Current status of economically important diadromous fish species of Turkey; European eel, Black Sea trout and sturgeon species

Abstract

Turkey has a rich variety of fish species in its rivers with a total length of 177 714 km. Freshwater fish live in rivers, streams, creeks, dam lakes, natural lakes, wetland areas, etc. The life of migratory fish is threatened by the anthropogenic impact on aquatic habitats. Human activities that disrupt river integrity can be listed as; dam and hydro power plant constructions, high levees, sluices, weirs and bridges, sand-gravel quarries, recreational works, wetland depletion, water pollutions, overfishing, habitat losses, climate changes, water pumping from a river to other river basins, drinking water, dried river beds etc. The most important diadromous fish species in Turkey are sturgeon species (Acipenseridae), European eel (Anguilla anguilla) and Black Sea trout (Salmo trutta labrax). In this study, the past and present status of these species are reviewed.

Genetic population structure of the critically endangered stellate sturgeon (Acipenser stellatus) in the Black Sea basin: Implications for conservation

“…Owing to the specific water current characteristics in the southern part of the Black Sea (Shapiro, 2009), it is difficult to specify which of these rivers is home to the orange cluster individuals. The presence of stellate sturgeon young‐of‐the‐year in the lower section of the Sakarya River was also reported by Memiş et al (2019, 2020). However, based on population structure, all of the individuals sampled in the proximity of the Sakarya River showed signs of admixture.…”

“…No spawning event was reported based on a larvae and juveniles survey, although adult sturgeons were found in the Yes ¸ilırmak River. For the Kızılırmak River, no data are available (Zengin et al, 2010), whereas, in the Sakarya River, reproduction was confirmed by capturing one young-of-the-year stellate sturgeon in the lower section of the river (Memis ¸et al, 2019(Memis ¸et al, , 2020.…”

“…In Turkey, the sturgeon populations are hampered in reaching their historical spawning grounds owing to the construction of dams in the lower sections of the rivers. The fish passage constructed on Sakarya River is not suitable for sturgeons (Memiş et al, 2020). No spawning event was reported based on a larvae and juveniles survey, although adult sturgeons were found in the Yeşilırmak River.…”

Anesthetic efficacy of clove oil and 2‐phenoxyethanol as hematological, histopathological and echocardiographic on broodstock Danube sturgeon ( Acipenser gueldenstaedtii )

“…Sturgeons have high economic value, which have become an important aquaculture species due to caviar (Song et al, 2022). Wild populations of sturgeons have decreased because of legal or illegal overfishing, dams and pollution (Williot et al, 2005; Memiş et al, 2020). Acipenser gueldenstaedtii , (Danube sturgeon) is a migratory fish species belonging to the Acipenseridae family that naturally distributing in the Caspian Sea, Azov Sea and Black Sea (Song et al, 2022).…”