Studying fishes in inland waters is important for management and conservation. Fishes are important because they require special conditions and resources for survival in inland waters. Aquatic conditions on Mediterranean islands are usually stressed by dynamic environmental features and often altered by humans. Inland water habitats include streams, stream mouths, coastal lagoons and any isolated waters behind the beach-fronts (including all wetland types of course). On mountainous islands such as Samothraki, stable inland water conditions are scarce. On islands, stream freshwater fishes have a hard time surviving – some species cannot live without freshwater, so even a single epic drought or prolonged desiccation event can render them extinct from an island stream basin. On the other hand, marine fishes that regularly enter and use inland waters for parts of their life cycle need barrier-free movement upstream. Human water exploitation and various barriers (road-crossings, dams, weirs etc.) artificially disrupts connectivity with the sea.

On Samothraki, fish sampling was undertaken in seven of the most representative of the island’s basins. We employed electrofishing techniques and used seine nets. So far we have confirmed 9 fish species in the inland waters of Samothraki, all of marine origin. Of these species, the eel is an important indicator of connectivity in streams. The eel is a globally endangered species, so these species’ populations lend special value to the inland waters of the island.