Freshwater fishes of Greece: Their biodiversity, fisheries and habitats

Abstract

In the present work, we review the current state of knowledge and research trends on freshwater fishes of Greece to assess a) the status of fish populations and their habitats; b) the state and priorities of fisheries science and legislation; c) priority gaps and needs in freshwater fish habitat management; and d) future strategies for freshwater fishes and aquatic resources. Freshwater fish fauna of Greece currently consists of 135 taxa including diadromous and introduced species. The taxonomy of some taxa is unclear. The distribution and origin of freshwater fishes, especially endemics, has been attributed mainly to the geological history of the country. Commercial fishing in inland waters is conducted mainly in 32 natural or artificial water systems. The total annual commercial catch for the 1988–2000 period ranged from 1,950 t in 1988 to 1,810 t in 2000 with a mean annual catch of about 1,500 t. The major part of inland catches comes from lakes, while catches from rivers are of minor importance. Aquaculture contributes greatly to the total production of freshwater fishes. The total annual aquaculture production for the period 1988–2000 ranged from 2,638 t to 3,656 t with a mean annual production of 2,832 t, 1.33 to 2.02 times higher than the traditional inland catches. Due to human activities, Greece has lost 75% of its wetland area since 1900. Today, the pressures upon the surface freshwater resources are moderate with the exception of some systems where human intervention is intense, leading to species extirpations from their type localities. Recently, surface waters have been classified under the auspices of the European Union Water Framework Directive where fishes have an essential role as indicators of the ecological integrity of running waters. Under this concept, there is an increasing emphasis on gathering biological data, to serve a broad-spectrum of environmental objects and plans such as the protection of endangered and threatened species. However, to date effective management and conservation of freshwater fishes and fisheries have not been much considered in the management of freshwaters of Greece. Existing plans for managing aquatic inland resources primarily focus on water usage and do not include specific, enforceable monitoring and management objectives, conservation actions, and control measures for aquatic habitats and fish communities, including endangered and threatened fishes. It is concluded that future efforts need to be directed to severely endangered or nearly extinct species. Furthermore, the creation of GIS-based databases for incorporating all the information on species, habitats and genetic diversity should be addressed under the guiding principle of conserving aquatic biodiversity.

The freshwater ichthyofauna of Greece - an update based on a hydrographic basin survey

“…On the other hand, our list contains several species which possibly enter freshwaters regularly. In fact, some species in this list were located in the lists of 'freshwater' species by ECONOMIDIS (1991) and BOBORI & ECONOMIDIS (2006). Pending accurate detailed information on these and other species' residence in freshwaters we retain them only within this provisional supplementary list.…”

“…DURAND et al, 2003). The following vicariant and dispersal events have been proposed to account for the structural diversity and high degree of endemicity of the Greek ichthyofauna (see ECONOMIDIS, 1974;ECONOMIDIS & B N RESCU, 1991;ZARDOYA et al, 1999;DURAND et al, 2003;B N RESCU, 2004;BOBORI & ECONOMIDIS, 2006;SKOULIKIDIS et al, 2008): (a) the gradual uplift of the Alps and the Balkan Mountains from late Oligocene to the end of the Miocene isolated the Balkan drainages preventing faunal exchanges with the rest of Europe; (b) the rise of the Pindos mountain range created a northwest-southeast barrier for fish range expansions, while the rise of the Mount Othrys cut the connections of the rivers of central-eastern Greece from those of northern Greece; (c) at the Pliocene-Pleistocene boundary, a communication of the NW Aegean drainages with the Danube R. was temporarily established through a river-capture involving the Morava R. and the Axios R.; (d) at about the same time, a similar communication of the Adriatic drainages with the Danube R. was established through a river capture involving the Ohrid-Drim-Skadar system in the area of Kosovo; (e) also in Plio-Pleistocene times, intrusion of Black Sea waters (then a freshwater lake) into the Mediterranean through the former Aegeopotamos R. permitted dispersal of Black Sea freshwater fish to the NE Aegean drainages; and (e) sea-level regressions at the glacial maxima of the Pleistocene had a homogenising effect on fish assemblages allowing dispersal among neighbouring river basins.…”

“…The last published checklist of the freshwater fish of Greece contains 105 native and introduced species (including euryhaline) plus five of doubtful occurrence (ECONOMIDIS, 1991). A recent re-evaluation gives 135 species, of which 89 are native exclusively freshwater, and 54 are endemic to the country or to the southern Balkans (BOBORI & ECONOMIDIS, 2006). However, a complete nation-wide inventory of fish occurrences by river basin has never been published.…”

Non-perennial Mediterranean rivers in Europe: Status, pressures, and challenges for research and management

“…As a consequence, they construct provisional weirs along river courses for surface water abstraction, which often leads to artificial desiccation and the conversion of PRS into NPRS (e.g. Chadzichristidi et al, 1991;Economou et al, 1999;Bobori and Economidis, 2006). In the Pinios River basin intensively irrigated agriculture causes the artificial desiccation of entire river stretches during particularly dry years.…”

DNA barcoding analysis of fish species diversity in four north Greek lakes

“…According to the most recent taxonomic reevaluation of the existing taxa, a total of 161 freshwater (including euryhaline and diadromous species) are present in Greece (Bobori and Economidis 2006;Economou et al 2007;Kottelat and Freyhof 2007): Forty seven (29.2%) of them are endemic to Greece,14 (8.7%) are shared with neighboring countries, and 28 (17.4%) are Balkan endemics (Economou et al 2007). Almost 40% of these are considered endangered or threatened (Bobori et al 2001) whereas for several species their taxonomic status is still unclear.…”