Distribution patterns of fish assemblages in an Eastern Mediterranean intermittent river

The distribution patterns of fish assemblages within streams can provide insights for river type classifications and may warrant specific conservation actions. However, there is limited knowledge of how fish assemblages assort along a longitudinal axis in Mediterranean intermittent streams. Patterns in spatial and temporal distribution of fish communities were analysed in a Mediterranean intermittent river (Evrotas River) located in Southern Greece, hosting three endemic range restricted species of high conservation concern, during the period 2007−2009, with 80% of the river’s total length desiccating in the 2007 and 2008 droughts. The general trend was an increase in fish density and species richness along an upstream-downstream gradient. Fish assemblages from upstream to downstream were characterized by a decrease of the most rheophilic species (Squalius keadicus) and an increase of the most stagnophilic species (Tropidophoxinellus spartiaticus). Three river segments, characterized by a high degree of homogeneity were delineated. Habitat and environmental preferences for the studied fish species were identified, with elevation and low flowing habitats being the most important environmental factors affecting fish distribution patterns. The current study provides evidence that even in an intermittent river an assemblage pattern following a longitudinal gradient can be identified, mainly due to the lack of instream barriers that allows recolonization after flow resumption

Nationwide tracing of two top freshwater fish invaders in Greece using environmental DNA sampling

Alien fish invasions are causing devastating impacts on native freshwater fauna; thus, rigorous, non-invasive and cost-effective biomonitoring of lotic and lentic freshwaters to design and implement appropriate prevention and control measures is now a priority. In this study, we used a species-specific qPCR eDNA assay to monitor two of the most invasive fish species (Gambusia holbrooki and Pseudorasbora parva) in 15 river basins of Greece and validated these results with conventional fish sampling as well as existing field sampling data. Our monitoring provided new records of invasive species indicating basins for rigorous future monitoring and possible eradication attempts. The eDNA proved more sensitive as a detection tool (56% detection rate) compared to conventional electrofishing (50% detection rate) for G. holbrooki. In contrast, it proved less sensitive for detecting P. parva (38% accuracy) compared to electrofishing (44% accuracy), as evident by the two locations where the eDNA failed to detect the target species. Our study illustrates the potential of the eDNA method for regular, standardised monitoring of riverine habitats for invasive fish species by local managers for early detection. Finally, we discuss the application of eDNA in management interventions for identifying invasive species’ hotspots for management prioritisation, for early detection of invaders and for the monitoring of eradication/control actions

ELNAIS: A collaborative network on Aquatic Alien Species in Hellas (Greece)

ELNAIS is a dynamic online information platform aiming to collect and report spatial information on Aquatic Alien Species in Greek waters. It covers freshwater, marine and estuarine waters, including not only established aliens but also casual records and cryptogenic species. The ELNAIS system includes: News, List of Greek experts, Literature of findings in Greece, List of species with information on their first introduction date and source as well as photos and distribution maps. Data providers are the scientific community (publications, grey literature, and databases) as well as citizen scientists. ELNAIS provides a useful tool towards national obligations and commitments under both the European and global frameworks in respect to Non Indigenous Species (CBD, WFD, MSFD).JRC.H.1-Water Resource

A global review and meta-analysis of applications of the freshwater Fish Invasiveness Screening Kit

The freshwater Fish Invasiveness Screening Kit (FISK) has been applied in 35 risk assessment areas in 45 countries across the six inhabited continents (11 applications using FISK v1; 25 using FISK v2). The present study aimed: to assess the breadth of FISK applications and the confidence (certainty) levels associated with the decision-support tool’s 49 questions and its ability to distinguish between taxa of low-to-medium and high risk of becoming invasive, and thus provide climate-specific, generalised, calibrated thresholds for risk level categorisation; and to identify the most potentially invasive freshwater fish species on a global level. The 1973 risk assessments were carried out by 70 + experts on 372 taxa (47 of the 51 species listed as invasive in the Global Invasive Species Database www.iucngisd.org/gisd/), which in decreasing order of importance belonged to the taxonomic Orders Cypriniformes, Perciformes, Siluriformes, Characiformes, Salmoniformes, Cyprinodontiformes, with the remaining ≈ 8% of taxa distributed across an additional 13 orders. The most widely-screened species (in decreasing importance) were: grass carp Ctenopharyngodon idella, common carp Cyprinus carpio, rainbow trout Oncorhynchus mykiss, silver carp Hypophthalmichthys molitrix and topmouth gudgeon Pseudorasbora parva. Nine ‘globally’ high risk species were identified: common carp, black bullhead Ameiurus melas, round goby Neogobius melanostomus, Chinese (Amur) sleeper Perccottus glenii, brown bullhead Ameiurus nebulosus, eastern mosquitofish Gambusia holbrooki, largemouth (black) bass Micropterus salmoides, pumpkinseed Lepomis gibbosus and pikeperch Sander lucioperca. The relevance of this global review to policy, legislation, and risk assessment and management procedures is discussed

Figure 2 in Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus?

Figure 2. Recent photograph of adult male S. fluviatilis specimen deposited in 1909 from Cyprus. Natural History Museum, London, UK.Published as part of Zogaris, Stamatis, Maclaine, James, Koutsikos, Nicholas & Chatzinikolaou, Yorgos, 2014, Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus?, pp. 347-357 in Journal of Natural History 49 (5) on page 351, DOI: 10.1080/00222933.2013.836761, http://zenodo.org/record/400408

Figure 3 in Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus?

Figure 3. Principal components analysis ordination on the abiotic descriptors of 22 Mediterranean islands, including the 10 islands where Salaria fluviatilis is present (P) with black dots. The axes refer to island areal size and distance to mainland; and the numbers refer to the island numbers as in Table 2.Published as part of Zogaris, Stamatis, Maclaine, James, Koutsikos, Nicholas & Chatzinikolaou, Yorgos, 2014, Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus?, pp. 347-357 in Journal of Natural History 49 (5) on page 352, DOI: 10.1080/00222933.2013.836761, http://zenodo.org/record/400408

Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus?

Zogaris, Stamatis, Maclaine, James, Koutsikos, Nicholas, Chatzinikolaou, Yorgos (2014): Does the river blenny Salaria fluviatilis (Asso, 1801) (Actinopterygii: Perciformes) still survive on the Mediterranean island of Cyprus? Journal of Natural History 49 (5): 347-357, DOI: 10.1080/00222933.2013.83676

Global distribution and climatic match of a highly traded ornamental freshwater fish, the sailfin molly Poecilia latipinna (Lesueur, 1821)

Predicting alien species' establishment through climate matching may inform management actions preventing future invasions. The aim of the current study was to evaluate the climate match of the sailfin molly (Poecilia latipinna) worldwide, with emphasis on Europe and the Mediterranean. A literature review indicated that the species presents a total of 100 non-indigenous occurrences in 29 countries worldwide. Predominantly, it has been introduced within tropical/subtropical climatic zones, where it is usually clustered near ornamental trade centers and malaria affected areas. Overall, sailfin molly distribution reflects a warm-stenothermic tolerance, however, there are validated populations outside the subtropical belt in geothermally heated water bodies. Its invasion potential, assessed by Climatch tool, indicated a low environmental match (5% of the assessed sites) within Europe, whereas in the Mediterranean this rose to 60%, though the species is recorded only at one location. This poor match of the model's output may reflect its inability to take into account local environmental filters. Intolerance to prolonged temperature drops appears to be the leading factor constraining sailfin molly establishment in Europe. Additional constrains on its successful invasion, i.e. specialized habitat requirements, limited propagule supply or reduced reproductive fitness, due to breeding manipulations of commercially available strains, are discussed