闽东渔场小黄鱼种群生态学参数的变化

研究了2003—2005年闽东渔场小黄鱼渔获群体的生态学参数,并结合历史资料和2008年总渔获量,探讨其群体变化趋势及管理策略.研究结果表明:2003—2005年小黄鱼渔获群体的渐近体长L∞为261.17 mm、渐近体质量m∞为217.28 g、生长速率k为0.513 0t、0为-0.601 0(理论体长为零时的年龄)、体质量生长拐点tr为1.234 7龄,总死亡系数为2.215 2,自然死亡系数为1.049 9,捕捞死亡系数为1.165 3,开发比率为0.526 0.与1996—1997年相比,渔获群体优势体长和平均体长略有增大,但与1960年相比,L∞、m∞趋小,生长系数k加大,体质量生长拐点tr提前,群体结构简单化、个体小型化、低龄化、性早熟化相当明显,说明目前小黄鱼群体的生态状态仍很脆弱.因此,必须进一步强化管理,严格控制渔业的投入量和产出量,实施开捕规格等有力措施,实现小黄鱼渔业的可持续发展.

Changes in Ecological Parameters of Small Yellow Croaker,Pseudosciaena polyactis,in Eastern Fujian Fishing Ground

According to the biological data of Pseudosciaena polyactis collected in eastern Fujian fishing ground during 2003～2005,the population structure,parameters of growth and mortality are studied.Compared with previous studies and the total fishing capture in 2008,variation tendency in population structure of P. polyactis was discussed.The growth parameters of P. polyactis were: L_∞=261.17 mm, m_∞=217.28 g, k =0.513 0, t_0 =-0.601 0 ( t_0 is the age when the theory body length is 0), t_r =1.234 7 ( t_r is the age of the inflexion point of body mass growth),the rates of total mortality,natural mortality and fishing mortality were found to be 2.215 2,1.049 9 and 1.165 3,respectively,and the exploitation rate was 0.526 0.The dominant body length and mean body length are longer than that of 1996～1997,but compared with the population structure of stocks in 1960,it is evident that the adults were premature in fast growth while they became smaller and younger,it may be caused by the reasons that the input-output of fishing in this area was enhanced,and the actual catch of P. polyactis annually has exceeded their maximum sustained yield and maximum sustained efforts.Therefore,the protection and management of the fish resources should be intensified,and powerful measures should be taken to control the fishing efforts and catches,especially the capture size,thus to restore the fishery resources,and achieve sustainable development and sustainable use of fish stocks.