绿鳍马面Tun年龄生长与合理利用

对东海区的绿鳍马面Ｔｕｎ样本鱼进行生物学测定，测出各龄鱼的年轮轮径及椎体半径，运算出各龄鱼的理论平均全长，求出生长参数，探讨生长规律。再依据Ｂ－Ｈ模型计算、分析在不同开捕年龄和不同捕捞强度下的单位补充量渔获尾数，单位补充量平均资源重量、渔获物平均年龄和单位补充量渔获量的情况。结果表明，该资源已过度捕捞，应采取降低捕捞强度和将开捕年龄控制为３龄等措施进行合理利用和保护。     

东海区黄鲫资源的利用现状及合理利用探讨

对采自东海区的315尾黄鲫样本鱼进行生物学测定,使用Bhattacharya方法把所获样品体长频率分布划分成不同的平均体长组,推算出各个组的年龄,求出生长参数,探讨生长规律.再依据B-H模型计算、分析在不同开捕年龄和不同捕捞强度下的单位补充量渔获量（YN/R和Yw/R）、单位补充量资源量（^-Pw/R和^-PN/R）、渔获质量（平均体质量Wy、平均体长^-L-y和平均年龄^-T-y）的情况.结果表明,该资源已过度捕捞,应采取适当措施来保持资源的可持续利用：若保持当前捕捞强度不变,则必须把开捕年龄限制在2.38龄较合适;若能同时改变捕捞强度和开捕年龄,则可以把当前的开捕年龄限制在1.50龄,捕捞死亡率降到1.34,这样黄鲫资源仍能够得到保护和合理利用.[中国水产科学,2006,13（3）：485-491]     

达里湖瓦氏雅罗鱼资源现状及合理利用探讨

采用2008年12月和2009年12月在达里湖获取的瓦氏雅罗鱼(Leucisus waleckii)样品,对其基础生物学进行测定,依据B-H模型,计算并分析在不同开捕年龄和不同捕捞强度下的单位补充渔获量(YN/R和Yw/R)及渔获质量(平均体重Wy、平均全长TLy和平均年龄Ty)。结果表明,达里湖瓦氏雅罗鱼的生长参数K、TL∞、t0分别为0.1437a-1、38.77cm和-0.5572a;目前开捕年龄和捕捞强度分别为3.52a和0.5256;若保持当前开捕年龄,目前的捕捞强度即可;若保持目前捕捞强度,则开捕年龄可提高到6龄;瓦氏雅罗鱼资源利用不合理之处为大量捕捞4龄以内的鱼,为了合理开发利用和保护达里湖瓦氏雅罗鱼,在当前捕捞强度下,应将开捕年龄应限制在6龄,对应的全长为24cm,体重为126g。     

东海北部和黄海南部鲐鱼生长特性及合理利用

采用2002年11月~2003年8月在东海北部和黄海南部区域(30°~34°N、126°E以西范围)所获取的鲐鱼(Scomberjaponicus)样品,通过观察鲐鱼耳石生长轮和基础生物学测定,研究了鲐鱼的年龄和生长;再依据不完全β函数渔获量方程,计算、分析在不同开捕年龄和不同捕捞强度下的单位补充量渔获量(Yw/R)的变化情况。结果表明,采用Walford方法拟合的鲐鱼生长方程,其生长参数K、L∞、t0分别为0.320、451.4和-1.203。比较不同时期鲐鱼的生长情况显示,20世纪60、80年代和21世纪初期鲐鱼的生长较接近,而20世纪70年代的鲐鱼生长情况与其他3个时期的鲐鱼生长相差较大。比较不同海域鲐鱼的生长情况显示,随着纬度的增加,鲐鱼的个体有增大的趋势,经分析很可能与海水温度有关。根据历史资料推算出鲐鱼的最大年龄(tλ)为9龄;根据最近的采样,推算出鲐鱼的开捕年龄和补充年龄都为0.4年,鲐鱼的自然死亡率为0.355,捕捞死亡率为2.27。利用上述参数,动态综合模型模拟的结果显示,该资源过度捕捞已很严重。若保持当前捕捞强度,则必须把开捕年龄限制在2.9龄;若能同时改变捕捞强度和开捕年龄,则可以把当前的开捕年龄限制在2.0龄,捕捞死亡率降到1.3,这样鲐鱼资源才能够得到保护与合理利用。     

达里湖瓦氏雅罗鱼资源现状及合理利用探讨

采用2008年12月和2009年12月在达里湖获取的瓦氏雅罗鱼（Leucisus waleckii）样品,对其基础生物学进行测定,依据B-H模型,计算并分析在不同开捕年龄和不同捕捞强度下的单位补充渔获量（YN/R和Yw/R）及渔获质量（平均体重Wy、平均全长TLy和平均年龄Ty）。结果表明,达里湖瓦氏雅罗鱼的生长参数K...     

北部湾二长棘鲷生长和死亡参数估计

根据上世纪90年代及60年代的生物学资料，运用体长频率分析法估算二长棘鲷的生长和死亡参数。vonBertlanffy生长方程的主要参数L∞=27．3cm，K=0．45，t0=-O．34；体重的生长拐点为2．12龄；瞬时总死亡率(Z)、瞬时自然死亡率(M)和瞬时捕捞死亡率(F)分别为2.825，1．045和1．78。当前开发率为0．63，资源处于过度利用状态。根据等渔量曲线图分析，当前的捕捞强度过高，而开捕年龄和开捕体长过低，资源出现衰竭现象。综合考虑当前的捕捞强度和社会经济效益，建议北部湾二长棘鲷的最适开捕年龄大于1龄，开捕体长大于120mm。     

长江中上游圆口铜鱼的种群死亡特征及其物种保护

根据葛洲坝(1998～2007年)、重庆(2006～2007年)和合江江段(1998～2005年)的渔业资源调查资料,对圆口铜鱼的种群死亡特征进行了评估,并利用Beverton-Holt模型的单位补充量渔获量方程,分析和探讨了长江中上游圆口铜鱼资源的合理利用.结果表明:1)3个江段各年间的圆口铜鱼开发率和捕捞死亡系数均远远大于相应年份最大允许的开发率和捕捞标准的基准尺度F0.1,3个江段的圆口铜鱼资源均处于严重过度捕捞状况;2)葛洲坝江段圆口铜鱼的最适开捕年龄为4龄(体长330mm),重庆和合江江段圆口铜鱼的开捕年龄应至少为5龄(体长375 mm).为保护圆口铜鱼的资源,建议葛洲坝江段三层流刺网的网日(2a)应大于75 mm为宜,重庆和合江江段的网目(2a)应不小于90 mm且同时需要控制各种渔具的日均作业次数.     

浙江南部海域银姑鱼的生活史参数估算及资源评价

为了评估银姑鱼资源开发状态，实验根据2016年在浙江南部海域底拖网的调查数据，研究了银姑鱼的生活史参数，并基于单位补充量模型对其资源状态进行评价，进而探讨不同自然死亡系数和捕捞选择性对资源评价结果的影响。结果显示，银姑鱼渐近体长估计值为25.36 cm，生长速率为0.32/年，当前开捕体长(13.52 cm)远小于其初次性成熟体长(17.79 cm)；自然死亡系数估计值为0.74，总死亡系数为2.62，当前捕捞死亡系数为1.88。基于以上参数，构建了单位补充量渔获量YPR模型和单位补充量亲体生物量SSBR模型，随着F的增加，YPR先增大后减小，而SSBR则减少。银姑鱼生物学参考点F_0.1为0.78，F_max为3.43，F_20%为0.66，F_40%为0.33，可知当前捕捞强度远大于防止补充型过度捕捞警戒线F_20%。敏感性分析结果显示，自然死亡系数的不确定性将明显影响单位补充量模型的研究结果和相关生物学参考点的估算值，而不同选择性系数，尤其是开捕体长，也直接影响单位补充量模型的结果。研究表明，当前浙江南部近海银姑鱼种群已处于补充型过度捕捞状态，为维持渔业资源的可持续发展，建议适当减小开发力度，增大开捕体长；为提高资源状态评价的准确性，建议减小自然死亡系数的不确定性。本研究可为银姑鱼资源的养护和管理提供科学建议。     

基于Beverton-Holt模型的鲇鱼山水库翘嘴鲌种群管理研究

2007年4月至2008年4月在鲇鱼山水库采集翘嘴鲌(Culter alburnus)样本885尾,对其种群进行了研究,建立了Beverton-Holt种群管理模型.在目前开捕年龄tc=2龄、自然死亡系数M=0.4654、捕捞死亡系数F=0.5485、生长系数k=0.2331的情况下,鲇鱼山水库翘嘴鲌渔获物的平均体长为29.91 cm,平均体重为278.76 g,平均年龄为2.05龄;单位补充渔获量(YW/R)为467.28 g/尾.建议将鲇鱼山水库翘嘴鲌的捕捞年龄提高到3龄,有效地保护性成熟个体,提高种群补充数量,以目前捕捞强度下渔获量达到最大值,获得最大的经济效益.     

东海带鱼繁殖力及其资源的合理利用

根据2003年东海区渔业资源监测网的调查数据，利用单位补充量繁殖力和单位补充量亲鱼资源生物量估算模型，对东海带鱼（Trichiurus japonicus Temminck et Schlegel，1844）渔业资源现状进行分析，结果表明：（1）根据单位补充量繁殖力的估算，当tc=0．5龄、F≥1．15时和当tc=1龄、F≥2．30时，带鱼渔业处在高危险区；而当tc≥1．5龄时，可以承受较大的捕捞压力。（2）根据单位补充量亲鱼资源生物量的估算，当tc=0．5龄、F≥1．22时和当t。=1龄、F≥2．40时，带鱼渔业处在高危险区；而当tc≥1．5龄以上时，可以承受较大的捕捞压力。（3）目前（2003年为例）东海带鱼现行渔业资源状况为：tc=0．5龄、F=2．60，处于高危险区的较高危险点上。因此，在降低现有捕捞强度较难的情况下，建议提高带鱼开捕规格，以便更好地养护东海带鱼，使其资源能得到可持续利用。     

Use of management strategy comparison scatterplots to identify clusters of high‐performing strategies

Abstract A management simulation model was developed to test quota, trip limits and reduced longline hook numbers as alternatives to yearly seasonal (November) closure in South Australian snapper fisheries. Population dynamics equations and maximum‐likelihood parameter estimates were supplied by an age‐ and length‐based stock assessment model. The relative performance of tested management strategies was quantified by comparing change in egg production vs change in average catch, to optimise the trade‐off between reproductive sustainability and catch foregone. Clusters of better‐performing strategies were visually identifiable in management strategy scatterplots. These scatterplots display percentage change from the status quo in egg‐production‐per‐female‐recruit (y‐axis) vs percentage change in catch‐per‐recruit (x‐axis). Evaluated strategies fell into three distinct performance clusters. The best performing strategy extended November closure by 2 weeks. Strategies that retained the November closure performed uniformly better than those that removed it. Further simulation showed this resulted from non‐closure strategies regulating only the commercial sector.     

Eel fishing management in a hypersaline lagoon of southern Sardinia

Some problems of eel fishing in hypersaline coastal lagoons are examined by an analysis of eel catches in Porto Pino, three connected basins of about 441 ha in southern Sardinia, where the average catch of eels, about 19 Kg/ha/year, is roughly half the total catch and over 65% of the gross economic return from these ponds.The parameters of the eel population dynamics and the exploitation rate were estimated from the number and weight of eels in each of three trade-weight categories, into which the catch is divided each day as requested by the market, and from examination of random samples, from each stratum, for age and sex. In the particular case of Porto Pino ponds, the estimated yield of 12 g per recruit seems to indicate that the stock of eels is under-fished.The catch is not proportional to the intensity of effort, but depends on environmental conditions, such as lunar phase and presence of wind and/or bad weather conditions. The catch could be increased by using a larger number of winged fyke nets, but should not be sought by extending the fishing period, because that might harm the juveniles of other commercially exploitable species. It is suggested that yield optimisation could be achieved by concentrating the maximum effort in the period of silver eel migration (October–February). In the Mediterranean area, these months are characterized both by suitable environmental conditions and by a peak in the demand for the product.     

澳洲鲭太平洋群系的资源评估与管理策略

澳洲鲭是西北太平洋重要的经济种类,了解和掌握澳洲鲭太平洋群系资源开发状况对确保其可持续利用具有重要的意义。根据日本中央水产研究所提供的1995—2015年澳洲鲭太平洋群系的生产统计和资源调查资料,利用基于年龄结构的实际种群模型和单位补充量产量模型等进行资源量评估,分析澳洲鲭太平洋群系资源利用情况及其管理策略。结果显示,历年澳洲鲭太平洋群系资源量虽有波动但仍保持在较高水平,2015年资源量最高约为65万t;年平均捕捞死亡系数呈波动下降趋势,2015年捕捞死亡系数只有0.15,近五年平均捕捞死亡系数Fcur=0.33,单位补充量亲体量是未开发时的32.7%,不存在生长型捕捞过度,也不存在补充型捕捞过度,处于可持续开发状态。研究还探讨了水温变化引起自然死亡波动以及不同开捕年龄对澳洲鲭太平洋群系资源状况的影响。研究表明,该渔业目前开发和利用程度合理,建议使用F0.1做为管理参考点进行渔业资源的管理。     

东海中华管鞭虾种群动态及持续渔获量分析

中华管鞭虾为东海区桁杆拖虾和沿岸定置张网作业重要的渔获对象。本文根据2006-2008年桁杆拖虾监测调查数据整理的各月体长频率数据,应用FiSATⅡ软件分析结果表明：Von Bertalanff生长方程的参数K=1.2,极限体长L∞=112.88mm,t0=0.267;根据Pauly经验公式估算的自然死亡系数M=2.03606;由变换体长渔获曲线法估算的总死亡系数Z=4.71,利用率E=56.77%,开捕体长Lc=65.32mm;应用体长VPA方法估算的年平均资源量为47.74×10^9ind、2.58×10^4t。通过单位补充量产量、产值分析表明,该群体利用合理,开捕体长亦处最佳位置,若降低10%左右的捕捞努力量水平,既能使产值最大化（4.92亿元）,又能实现中华管鞭虾的可持续利用。     

闽南、台湾浅滩渔场二长棘鲷的生长特性

根据1998年7月至2000年6月闽南、台湾浅滩渔场二长棘鲷的生物学资料,研究其年龄组成和生长特性.二长棘鲷捕捞群体由0～Ⅵ龄组7个世代组成,以0龄组为主,Ⅰ龄组次之,平均年龄为0.71龄.应用vonBertalanffy生长方程拟合的生长参数L∞=244.56mm,K=0.2313,t0=-1.1817,体重的生长拐点为3.71龄.与上世纪80年代初相比,二长棘鲷群体结构已发生很大的变化,个体早熟化,生长速度加快,捕捞群体小型化、低龄化,二长棘鲷幼鱼损害情况严重,资源处于过度利用状态.根据渔获组成、资源现状及生长特性,建议加强对二长棘鲷幼鱼的保护和管理,合理利用其资源.     

南海北部主要捕捞种类最适开捕规格研究

根据南海水产研究所使用elefan技术基于体长数据求得的南海北部50种主要捕捞种类的von Bertalanffy生长参数，以Beverton-Holt模型计算最适开捕年龄后用von Bertalanffy生长方程计算其相应开捕体长，再参考实际调查最小性成熟体长、临界体长、拐点体长和Froese-Binohlan经验公式计算的初次性成熟体长范围等数据确定最适开捕规格；部份分海区研究的种类先确定同一种类于各海区的最适开捕规格，再考虑不同海区的适用性确定其在南海北部的最适开捕规格。本文研究了南海北部50种主要捕捞种类的最适开捕规格，结果表明，所求得的最适开捕规格比原广东、广西、福建“水产资源繁殖保护实施细则暂行规定”的开捕规格都大；建议选择19种在以往的生产中和历次调查研究中出现频率较高、产量较高的主要捕捞种类作为南海北部实行开捕规格保护幼鱼幼虾措施的指标种，并提出开捕规格的随机抽样检查方法。     

Age‐based demographic assessment of fished stocks of Lethrinus nebulosus in the Gascoyne Bioregion of Western Australia

Abstract Age‐based demographic analyses were undertaken to assess the current status of fished stocks of spangled emperor, Lethrinus nebulosus (Forsskål) in the Gascoyne Bioregion of Western Australia. Differences in age and growth characteristics were detected for samples collected from different assessment zones, with North Gascoyne fish observed to grow faster and reach a shorter average maximum length and younger average age than South Gascoyne fish. A significant difference in North Gascoyne catch‐at‐age data from different time periods demonstrated historical effects of fishing on population age structure. Instantaneous rates of fishing mortality (F) from catch‐curve analyses of age – frequency data sampled for the North Gascoyne stock from recreational fishing catches from April 2007 to March 2008 were beyond the limit reference point compared with estimated instantaneous rates of natural mortality (M) (i.e. F > 1.5M), indicating that there is currently a risk to the sustainability of that stock.     

Demographic characteristics of southern flounder,Paralichthys lethostigma,harvested by an estuarine gillnet fishery

Abstract The North Carolina (NC) southern flounder, Paralichthys lethostigma (Jordan and Gilbert), stock has experienced heavy exploitation during the past two decades. Recently, several management changes were initiated to lower harvest rates and restore stock biomass. Here, the age, growth and maturity of southern flounder harvested by a southeast NC estuarine gillnet fishery are characterised and compared with observations from previous studies and with statewide data on the stock to evaluate any regulatory effects and assess the potential for selective removal by the fishery. Despite regulatory changes, the estuarine gillnet fishery still harvested mainly age‐0 and age‐1 individuals that were mostly immature, meaning that the current fishing practices likely only allow a small portion of the harvestable stock the opportunity to reproduce. Relative to length‐at‐age patterns observed within the stock from statewide collections, fish captured by the gillnet fishery were above average length at each age; the legal size and the gear appeared to cause selective harvest of the fastest growers within each cohort. If the demographic characteristics of the catch observed in this study are broadly representative of gillnet fisheries in other estuarine nursery habitats throughout NC, the harvesting tactics in this sector of the fishery have the potential to cause population‐level effects and negatively affect long‐term fishery yield.     

Results of whitefish, Coregonus lavaretus L., fingerling stocking in the lower part of the Sotkamo water course, northern Finland

Abstract. The efficiency of stocking with whitefish, Coregonus lavaretus L., fingerlings was assessed in a large lake system with a naturally reproducing local whitefish stock. After the start of the stocking programme, the whitetish catch increased. The proportion of stocked whitefish in the catch was ca. 50%. The calculated yield per thousand released fingerlings was 57 ± 18kg. Further, the efficiency of stocking may be indicated by the following facts. Prior to stocking, the whitefish catch decreased, evidently due to recruitment overfishing. It was suggested that this situation was corrected by stocking with fingerlings and the whitefish catch then increased. The catch per unit of effort (CPUE) generally decreases with increasing fishing effort, but in this case the CPUE remained at the same level in spite of a considerable increase in fishing effort. The growth rate depends on the density of the fish stock. In this case the growth rate declined, possibly due to the fact that fingerling stocking increased the population density.     

Development and testing of a Bayesian population model for the bigeye thresher shark,Alopias superciliosus,in an area subset of the western North Pacific

A Bayesian population modelling tool integrating separable virtual population analysis, per‐recruit models and age‐structured demographic analysis was developed for the bigeye thresher Alopias superciliosus (Lowe) population in an area subset of the western North Pacific. The mortality rates for years 1989–2016 were estimated, various biological reference points and associated risks of decline were also estimated, and alternative harvest strategies for the stock were evaluated. Estimates of the posterior mean of fishing mortality for bigeye thresher shark suggest fishing pressure has been high in recent years (2011–2016). The estimated population growth rate (λ) (without fishing) obtained from age‐structured demographic model was relatively low (λ = 1.01 per year; 95% confidence intervals of 1.00 and 1.03 per year). Risk analyses revealed that only low levels of fishing pressure (10% of the current fishing pressure) over a wide range of ages could maintain a relatively low risk of population decline for bigeye threshers. Sensitivity testing indicated that the model is robust to prior specification. The developed framework could be used as an assessment tool to evaluate the risk of decline for other widely distributed pelagic shark species where insufficient catch and effort data are available.