Investigation of some growth characteristics of dipturus oxyrinchus (Linnaeus, 1758) inhabiting the Northeast Mediterranean

This study aimed to determine the age and growth characteristics of long-nosed skate (Dpturus oxyrinchus) from North East Mediterranean. For thispurpose, total 255 long-nosed skate ranged 12.2-93.5 cm in total lenght and 8.34-3828 g in weight were collected as non-target species from a commercial fishing boat between May 2015-June 2016. The percentage of females and males in all samples was 56.07 % and 43.93 % respectively. The female/male ratio was determined as 1:1.27. The total length-weight relationship equations for all indivuals was found as W = 0,0016(TB)3,1974 with determination coefficient R² = 0.9728. By using the von Bertanlanffy equation, the growth parameters of long-nosed skate were found as L∞ = 178.340 cm, k = 0.0477, t0 = -1.2704 for all individuals; L∞ = 171.185 cm, k = 0.0576, t0 = -1.2693 for females and L∞ = 177.781 cm, k = 0.0545, t0 = -1.0970 for males and W∞ = 25064.259, k = 0.053, t0 = -1.259 for all individuals; W∞ = 27905.260, k = 0.049, t0 = -1.196 for females and W∞ = 35982.320, k = 0.051, t0 = -1.268 for males. In this study, age reading was conducted by two indepentedent readers and mean percentage error index (IAPE) was found as 7.73 %. The maximum absolute growth was found as 9.33 cm in fish with 5-6 years of age. The maximum relative growth was calculated as 36.39 % in fish with 1-2 years of age. Both in absolute and relative growth abserved as minimum in the 11-12 age group fishes. Mean condition factor valu of population was calculated as 0.363. The highest condition fac-tor value calculated as 0.416 in the age group 8 and the lowest condition factor value was cal-culated as 0,308 in the age group 2. In conclusion, growth data belonging long-nosed skate from North East Mediterranean was obtained.