北部湾花斑蛇鲻生物学特征的演化

摘要

根据1959-1960年、1992-1993年、1997-1999年和2009-2010年北部湾底拖网渔业资源调查的生物学资料,对花斑蛇鲻(Saurida undosquamis)群体组成、生长和生殖力参数等生活史特征进行了研究.结果表明,花斑蛇鲻的平均体长从1959-1960年的185.5 mm下降到1992-1993年的163.1mm、1997-1999年的133.2 mm和2009-2010年的130.5 mm,相应地平均体质量分别为66.5 g、46.4 g、23.8 g和22.6 g.1959-1960年、1992-1993年、1997-1999年和2009-2010年间的Von Bertanaffy生长方程的渐近体长(L∞)、生长参数(k)和理论初始年龄(t0)分别为497.8 mm,0.26,-0.49; 424.1 mm,0.28,-0.48; 385.3 mm,0.33,-0.41和342.5 mm,0.39,-0.36.体质量拐点年龄(tr)分别从1959-1960年的4.05龄提前到1992-1993年的3.66龄、1997-1999年3.05龄和2009-2010年2.43龄.50％性成熟体长(L50)则从1959-1960年111.2 mm下降到1992-1993年的105.2 mm、1997-1999年的95.6 mm和2009-2010年的96.7 mm.对于同一体长组,当前花斑蛇鲻的个体相对生殖力比20世纪60年代上升了56.4％.花斑蛇鲻种群生活史特征参数的一系列变化表明,在捕捞引起进化背景下,北部湾花斑蛇鲻种群产生了适应性进化反应,种群明显趋向小型化和低龄化,生长速度加快,性成熟提前.%We evaluated the population structure, growth and fecundity of Saurida undosquamis (Richardson) in the Beibu Gulf using biological data obtained from bottom trawls conducted during 1959-1960, 1992-1993, 1997-1999 and 2009-2010. The mean body length of S. undosquamis decreased from 185.5 mm in 1959-1960 to 163.1 mm in 1992-1993, 133.2 mm in 1997-1999, and 130.5 mm in 2009-2010. Similarly, mean body weight decreased from 66.5 g in 1959-1960 to 46.4 g in 1992-1993, 23.8 g in 1997-1999, and 22.6 g in 2009-2010. The asymptotic length (L∞), growth coefficient (k), and zero-length age (t0) in the von Bertanaffy growth equation during the periods 1959-1960, 1992-1993, 1997-1999, and 2009-2010 were 497.8 mm, 0.26, -0.49; 424.1 mm, 0.28, -0.48; 385.3 mm, 0.33, -0.41, and 342.5 mm, 0.39, -0.36, respectively. The inflexion age of body weight decreased from 4.05 years between 1959-1960 to 3.66 years between 1992-1993, 3.05 years in 1997, and 2.43 years between 2009-2010. Body length at 50% sexual maturity (L50) decreased from 111.2 mm between 1959-1960 to 105.2 mm between 1992-1993, 95.6 mm between 1997-1999, and 96.7 mm between 2009-2010. For the same body length, the current individual relative fecundity of S. undosquamis increased by 56.4% compared to the early 1960s. The changes in the life history traits of S. undosquamis in the Beibu Gulf during the last five decades suggest that the stock has undergone fishing-induced evolution (FIE), characterized by miniaturization, an increase in the speed of growth, and a decrease in time to maturity.