Tarek is an important endemic species which live in only Van Basin. This species is
assessed as NT according to IUCN. The aim of this study is to determine the shape index values and
dimensions of tarek sampled from Lake Van. Material-Methods: The tarek samples were obtained
from Lake Van (120 samples) in September 2016-August 2017. Lake Van, the largest lake in Turkey.
Due to the highly salty-alkaline waters of the lake, it is known as a ‘soda lake’. All samples were
obtained from fishermen. All captured fish were measured (± 0.1cm) for total length and weighted (±
0.01g). Utricular, lagenar and sagittal otoliths were removed by making left and right distictions. All
otoliths were photographed on distal side using Leica DFC295. Otolith breadth (OB), length (OL), area
(A) and perimeter (P) (± 0.001mm) were determined by Leica Application Suit Ver.3.8 Imaging
Software. Form Factor (FF), Circularity (C), Roundness (RD), Rectangularity (REC), Aspect Ratio (AR)
and Ellipticity (EL) were used for otolith shape analyses. Paired t-test, Wilcoxon tests were used for
analyses. Results-Discussion: There is no differences between right and left asteriscus in terms of
otolith length. But otolith breadth of asteriscus are different from between right and left (P?0.01). OL
and OB are different in the lapillus between right and left otoliths (P?0.01). Right and left sagittal
otoliths are similar in terms of OL and OB (P?0.05). Otolith shape index are separately calculated for
right and left three otolith pairs. FF, C, RD, REC, AR, EL for left asteriscus are 5.0542 ± 0.0404, 18.459
± 0.166, 0.24733 ± 0.00163, 2.6522 ± 0.0388, 1.1295 ± 0,00560, 0.06005 ± 0.00250, for left lapillus
are 4.0233 ± 0,0268, 14.901 ± 0.0391, 0.22613 ± 0.00141, 1.1725 ± 0.0193, 1.3194 ± 0.00733, 0.08883
± 0.00175, for left sagittal otoliths are 1.8049 ± 0.0349, 52.170 ± 0.756, 0.041396 ± 0.000987, 0.2084
± 0.0108, 5.3108 ± 0.0610, 0.67725 ± 0.00591, respectively. This is the first study for determining the
shape index for lapillus, sagittal otoliths of tarek. Acknowledgements:This study was supported by
TUBITAK(Project No:215Z148).

Tarek is an important endemic species which live in only Van Basin. This species is
assessed as NT according to IUCN. The aim of this study is to determine the shape index values and
dimensions of tarek sampled from Lake Van. Material-Methods: The tarek samples were obtained
from Lake Van (120 samples) in September 2016-August 2017. Lake Van, the largest lake in Turkey.
Due to the highly salty-alkaline waters of the lake, it is known as a ‘soda lake’. All samples were
obtained from fishermen. All captured fish were measured (± 0.1cm) for total length and weighted (±
0.01g). Utricular, lagenar and sagittal otoliths were removed by making left and right distictions. All
otoliths were photographed on distal side using Leica DFC295. Otolith breadth (OB), length (OL), area
(A) and perimeter (P) (± 0.001mm) were determined by Leica Application Suit Ver.3.8 Imaging
Software. Form Factor (FF), Circularity (C), Roundness (RD), Rectangularity (REC), Aspect Ratio (AR)
and Ellipticity (EL) were used for otolith shape analyses. Paired t-test, Wilcoxon tests were used for
analyses. Results-Discussion: There is no differences between right and left asteriscus in terms of
otolith length. But otolith breadth of asteriscus are different from between right and left (P?0.01). OL
and OB are different in the lapillus between right and left otoliths (P?0.01). Right and left sagittal
otoliths are similar in terms of OL and OB (P?0.05). Otolith shape index are separately calculated for
right and left three otolith pairs. FF, C, RD, REC, AR, EL for left asteriscus are 5.0542 ± 0.0404, 18.459
± 0.166, 0.24733 ± 0.00163, 2.6522 ± 0.0388, 1.1295 ± 0,00560, 0.06005 ± 0.00250, for left lapillus
are 4.0233 ± 0,0268, 14.901 ± 0.0391, 0.22613 ± 0.00141, 1.1725 ± 0.0193, 1.3194 ± 0.00733, 0.08883
± 0.00175, for left sagittal otoliths are 1.8049 ± 0.0349, 52.170 ± 0.756, 0.041396 ± 0.000987, 0.2084
± 0.0108, 5.3108 ± 0.0610, 0.67725 ± 0.00591, respectively. This is the first study for determining the
shape index for lapillus, sagittal otoliths of tarek. Acknowledgements:This study was supported by
TUBITAK(Project No:215Z148).