نوع مقاله : مقاله پژوهشی
نویسنده
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
This survey was conducted from Babolsar to Bandar-e-Torkaman in the southern part of the Caspian Sea. Specimens were collected from commercial catchs (Beach seine net, mesh size 5 mm). Sampling was carried out monthly (from Sep. 1993 to Sep. 1994 ) to evaluate the biological charactristics, including total and fork length, weight, age, gonad weight and sex. The results indicated that the scales and operculum were suitable for determining the age though the operculum gave better results than the scale. Since the first annulus has not appeared on the scale and it is very difficult to distinguish annuli on the scales of old specimens. This study also shows that the maximum growth rate is belong to the age of 3 years. The b value regression between fork length and weight was 2.940. The relation between scale radius and circuli number, and growth were: C = 4.609 R 0.8282 , L(t) = 322.4 [1-exp(-0.361(t+0.013))]. Sex ratio was 1:3.14 and female dominated. The Gonado Somatic Index (GSI) indicates that the spawning activity occures on July-August. Males ripen earlier than females. Furthermore the numbers of circuli in different ages and condition factor (k) relation between total length and fork length and between age and weight were obtained.
کلیدواژهها [English]
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