a country level or wider regions, observations of species presence tend to remain unpublished, buried in scattered repositories or in the personal databases of experts. Through an initiative to collect, harmonize and make such unpublished data for marine alien and cryptogenic species in the Mediterranean Sea available, a large dataset comprising 5376 records was created. It includes records of 239 alien or cryptogenic taxa (192 Animalia, 24 Plantae, 23 Chromista) from 19 countries surrounding the Mediterranean Sea. In terms of records, the most reported Phyla in descending order were Chordata, Mollusca, Chlorophyta, Arthropoda, and Rhodophyta. The most recorded species was Caulerpa cylindracea, followed by Siganus luridus, Magallana sp. (cf. gigas or angulata) and Pterois miles. The dataset includes records from 1972 to 2020, with the highest number of records observed in 2018. Among the records of the dataset, Dictyota acutiloba is a first record for the Mediterranean Sea. Nine first country records are also included: the alga Caulerpa taxifolia var. distichophylla, the cube boxfish Ostracion cubicus, and the cleaner shrimp Urocaridella pulchella from Israel; the sponge Paraleucilla magna from Libya and Slovenia; the lumpfish Cyclopterus lumpus from Cyprus; the bryozoan Celleporaria vermiformis and the polychaetes Prionospio depauperata and Notomastus aberans from Malta.
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ALAS aims to fill knowledge gaps on the impacts of marine alien species in the Aegean Sea, and support marine managers and policy makers in prioritizing mitigation actions. The project will focus on under-studied alien-native interactions, priority and vulnerable habitats (such as shallow forests of canopy algae and underwater caves), and apply a multitude of approaches. It will apply a standardized, quantitative method for mapping Cumulative IMpacts of invasive Alien species on marine ecosystems (CIMPAL), according to which cumulative impact scores are estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. Towards that direction, ALAS will improve our knowledge base and compile the needed information to estimate CIMPAL by (1) conducting a series of field experiments and surveys to investigate the impacts of selected invasive alien species on marine habitats, (2) producing high-resolution habitat maps in the coastal zone, refining the results of previous research efforts through fieldwork, remote sensing and satellite imaging, (3) producing species distribution models for all invasive species, based on extensive underwater surveys for the collection of new data and integrating all existing information. ALAS will incorporate skills and analyses in novel ways and provide high-resolution results at a large scale; couple classic and novel tools and follow a trans-disciplinary approach, combining knowledge from the fields of invasion biology, conservation biology, biogeography, fisheries science, marine ecology, remote sensing, statistical modelling; conduct for the first time in the Aegean Sea a comprehensive, high-resolution analysis of cumulative impacts of invasive alien species; and report results in formats appropriate for ‡ ‡ ‡ § |
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Here we present an update of the Mediterranean distribution of the lionfish Pterois miles, based on a comprehensive list of geo-referenced occurrences up to October 2019. New data were provided by multiple reporting tools and citizen science initiatives. Our findings suggest that well established populations of P. miles exist in the Levantine Sea, in the southern and central Aegean Sea, as well as in the Greek Ionian Sea, whilst so far, only a few individuals were reported from Tunisia and southern Sicily (Italy). We also argue about the future expansion of this invasive species in the Mediterranean region and about the role of climate change by projecting the limits of winter isotherms under different climate change scenarios. Under the assumption that the mean winter sea surface temperature is the main limiting factor of the range expansion of the species (i.e. 15.3oC winter isotherm), P. miles could substantially expand in the Mediterranean Sea, except the coolest northernmost regions, under future climatic scenarios. These results were discussed in comparison to published outcomes of species distribution modelling.
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1. The disproportionately low presence of marine species in the list of invasive alien species (IAS) of union concern of the European Union (EU) Regulation 1143/2014 does not fully acknowledge the threat they pose to the EU marine environment. 2. In this study, the first EU-scale horizon scanning focusing on marine alien species was performed, aiming to deliver a ranked list of species that should be of high priority for risk assessment (Article 5 of the EU IAS Regulation). 3. Species absent from or with a limited distribution in EU marine waters were targeted. In total, 363 alien species were initially screened for HS by a panel of experts, including a broad range of taxonomic groups. Species were scored for their likelihood of arrival, establishment, spread, and impact in EU waters. 4. A consensus workshop ranked 267 species, including a subset of 26 prioritized species. These species are considered to be mainly introduced by shipping (fouling and ballast water), the Suez Canal, and aquaculture activities. The 26 priority species were also scrutinized in terms of feasibility of their management; 18 of them were suggested for performing risk assessments on the basis of the EU IAS Regulation. 5. Since biological invasions are dynamic and connected with accelerated globalization and diversified human activities, we recommend HS to be repeated periodically to review the species already listed and assess new ones.
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The diet composition of devil lionfish, Pterois miles (Bennet, 1828), from the Aegean Sea was investigated. The stomach contents of 42 samples (10 of which were empty) collected between May 2016 and November 2017 from Rhodes Island, Greece, were studied. The diet was composed predominantly of bony fish (78.5% in number, approximately 94.7% in biomass) belonging to a large variety of families, and invertebrates (15.4% in number, 5.1% in biomass), thus indicating an opportunistic feeding behaviour of the species in the study area. The length–length and length–weight relations were also determined.
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Shallow rocky reef fish assemblages were studied in sites of low versus high fishing pressure (FP) across different parts of the Aegean Sea, in order to assess community structure at a large scale and investigate spatial variability in relation to FP, depth, and geographic location. A total of 15 pairs of high and low FP sites were selected (18 sites in North Aegean, 12 in South Aegean). The level of FP was defined based on a fishing pressure index specifically developed for coastal small-scale fisheries in the region. In each site, fish communities were investigated at two depth zones (5 and 15 m). Number of species, fish size (TL) and abundance were recorded along strip transects through underwater visual surveys. Abundance and TL were used to estimate biomass, and fish species were assigned to distinct trophic and commercial status groups. An 8-fold range in fish density and a 14-fold range in fish biomass were detected, while community structure was affected by all spatial variables considered (FP, depth, geographic location). The N Aegean sites scored higher in number of species and biomass of carnivorous fish, whereas the S Aegean had a higher biomass of several allochthonous and thermophilous species. Abundance and biomass estimates were higher in low FP sites, and primarily at the 15 m depth zone, where low FP sites had 2 times higher abundance and 2.8 times higher biomass. However, differences were mainly due to an increase of fish with low or no commercial value, whereas biomass of highly-priced fish was overall low. Given that sites of lower FP represent areas of lower conflicting interests for fisheries whilst providing enhanced biomass levels, they should be included in future marine conservation planning schemes, as they could contribute to the replenishment of fisheries and the boosting of conservation benefits provided by MPAs, once properly managed.
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The distribution of marine life has been alarmingly reshaped lately and the number of non-indigenous species and their impacts are rapidly escalating globally. Timely and accurate information about the occurrence of non-indigenous species are of major importance for the mitigation of the issue. However, still large gaps in knowledge about marine bioinvasion exist. Mediterranean Sea is among the most impacted ecoregions globally. In this work we present a comprehensive overview of the project “Is is Alien to you? Share it!!!” which monitors non-indigenous species in Greece and Cyprus with the help of citizen scientists. The goal of this work is to present this project as a case study in order to demonstrate how citizen science can substantially contribute to the monitoring of biological invasions. We compared the projects database with the databased of ELNAIS and EASIN, for discuss weaknesses and advantages and future steps for advancing the effort. In total 691 records of marine alien and cryptogenic species were collected in these 2 years from Greece and Cyprus, with the density of records reaching 20 observations per km² in some locations. The project has contributed significantly in the assessment of descriptor D2 “Exotic Species” of the Marine Strategy Framework Directive, with 3 new species for Greece. Future steps should focus on training citizens to report less reported taxa and raising the awareness of all relevant stakeholders. Find the full text here: https://rdcu.be/bPTDQ
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Marine Protected Areas (MPAs) are an essential tool for marine biodiversity conservation. Yet, their effectiveness in protecting marine ecosystems from global stressors is debated. Biological invasions are a major driver of global change, causing biodiversity loss and altering ecosystem functioning. Here, we explored the relationships between MPAs and alien/native range‐expanding fishes in the Mediterranean Sea, the world's most invaded sea. We surveyed fish and benthic communities in nine MPAs and adjacent unprotected areas across six countries. In the South and Eastern Mediterranean MPAs, the biomass of alien and native range‐expanding fishes often exceeded 50% of the total fish biomass. Conversely, in the North and Western Mediterranean, alien fishes were absent. A negative relationship was found between native and alien species richness. Average and minimum sea surface temperature (SST) over six consecutive years were positively correlated with the total biomass of alien species; no alien fishes were recorded below 20.5°C average SST and 13.8°C minimum SST. We also found a negative relationship between alien fishes’ biomass and the distance from the Suez Canal, which is the main pathway for the introduction of alien fish in the Mediterranean Sea. The biomass of alien and native range‐expanding fishes was found to be higher in the South and Eastern Mediterranean MPAs than in adjacent unprotected areas. The association of barrens (rocky reefs deprived of vegetation) and invasive herbivores was observed at all eastern sites, regardless of protection status. Currently, the level of fishing pressure exerted on alien and native range‐expanding fishes seems to be the most influential factor determining the lower biomass of invasive fishes at unprotected sites compared to MPAs. Our findings suggest that complementary management actions, such as species‐targeted removals, should be taken in MPAs to effectively control invasive fish populations.
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Managing invasive alien species is particularly challenging in the ocean mainly because marine ecosystems are highly connected across broad spatial scales. Eradication of marine invasive species has only been achieved when species were detected early, and management responded rapidly. Generalized approaches, transferable across marine regions, for prioritizing actions to control invasive populations are currently lacking. Here, expert knowledge was elicited to prioritize 11 management actions for controlling 12 model species, distinguished by differences in dispersion capacity, distribution in the area to be managed, and taxonomic identity. Each action was assessed using five criteria (effectiveness, feasibility, acceptability, impacts on native communities, and cost), which were combined in an ‘applicability’ metric. Raising public awareness and encouraging the commercial use of invasive species were highly prioritized, whereas biological control actions were considered the least applicable. Our findings can guide rapid decision-making on prioritizing management options for the control of invasive species especially at early stages of invasion, when reducing managers' response time is critical.
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The blue crab, Callinectes sapidus Rathbun, 1896, is native to the Atlantic coasts of the Americas and globally one of the most highly invasive marine species. In the present study, the species diet and the foraging behaviour was studied in the Thermaikos Gulf and Papapouli Lagoon for the first time. Surveys were undertaken using fyke nets, shore surveys, scuba and snorkelling. Additional data were compiled from systematic interviews with mussel farmers, shellfish traders and fishermen. In both Thermaikos Gulf and Papapouli Lagoon C. sapidus was found to prey on a wide variety of species including economically important molluscs, fishes, and crustaceans, indicating a substantial potential impact on fisheries and aquaculture in the region. Observation showed that over 6 (2009-2014) years, the blue crabs became dominant in Papapouli Lagoon at the expense of the native commercially fished crab Carcinus aestuarii Nardo, 1847 according to fisheries data. Potential management implications are discussed.
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Many invasive alien species highly impact fisheries and aquaculture in European Seas. Despite the fact that mostly negative impacts are reported in the literature, many alien species can have important positive impacts and can restore or secure ecosystem processes and functions, especially in degraded ecosystems. These negative or positive impacts occur through a variety of mechanisms such as blooms of toxic algae, the degradation of important habitats, predation, competition, fouling shellfish, gear or equipment, damage of catch or fishing gear, entanglement in nets, disease transmission, new commodities, new food source for commercial species, biological control of other invasives, and creation of novel habitats. The balance between positive and negative impacts is difficult to assess, and in many regions alien species are considered as a boon to fisheries and aquaculture. In some regions, climate change has caused the loss of temperature-sensitive species. In such cases, alien species can be overall beneficial by fulfilling the lost ecological roles. Further research is needed to conduct proper impact and risk assessments and address the inherent uncertainty.
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There is no sign of saturation in accumulation of alien species (AS) introductions worldwide, additionally the rate of spread for some species has also been shown to be increasing. However, the challenges of gathering information on AS are recognized. Recent developments in citizen science (CS) provide an opportunity to improve data flow and knowledge on AS while ensuring effective and high quality societal engagement with the issue of IAS (Invasive Alien Species). Advances in technology, particularly on-line recording and smartphone apps, along with the development of social media, have revolutionized CS and increased connectivity while new and innovative analysis techniques are emerging to ensure appropriate management, visualization, interpretation and use and sharing of the data. In early July 2018 we launched a European CO-operation in Science and Technology (COST) Action to address multidisciplinary research questions in relation to developing and implementing CS, advancing scientific understanding of AS dynamics while informing decision-making specifically implementation of technical requirements of relevant legislation such as the EU Regulation 1143/2014 on IAS. It will also support the EU biodiversity goals and embedding science within society. The Action will explore and document approaches to establishing a European-wide CS AS network. It will embrace relevant innovations for data gathering and reporting to support the implementation of monitoring and surveillance measures, while ensuring benefits for society and citizens, through an AS CS European network. The Action will, therefore, increase levels of participation and quality of engagement with current CS initiatives, ensuring and evaluating educational value, and improve the value outcomes for potential users including citizens,scientists, alien species managers, policy-makers, local authorities, industry and otherstakeholders.
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This work presents a current (2018) annotated list of marine NIS and cryptogenic species in Greek marine waters. For this purpose, we updated information from previous lists, included new data from several new NIS and cryptogenic records and recent taxonomic studies, and followed current taxonomic modifications for the alien/cryptogenic status of several introduced species. Our extensive literature survey and revisions resulted in the exclusion of 61 species, which were included in previous lists, and the addition of 41 new alien species reported in the 2016-2018 period plus ten old NIS records. The current number of introduced species in Greek waters whose presence is not questionable includes 214 alien species and 62 cryptogenic species. Approximately 80% of the introduced species in Greek Seas consists of the taxa-in decreasing order-Mollusca, Polychaeta, Crustacea, Fishes, and Macroalgae. Nevertheless, a considerable increase in the number of NIS Bryozoa and Ascidiacea was observed within the last decade. Unaided natural dispersal of Lessepsian immigrants (57%) and transport-stowaways (36.7%) are the major pathways of introduction reported for Greek waters. However, with few exceptions (6.8% of species), the confidence level in assigning a pathway was medium to low. Several species reported from adjacent marine areas are expected to reach Greek waters within the next years. The intensification of underwater observations by citizen scientists combined with further research in hot spot areas, understudied habitats and overlooked taxa will significantly raise the number of NIS species in Greek waters. This study can serve as a basis that could greatly benefit from the coordination and harmonization of monitoring initiatives under international, EU and Regional Policies, and the compilation of new data from established monitoring programs, and rapid assessment surveys.
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The human-mediated introduction of marine non-indigenous species is a centuries- if not millennia-old phenomenon, but was only recently acknowledged as a potent driver of change in the sea. We provide a synopsis of key historical milestones for marine bioinvasions, including timelines of (a) discovery and understanding of the invasion process, focusing on transfer mechanisms and outcomes, (b) methodologies used for detection and monitoring, (c) approaches to ecological impacts research, and (d) management and policy responses. Early (until the mid-1900s) marine bioinvasions were given little attention, and in a number of cases actively and routinely facilitated. Beginning in the second half of the 20th century, several conspicuous non-indigenous species outbreaks with strong environmental, economic, and public health impacts raised widespread concerns and initiated shifts in public and scientific perceptions. These high-profile invasions led to policy documents and strategies to reduce the introduction and spread of non-indigenous species, although with significant time lags and limited success and focused on only a subset of transfer mechanisms. Integrated, multi-vector management within an ecosystem-based marine management context is urgently needed to address the complex interactions of natural and human pressures that drive invasions in marine ecosystems.
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In this study we present a list of invasive/potential invasive alien species in the East and South European Network for Invasive Alien Species (ESENIAS) countries with marine borders. The species were classified according to the existing literature and experts’ judgment, as established, casual, invasive and expected. Finally, factsheets were compiled for ten species of high importance based on their expanding/invading character. Of the 160 species comprising the list, 149 were already present in the ESENIAS countries, while eleven were invasive species either present in the Mediterranean or in other European Seas, likely to be recorded in the ESENIAS countries. The majority of the species were of Red Sea/IndoPacific origin (97 species; 60.6%). Italy, Turkey and Greece were the countries with the highest representation of species (159, 152 and 139 species respectively), due to their extended coastline and the number of scholars working on marine invasive species. The highest number of established species was recorded in Turkey (116 species), whereas in Italy and Greece the most numerous species were the “expected” ones (85 and 48 species, respectively). The eastern Adriatic Sea countries (i.e. Albania, Croatia, Montenegro and Slovenia) had generally low numbers of species in this list, many of which are still “expected” to arrive from the neighbouring countries of Greece and Italy. Finally, the most frequently potential pathway was transfer stowaways (ship ballast water: 41 cases; ship hull fouling: 55), whereas unaided spread of Lessepsian immigrants followed (95 cases). This list is intended to serve as an early warning system that through horizon scanning process would assist ESENIAS countries to prioritise invasive alien species, their pathways and the areas of higher likelihood to appear, in order to take management measures. © 2018, Institute of Oceanography and Fisheries. All rights reserved.
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The assessment of impacts of alien species is one of the most critical steps for the prioritisation of policy and management actions and this requires assessment schemes that can compare impacts across different taxa, ecosystems and socio-economic contexts. The Environmental and Socio-Economic Impact Classification of Alien Species (EICAT and SEICAT) are two methodologies that facilitate such comparisons. They classify alien taxa along a 5-level, semi-quantitative scale based on the magnitude of their impacts on the environment and human well-being, respectively. In this study, we applied both protocols to seven invasive marine fishes that that are already considered “high-risk” and have been singled out for monitoring in relation to fisheries in the Mediterranean (Plotosus lineatus, Pterois miles/volitans, Fistularia commersonii, Lagocephalus sceleratus, Siganus rivulatus/Siganus luridus and Saurida lessepsianus). Here, we focus in particular on their socio-economic impacts. By systematically reviewing the published literature and scoring the demonstrated impacts we show that the taxa with the highest environmental impacts (Major) are P. miles/volitans and the two siganids. In contrast, L. sceleratus had the highest socio-economic impact (Moderate) and highest number of impact records. The high and uniform densities of P. lineatus caused widespread, albeit less severe, impacts in the invaded areas. Human activities that are primarily affected by the selected taxa are commercial and recreational fishing and other recreational uses of the sea through impacts on, mainly, material assets and human health. We found significant data gaps regarding the species’ environmental impacts, especially relating to predation, and make specific recommendations for future research. The links between environmental and socio-economic impacts, especially their cultural dimensions, are poorly documented and require novel approaches. Surveys specifically adapted to capture the distinction between socio-economic impact classes would strengthen our confidence in the assessments and better inform prioritisation and decision-making.
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On 7 November 2017 a solitary Indian Ocean humpback dolphin, Sousa plumbea (G. Cuvier, 1829), was sighted in Karavolas Bay, near the port of Heraklion, Crete, Greece. On 14, 16 and 17 November 2017 another humpback dolphin sighting, likely the same individual, was recorded 100 km further west in Souda Bay, Crete. North Crete is the third area where this Lessepsian species was sighted in the Mediterranean Sea after records in Israel in 2001 and in SE Turkey in 2016. To reach the north coast of Crete, the dolphin crossed deep offshore waters that are theoretically incompatible with its typical coastal and shallow habitat. The distance travelled by this dolphin (1000-2330 km depending on the path followed) is the largest movement recorded for this species. Our observations show the potential of humpback dolphins to reach the shallow and coastal waters of the Cyclades in the Aegean Sea, where native populations of the vulnerable common bottlenose dolphin (Tursiops truncatus) and the endangered short-beaked common dolphin (Delphinus delphis) occur.
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Lagocephalus sceleratus is widely distributed in the tropical Indo-West Pacific Ocean as well as the Red Sea, and more recently in the eastern basin of the Mediterranean Sea. L. sceleratus in the Mediterranean has been first recorded from Gökova Bay, southern Aegean Sea in 2003. Since then, this fish invaded rapidly whole Levantine basin, especially western and southern Anatolian coasts, Israel and Lebanon, Greek Islands in the Aegean Sea, especially Crete and Rhodes, Egypt and Libya. The northernmost records of L. sceleratus were given from the Adriatic Sea in both 2012 and 2013. Lately, the fish reached to Algeria and Spain in 2014. Along the Mediterranean, we have just gathered a total of 53 recording locations for L. sceleratus and this compilation work presents the update of the spreading of this invasive species throughout the Mediterranean Sea. Considering the recent locations where L. sceleratus has been recorded, we advise the regional fisheries management authorities that the problem of L. sceleratus is not only problem of the eastern Mediterranean anymore but also all Mediterranean marine ecosystem. Recent developments show that it is time to work on a guideline to monitor its impacts and mitigate the negative effects of this species in the Mediterranean.
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Invasive species from the Suez Canal, also named "Lessepsian species", often have an ecological and financial impact on marine life, fisheries, human well-being and health in the Mediterranean Sea. Among these, the silver-cheeked toad-fish Lagocephalus sceleratus (Gmelin, 1789) has rapidly colonised the eastern Mediterranean basin and is currently moving westwards. This pufferfish has a highly opportunistic behaviour, it attacks fish captured in nets and lines and seriously damages fishing gears and catch. It is a highly-toxic species with no immediate economic value for the Mediterranean market, although it currently represents 4% of the weight of the total artisanal catches. Consequently, the possible effects on Mediterranean fisheries and health require to enhance our understanding about the future geographical distribution of this pufferfish in the whole basin. In this paper, an overall habitat suitability map and an effective geographical spread map for L. sceleratus at Mediterranean scale are produced by using cloud computing-based algorithms to merge seven machine learning approaches. Further, the potential impact of the species is estimated for several Mediterranean Sea subdivisions: The major fishing areas of the Food and Agriculture Organization of the United Nations, the Economic Exclusive Zones, and the subdivisions of the General Fisheries Commission for the Mediterranean Sea. Our results suggest that without an intervention, L. sceleratus will continue its rapid spread and will likely have a high impact on fisheries. The presented method is generic and can be applied to other invasive species. It is based on an Open Science approach and all processes are freely available as Web services.
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The mitochondrial genetic diversity, distribution and invasive potential of multiple cryptic OTUs of the red invasive seaweed Asparagopsis were assessed by studying introduced Mediterranean and Hawaiian populations. Invasive behavior of each Asparagopsis OTU was inferred from phylogeographic reconstructions, past historical demographic dynamics, recent range expansion assessments and future distributional predictions obtained from demographic models. Genealogical networks resolved Asparagopsis gametophytes and tetrasporophytes into four A. taxiformis and one A. armata cryptic OTUs. Falkenbergia isolates of A. taxiformis L3 were recovered for the first time in the western Mediterranean Sea and represent a new introduction for this area. Neutrality statistics supported past range expansion for A. taxiformis L1 and L2 in Hawaii. On the other hand, extreme geographic expansion and an increase in effective population size were found only for A. taxiformis L2 in the western Mediterranean Sea. Distribution models predicted shifts of the climatically suitable areas and population expansion for A. armata L1 and A. taxiformis L1 and L2. Our integrated study confirms a high invasive risk for A. taxiformis L1 and L2 in temperate and tropical areas. Despite the differences in predictions among modelling approaches, a number of regions were identified as zones with high invasion risk for A. taxiformis L2. Since range shifts are likely climate-driven phenomena, future invasive behavior cannot be excluded for the rest of the lineages.
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A review of the scientific literature and an analysis of unpublished material identified ~ 50 possible alien molluscs from Greece, four of which were newly reported here. Records of ~ 100 additional taxa, which would strongly inflate the alien species numbers, were excluded. Among the ~ 50 candidate species, 43 were confirmed as alien and 12 as cryptogenic. Twenty-nine alien species were considered established, and four deemed invasive. Our results are consistent with the position of Greece in the east-west Mediterranean gradient, as well as the Aegean marine environment. The contribution of well-informed citizen scientists appears to be crucial to our overall knowledge of alien molluscan biotas because only 12 alien taxa were detected during formal research projects, while 31 were first found by amateurs. No molluscan introductions were confirmed from Greece pre-1960s, and subsequent periods had variable numbers of introductions, ranging from 0 (1976–1980) to 9.5 (2006–2010). The areas with the highest alien species concentrations were the Saronikos Gulf, near the Piraeus port area, and the Dodekanisa, near the Levantine coastline. Despite a general decline in taxonomic expertise and in local knowledge, we show that these are still needed when compiling and analyzing alien species inventories that subsequently influence policy and management decisions.
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The European Union’s Marine Strategy Framework Directive (MSFD) aims to adopt integrated ecosystem management approaches to achieve or maintain “Good Environmental Status” for marine waters, habitats and resources, including mitigation of the negative effects of non-indigenous species (NIS). The Directive further seeks to promote broadly standardized monitoring efforts and assessment of temporal trends in marine eco- system condition, incorporating metrics describing the distribution and impacts of NIS. Accomplishing these goals will require application of advanced tools for NIS surveillance and risk assessment, particularly given known challenges associated with surveying and monitoring with traditional methods. In the past decade, a host of methods based on nucleic acids (DNA and RNA) analysis have been developed or advanced that promise to dramatically enhance capacity in assessing and managing NIS. However, ensuring that these rapidly evolving approaches remain accessible and responsive to the needs of resource managers remains a challenge. This paper provides recommendations for future development of these genetic tools for assessment and management of NIS in marine systems, within the context of the explicit requirements of the MSFD. Issues considered include technological innovation, methodological standardization, data sharing and collaboration, and the critical im- portance of shared foundational resources, particularly integrated taxonomic expertise. Though the re- commendations offered here are not exhaustive, they provide a basis for future intentional (and international) collaborative development of a genetic toolkit for NIS research, capable of fulfilling the immediate and long term goals of marine ecosystem and resource conservation.
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Following aquarium releases, invasive lion shes have colonized large areas of the Caribbean and western Atlantic, resulting in an immense ecological damage. The early stages of that invasion are poorly known. Indeed, a lag of time between the introduction and detection often preclude genetic characterization of that crucial phase. With elevated awareness, the recent invasion of Pterois miles was quickly detected in the Mediterranean Sea. We hereby show that the very rst individuals establishing populations in the Mediterranean Sea display haplotypes that nest within the large genetic diversity of Red Sea individuals, thus indicating an invasion via the Suez Canal. We also show that only two haplotypes are detected in the Mediterranean Sea, suggesting that few individuals may have been involved in the invasion. Thus, we conclude that the Mediterranean invasion is the result of a movement of individuals from the Red Sea, rather than from other means, and that low genetic diversity does not seem to have a negative e ect on the success and spread of lion sh into the Mediterranean Sea.
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Invasive Alien Species (IAS) are a growing threat to Europe's biodiversity. The implementation of European Union Regulation on IAS can benefit from the involvement of the public in IAS recording and management through Citizen Science (CS) initiatives. Aiming to tackle issues related with the use of CS projects on IAS topics, a dedicated workshop titled “Citizen Science and Open Data: a model for Invasive Alien Species in Europe” was organized by the Joint Research Centre (JRC) and the European Cooperation in Science and Technology (COST Association). Fifty key stakeholders from all Europe, including two Members of the European Parliament, attended the workshop. With a clear focus on IAS, the workshop aimed at addressing the following issues: a) CS and policy, b) citizen engagement, and c) CS data management. Nine short presentations provided input on CS and IAS issues. Participants discussed specific topics in several round tables (“world café” style) and reported back their conclusions to the audience and full assembly moderated discussions. Overall, the workshop enabled the sharing of ideas, approaches and best practices regarding CS and IAS. Specific opportunities and pitfalls of using CS data in the whole policy cycle for IAS were recognized. Concerning the implementation of the IAS Regulation, CS data could complement official surveillance systems, and contribute to the early warning of the IAS of Union concern after appropriate validation by the Member States’ competent authorities. CS projects can additionally increase awareness and empower citizens. Attendees pointed out the importance for further public engagement in CS projects on IAS that demonstrate specific initiatives and approaches and analyze lessons learned from past experiences. In addition, the workshop noted that the data gathered from different CS projects on IAS are fragmented. It highlighted the need for using an open and accessible platform to upload data originating from CS sources or to mirror validated data into a single, easy-to-use web service, in line with the EU Open Science Strategic Priority. The workshop provided ten key recommendations of best practices for CS projects on IAS, addressed to researchers, policy makers and implementing authorities, indicating future research and policy directions and opportunities.
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A circulation model is coupled to a Lagrangian particle-tracking model to simulate the transport floating litter particles in the Aegean Sea, Greece (Eastern Mediterranean). Considering different source regions and release dates, simulations were carried out to explore the fate and distribution of floating litter over 1990–2009, taking into account the seasonal and interannual variability of surface circulation. Model results depicted recurrently high concentrations of floating litter particles in the North Aegean plateau, the Saronikos Gulf, and along Evia and Crete islands. Modeled transport pathways of floating litter demonstrated that source regions are interconnected, with Saronikos Gulf being a main receptor of litter from other sources. Notably higher percent of litter exit (~35%) than enter the model domain (~7%) signified that Aegean Sea seems to act as a source rather than receptor of floating litter pollution in the Eastern Mediterranean Sea. Beached litter was found around 10%, mostly located in the western part of the Aegean Sea. This is the first modeling study to explore the transport of floating marine litter in Greek waters.
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The book presents an analysis of the ecological, economic and social threats posed by the introduction and spread of non-native species. It provides a comprehensive description of impacts of non-native species from all five kingdoms of life across all ecosystems of the world. New insights into the impacts arising from biological invasions are generated through taking an ecosystem services perspective. This work highlights that management of biological invasions is needed not only to sustain biodiversity and the environment, but also to safeguard productive sectors such as agriculture, forestry and fisheries, as well as to preserve human health and well-being.
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Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.
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Even during the current biodiversity crisis, reports on population collapses of highly abundant, non-harvested marine species were rare until very recently. This is starting to change, especially at the warm edge of species' distributions where populations are more vulnerable to stress. The Levant basin is the southeastern edge of distribution of most Mediterranean species. Coastal water conditions are naturally extreme, and are fast warming, making it a potential hotspot for species collapses. Using multiple data sources, I found strong evidence for major, sustained, population collapses of two urchins, one large predatory gastropod and a reef-building gastropod. Furthermore, of 59 molluscan species once-described in the taxonomic literature as common on Levant reefs, 38 were not found in the present-day surveys, and there was a total domination of non-indigenous species in molluscan assemblages. Temperature trends indicate an exceptional warming of the coastal waters in the past three decades. Though speculative at this stage, the fast rise in SST may have helped pushing these invertebrates beyond their physiological tolerance limits leading to population collapses and possible extirpations. If so, these collapses may indicate the initiation of a multi-species range contraction at the Mediterranean southeastern edge that may spread westward with additional warming.
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This contribution forms part of a series of collective articles published regularly in Mediterranean Marine Science that report on new biodiversity records from the Mediterranean basin. The current article presents 51 geographically distinct records for 21 taxa belonging to 6 Phyla, extending from the western Mediterranean to the Levantine. The new records, per country, are as follows: Spain: the cryptogenic calcareous sponge Paraleucilla magna is reported from a new location in the Alicante region. Algeria: the rare Atlanto-Mediterranean bivalve Cardium indicum is reported from Annaba. Tunisia: new distribution records for the Indo-Pacific lionfish Pterois miles from Zembra Island and Cape Bon. Italy: the ark clam Anadara transversa is reported from mussel cultures in the Gulf of Naples, while the amphipod Caprella scaura and the isopods Paracerceis sculpta and Paranthura japonica are reported as associated to the –also allochthonous–bryozoan Amathia verticillata in the Adriatic Sea; in the latter region, the cosmopolitan Atlantic tripletail Lobotes surinamensisis also reported, a rare finding for the Mediterranean. Slovenia: a new record of the non-indigenous nudibranch Polycera hedgpethi in the Adriatic. Greece: several new reports of the introduced scleractinian Oculina patagonica, the fangtooth moray Enchelycore anatina, the blunthead puffer Sphoeroides pachygaster (all Atlantic), and the lionfish Pterois miles (Indo-Pacific) suggest their ongoing establishment in the Aegean Sea; the deepest bathymetric record of the invasive alga Caulerpa cylindracea in the Mediterranean Sea is also registered in the Kyklades, at depths exceeding 70 m. Turkey: new distribution records for two non indigenous crustaceans, the blue crab Callinectes sapidus (Atlantic origin) and the moon crab Matuta victor (Indo-Pacific origin) from the Bay of Izmir and Antalya, respectively; in the latter region, the Red Sea goatfish Parupeneus forsskali, is also reported. Lebanon: an array of records of 5 alien and one native Mediterranean species is reported by citizen-scientists; the Pacific jellyfish Phyllorhiza punctata and the Indo-Pacific teleosteans Tylerius spinosissimus, Ostracion cubicus, and Lutjanus argentimaculatus are reported from the Lebanese coast, the latter notably being the second record for the species in the Mediterranean Sea since 1977; the native sand snake-eel Ophisurus serpens, rare in the eastern Mediterranean, is reported for the first time from Lebanon, this being its easternmost distribution range; finally, a substantial number of sightings of the lionfish Pterois miles further confirm the current establishment of this lessepsian species in the Levantine.
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Significance Invasive species represent a largely unquantified threat to ecosystem services. Although investment in the prevention of species invasions may sustain ecosystem services, these effects of invasions are rarely measured in monetary terms useful to decision makers. We quantify the economic damages of the degradation of an important ecosystem service, water clarity, caused by invasion by the spiny water flea. We find that the costs of restoring this service, US86.5millionUS86.5 million–US163 million, are comparable with the willingness to pay for the service itself: US$140 million. This finding highlights the severity of invasive species’ impacts when their damages to ecosystem services are considered. Costs of invasive species’ secondary spread aggregated across many invasive species and ecosystem services may be large.
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Aim: To develop a standardized, quantitative method for mapping cumulative impacts of invasive alien species on marine ecosystems. Location: The methodology is applied in the Mediterranean Sea but is widely applicable. Methods: A conservative additive model was developed to account for the Cumulative IMPacts of invasive ALien species (CIMPAL) on marine ecosystems. According to this model, cumulative impact scores are estimated on the basis of the distributions of invasive species and ecosystems, and both the reported magnitude of ecological impacts and the strength of such evidence. In the Mediterranean Sea case study, the magnitude of impact was estimated for every combination of 60 invasive species and 13 habitats, for every 10x10 km cell of the basin. Invasive species were ranked based on their contribution to the cumulative impact score across the Mediterranean. Results: The CIMPAL index showed strong spatial heterogeneity. Spatial patterns varied depending on the pathway of initial introduction of the invasive species in the Mediterranean Sea. Species introduced by shipping gave the highest impact scores and impacted a much larger area than those introduced by aquaculture and the Suez Canal. Overall, invasive macroalgae had the highest impact among all taxonomic groups. These results represent the current best estimate of the spatial variation in impacts of invasive alien species on ecosystems, in the Mediterranean Sea. Main Conclusions: A framework for mapping cumulative impacts of invasive alien species was developed. The application of this framework in the Mediterranean Sea provided a baseline that can be built upon with future improved information. Such analysis allows the identification of hotspots of highly impacted areas, and prioritization of sites, pathways, and species for management actions.
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