Population dynamics of kiddy shrimp, Parapenaeopsis stylifera (H. Milne Edwards, 1837) in the north-west of Qeshm Island, Iran

摘要

This study was conducted to determine the population dynamics of Parapenaeopsis stylifera in the coastal waters of the Persian Gulf. A total of 423 male and 449 female shrimps was collected monthly by a bottom-trawl net, from March 2011 to June 2012. The populations of male and female shrimps were dominated by adult shrimps (CL > 15 mm) from January to May. Whereas, the juvenile shrimps were dominant from June to September and the averages of CPUE uptrend in these periods, too. The carapace length and weight relationship demonstrated that growth in both sexes was allometric. The asymptotic carapace length (CL infinity) was estimated at 21mm for males and 27mm for females. The growth parameter K was calculated as 1.1 Yr (-1) for males and 1.2 Yr (-1) for females. The total mortality rate for males was more than for females. And the exploitation rates were 0.58 for males and 0.52 for females. The sex ratio identified that it was not a constant 1:1 throughout the year, with 51.49 females. Kiddy shrimps can spawn all year round and have a spawning peak from February to May. The L(m)50 was estimated at 19.03 mm carapace length of female shrimps.