文章摘要
麻秋云,牟秀霞,任一平,孙远远.东、黄海星康吉鳗生长、死亡和单位补充量渔获量[J].水产学报,2018,42(6):881~888
东、黄海星康吉鳗生长、死亡和单位补充量渔获量
The growth, mortality and yield per recruitment of white-spotted conger (Conger myriaster) in the Yellow Sea and the East China Sea
投稿时间:2017-11-10  修订日期:2018-01-07
DOI:10.11964/jfc.20171111040
中文关键词: 星康吉鳗  生长  死亡  单位补充量渔获量  东海  黄海
英文关键词: Conger myriaster  growth  mortality  yield per recruitment  East China Sea  Yellow Sea
基金项目:中央高校基本科研业务费专项(201612004)
作者单位E-mail
麻秋云 中国海洋大学水产学院, 山东 青岛 266003  
牟秀霞 中国海洋大学水产学院, 山东 青岛 266003  
任一平 中国海洋大学水产学院, 山东 青岛 266003
青岛海洋科学与技术国家实验室, 海洋渔业科学与食物产出过程功能实验室, 山东 青岛 266237 
renyip@ouc.edu.cn 
孙远远 日照市海洋与渔业研究所, 山东 日照 276800  
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中文摘要:
      依据2011年、2016年和2017年在东、黄海进行的底拖网调查数据,研究了星康吉鳗的生长参数、死亡系数和单位补充量渔获量(YPR)。星康吉鳗的体长体质量关系和生长方程的拟合结果表明,其条件因子a估计值为4.5×10–4,其异速生长系数b的估计值为3.3。其渐近体长L的估计均值为102 cm,生长速率K的均值为0.21/年,理论上体长为零时的年龄t0估计均值为–0.19。通过Pauly经验公式求得星康吉鳗的自然死亡系数(M)为0.33。体长转换的渔获曲线求得总死亡系数为3.36,进而求得现阶段的捕捞死亡系数(F)为3.03,开发率高达90%。此外求得现阶段星康吉鳗的开捕体长为30 cm,对应的开捕年龄为1.47龄,远小于其体质量生长的拐点年龄(3.70龄)和临界年龄(3.39龄)。本研究根据单位补充量渔获量模型,估计其在不同自然死亡系数和开捕体长的情况下随捕捞死亡系数的变化曲线,并估算其生物学参考点。随F增加,YPR先增加到最大值,再逐渐减小。现阶段星康吉鳗的YPR为27.14,而当M为0.33时Fmax估计值为0.38,YPRmax为52.89,即将F降低为1/8,可获得将近2倍的YPR;对应的F0.1为0.255,比Fmax降低了三分之一,YPR0.1(50.38)只比最大值降低了不足5%。M越大,求得的生物学参考点越大,可获得的YPR越小;当开捕体长增加时,FYPR都会有不同程度的增加。因此,现阶段中国东黄海星康吉鳗的开发率过高,开捕体长过小,处于过度捕捞的状态。为了维持星康吉鳗种群的生态健康、实现该渔业的可持续发展,建议大幅削减其捕捞强度,降低捕捞死亡系数,同时增加开捕体长。
英文摘要:
      The objective of this study was to provide biological reference points for the fisheries management of Conger myriaster in Yellow Sea and East China Sea. Specifically, we projected the yield per recruitment (YPR) model for C. myriaster, and obtained the biological reference points, such as Fmax and F0.1, and the suggested length of first capture (L50). Through the scientific survey and the commercial fishery survey in the Yellow Sea and East China Sea in 2016 and 2017, 657 individuals of C. myriaster were collected and measured for the total length (cm) and weight (g), in which 256 samples were analyzed for their age according to the otoliths. Based on these 657 samples, the weight-length relationships were studied by a power law model. The condition factor a estimate was 4.5×10-4, indicating the slender eel-like body shape of C. myriaster, while the estimate of parameter b was 3.3, meaning that C. myriaster tends to become relatively fatter or have greater girth as it grows longer. The von Bertalanffy growth model was used to analyze the length-age relationships based on those 256 samples with age data. The asymptotic length L was estimated to be 102 cm, and the estimate for t0, the age at which weight and length were zero, was -0.19. The exponential rate K of approach to the asymptotic length was 0.21 per year, indicating the slow growth rate of this larger demersal carnivorous species. Five scientific bottom trawl surveys were conducted in Haizhou Bay in March, May, July, September and December, 2011, in which 715 samples were collected and measured. In order to estimate the instantaneous total mortality rate Z, these samples were used to project the (length-converted) linearized catch curve to length-frequency data. This catch curve indicated that the estimate of Z was 3.36 and the length of first capture (L50) was 30 cm, meaning that the age of first capture is 1.47 years. The Pauly empirical formula evaluated the natural mortality M to be 0.33, according to the above growth parameters and the water temperature. Therefore, the fishing mortality F was 3.03, and the exploitation ratio was 90%. Based on all above estimates for the growth and mortality parameters, the yield per recruitment models were projected for C. myriaster. YPR increased to maximum, then decreased, when F kept increasing. Different M (0.23, 0.28, 0.33, 0.38 and 0.43) and different lengths of first capture (30 cm, 40 cm, 48 cm, 56 cm and 67 cm) were considered in the YPR model. When M increased, the estimates for Fmax and F0.1 would increase with smaller YPR, while the increase of L50 would result in greater Fmax, YPRmax, F0.1, and YPR0.1. The current YPR of C. myriaster was 27.14. When M=0.33, Fmax was 0.38, one eighth of the current F, while YPRmax was 52.89, nearly double of the current YPR. And when M=0.33, F0.1 was 0.255, 30% smaller than Fmax, while YPR0.1 was smaller than YPRmax by 5%. In conclusion, this fishery is undergoing heavy fishing pressure, with less length of first capture and extremely high fishing effort. Therefore, in order to keep this population health and the sustainable development of this fishery, we suggest to decrease the fishing effort largely and increase the length of first capture. For example, if F decreases from 3.03 to 2 and L50 increases from 30 to 40 cm, YPR would increase by 89%.
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