Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
The characteristics of age distribution and growth parameters of lobster population (N. norvegicus) in Icelandic waters were analysed based on length frequency distribution and cohort slicing method. The lobster population had twenty five age groups in which the mean carapace length (CL) was ranged from 7.22 mm at the first age to 76.08 mm at the twentieth five ages. | Journal of Fisheries science and Technology No.3 - 2016 CHARACTERISTICS OF AGE DISTRIBUTION AND GROWTH PARAMETERS OF LOBSTER (Nephrops norvegicus LINNAEUS, 1758) IN ICELAND Vu Trong Dai1, Hreidar Thor Valtysson2 Received: 28/7/2016; Revised: 20/9/2016; Accepted 26/9/2016 ABSTRACT The characteristics of age distribution and growth parameters of lobster population (N. norvegicus) in Icelandic waters were analysed based on length frequency distribution and cohort slicing method. The lobster population had twenty five age groups in which the mean carapace length (CL) was ranged from 7.22 mm at the first age to 76.08 mm at the twentieth five ages. In the period from 1970 to 2011, the age groups of 5 to 10 year olds were in high abundant with 81% of catch prorduction as well as the mean carapace length ranged from 32.41 to 52.42 mm. The mean carapace length of lobster catched in the Southwest fishing area (47.94 mm) was signifficantly higher when compared to those in the Southeast fishing area (44,84 mm). The growth parameters of this species estimated according to von-Bertalanffy equation were: CL∞ = 82.5 (mm), k = 0.1 (yr-1), t0 = - 0.1 and the growth performance index (Φ’) is 3.87. Keywords: Age distribution, carapace length, growth parameter, Nephrops I. INTRODUCTION Norway lobster or Nephrops (N. norvegicus) is a high value benthic decapod crustacean species and is a commercially important target in fisheries of many European countries due to its wide distribution [17]. The global capture production of this species is 66.5 thousand tons [6]. They are caught mainly by trawling during their periodic emergence [2, 3]. In Icelandic waters, this species is distributed in the warmer waters off the southern coast, being most abundant at depths of 110-270 m and temperatures of 6-9°C. Stock assessment of Nephrops seems to be complicated and difficult because of the fact that this species is only caught during the periodic emergence of the individual from them the burrows. .