نوع مقاله : مقاله پژوهشی
نویسنده
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
The bivalvia of Abra ovata belongs to SEMELIDAE family inhabits in Black Sea and Azov Sea; and was introduced to the Caspian Sea in 1939. This species has a significant role on sturgeons' feeding.
384 specimen of this species were studid to determine the growth rate and age composition. The results indicated that the mean length of this bivalve was measured 9.33±2.26 mm with minimum and maximum length of 3.40 and 15.0mm, respectively. There was found a significant difference between the samples of two different depths of 10 and 20m. The dominant length groups for different seasons were as follow:
spring: 3-5mm, summer: 5-7mm, autumn and winter: 9-11mm.
By using Bhattacharya method, 3 individual Cohorts was determined. The length- weight relationship was W=0.0008L2.97 (R2=88.35, n=383). This species has an allometric growth and the Von- Bertalanfy growth equation was calculated L (t) = 14.5 [1 - exp-1.5 (t + 1.89)].
The natural mortality coefficient and relative condition factor were estimated 1.56 per year and 1.053, respectively.
کلیدواژهها [English]
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