Summary Length–weight relationships were calculated for nine freshwater fish species belonging to two families using 1020 specimens from 15 water sources in the western part of Anatolia, Turkey. This study is the first reference on length–parameters for these species, eight of which are endemic, and with new maximum length records for three of the species.

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Heavy metals, which can be strongly accumulated and biomagnified along water, sediment, and aquatic food chain, are the most important inorganic contamination factors and have significant hazardous effects on the ecological balance of the environment. It is clearly revealed and clearly known that sediment may act as a sink of various contaminants and pose a significant risk to water quality [1][2][3][4][5].Porsuk Stream is one of the most important and the longest branches of the Sakarya River. Porsuk, with a length of 448 km, has a reservoir on the watershed Pol. J. Environ. Stud. Vol. 27, No. 2 (2018), 747-752 Original Research Sediment Quality Assessment in Porsuk StreamBasin ( AbstractPorsuk Stream Basin is a significant aquatic habitat located in the middle of the Aegean and Central Anatolian Regions of Turkey. Similar to may aquatic habitats, it is exposed to intensive agricultural, domestic, and industrial pollution. The aim of this study was to determine the toxic element levels in Porsuk Stream Basin sediment and evaluate the detected data using a multi-statistical technique. For this purpose, sediment samples were collected from 18 stations selected on the basin (three of them located on Porsuk Dam Lake) in summer 2015, and zinc, copper, lead, cadmium, nickel, and chromium accumulations in sediment samples were determined. All the detected data were compared with the consensus-based threshold effect concentrations (TEC), and factor analysis (FA) also was applied to detected data in order to evaluate the contamination grades in the basin. According to detected data, although Cu, Pb, and Cd concentrations were detected below the limit values, Zn, Cr, and Ni concentrations exceeded the limit values in general. According to results of FA, 3 factors -industrial, agricultural, and lead -explained 81.56% of the total variance.

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The relationships between otolith size and body length of North African catfish Clarias gariepinus (Burchell, 1822), collected from Sakaryabaşı (the main spring area of the Sakarya River) between July 2014 and November 2014, were examined. Length-weight relationship was also calculated for overall specimens. The wild fish were captured by electrofishing using SAMUS 725MP. A total of 132 individuals ranging from 13.6 to 59.0 cm in total length and from 15.9 to 1755.0 g in weight were sampled. The lagenar otolith (asteriscus) length and height, and the utricular otolith (lapillus) length and width were recorded for each fish. The relationships between otolith measurements and fish somatic growth were described by a non-linear function (power model). The t test revealed no considerable differences in these relationships between left and right otoliths. The ANCOVA test on the relationships between total length and otolith variables did not show significant differences between females and males. All relationships were highly significant and the mean percent prediction errors were less than 7%. The results showed that otolith growth reflected body growth.