Study on some of population dynamics parameters of Austruca iranica (Pretzmann, 1971) in the northern coastline of Qeshm Island

The present study aimed to investigate some population dynamics parameters of Austruca iranica on northern beaches of Qeshm Island from February 2019 to January 2020. Of the 551 specimens examined (327 males and 224 females), the overall sex ratio (m/f=1.5 obtained. ( p<0.01). The minimum, maximum, average carapace width (±SD) obtained 1.89, 17.04 and 10.9 ± 2.34 mm for males and 3.56, 16.59 and 10.61 ± 2.36 mm for the females. The average weight (±SD) of male and female crabs was calculated 0.86 ± 0.65 g (with a range of 0.009-2.72 g) and 0.58 ± 0.32 g (with a range of 0.02-1.97 g), respectively. The carapace width-body mass relationship was estimated W=0.0005CW^2.98 for males and W=0.0009CW^2.69 for females. The male and females crabs showed isometric growth pattern and negative allometric pattern, respectively. The estimated growth parameters were 〖CW〗_∞=22.58 mm, k=0.79 year-1 and t_0=-0.22 year-1. Total mortality rate and maximum life span were calculated 3.64 year-1 and 3.6 years, respectively. The minimum, maximum and average (±SD) fecundity were 7946, 2953 and 15038 eggs, respectively. Size at the onset of maturity was 9.7 mm based on carapace width in females. The results will help to better understand the biological characteristics of this species in order to conserve it. Additionally, due to the high ecological value of this species and its role in the food chain, the basic information obtained can be used in ecosystem-based fisheries management.