Developing policy-relevant river fish monitoring in Greece: Insights from a nation-wide survey

A wide-ranging river fish survey was executed in the summer of 2009 as part of the preparatory actions for the establishment of a monitoring programme for the EU Water Framework Directive (WFD). This was the first extensive electrofishing campaign for WFD standardized bioassessment in Greece and the experience and insights gained are used here to provide a review of fish-based assessment conditions and requirements in this country. The survey sampled 85 sites on 25 rivers throughout mainland Greece, collecting 70 species of freshwater fish. Quantitative site-based assemblage data is used for taxonomic and ordination analyses revealing a strong biogeographic regionalization in the distribution of the ichthyofauna. The structural and spatial organisation of the fish fauna through the use of species-level and community-level data analyses is explored in three ecoregions where data was deemed sufficient. Transitions in community taxonomic composition among ecoregions were abrupt and concordant with geographical barriers and reflect the influence of historical biogeographic processes. Community-based analysis revealed a substantial degree of variation in quantitative attributes of the fish assemblages among ecoregions. Key conclusions of this work are: (a) the fish-based bioassessment system must be regionalised to reflect biogeographic variation, (b) high faunal heterogeneity among ecoregions (taxonomic, structural), and to a lower degree among basins, constrain the transferability of bioassessment metrics and indices created for explicit regions to other regional frameworks; (c) faunal depauperation in most of the study areas reduce the utility of functional bioassessment metrics and also limits the utilization of rare species and the applicability of the classical form of the “Index of Biotic Integrity” concept. Recommendations to cope with these problems are discussed

First confirmed record of an established population of sailfin molly, Poecilia latipinna (Actinopterygii: Cyprinodontiformes: Poeciliidae), in Europe

The ornamental aquarium trade has been responsible for several introductions of non-indigenous species in freshwater ecosystems. This report confirms the presence of an established non-native molly population in a tectonic, brackish, geothermal lagoon located in Greece (Lake Vouliagmeni near Athens). The Vouliagmeni molly was positively identified as the true sailfin molly, Poecilia latipinna (Lesueur, 1821), using the number of scales around the caudal peduncle as the principal diagnostic character within the sailfin molly species complex. To our knowledge, this is the first documented record of an established sailfin molly population in European waters

Ornamental fish in pet stores in Greece: a threat to biodiversity?

The aquarium trade has been recognized as an important pathway for the introduction of invasive species around the world. This study investigates the availability of ornamental fish species in ten large-size, centrally positioned aquarium stores that control a large share of imports and the Hellenic market chain, and aims to provide a provisional checklist on the aquarium fish trade in Greece. For each recorded species, additional data concerning various aspects (e.g. natural environment, native range, established as aliens, conservation status and threats to humans) were collected from Fishbase, the IUCN red list and scientific literature. Overall, 326 fish species belonging to 64 families were reported according to the store labels. The majority of the species recorded were freshwater (66%), originating mainly from South America and Asia, while most of the marine species (26%) had primarily an Indo-Pacific native distribution. Among the freshwater fishes, Cichlidae and Cyprinidae were the dominant families with 64 and 27 species, respectively, while the family Acanthuridae dominated within the marine fishes with ten species. The vast majority of both freshwater and marine species (>90%) were tropical. Concerning the presence of alien species, 62 ornamental species have been established outside their natural range, with 22 of them positively confirmed as aliens in European waters. Moreover, 25 species were listed in the critically endangered (CR), endangered (EN) and vulnerable (VU) categories of the IUCN red list. Even more surprisingly, for 192 species recorded, data were missing to assign their conservation status or had not been assessed at all. Finally, the majority of the species (84%) were harmless to humans. However, 35 species (11%) were recognised as potentially harmful (i.e. venomous, ciguatera poisoning, traumatogenic) and two were found to be poisonous if consumed. In conclusion, the aquarium fish sector in Greece is practically uncontrolled given the presence of: a) threatened species, b) species potentially harmful to humans and c) species capable of establishing non-indigenous populations, if released into the wild