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Specimens of the three known Greek crayfish species, Astacus astacus (Linnaeus, 1758), Astacus leptodactylus Eschscholtz, 1823 and Austropotamobius torrentium (Schrank, 1803), were collected from seven localities in Greece and were examined for the epibionts of Branchiobdella sp. (Annelida: Clitellata) and the aelosomatid Hystricosoma chappuisi Michaelsen, 1926 and the copepod Nitocrella divaricata (Chappuis, 1923). As a result, three branchiobdellid species, Branchiobdella parasita (Braun, 1805), Branchiobdella pentodonta Whitman, 1882 and Branchiobdella hexodonta Grüber, 1883 were found. This was also the first report of B. pentodonta from Greece as well as H. chappuisi, the latter being found on crayfish gills in one of the localities investigated. Moreover, the current work represents the first documentation of the presence of B. parasita and B. hexodonta in several localities in Greece.

The narrow-clawed crayfish Astacus leptodactylus Eschscholtz, 1823, is widely distributed in eastern European and western Asian countries. However, species presence in Greece was documented only by limited museum conserved specimens dating back to 1893. Recently (May 2005) several crayfish were captured in the Evros River (close to city of Didimotiho) and these were identified as A. leptodactylus. The present work confirms the presence of A. leptodactylus in the Evros River still hundred and twelve years later and introduces the possibility of A. leptodactylus being indigenous to Greece.

Freshwater crayfish are found in 20 out of 53 Prefectures of Greece (38%) and they form isolated populations in relatively pristine water bodies. Three indigenous crayfish species (ICS) occur in Greek waters: Astacus astacus, Astacus leptodactylus and Austropotamobius torrentium, as well as one non-indigenous crayfish species (NICS) Pacifastacus leniusculus. Greece represents probably the most southern natural distribution limit for A. astacus and A. torrentium in the world. Concerning NICS, P. leniusculus was imported, at least in two cases, from Sweden and Germany during the early and late 1980’s respectively, in order to replace A. astacus stocks impoverished by human activities. Recently, Cherax quadricarinatus specimens have been seen in a restaurant’s aquarium and pet shop, raising fears about uncontrolled imports of alien pet species. During our 2004-2005 survey, we found that P. leniusculus established not only a thriving population in the artificial Lake Agra (Region of Central Macedonia), but also they co-occur with A. torrentium there. It is also suspected that A. astacus may co-occur there with these two species, as three large male specimens of A. astacus were caught in a creek close to the lake. Concerning A. leptodactylus, there are three sets of preserved samples from the River Evros (state border with Turkey in Thrace today), dated back to the 19th century, but no recent information about occurrence was available. But the accidental catch of six specimens of A. leptodactylus during May 2005 in that river re-documented the occurrence of the species. Finally, a deep-dwelling A. torrentium population with bluish legs was found to live in depths up to 7,800 meters inside the Aggitis Cave in northeastern Greece. There is a lot of work to be done on geographic distribution, population dynamics, genetics, reproduction, nutrition, diseases, and farming of crayfish species in Greece. Moreover, several actions should be undertaken to reform the existing legislation, in order to protect the native species and their habitats.

Some fish species exhibit a biochemical response to low winter temperatures. For example, after a period of cold acclimation, an increase in enzyme activity occurs. This can result in at least partial compensation in the rate of biochemical reactions of aerobic metabolism. Sea bass (Dicentrarchus labrax L. 1758) is a commercially important fish for the Mediterranean mariculture industry, which can grow satisfactorily in both freshwater (FW) and seawater (SW) conditions. The purpose of the present work was to evaluate the survival and growth of sea bass in FW earthen ponds. The experiment was initiated in September 2003 in order to avoid the water temperature highs during spring-summer and allow several weeks for acclimation before the winter temperature lows. Fish growth occurred for several months, but by the end of December 2003, ambient water temperature reached levels below 5°C and mass mortality occurred. The capacity of sea bass for thermal compensation was evaluated by monitoring the activity of cytochrome c oxidase (CCO) of red axial muscle. The activity of CCO initially increased from 6.4 (±0.98) in September (ambient water temperature 19°C) to 10.4 (±1.49) in October (ambient temperature 15.4°C), but decreased again to 8.8 (±1.45) in November (ambient temperature 12.3°C). A similar trend was exhibited by the glycolytic enzyme lactate dehydrogenase in white muscle. The results do not indicate a capacity of thermal acclimation in FW ponds with low temperature (<13°C) for sea bass. Evidently, seasonally extremely low temperature is a challenge for the production of sea bass. [ABSTRACT FROM AUTHOR]

Under the increasing threat to native ecosystems posed by non-native species invasions, there is an urgent need for decision support tools that can more effectively identify non-native species likely to become invasive. As part of the screening (first step) component in non-native species risk analysis, decision support tools have been developed for aquatic and terrestrial organisms. Amongst these tools is the Weed Risk Assessment (WRA) for screening non-native plants. The WRA has provided the foundations for developing the first-generation WRA-type Invasiveness Screening Kit (ISK) tools applicable to a range of aquatic species, and more recently for the second-generation ISK tools applicable to all aquatic organisms (including plants) and terrestrial animals. Given the most extensive usage of the latter toolkits, this study describes the development and application of the Terrestrial Plant Species Invasiveness Screening Kit (TPS-ISK). As a second-generation ISK tool, the TPS-ISK is a multilingual turnkey application that provides several advantages relative to the WRA: (i) compliance with the minimum standards against which a protocol should be evaluated for invasion process and management approaches; (ii) enhanced questionnaire comprehensiveness including a climate change component; (iii) provision of a level of confidence; (iv) error-free computation of risk scores; (v) multilingual support; (vi) possibility for across-study comparisons of screening outcomes; (vii) a powerful graphical user interface; (viii) seamless software deployment and accessibility with improved data exchange. The TPS-ISK successfully risk-ranked five representative sample species for the main taxonomic groups supported by the tool and ten angiosperms previously screened with the WRA for Turkey. The almost 20-year continuous development and evolution of the ISK tools, as opposed to the WRA, closely meet the increasing demand by scientists and decision-makers for a reliable, comprehensive, updatable and easily deployable decision support tool. For terrestrial plant screening, these requirements are therefore met by the newly developed TPS-ISK., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Even though the ecological impacts of invasive alien species (IAS) have been well studied, social aspects of IAS in freshwater ecosystems are still poorly explored. This study aimed to assess the perceptions associated with non-indigenous freshwater fish species (NIFS) among environmental-related professional and non-professional stakeholders in a Mediterranean country that displays high levels of fish species endemism, by using a questionnaire survey approach. Overall, 203 individuals participated, from which, the majority (n = 144) were related to environmental sciences. Most of the respondents perceived NIFS to be a threat of national importance, possibly attributed to the emotional effect of the term non-indigenous (conceived as intruder). However, NIFS were indicated as the least important threat affecting aquatic ecosystems when compared with other pressures. This contrasting perception could be explained by the fact that broad-scale impacts (i.e., climate change) exert stronger reactions compared to NIFS. Interestingly, non-professionals were more successful in identifying NIFS and native species compared to professionals, however both indicated low overall identification success. The majority of the respondents, both professionals and non-professionals, considered that: (a) the official authorities do not implement actions for NIFS management, (b) government spending should be increased to manage NIFS even if it should be reduced for other needs, and (c) early detection is the best way to manage NIFS. The establishment of a nationwide network consisting of all related stakeholders on NIFS issues, aiming to public awareness and preventive management actions to limit the spread and impacts of NIFS should be set as a priority., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The threat posed by invasive non-native species worldwide requires a global approach to identify which introduced species are likely to pose an elevated risk of impact to native species and ecosystems. To inform policy, stakeholders and management decisions on global threats to aquatic ecosystems, 195 assessors representing 120 risk assessment areas across all six inhabited continents screened 819 non-native species from 15 groups of aquatic organisms (freshwater, brackish, marine plants and animals) using the Aquatic Species Invasiveness Screening Kit. This multi-lingual decision-support tool for the risk screening of aquatic organisms provides assessors with risk scores for a species under current and future climate change conditions that, following a statistically based calibration, permits the accurate classification of species into high-, medium- and low-risk categories under current and predicted climate conditions. The 1730 screenings undertaken encompassed wide geographical areas (regions, political entities, parts thereof, water bodies, river basins, lake drainage basins, and marine regions), which permitted thresholds to be identified for almost all aquatic organismal groups screened as well as for tropical, temperate and continental climate classes, and for tropical and temperate marine ecoregions. In total, 33 species were identified as posing a 'very high risk' of being or becoming invasive, and the scores of several of these species under current climate increased under future climate conditions, primarily due to their wide thermal tolerances. The risk thresholds determined for taxonomic groups and climate zones provide a basis against which area-specific or climate-based calibrated thresholds may be interpreted. In turn, the risk rankings help decision-makers identify which species require an immediate 'rapid' management action (e.g. eradication, control) to avoid or mitigate adverse impacts, which require a full risk assessment, and which are to be restricted or banned with regard to importation and/or sale as ornamental or aquarium/fishery enhancement., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Purpose: Fish is a delicate and valuable source of protein, and aquaculture is expected to provide the required amount of fish needed at reasonable prices. Packaging is a vital stage to preserve hygiene, quality and freshness of aquaculture products. The purpose of this study was to identify environmental hotspots in farmed seabass and meagre during the packaging stage and to examine scenarios for reducing environmental impacts, aiming at greenhouse gas neutrality., Methods: The life cycle assessment method was applied for the first time at three packaging plants of farmed seabass and meagre in western Greece, in order to assess their environmental impacts, taking into account the amount of electricity, expanded polystyrene, and other plastic and packaging materials needed. Moreover, different scenarios were designed involving the energy mix/alternative sources, recycling and reuse of packaging materials, and the replacement of standard polystyrene boxes and wooden pallets, in order to suggest environmentally friendly improvements in the packaging process., Results and Discussion: Conventional operation of seabass and meagre packaging plants requires significant amounts of energy and packaging materials. In fact, electricity, boxes and pallets were documented as the main contributors to most of the environmental impact indicators. Seabass packaging had a slightly lower overall environmental impact compared to meagre, due to its smaller market size. Impact minimization scenarios resulted in various degrees of reduction of environmental burdens in both species; however, near-zero GHG emissions were achieved when energy from photovoltaic panels and recycling/reuse of packaging materials were combined with the use of non-fossil-based boxes and recyclable pallets. Such readily applicable adjustments to the conventional operation of packaging plants would contribute to overall environmental sustainability and to better consumer acceptability of the final product., Conclusions: In a nutshell, the life cycle assessment method proved to be a valuable tool for assessing the environmental performance of Mediterranean aquaculture packaging processes. Moreover, it served to identify critical factors directly related to the EU GHG neutrality target. Accordingly, environmentally friendly decision-making/strategic management in the farmed fish packaging sector will inevitably rely on alternative energy sources, recycling of packaging materials, and use of recyclable corrugated board boxes or similar non-fossil-based materials., (© The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2021.)