Investigating the relationship between Length weight and reproductive characteristics (Rutilus rutilus caspicus, Yakovlev, 1870) on the shores of the Caspian Sea, 2018-2019

Abstract

Introduction: The present research aims to investigate the biological properties of )Rutilus
rutilus caspicus Yakovlev, 1870( The relationship between length and weight was done
with absolute and relative summation.
Materials & Methods: Out of a total of 316 pieces (144 males and 172 females) were
caught in fishing cooperative companies in Golestan province. It was analyzed in the
fishing season of 2017-2018.
Results: The results indicate that the maximum and minimum fork length of the female is
in December and November, respectively (32.5 and 11.3 cm) and in males (25.5 and 10.6
cm) respectively in November. The highest and lowest mean length of the fork in males
were 17.3±0.66 and 15.2±1.27 cm in Bahman, December and Bahman, respectively, and
in females, respectively, in October and November 20.4±2.95 and 16.9±4.71 were
obtained. The sex ratio of male to female fish was calculated as 1:1.2, and no significant
difference was observed with the ratio of 1:1 (p>0.05). The length-weight relationship was
obtained by using statistical chi-square test for female sex W= 0.009 FL3.17111 and for male
sex W= 0.0065 FL3.2818 which indicates a heterogeneous growth pattern (positive
allometric). The mean relative homogeneity with respect to fork length and weight for stage
4 and 5 of sexual maturity was 899±240, 1050±470, and 144±32, 144±32, 159±34,
respectively. The highest and lowest mean absolute correlation of fork length and weight
are 16229±5259 and 21755±12766, respectively, with 45000 and 8000 eggs in fishes, with
a length range of 30-35 cm, 15-20 cm and a weight range of 500-600 gr. 0-100 gr egg count
was observed.
Conclusion: In general, it seems that the stocks of Kalama fish in the Caspian Sea coasts
are highly endangered and it is necessary to provide effective management solutions to
preserve its stocks.