黄鮟鱇繁殖生物学研究

Reproductive biology of yellow goosefish Lophius litulon

以2008年9月至2009年7月在黄海南部捕获的644尾黄鮟鱇(Lophius litulon)为对象,对该种鱼的繁殖生物学进行了研究。结果表明,所采样本性比接近于1︰1(2=2.61,P>0.05);但全长在251～400mm范围时,雄性个体数量远超过雌性(P<0.01);全长在450～550mm范围时,雌性个体数量多于雄性(P<0.01);全长大于550mm范围时,个体均为雌性;冬季,雄性个体数量占绝对优势(P<0.01)。利用逻辑斯蒂拟合方程估算的黄鮟鱇50%个体初次性成熟全长L50,雄性为332mm,雌性为483mm。通过对性腺指数的月变化和不同卵巢发育阶段雌性个体所占比例的分析,初步推测黄鮟鱇产卵时期为2-6月份,繁殖盛期为3-4月份;其绝对繁殖力为(614820±253800)粒,相对繁殖力为(244±43)粒/g。黄鮟鱇不同性腺发育阶段的肝脏指数存在显著变化,雌性,F=9.97、P<0.01;雄性,F=4.48、P<0.01,肝脏在该鱼种卵巢发育过程中可能起到了能量供给作用。鮟鱇类资源对捕捞的承受压力极其脆弱,50%个体初次性成熟全长可作为其资源管理的基础生物学指标。本研究旨在为黄鮟鱇的种群数量变动研究和渔业管理提供基础资料。

Yellow goosefish （Lophius litulon） is distributed in western Pacific,including East China Sea,Yellow Sea,Bohai Sea,Japan and Korean waters.In recent years,as traditional fishery resources recession being serious,yellow goosefish is playing a more and more important role in Chinese fisheries.Presently,it is mainly captured by movable stow net,with an average yearly catch of 1.2×104 t in Jiangsu and Zhejiang provinces.However,there were few studies on this species,especially on its reproduction biology.The reproduction of yellow goosefish was studied from the data collected between September 2008 and July 2009 in Southern Yellow Sea.A total of 644 specimens were studied.The overall sex ratio was close to one （X2 =2.61,P0.05）,but male outnumbered female when its total length was in the range of 251 400 mm （P0.01）.Moreover,there were more male specimens in October,November and December than females （P0.01）.Females outnumbered males in size classes greater than 450 mm （P0.01） and no male larger than 550 mm was found,which was thought to be caused by different growth rate of female and male specimens,while females grew faster than males.The total body length of 50% male and female individuals reaching sexual maturity （L50） was estimated by logistic equation.The estimated mean total body length L50 was 332 mm for males and 483 mm for females,which indicated that the stock was vulnerable to overfishing.By analyzing the monthly changes in the values of the gonadosomatic index （GSI） and percentage of females in different gonadal stages,it was found that the reproduction of yellow goosefish took place during February and June,especially in March and April.The mean absolute fecundity and relative fecundity were found to be 614 820 ± 253 800 and 244±43,respectively.The absolute fecundity （F） was of apparent functional relation with total length （TL） and of linear functional relation with body weight （BW）,and the expressions of the relations were F=0.029 7TL 2.6511 （R2 =0.903 8） and F= 122.87 BW＋120 287 （R2 =0.794 5）,respectively.The mean diameter of ripe gonadal eggs was 1.2 mm,which showed just one peak value,indicating this species was total spawners.Along with the development of gonad,hepatosomatic index （HSI） also changed apparently,which indicated that liver played an important role in the maturity process of yellow goosefish.The condition factor （K） changed apparently all through the year for females and males,which had the smallest value in February and March,respectively,corresponding to the highest GSI value.