【作者】 张国政；

【导师】 金显仕； 李显森；

【作者基本信息】 中国海洋大学 ， 渔业资源， 2010， 硕士

【摘要】 伴随全球海洋渔业资源的全面衰退和生态系统的不断退化,海洋渔业资源的管理理念正在发生深刻变化；特别是在高强度的捕捞之后,充分了解鱼类生物学特征、种群动态及其对环境变化的响应机制就成为资源合理利用的重要前提。小黄鱼(Larimichthys polyactis Bleeker,1877)是我国重要的海洋经济鱼类之一,广泛分布于渤海、黄海和东海,是底拖网作业的主要捕捞对象之一,60年代中期以后,由于捕捞强度的不断增大,资源量开始大幅下降,其群体结构和生物学特征也发生了很大的变化,个体小型化、低龄化趋势逐渐加剧。本研究根据1960、1985、1998、2008年和2009年在黄海中南部的小黄鱼底拖网调查资料,研究了黄海中南部小黄鱼的种群结构和生物学特征及其年际变化情况,初步讨论了小黄鱼生物学特征对人类捕捞活动和环境变化的响应情况。主要结果如下：首先,根据1960、1985、1998和2008年以及2009年黄海中南部渔业资源底拖网调查数据,研究了小黄鱼群体结构及其年际、季节变化情况,并对产卵群体的年际变化特征进行了分析。结果表明,黄海中南部小黄鱼的体长、体重组成及其年龄结构均具有逐渐减小的趋势,且年代间差异显著,体长频率分布逐渐由双峰态向单峰态转变；对吕泗渔场产卵群体的结构分析表明：2009年3个月份(3月、4月、5月)的平均体长、优势体长组并无显著差异；产卵群体的年间变化分析显示,平均体长、平均体重亦均具有逐渐减小的趋势。其次,利用2008年7～12月中旬黄海中南部的底拖网调查资料,研究了2～7月龄小黄鱼当年幼鱼的生长情况,阐述了耳石生长与体长、体重生长的关系,通过决定系数(R2)和残差平方和(RSS)两项指标,比较和论述了7种生长方程对小黄鱼当年幼鱼生长描述的拟合程度。结果表明：从7月到12月,小黄鱼当年幼鱼的体长月均增加1.32±0.57 cm,体重月均增加4.34±0.65 g；体长-体重关系式为W=3.76×10-5L2.8303,幂指数b接近于3；通过研究耳石的长度、重量与体长、体重的关系,发现耳石的长度和重量与体长、体重关系密切,在三种回归方式(Liner、Power、Quadratic)中,乘幂函数的相关性最好；采用七种生长方程对小黄鱼当年幼鱼的生长进行拟合,从决定系数R2及残差平方和RSS的数值来看,VBGF(Von Bertalanffy生长方程)、LGF(Logistic生长方程)、GGF(Gompertz生长方程)三种数学模型的拟合度较为接近,而Logarithmic、Inverse、Quadratic以及Cubic四种生长方程的拟合度较为接近且拟合效果明显好于VBGF、LGF、GGF;七种拟合模型中,Cubic生长方程对小黄鱼当年幼鱼生长的拟合度最高。第三,根据2008年4月到2009年3月在黄海南部海域底拖网采集的小黄鱼样品的生物学资料,研究了黄海中南部小黄鱼群体的生长、死亡情况,通过Beverton-Holt模型评价了资源的利用状况,并与临界体长、拐点体长等进行比较,确定了最适开捕体长。结果显示：(1)小黄鱼的体长和体重关系式为W=0.0268×L2.814；(2)应用FiSAT软件拟合的von Bertalanffy生长方程参数为L∞= 27 cm, k=0.45 a-1, t0=-0.47 a;(3)总死亡系数Z=2.40,自然死亡系数M=0.77,捕捞死亡系数F=1.63,开发率E=0.68；(4)在现行的捕捞死亡系数F=1.63下,Yw/R达到最大值时开捕年龄和开捕体长分别为1.41 a和15.42 cm；拐点年龄和体长为1.83 a和17.41 cm；临界年龄和体长为1.70 a和16.82 cm。现阶段小黄鱼资源已处于过度开发状态,综合考虑渔民利益和资源修复需要,建议黄海南部小黄鱼的最适开捕规格定为14.83 cm。最后,根据1960年、1985年、1998年和2008年4个年份在黄海中南部进行底拖网调查获得的小黄鱼生物学资料,对其生物学特征及其年代际变化进行分析,并运用灰色关联分析法和计算相关系数研究摄食等级、渔船功率以及海表温度3因素对小黄鱼生物学特征年代际变化的影响程度。结果表明,黄海中南部小黄鱼的生物学特征在4个年代间发生了明显变化,其个体生长加快、渐近体长减小、体重生长拐点提前、死亡系数增大；灰色关联分析显示,渔船功率、摄食等级和海表温度与黄海中南部小黄鱼生物学特征年代际变化的关联度分别为0.7238,0.6903,0.6396。综合各因素的关系,捕捞因素是造成小黄鱼生物学特征年代际变化的最主要原因。更多还原

【Abstract】 With the recession of world marine fishery resource and the degradation of ecosystem, the management ideology of marine fishery resource is undergoing profound changes; particularly under the high intensity fishing environment, it is very important to fully understand fish biological characteristics, the dynamics of populations and their response to environmental changes, which is the important prerequisite for rational utilization of fishery resource.Small yellow croaker (Pseudosciaena polyatics bleeker) is a warm-temperate species and one of the most important commercial marine fish in our country, and is widely distributed in the Bohai Sea, the Yellow Sea and the East China Sea. It is the main target fish of bottom trawl fishery. Since the mid-1960s, its resource amount greatly declined for the increase of fishing intensity, its population structure and biological characteristics had also changed greatly, such as individual miniaturization and low age structure of population.Based on the data of small yellow croaker collected from the bottom trawl surveys carried out by R/V Beidou in the central and southern Yellow Sea in 1960, 1985,1998,2008 and 2009, the population structure and biological characteristics and their interannual variabilities were analyzed, as well as the responses of small yellow croaker biological chaacteristics to fishing pressure and environmental changes. The main results were as follws:First of all, based on the data collected by the bottom trawl surveys in the central and southern Yellow Sea in 1960,1985,1998,2008 and 2009, the population structure of small yellow croaker and its interannual and seasonal variations were analyzed, especially for the interannual variations of spawning stock. The result showed that the body length and body weight of small yellow croaker population in the central and southern Yellow Sea gradually decreased, age structure became simpler, and the significant differences of these characteristics were found during different years. According to the analysis of small yellow croaker spawning stock structure in Lusi fishing ground, no significant differences were found in the average body length and dominant body length group in March, April and May 2009, however, the average body length of spawnning stock gradually decreased, the distribution of body length frequency changed from double peak to single peak.Secondly, according to the biological data of small yellow croaker collected by the bottom trawl surveys in the central and southern Yellow Sea from July to December in 2008, the growth of small yellow croaker juveniles aged 2-7months was studied, the relationships amont the growth of otolith, body length and body weight were elucidated, the fitting degree of seven growth equation to the growth of small yellow croaker juveniles by two indicators (R2 and RRS). The results showed that the average monthly increase of body length and body weight were 1.32±0.57 cm and 4.34±0.65 g from July to December, respectively. The relationship between body length and body weight was W=3.76×10-5L2.8303, the exponent b was 2.8303. According to the analysis of the relationships among the length and weight of otolith, and body weight and body length of smal yellow croaker, the length and weight of otolith was closely connected with the body length and body weight. The power function is the best model to describe the relationship between the otolith growh with the body length and body weight. von Bertalanffy growth function(VBGF), Logistic growth function(LGF), Gompertz growth function(GGF), Logarithmic growth function(LF), Inverse growth function(IGF), Quadratic growth function(QGF) and Cubic growth function(CGF) were chosen to describe the growth of yearling small yellow croaker. Based on the value of R2 and RSS criterion, the VBGF、LGF、GGF had the similar fitness, the Logarithmic、Inverse、Quadratic、Cubic had the similar fitness, and their fitness was better than those of VBGF. LGF、GGF. The Cubic function had the highest fitness to describe the growth of yearling small yellow croakerThirdly, based on the biologipal characteristics data collected from the bottom trawl surveys in the southern Yellow Sea from April in 2008 to March in 2009, the growth and mortality of small yellow croaker were estimated by the FiSATⅡsoftware, and stock status was evaluated by Beverton-Holt model, combined with the critical body length and the body length of growth inflexion, the optimal capture size was determined. The result showed that:(1) the relationship between body length and body weight of small yellow croaker was W=0.0268 L2.814; (2) growth parameters of the von Bertalanffy growth equation by FiSAT software were as follows:L∞=27.00 cm,k=0.45a-1 and t0=-0.47 a; (3) the total mortality coefficient (Z) was 2.40, the natural mortality coefficient (M) was 0.77, the fishing mortality coefficient (F) was 1.63, and exploration rate (E) was 0.68; (4) Under the fishing mortality coefficient F= 1.63, when Yw/R reached the maximum value, the optimum capture age and size were 1.41a and 15.42 cm, respectively. The age and body length of growth inflextion for small yellow croaker were 1.83a and 17.41cm, respectively, and the critical age and body length were 1.70a and 16.82 cm, respectively. In the present, the fishery resource of small yellow croaker was overexploited, combined with the benefits of fishemen and the demands of fishery resource restoration, we suggest that the optimum catchable size of small yellow croaker in the Southern Yellow Sea is 14.83 cm in the future.Finally, based on biological characteristics data collected by the bottom trawl surveys in the central and southern Yellow Sea in 1960,1985,1998 and 2008, the biological characteristics and their decadal changes of small yellow croaker were analyzed, the gray correlation analysis and correlation coefficient were used to study the effects of sea surface temperature, fishing vessels power and the feeding intensity on the decadal changes of biological characteristics. The result showed that significant changes were found in biological characteristics of smal yellow croaker during different decades, such as the growth rate increased, asymptotic bodylength decreased, the inflexion of body weight decreased, and the mortality rate increased. According to the analysis of gray correlation analysis, the correlation degrees of fishing vessels, feeding intensity and sea surface temperature with the biological characteristics were 0.7238,0.6903 and 0.6396, respectively. From above-mentioned, the decadal changes of small yellow croaker biological characteristics were mainly caused by fishing.更多还原