Akademik Veri Yönetim Sistemi
the 16th International Congress on the Zoogeography and Ecology of Greece and Adjacent Regions (ICZEGAR), Athens, Yunanistan, 3 - 07 Temmuz 2025, cilt.1, sa.1, ss.64, (Özet Bildiri)
To evaluate the impacts of hydraulic barriers on fish assemblage patterns in the İstanbul, Mahmudiye, Yanık, and Balıkhane Streams which discharge into Lake Sapanca, monthly electrofishing surveys were conducted between February 2023 and March 2025 using a SAMUS- 725G electroshock device. Sampling was systematically carried out both upstream and downstream of the first hydraulic barrier in each stream. Throughout the study period, 12 fish species were recorded downstream of the barriers in the both İstanbul and Yanık streams, 9 species in the Mahmudiye Stream, and 17 species in the Balıkhane Stream. In contrast, upstream sections contained only 3 species in the İstanbul Stream, 2 in the Mahmudiye Stream, 1 in the Yanık Stream, and 17 in the Balıkhane Stream. Notably, the culvert structure (Barrier 1) in the Balıkhane Stream did not seem to hinder fish movement or alter distribution patterns. Conversely, the first hydraulic barriers in the İstanbul, Mahmudiye, and Yanık Streams were found to significantly restrict upstream fish passage and contribute to habitat fragmentation. These findings underscore the necessity of either removing such barriers or implementing effective fish passage solutions to mitigate their ecological impacts.
Keywords: Anthropogenic effects, Barrier removal, Downstream, Fish migration, Fish passage, Longitudional connectivity, This work was supported by the TÜBİTAK-1001 (Project Number 122Y318).