Freshwater fishes of Greece: Their biodiversity, fisheries and habitats

Freshwater fishes of Greece: Their biodiversity, fisheries and habitats D. C. Bobori1∗ and P. S. Economidis2 1

Aristotle University of Thessaloniki, School of Biology, Department of Zoology, Lab. of Ichthyology, UP Box 134, 54124 Thessaloniki, Greece 2 Karakasi Str.79, 544 53 Thessaloniki, Greece E-mail: [email protected] ∗ Corresponding author: E-mail: [email protected]

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. Keywords: conservation, management, endangered species

407 C 2006 AEHMS. ISSN: 1463-4988 print / 1539-4077 online Aquatic Ecosystem Health & Management, 9(4):407–418, 2006. Copyright DOI: 10.1080/14634980601027855

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Bobori and Economidis / Aquatic Ecosystem Health and Management 9 (2006) 407–418

Introduction Due to the steady increase of human impacts upon aquatic ecosystems, especially on inland waters (Perry and Vanderklein, 1996; Maitland and Morgan, 1997; Trudgill et al, 1999; Boon et al., 2000), the conservation and protection of freshwater fishes, their biodiversity and habitats have become a major concern (Kirchhofer and Hefti, 1996; Collares-Pereira et al., 2002). However, the public may be unaware which species in those environments are under threat. In fact, many taxa are under various threats or in danger of extinction (Economidis 1992, 1995; Povˇz, 1996; Bobori et al., 2001a; Minns, 2001; Souchon and Keith, 2001). In Greece, the situation is not different from elsewhere, especially because of the small size of the watersheds and the dramatic increase of water demand over the past 30 years (Angelakis and Diamadopoulos, 1995). Furthermore, water pollution, eutrophication, channelization and flow regulation have contributed to the degradation of surface water resources and aquatic habitats (for a review see Bobori et al., 2001a). As a result of these human impacts, as well as the uncontrolled introduction of exotic species (Economidis et al., 2000b), some fish populations have gradually become locally vulnerable, threatened or extirpated (Economidis 1991, 1992, 1995, 2002; Economidis et al., 1996, 2000a; Economou et al., 1999b; Stoumboudi et al., 2002). 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 on fisheries science and legislation; c) priority gaps and needs in freshwater fish habitat management; and d) future strategies for management of freshwater fishes and aquatic resources.

Freshwater resources in Greece Greece (132,000 km2 , population ∼11.6 million) is located in the southeast part of the Balkan Peninsula (Europe). The country has a diverse topography (40% of land exceeds 500 m in altitude and reaches 2,000 m; (OECD, 2000), and receives an uneven distribution of rainfall (precipitation in western part is three times greater than in eastern parts; Koussouris, 1998). This produces major differences in hydrology and catchment areas, both in time and space (Zacharias et al., 2002), and has created local distinct environments that favoured freshwater fish species isolation and endemism (Economidis, 1995).

The post-glacial climate changes in combination with the recent geomorphology (upper Quaternary), gave rise to rather small, alkaline river basins and lakes situated mainly in the southern part of the country (Hadjibiros et al., 1998; Skoulikidis et al., 1998). Up to 80% of the total surface river flow comes from the catchment area of eight large rivers. There are also 41 natural lakes with total area of 610 km2 , 14 artificial or dam lakes or reservoirs (total area 26 km2 ) (for a synopsis see Koussouris, 1998; OECD, 2000) and 378 wetlands (total area 2,000 km2 ) (Zalidis and Mantzavelas, 1996; OECD, 2000), 90 of which have been proposed for inclusion in the Natura 2000 Network of the European Union according to the directive 92/43/EEC (Dafis et al., 1996). Eleven wetland complexes (consisting of 59 sites) are Ramsar sites (Ramsar Convention Bureau, 1990). The majority of the Greek rivers are moderately polluted, and only a few of them show significant human impact (Skoulikidis et al., 1998). Lakes can be classified as warm monomictic deep lakes, warm monomictic shallow lakes, and dimictic shallow lakes with high concentrations of nutrients and heavy metals in some (Mourkides et al., 1978; Kilikidis et al., 1984; Fytianos et al., 1986; Koussouris et al., 1990; Skoulikidis, 1993, 2000; Bobori, 1996; 2001; Zacharias et al., 2002).

Freshwater fish fauna Overall, 135 freshwater fish taxa belonging to 26 families, including diadromous, euryhaline, and introduced species, have been reported in the rivers and lakes of Greece (Table 1) (Economidis, 1991, 1995; Kottelat, 1997; Economidis et al., 2000b; Bobori et al., 2001a). This number is expected to increase, since the taxonomic status of several fish families is still under revision. Cyprinidae is the most diverse family (accounting for 40.7% of the fish species) including the most commercially important species (e.g. carp, barbels). The degree of endemism is also high. Of the 89 primary, and primary-like, freshwater fish species, 54 (60.7%) are endemic to Greece or to southern drainages of the neighbouring Balkan countries (Economidis, 1991, 1995; Bobori et al., 2001a). Most of them are in isolated areas, especially in the south and west of the country, where they usually form small populations of restricted range (Economidis, 1995). The distribution and origin of freshwater fishes, especially the endemics, has been attributed mainly to the geological history of the country. Regarding the ichthyogeographical arrangement, Petit (1930) initially proposed the division into two principal faunal


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Table 1. Freshwater fish fauna of Greece (including euryhaline, diadromous and introduced species).

Family/Species

Family/Species

Petromyzontidae Eudontomyzon hellenicus Vlad., Ren., Kott & Ec., 1982 Petromyzon marinus Linnaeus, 1758 Acipenseridae Acipenser baeri Brandt, 1869 Acipenser gueldenstaedti Brandt & Ratzeburg, 1833 Acipenser naccari Bonaparte, 1836 Acipenser ruthenus Linnaeus, 1758 Acipenser stellatus Pallas, 1771 Acipenser sturio Linnaeus, 1758 Huso huso (Linnaeus, 1758) Polyodontidae Polyodon spathula (Walbaum, 1792) Anguillidae Anguilla anguilla (Linnaeus, 1758) Clupeidae Alosa fallax (Lacepèpe, 1803) Alosa macedonica (Vinciguerra, 1921) Alosa vistonica Economidis & Sinis, 1986 Cyprinidae Abramis brama (Linnaeus, 1758) Alburnoides bipunctatus (Bloch, 1782) Alburnus alburnus (Linnaeus, 1758) Aspius aspius (Linnaeus, 1758) Barbus albanicus Steindachner, 1895 Barbus cyclolepis Heckel, 1837 Barbus euboicus Stephanidis, 1950 Barbus graecus Steindachner, 1895 Barbus macedonicus Karaman, 1928 Barbus peloponnesius Valenciennes, 1842 Barbus prespensis Karaman, 1924 Carassius auratus (Linnaeus, 1758) Carassius carassius (Linnaeus, 1758) Carassius gibelio (Bloch, 1782) Chalcalburnus belvica (Karaman, 1924) Chalcalburnus chalcoides (Güldenstädt, 1772) Chondrostoma prespense Karaman, 1924 Chondrostoma vardarense Karaman, 1928 Ctenopharyngodon idella (Valenciennes, 1844) Cyprinus carpio Linnaeus, 1758 Gobio banarescui Dimovski & Grupce, 1974 Gobio elimeius Katt., Steph. & Econ., 1973 Gobio gobio (Linnaeus, 1758) Hypophthalmichthys molitrix (Valenciennes, 1844) Hypophthalmichthys nobilis (Richardson, 1845) Ladigesocypris ghigii (Gianferrari, 1927) Leucaspius delineatus (Heckel, 1843)

Cobitis strumicae Karaman, 1955 Cobitis trichonica Stephanidis, 1974 Cobitis vardarensis Karaman, 1928 Sabanejewia balcanica (Karaman, 1922) Balitoridae Barbatula barbatula (Linnaeus, 1758) Barbatula bureschi (Drensky, 1928) Barbatula pindus Economidis, 2005 Siluridae Silurus aristotelis Garman, 1890 Silurus glanis Linnaeus, 1758 Clariidae Clarias gariepinus (Burchell, 1822) Esocidae Esox lucius Linnaeus, 1758 Coregonidae Coregonus lavaretus (Linnaeus, 1758) Salmonidae Oncorhynchus mykiss (Walbaum, 1792) Oncorhynchus kisutch (Walbaum, 1792) Salmo dentex Heckel, 1852 Salmo cf. farioeides Karaman, 1938 Salmo louroensis Delling, 2003 Salmo macedonicus (Karaman, 1924) Salmo macrostigma (Dumeril, 1858) Salmo pelagonicus Karaman, 1938 Salmo peristericus Karaman, 1938 Salmo salar (Linnaeus, 1758) Salvelinus fontinalis (Mitchill, 1814) Mugilidae Chelon labrosus (Risso, 1826) Liza aurata (Risso, 1826) Liza ramada (Risso, 1826) Liza saliens (Risso, 1826) Mugil cephalus Linnaeus, 1758 Mugil soiuy Basilewsky, 1855 Atherinidae Atherina boyeri Risso, 1810 Atherina hepsetus Linnaeus, 1758 Valenciidae Valencia letourneuxi (Sauvage, 1880) Cyprinodontidae Aphanius fasciatus (Valenciennes, 1821) Poeciliidae Gambusia affinis (Baird & Girard, 1853) Gasterosteidae Gasterosteus aculeatus Linnaeus, 1758 (Continued on next page)

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Table 1. Freshwater fish fauna of Greece (including euryhaline, diadromous and introduced species). (Continued)

Family/Species

Family/Species

Leuciscus cephalus (Linnaeus, 1758) Leuciscus cf. svallize (Heckel & Kner, 1858) Pachychilon macedonicum (Steindachner, 1892) Pachychilon pictum (Heckel & Kner, 1858) Parabramis pekinensis (Basilwesky, 1855) Petroleuciscus borysthenicus Kessler, 1859 Phoxinellus epiroticus (Steindachner, 1896) Phoxinellus pleurobipunctatus (Stephanidis, 1939) Phoxinellus prespensis (Karaman, 1924) Phoxinus phoxinus (Linnaeus, 1758) Pseudophoxinus beoticus (Stephanidis, 1939) Pseudophoxinus laconicus Kottelat & Barbieri, 2004 Pseudophoxinus marathonicus Vinciguerra, 1921 Pseudophoxinus stymphalicus (Valenciennes, 1844) Pseudorasbora parva (Temminck & Schlegel, 1842) Rhodeus amarus (Bloch, 1782) Rutilus prespensis (Karaman, 1924) Rutilus rutilus (Linnaeus, 1758) Rutilus vegariticus Stephanidis, 1950 Rutilus ylikiensis Economidis, 1991 Scardinius acarnanicus Economidis, 1991 Scardinius erythrophthalmus (Linnaeus, 1758) Scardinius graecus Stephanidis, 1937 Squalius keadicus Stephanidis, 1971 Tinca tinca (Linnaeus, 1758) Tropidophoxinellus hellenicus (Stephanidis, 1939) Tropidophoxinellus spartiaticus (Stephanidis, 1971) Vimba melanops (Heckel, 1837) Cobitidae Cobitis arachthosensis Economidis & Nalbant, 1997 Cobitis hellenica Economidis & Nalbant, 1997 Cobitis meridionalis Karaman, 1924 Cobitis punctilineata Economidis & Nalbant, 1997 Cobitis stephanidisi Economidis, 1992

Pungitius hellenicus Stephanidis, 1971 Pungitius platygaster (Kessler, 1859) Syngnathidae Nerophis ohidion (Linnaeus, 1758) Syngnathus abaster Risso, 1826 Syngnathus acus Linnaeus, 1758 Syngnathus taenionotus Canestrini, 1871 Syngnathus typhle Linnaeus, 1758 Moronidae Dicentrarchus labrax (Linnaeus, 1758) Dicentrarchus punctatus (Bloch, 1792) Centrarchidae Lepomis gibbosus (Linnaeus, 1758) Percidae Perca fluviatilis Linnaeus, 1758 Sander lucioperca (Linnaeus, 1758) Zigel balcanicus (Karaman, 1936) Blenniidae Salaria economidisi Kottelat, 2003 Salaria fluviatilis (Asso, 1801) Salaria pavo (Risso, 1810) Gobiidae Economidichthys pygmaeus (Holly, 1929) Economidichthys trichonis Economidis & Miller, 1990 Knipowitschia caucasica (Berg, 1916) Knipowitschia goerneri Ahnelt, 1991 Knipowitschia milleri (Ahnelt & Bianco, 1991) Knipowitschia panizzae (Verga, 1841) Knipowitschia thessala (Vinciguerra, 1921) Proterorhinus marmoratus (Pallas, 1814) Zosterisessor ophiocephalus (Pallas, 1814) Pleuronectidae Platichthys flesus (Linnaeus, 1758)

regions, which correspond to the main drainage basins separating eastern and western Greece. Stephanidis (1939) followed this system and named the western zone as Ioniankorinthian. Economidis and Banarescu (1991) examined in detail the distribution and the origin of the freshwater fishes in the Balkan Peninsula, especially in Greece, summarising all previous approaches, and naming these two districts the Ponto-Aegean and the South Adriatic-Ionian. Similar approaches were proposed by Bianco (1990). More recently, Maurakis et al. (2001) proposed a modified system using the native cyprinids and cladistic methodologies, and recognized two biogeographical divisions of river drainages in Greece: Ponto-Aegean (composed

of two subdivisions: Thracian-East Macedonia and Macedonia-Thessaly) and Ponto-Hellas. The PontoAegean district, after Economidis and Banarescu (1991), is dominated by Danubian species, while the South Adriatic-Ionian one is rich in endemic species. Maurakis and Economidis (2001), based on their examination of native cyprinid fishes, stated that relationships among major river drainages in Peloponnesos and their historical affinities to rivers of southern mainland Greece are related to vicariant events (e.g., marine transgression and regression, stream piracy, orogeny), which were the major factors determining the current distribution of the cyprinid species in the area.


Many authors (for discussion see: Bianco, 1990; Economidis and Banarescu, 1991; Economidis and Nalbant, 1996) provided information about the routes of the freshwater fish species dispersion through the Balkan Peninsula. According to Economidis and Banarescu (1991), the central European and Danubian species dispersed during the upper Pliocene and the Pleistocene using three main corridors: a) by the Black Sea coastal drainages; b) directly from the north through the Morava-Axios valley; and, c) by hade water capture among Danube and Drin catchments around Kosovo and Albania. Some central European, or more widely distributed, species dispersed further to the south. The introduction of exotic fish species into the inland waters of Greece dates back to 1920 (Livadas and Sfagos, 1940; Stephanidis, 1950). Since then, 23 exotic fish species have been introduced (Economidis et al., 2000b). Translocation of native species from one drainage system to another has also taken place in a smaller scale due to both deliberate and accidental actions (Economidis et al., 2000b).

State of freshwater fish science in Greece Current state of knowledge In Greece, while there is a paucity of ecological and distributional data for fishes (Economou et al., 1999a; Maurakis and Grimes, 2003) a total of 492 publications dealing with fish (dated from 1831 to 2001) are available (Economou et al., 2004). Most of these refer to distribution (121), systematics (107) and biology/ life history (103) of freshwater fishes. As well, there are a number of publications dealing with the protection/conservation of endangered species (54), biogeography (40), genetics (33), and phylogenetics (44). The stresses on and the physical habitat requirements of some threatened species are known through 24 publications, while information on applied ichthyology (mostly fisheries and aquaculture) is treated in 38 publications (for a review see Economou et al., 2004). Until the middle of the 1990s, attention had been focused mainly on taxonomy, systematics, biology and distribution of freshwater fish species (Bobori et al., 2001a; Economou et al., 2004). One new species of Economidichthys (Economidis and Miller, 1990) and four species of the genus Cobitis (Economidis and Nalbant, 1996) have been described while Bogutskaya (2002) recently placed Leuciscus borysthenicus in the genus of Petroleuciscus. There are some taxa (e.g., Leu-

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ciscus, Salmo) whose taxonomy is unclear (Economou et al., 1991; Kottelat, 1997), or their taxonomic diversity is underestimated because of their small size, which makes species easily overlooked or misidentified (e.g., species of Pseudophoxinus, Kottelat and Barbieri, 2004). A new species of minnow (Pseudophoxinus laconicus) from Peloponnesos was recently described (Kottelat and Barbieri, 2004). Over the last ten years, genetic and phylogenetic studies of freshwater fishes have focused attention on the above taxonomic problems and on populations of Salmo (e.g., Apostolidis et al., 1996, 1997, 1999), Leuciscus (e.g., Tsigenopoulos and Karakousis, 1996; Imsiridou et al., 1998), Silurus (e.g., Triantafyllidis et al., 1999a,b, 2002) and several cyprinid species (e.g., Zardoya et al., 1999). Doadrio and Carmona (1998) examined 23 populations of Greek Leuciscus (Squalius) and concluded that their current taxonomy is confusing and does not correspond to genetic data which indicates the presence of at least seven different species in Greece. On the other hand, Imsiridou et al. (1998) analyzed the phylogenetic and systematic relationships among 12 populations of Leuciscus and found high inter-population diversity suggesting the need of further genetic studies to clarify the above relationships. Still, phylogenetic relationships among Greek fish species are poorly understood (Zardoya et al., 1999) and the taxonomic validity of genera such as Tropidophoxinelus or Pachychilon is in question (Kottelat, 1997). Studies on the ecological and habitat requirements (e.g., Economou et al., 1999b; Barbieri, 2000; Stoumboudi et al., 2000), and the protection and conservation status of fish species, have recently increased (e.g., Economidis, 1995, 1999, 2002; Economidis et al., 1996, 2000a; Daoulas et al., 1999; Economou et al., 1999b; Stoumboudi et al., 2000, 2002; Bobori et al., 2001a,b; Barbieri et al., 2002). The conservation status of freshwater fishes in Greece was reviewed by Economidis (1991, 1992, 1995). Several species (32%) were classified as endangered and/or vulnerable or locally vulnerable, and two species, Tropidophoxinelus spartiaticus and Knipowitschia goerneri, classified as threatened. Recently, the conservation status of the native, primary and primary-like freshwater fish species was reassessed (Bobori et al., 2001a). Two species (Alosa vistonica and Cobitis stephanidisi) are considered extinct, while several others have been extirpated, at least from their type localities (Economidichthys pygmaeus, Knipowitschia thessala, Pungitius hellenicus, Pseudophoxinus thesproticus, Barbus euboicus). Furthermore, 5 species are classified as critically endangered,

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and 29 species are endangered and/or vulnerable. Genetic analyses of these populations, which have not been studied in sufficient detail, could be valuable for the taxonomy of the species and could identify natural genetic reservoirs for recolonizing restored waters in the formerly damaged landscapes. As a result, the regions occupied by these populations are more suitable for the establishment of protected areas. Maurakis and Grimes (2003), taking into account stream physical properties (e.g., stream order, width, depth), developed a mathematical model in accord with the stream classification system proposed by the European Environmental Agency (EEA), that predicts fish diversity in small and medium sized freshwater systems. Furthermore, in response to the EEA biodiversity initiative, the first geographical information system for freshwater fishes and crabs in Greece was created (Maurakis et al., 2003) based on collections made by Aristotle University (1,568 records) and the Science Museum of Virginia (791 records).

Current status of freshwater fisheries Commercial fisheries in inland waters of Greece are conducted mainly in 32 natural or artificial water systems (lakes, rivers, reservoirs) (Ministry of Rural Development and Food, 2000; former Ministry of Agriculture). The total annual commercial catch for the 1988 to 2000 period ranged from 1,950 t in 1988 to 1,810 t in 2000 (mean ± SE: 1,500 ± 86 t; Figure 1a), while during the same period marine production increased from 46,700 t in 1988 to 150,000 t in 1994 and declined to 76,700 t in 2000 (Figure 1b) (National Statistical Service of Greece, NSSG, 1988–2000). The NSSG, which is responsible for gathering this information, provides catches from 1969 onward, but these catches are thought to be underestimates since the data set does not include illegal unreported by-catches, recreational and sport. Most inland catches come from lakes. In 1996 the reported catch from 7 lakes (Volvi, Vegoritida, Kastoria,

Figure 1. Total annual (a) freshwater and (b) marine catches, and (c) inland aquaculture production (in t) in Greece for the period 1988 to 2000 (data from National Statistical Service and Ministry of Rural Development and Food).


Vistonida, Pamvotida, Mikri and Megali Prespa) accounted for 57.5% of the total annual commercial catch, while for the period 1994 to1999 the mean contribution production of these lakes to the total catch was 36%. However, the annual production from large lakes has decreased over the last 40 years, mainly due to overfishing, habitat destruction and pollution (Bobori et al., 2001a). Several cyprinids (e.g., carps, barbels, loach, bream) and atherinids are commercially fished in shallow lakes whereas, coregonid and trout species in deep reservoirs and lakes. Carp, perch, barbel and chub species are fished commonly in rivers, while in upstream portions of rivers local wild trouts are fished (Bobori et al., 2001a). The most common cyprinids, such as bream (Abramis brama) and roach (Rutilus rutilus) are not marketable so there is little fishing interest. On the other hand, pike (Esox lucius), common carp (Cyprinus carpio) and trouts (Salmo species and Oncorhynchus mykiss) are preferred by anglers. Commercial fisheries are operated primarily by independent fishers or co-operatives. The most commonly used fishing gears are gill nets and trammel nets operated in lakes and the lower parts of the rivers. Several kinds of fyke nets, bag seines, long lines, and fish entrapment devices (similar to the French bordigue described by Pauly and Yanez-Arancibia, 1994) are also used. Regional governmental fisheries administrations, under the Ministry of Rural Development and Food, are responsible for the control and application of governmental regulations (i.e., net limitations, fishing periods, introductions). The aquaculture sector in Greece contributes greatly to the total production of freshwater fish. The total annual aquaculture production for the period 1988 to 2000 ranged from 2,638 t to 3,656 t (mean annual production of 2,832 (±130) t; Figure 1c), which is 1.33 to 2.02 times higher than traditional inland catches. Total production in 2001 was 3,390 t (National Statistical Service of Greece, 2004), deriving from 128 aquaculture enterprises established in inland waters (Ministry of Rural Development and Food, 2000). The preferred fish species are rainbow trout, Atlantic salmon, eels, carps and euryhaline species such as mugils. Trout aquaculture was the first intensive fish culture practiced in Greece, beginning in the 1960s. Currently, 96 enterprises have developed, most of which are small, household ones with low production (about 23 t average annual production for 2001). Carp aquaculture (12 enterprises with total production of 112 t in 2001) is not considered as a developed sector, due to the high land requirements and the low market value and demand. In contrast, there is an increasing interest in eel breeding

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that depends on the direct collection and purchase of wild elvers.

Current status of freshwater habitats Until the 1960s, the quality of Greek inland waters was characterised as ‘good,’ even though some slight harbingers of pollution had appeared (Economidis, 1991, 1995; Hadjibiros et al., 1998). Due to human activities, Greece has lost 75% of its wetland area since 1900 (OECD, 2000). Today, the pressures upon surface freshwater resources are intermediate. However, in some systems, for instance in the part of the River Axios that flows in Greece, human intervention is intense (Lazaridou et al., 2000). Hadjibiros et al. (1998) evaluated the ecological status of major rivers and lakes in Greece relative to anthropogenic and environmental perturbations and concluded that many native fish species are at risk of further decline and extirpation from their indigenous habitats. Due to extended droughts and uncontrolled use of surface and underground water, parts of several permanent rivers and many streams have become xeric, especially during the dry season, resulting in high concentrations of pollutants. These extreme conditions impact fish biological activity, distribution and abundance, often with fatal results for fish populations, for example, the collapse of populations in Lake Koronia in August 1995 (Gregoriadou et al., 1997). Economou et al. (1999b) reported several native fish populations were extirpated from isolated catchments within some drainages in western Greece and Peloponnesos due to a prolonged drought period (1989–90), as well as habitat disturbance resulting from careless construction of irrigation channels. As a result, three endemic species, Eudontomyzon hellenicus, Leuciscus keadicus and Valencia letourneuxi, were placed under statutory protection, which mainly invites monitoring programs. The reduction in the surface runoff, combined with the increased requirements for potable and irrigation water, has also affected many karstic springs where unique biological assemblages and endemic fish taxa are located (e.g., Phoxinus phoxinus, Gasterosteus aculeatus, Pungitius platygaster, Eudontomyzon hellenicus, Economidichthys pygmaeus, Cobitis punctilineata; Economidis, 1992, 1995; Economidis et al., 1996). Furthermore, two endemic fish species, Knipowitschia thessala and Cobitis stephanidisi, are now extinct in their type localities (Hasabali and Velestino springs, Thessaly; Economidis et al., 2003). Dam construction and operation, stream channelization, high exploitation pressures, habitat disturbance

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and careless introductions have also been related to fish population declines (Economidis, 1991, 1992, 1995; Economidis et al., 1996; Hadjibiros et al., 1998; Economou et al., 1999b; Bobori et al., 2001a). This, in combination with habitat alteration, has resulted in the dramatic decrease of trout populations in the headwaters of the country. Diadromous species such as Anguilla anguilla, Alosa fallax, Acipenser sturio and Acipenser stellatus, have to face increasing anthropogenic impacts, mainly discharge of pollutants, shallow waters and river damming, when attempting to access spawning and/or feeding grounds (Economou et al., 1999b; Bobori et al., 2001a). The two native sturgeon species (Acipenser sturio and Acipenser stellatus) have almost lost the opportunity to move upstream in the River Evros, where their main spawning grounds are located (Economidis et al., 2000a). Furthermore, stagnant and running waters, particularly restricted ones (marshes, ponds, springs), are exceptionally vulnerable to anthropogenic activities such as tourist development (Economidis, 1995, 2002; Barbieri et al., 2002; Stoumboudi et al., 2002).

Survey of freshwater fish management in Greece Legislative and regulatory treatment of fishes, habitats, and fisheries A number of several governmental sectors under the direction of the Ministry of Rural Development and Food, are directly involved in the legislative and regulatory treatment of fishes and their habitats in Greece. The management regulations currently in force for Greek inland waters were established through several statues and presidential decrees since 1970 (Hadjibiros et al., 1998; OECD, 2000). Greece has also ratified several international conventions (e.g., Ramsar, Berne, Biological Diversity Convention, Convention on International Trade of Endangered Species (CITES), and European Union (EU) legislation, mainly Directives (the Habitats Directive 92/43/EEC and the Water Framework Directive 2000/60/EC)). The first effort to conserve the natural habitats with their wild flora and fauna was made during the implementation of the Habitats Directive (EC Council Directive 92/43/EEC, 1992), which implemented the EU approach to the protection of biodiversity. Of the 296 sites designated as protected areas (Dafis et al., 1996), 277 are inhabited by fishes but only 49 are rated as ‘excellent’ for fish biodiversity. Twenty eight freshwater fish

species present in Greece are included in Annex II of the same directive (Economidis et al., 1996). The majority of them are also protected by international conventions and/or national legislation (e.g., Berne, CITES, Ramsar, Greek Presidential Decree 67/81). Recently, surface waters have been assigned under the auspices of the Water Framework Directive (WFD 2000/60/EC) of the European Parliament and the Council of the EU that imposes a new approach for the ecological assessment of groundwater, inland surface and transitional, and coastal waters. Fishes have an essential role in this framework as indicators of the ecological integrity of running waters (Schmutz et al., 2000). Under this approach, increasing pressure to gather biological data is evident, which will serve a broad-spectrum of environmental objects and plans, that is, the protection of endangered and threatened species (Economou et al., 2004).

Habitat management linkages The continuous increase in water demand has resulted in competition among several users. The same waterbodies that support significant fish populations and fisheries are heavily exploited for human consumption, irrigation and electricity generation. Rivers Mornos and Evinos are the most recent examples of river diversion to supply heavily populated cities with potable water. On the other hand, surface waters suffer from partial or total destruction, as a result of water abstraction for irrigation. Freshwater fish habitats near urban, industrial and intensive agricultural areas have been chemically degraded and physically decimated. As a result, fish populations have declined and several species are under threat (Economidis, 1991, 1992, 1995; Hadjibiros et al., 1998). There is a trend in Europe to reclaim natural habitat wherever possible by encouraging landowners and local communities to restore landscape for uses other than agriculture. Point and non-point pollution, as well as other human activities (e.g., damming, silt removing, canalization, water abstraction) negatively affect fish populations and, in some cases, were reported as the main factors for their extinctions (Economidis, 1991, 1995; Economou et al., 1999b). Among other costs in terms of aquatic habitat and living resources (see Bobori et al., 2001a), is the certified extinction (Economidis et al., 2003) of the loach Cobitis stephanidisi from its type locality (Velestino springs) due to uncontrolled water abstraction for irrigation purposes. Nonetheless, the Ministry of Rural Development and Food, which is responsible for development,


conservation and management of water as a national resource, has established a monitoring network for assessing the water quality of lakes, rivers and wells since 1972 (a data set for the years 1972–2001 is available on line; http://www.minagric.gr/greek/2.9.3a.html). Water quality data are also gathered by several other governmental and non-governmental organizations (e.g. Ministry of Macedonia-Thrace, Water supply and Sewage Corporation of Athens, Electrical Power Corporation) though not necessarily related to the habitat quality requirements of fishes. Recent studies, carried out by several institutions (e.g., Institute of Inland Waters of the Greek Center for Marine Research, Biological School of the Aristotle University, Department of Biological Applications and Technology of the Ioannina University), have focused on creating databases of freshwater fish ecological requirements and growth, abundance and distributions of fish stocks, and to relate them to the impacts on their habitats caused by all pressures integrated in their range (e.g., Tachos, 2003). Additionally, the water framework directive of the European Parliament requires that EU member states establish monitoring and ecological quality classification systems for the purpose of systematically assessing the ecological status of surface waters, and for determining the level of human impact on ecosystems. In line with these requirements, the Fish-based Assessment Method for the ecological status of European waters (FAME) project (a project under the 5th Framework Programme for Energy, Environment and Sustainable Management) under Key Action 1: Sustainable Management and Quality of Water) was conducted in Greece aiming to develop and deliver a European ecological status assessment and classification system, using fish-based indicators as measures of ecological quality (Economou, 2002). Furthermore, biological assessment of running waters based on macroinvertebrates has progressed over the last two decades (e.g., Yfantis et al., 1999; Gritzalis et al., 2000; Lazaridou-Dimitriadou et al., 2000; Kampa et al., 2000; Skoulikidis et al., 2002) and the first index of biotic integrity has been developed (Artemiadou and Lazaridou, 2005).

Conclusions To date, effective management and conservation of freshwater fishes and fisheries have not been featured in the management of freshwater ecosystems of Greece. Despite the considerable progress of Greek authorities in terms of legislation and policies, the high social pressure for development has resulted in careless management of several aquatic ecosystems with harm-

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ful effects on fish stocks. So far, public water policy tends to ignore all previous damage and continues the same development policies. At the same time, official mechanisms are insufficient to force the efforts for conservation. 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 (Bobori et al., 2001a). In the face of escalating problems of habitat destruction and degradation, it is expected in the near future that the number of threatened species will increase. The adoption of EU directives for water resources conservation forces Greek authorities to work under the concept that fish community structure integrates and reflects the functioning of the ecosystem (Economou, 2002). Thus, the conservation of local fish populations and especially of the endemics is of primary importance (Barbieri, 2000). One of the highest priorities lies in the establishment of refuge populations, either to replace those which are extinct or to provide additional safeguards for those still extant. Also, additional research is required on the biology and ecology of, and threats to, freshwater fish species. Bearing in mind that Greece is currently without a national action plan to monitor and manage aquatic environments (i.e., aquatic habitats, threatened species, inland fisheries) (Hadjibiros, 1998; Lekakis, 1998; OECD, 2000; Bobori et al., 2001a), future efforts need to be directed to other severely endangered or extinct species such as Acipenser sturio, Eudontomyzon hellenicus, Valencia letourneuxi, Alosa vistonica, Cobitis stephanidisi and Salmo species. Furthermore, the creation of geographical information system (GIS) databases for incorporating all the information on species and habitats should be developed to aid the guiding principle of saving aquatic biodiversity. To fill this gap, the already proposed GIS for freshwater crabs and fishes in Greece by Maurakis et al. (2003) should serve as a starting point. Moreover, in applied studies, the freshwater GIS would be an integral tool for the European Environmental Agency’s biodiversity inventory of the southern Balkan peninsula (Maurakis et al., 2003), and in developing the inland fisheries management plan (including environmental impact studies) proposed by Bobori et al. (2001).

Acknowledgements The authors would like to thank the Assoc. Prof. K.I. Stergiou for his critical comments on an earlier version of the manuscript and the two anonymous reviewers for their thorough and constructive comments.

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