Assessment of movements and habitat use of Salmo opimus in Fırnız stream, river Ceyhan of Turkey using radio telemetry techniques

This study was carried out to provide information about movement and habitat use by an endemic Salmonid species ( Salmo opimus Turan et al. Ichthyol Explor Freshw 23: 219–236, Turan et al. 2012 ) in Fırnız Stream, a tributary of River Ceyhan in Turkey, using manual tracking as a radio telemetry technique. During the study, 19 of the 23 tagged trout were relocated by eight to 20 times (mean: 15 relocations per fish) in Fırnız Stream. The time between the tracking surveys and relocations varied from 21 to 44 days (mean: 30 days) and the mean distance between relocations was 151 m (26 to 881 m). Tagged trout showed a distribution within a distance of 9350 m in Fırnız Stream. 95% of the relocations clustered at a distance of 4500 m, while 75 and 50% of them were distributed at a distance of 1935 m and 1488 m, respectively. The linear home range of the individual ranged from 199 to 5087 m (mean 792 m), whereas mean 95% Kernel Density Home Range (KDHR), 75% KDHR, and mean core range (50% KDHR), were 632 m, 477 m and 290 m, respectively. The depths and velocities of the locations where tagged trout occurred varied from 20 to 185 cm (mean depth: 43 cm) and 11 to 240 cm/s (mean velocity: 45.9 cm/s). There was no correlation between fish size and depth and fish size and velocity. Hydropower stations and trout farms negatively affected movement of the brown trout in the stream. The fish passage in Fırnız Hydropower Station (HPP) is inefficient due to low water mark downstream. Thus, all the obstructions that prevent fish movements must be arranged to enable fish passage in Fırnız Stream in order to preserve the brown trout population in the stream.