The impact of large dams on the autochthonous, threatened freshwater ichthyofauna of Greece: Current knowledge and gaps to be fulfilled
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1
Hellenic Centre for Marine Research (HCMR), Institute of Marine Biological Resources and Inland Waters, Greece
Information on dams of various sizes and their impact on the autochthonous freshwater ichthyofauna in Greece is mostly lacking. This is a first attempt to utilize the existing georeferenced data about the Greek large dams, investigating the relation of their location to the NATURA 2000 network and the Water Framework Directive (2000/60/EC, WFD) monitoring network of Greece, as well as their potential impact on native, threatened fish species.
Location data were retrieved for 125 large dams from the only relevant official register (Greek Committee on Large Dams, 2013); however, for 25 of them the latitude and longitude had to be corrected, according to the maps provided in the same publication. Moreover, considering the seven dams of the Aoos River springs as one (since they all form one reservoir), the total number of the large dams examined falls to 119.
29.4% of these dams (35 out of the 119) are located either in or in close proximity to a NATURA 2000 site.
The national monitoring network of the WFD includes nowadays 490 riverine sampling sites, where ichthyological sampling is performed (among other biological quality elements’ samplings), to estimate the ecological status of waters. This network has sampling stations in the vicinity of only 17 large dams, one of which is found on Rhodes island and the rest on the mainland.
In total, 21.8% of the large dams examined are found on the Greek islands, in basins that are either seasonally waterless (in at least two cases) or hold no autochthonous freshwater fish fauna, with the exception of two dams on Rhodes island, located in streams inhabited by populations of the endangered, endemic Ladigesocypis ghigii (Gianferrari, 1927). Some introductions of alien fish in islands’ reservoirs have been reported, including Carassius auratus (Linnaeus, 1758) in the Pezi reservoir of Ikaria (Barbieri et al., 2015) and Cyprinus carpio Linnaeus, 1758 and Carassius gibelio (Bloch, 1782) in the Apolakkia reservoir of Rhodes. In the latter, grass carps have been introduced in the past as well, however they have progressively died out. A single, documented case of native fish introductions has occurred in the Eressos reservoir of Lesvos island, located in a formerly fishless stream, where native Squalius sp. and Petroleuciscus smyrnaeus (Boulenger, 1896) were introduced from the nearest stream.
On the mainland, WFD ichthyological monitoring data indicate that the threatened species Alburnoides prespensis (Karaman, 1924), Alburnus vistonicus Freyhof & Kottelat, 2007, Anguilla anguilla (Linnaeus, 1758), Cobitis hellenica Economidis & Nalbant, 1996, Cobitis meridionalis Karaman, 1924, Gobio feraeensis Stephanidis, 1973, Pelasgus laconicus (Kottelat & Barbieri, 2004) and Tropidophoxinellus spartiaticus (Schmidt-Ries, 1943), are probably adversely affected by the existence and operation of 16 large dams. Data collected from different projects than the WFD monitoring show that there are more threatened native fish species than the above potentially affected by large dams. As for alien species introduced in reservoirs on the mainland, existing knowledge remains quite limited (Barbieri et al., 2015).
No fish passage exists in any of the large dams in Greece. In addition, ecological flows are generally not applied, most possibly with the unique exception of the Gadouras dam on Rhodes island, where ecological flow was specifically calculated and is applied to protect the local L. ghigii population downstream.
Dams are considered by the WFD as “heavily modified water bodies” (HMWB), which have to be firstly identified and designated by each Member State and then monitored and managed, to achieve the respective environmental objective, which is “good ecological potential”. Greece has to start performing the aforementioned tasks as soon as possible. In addition, more data have to be collected and analysed in relation to dams of all sizes, the ichthyofauna in the reservoirs, as well as upstream and downstream and managerial measures have to be synthesized and applied to mitigate the adverse effect of dams to the autochthonous biota.
Acknowledgements
This work was partially supported by the projects "Ecological Quality National Monitoring" funded by the EPPERAA 2012-2015 and "Monitoring and Recording of the Water Status (Quality, Quantity, Pressures, Use) in Greece" funded by the EPERAA 2017-2023.
References
Greek Committee on Large Dams, 2013. The dams of Greece. November 2013, 112 p.
Barbieri R., S. Zogaris, E. Kalogianni, M. Th. Stoumboudi, Y. Chatzinikolaou, S. Giakoumi, Y. Kapakos, D. Kommatas, N. Koutsikos, V. Tachos, L. Vardakas & Economou A.N., 2015. Freshwater Fishes and Lampreys of Greece: An annotated checklist. Monographs on Marine Sciences No. 8. Hellenic Centre for Marine Research: Athens, Greece, 130 p.
Keywords:
Large dams,
Greece,
Threatened,
freshwater fish,
WFD (Water Framework Directive)
Conference:
XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019.
Presentation Type:
Oral
Topic:
THREATS AND CONSERVATION
Citation:
Stoumboudi
MT,
Spiliopoulou
K and
Oikonomou
A
(2019). The impact of large dams on the autochthonous, threatened freshwater ichthyofauna of Greece: Current knowledge and gaps to be fulfilled.
Front. Mar. Sci.
Conference Abstract:
XVI European Congress of Ichthyology.
doi: 10.3389/conf.fmars.2019.07.00139
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Received:
07 Jun 2019;
Published Online:
14 Aug 2019.
*
Correspondence:
Dr. Maria T Stoumboudi, Hellenic Centre for Marine Research (HCMR), Institute of Marine Biological Resources and Inland Waters, Anavyssos, Greece, mstoum@hcmr.gr