All five native trout species of Greece are characterized by limited population size and limited distribution. Some species populations are declining and in several cases have become extinct due to adverse effects by human exploitation.
All trout species are endemic to Balkan peninsula internal waters, except for Salmo lourosensis which is an endemic species to the Greek internal waters. In Greece, the species Salmo farioides is distributed in northwestern Greece and the southernmost limit of its distribution is the western Peloponnese. Τhe species Salmo macedonicus is found in Thrace (mainly in Nestos river), the species Salmo pelagonicus is found in Aliakmonas and Axios rivers, while the species Salmo lourosensis and Salmo peristericus have extremely limited distribution in the upper reaches of the Louros River and the Agios Germanos River (Megali Prespa catchment basin) respectively.
The most significant pressure on these species is river ecosystem fragmentation by artificial barriers built across the rivers longitudinal axis for water supply, irrigation, flood control and hydroelectric power generation, preventing fish from migrating upstream and downstream. Dams cause a range of indirect effects such as river system qualitative and quantitative degradation, habitat loss and fragmentation, as well as irreversible changes in the physicochemical, hydrological and geomorphological characteristics of river systems.
Other significant pressures and threats to fish populations are water pollution, degradation and/or loss of riparian vegetation (riparian vegetation limits erosion), fishing exploitation and competition and/or hybridization with non-native trout species, gravel extraction, sand mining or river bed regulation projects, riverside road construction. In the light of climate change all the above pressures and threats when combined with changes caused by natural causes may intensify in frequency and/or duration. It is emphasized that in Prespa National Park there is a total ban on fishing for the species S. peristericus.
All five trout species are included in Annex II of Directive 92/43/EEC. In the Red Book of Threatened Animals of Greece the two endemic species (S. lourosensis and S. peristericus) are listed as “Endangered”, the species S. farioides and S. pelagonicus as “Endangered”, while the species S. macedonicus is listed as “Poorly Known”. In addition, in the IUCN Red List of Threatened Species the species S. peristericus has been categorized as “Endangered”, S. pelagonicus as “Vulnerable”, S. macedonicus as “Poorly Known”, while the species S. lourosensis is proposed to be included in the “Critically Endangered” category due to its very small population size and extremely limited distribution. In Greece, the conservation status of all species according to the 4th National Report under Article 17 of Directive 92/43/EEC for the period 2013-2018 was assessed as “unfavourable – bad” (U2) except for Salmo farioides which due to of the extended spread was set as “unfavourable – inadequate” (U1).
National Action Plan
The aim of the National Action Plan (NAP) is to halt the downward trend and improve the conservation status of trout species population sizes and habitats. In order to achieve the NAP objectives, specific management actions will be implemented in the first stage, which were selected based on prioritization and after available funding possibilities had been taken into consideration.
NAP management actions to be implemented include population genetic analysis studies that will be carried out in order to clarify the genetic identity of trout populations, with an emphasis on geographically isolated ones. These NAP actions aim to supplement any knowledge gaps about Greek trout populations.
The abovementioned management action will further enable the implementation of pilot programmemes which will aim to support local trout populations, either by supportive breeding methods, or by “assisted transport” of fish individuals for the resettlement or re-establishment of populations. The resettlement or re-establishment of populations will be carried out under specific conditions that will minimize any risk for genetic degradation, alteration of biodiversity, transfer of parasites, etc.
In addition, a strict framework for the implementation of enrichment actions will be established to prevent the uncontrolled transfer of juvenile fish that may alter the genetic composition of host populations and increase the spread of alien species.
In order to control the spread of non-native trout species, systematic monitoring will be carried out of the activity of fish farming units hosting non-native species, and periodic controls of their functionality will be carried out in order to limit cases of escapes from the units. Mechanical removal of individuals with small-scale targeted harvests will also be piloted in three areas to limit the spread of non-native trout species. Other actions related to protection and restoration of native trout species populations and habitats include mapping of existing artificial barriers. This action will help identify which artificial barriers need restoration of connectivity through the construction of new fish passages.
In order to avoid surface water pollution from grazing animals, an assessment and installation of livestock waste collection walls in specific locations on both habitat stream sides where the species S. peristericus lives is under consideration. Also, the degree of compliance of agro-livestock activities with the rules of good agricultural practice will be assessed, which is expected to significantly improve the river system water quality.
In an area where the species S. pelagonicus (ex. Tripotamos Veria) is present, a study and pilot planting restoration will be carried out, in order to restore the riparian vegetation and reduce the stream slope erosion. In addition, a study followed by pilot restoration of plane trees loss (caused by a pathogenic fungus) in critical habitats of the species S. farioides (e.g. Erymanthos and Ladonas) will be implemented.
Finally, there will be assessment studies of the effects of fishing activity which will lead to the development of proposals of mitigation measures of the native trout species populations. Training of competent authorities and information and awareness campaigns for the citizens are complementary actions to be implemented in order to successfully protect and manage the species in question.
To evaluate the effectiveness of management actions, a monitoring programmeme will be implemented that will use evaluation indicators, in order to [evaluate] [assess] the action in an objective and measurable way, to the extent that this is possible.
The success of the National Action Plan design and implementation depends on coordination between many and different involved parties who will accept and commit to work together for the conservation and protection of the species. Finally, the National Action Plan implementation is expected to significantly favor other migratory and non-migratory fish species, and to improve the water quality of important rivers of the country.
- The National Action Plan for the native species of trout belonging to the common genus Salmo was legally approved by the Ministry of Environment and Energy in September 2021 (the Ministerial Decision is available here).
- The Ministerial Decision was based on the corresponding study prepared and received by the Natural Environment and Biodiversity Management Directorate of the Ministry of the Environment and Energy, in the framework of the Integrated Project LIFE-IP 4 NATURA “Integrated actions for conservation and management of Natura 2000 sites, species, habitats and ecosystems in Greece” (Ref. LIFE16 IPE/GR/000002).
- The full text of the study is available on the LIFE-IP 4 NATURA deliverables webpage (Action A.1).