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Kalhoro Muhsan Ali,Liu Qun,Memon Khadim Hussain,Chang Mohammad Saleem,Zhang Kui. 2014. Population dynamics of Japanese threadfin bream Nemipterus japonicus from Pakistani waters. Acta Oceanologica Sinica, 33(10):49-57
Population dynamics of Japanese threadfin bream Nemipterus japonicus from Pakistani waters
巴基斯坦国日本金线鱼(Nemipterus japonicus)种群动力学的研究
Received:June 04, 2013  Revised:December 29, 2013
DOI:10.1007/s13131-014-0401-1
Key words:Pakistan  Nemipterus japonicus  length-weight relationship  growth  mortality
中文关键词:  巴基斯坦  日本金线鱼(Nemipterus japonicus)  体长体重关系  生长  死亡
基金项目:The special research fund of Ocean University of China under contract No. 201022001.
Author NameAffiliationE-mail
Kalhoro Muhsan Ali College of Fisheries, Ocean University of China, Qingdao 266003, China
Marine Fisheries Department, Fish Harbor west wharf Karachi, Karachi 74000, Pakistan 
 
Liu Qun College of Fisheries, Ocean University of China, Qingdao 266003, China qunliu@ouc.edu.cn 
Memon Khadim Hussain College of Fisheries, Ocean University of China, Qingdao 266003, China
Marine Fisheries Department, Fish Harbor west wharf Karachi, Karachi 74000, Pakistan 
 
Chang Mohammad Saleem College of Fisheries, Ocean University of China, Qingdao 266003, China
Department of Zoology, University of Sindh, Jamshoro 76080, Pakistan 
 
Zhang Kui College of Fisheries, Ocean University of China, Qingdao 266003, China  
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Abstract:
      Japanese threadfin bream Nemipterus japonicus (Bloch, 1791) is among the most abundant and commercially important species in Pakistan. From the coast of Pakistan, four demersal trawl surveys in October-November 2009 and May-June, August, October and November in 2010 were carried out. The purpose of this study is to estimate the population dynamics and status of the stock of the N. japonicus from Pakistani waters based on the research trawl surveys from the research area. The data consist of n=784 length-weight pairs and n=7 530 length frequency with the maximum length and weight of 29 cm and 358 g respectively. The length frequency data were analyzed using ELEFAN method in FiSAT computer package. The parameters of length and weight relationship were b=2.778, a=0.032 and R2=0.973. The estimated von Bertalanffy growth function parameters were L=30.45 cm, K=0.270 year-1. Based on length-converted catch curve analysis the total mortality (Z) during this study was estimated at 0.960 year-1. The natural mortality coefficient (M) was 0.74 year-1 using Pauly's equation (the annual average sea surface temperature was 27℃), therefore, the fishing mortality coefficients (F) were 0.22 year-1. The yield per recruit analysis indicated that when tc was 2, Fmax was estimated at 1.2 and F0.1 at 1.1. When tc was 1, Fmax was estimated at 0.95 and F0.1 at 0.8. Because current age at first capture is about 1 year and Fcurrent was 0.22, Fcurrent is smaller than F0.1 and Fmax, which indicated that the fishery is about in a safe condition. When using Gulland (1971) biological reference point, Fopt was equals to M (0.74). The current fishing mortality rate of 0.22 was smaller than the target biological reference point.
中文摘要:
      在巴基斯坦国日本金线鱼(Nemipterus japonicus,Bloch, 1791)是一个具有重要商业价值的鱼类。在2009年10月,2010年5、8、10月巴基斯坦国执行了四次底拖网调查。基于以上调查数据,本文研究了巴基斯坦国日本金线鱼的种群动力学和种群状态。此数据包括784对体长体重测量、7530个体长测量,最大体长体重分别为29cm和358g。本文应用FiSAT计算机软件的ELEFAN方法分析了体长频数数据。体长体重关系为b=2.778, a=0.032 和 R2=0.973。von Bertalanffy生长方程参数为L=30.45 cm, K=0.270/年。基于体长转换的渔获曲线分析总死亡系数(Z)估计为0.960/年。应用Pauly公式(年平均表层水温为27℃)自然死亡系数(M)为0.22/年。单位补充量渔获量分析指示当tc为2时, Fmax为1.2 和F0.1为1.1。当tc为1时,Fmax为0.95和 F0.1为0.8。因为当前的首次捕捞年龄为1龄和Fcurrent为0.22,Fcurrent 小于F0.1Fmax,所以这个渔业处于安全状态。当应用Gulland (1971)生物学参考点时,Fopt为M(0.74),当前捕捞死亡率(0.22)小于目标生物学参考点。
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