长江口、杭州湾海域渔业资源增殖放流与效果评估

通过长江口、杭州湾海域2004—2006年渔业资源增殖放流前后调查、分析与评估结果表明,增殖放流种类对放流海域总资源补充量的增加有显著作用,放流种类的资源密度指数呈上升趋势,放流种类的资源补充量逐年增加;三疣梭子蟹、海蜇等放流种类在增殖放流区附近形成了区域性渔场,说明资源增殖、修复的效果非常明显;增殖放流整体的经济效益明显,3年总的苗种放流资金与捕捞经济效益的投入产出比平均达到1∶5,连续放流3年以上时增殖的累积效应得以逐渐体现;增殖放流使渔民的收入明显增加,促进了渔区社会稳定。     

象山港黄姑鱼增殖放流效果评估及增殖群体利用方式优化

以回捕渔获重量和对繁殖群体的补充能力为评价指标,借助标志放流-回捕实验,利用模型模拟分析方法,定量评估浙江象山港黄姑鱼(Nibea albiflora)的增殖放流效果;同时,结合其增殖目标定位,探索构建生态高效的增殖群体利用方式。研究结果表明,象山港黄姑鱼增殖群体的捕捞死亡系数为1.31,在该捕捞强度下,11055尾增殖放流鱼苗可产生737 kg回捕渔获收益,同时还向增殖水域补充了554尾初次性成熟个体,增殖放流活动在一定程度上起到了修复象山港黄姑鱼资源、促进渔民增产增收的效果。结果表明,捕捞强度过大是制约象山港黄姑鱼增殖放流功效发挥的重要因素,捕捞死亡系数应降至0.46,同批次黄姑鱼增殖放流所能提供的回捕渔获重量和性成熟个体尾数可分别较现行捕捞强度提升41.49%和326.90%。综上述,象山港黄姑鱼增殖放流的生态和经济功效较为显著,合理降低对增殖群体的捕捞强度是进一步提升其增殖放流效果的必要措施。     

乳山市增殖放流数量又创新高

在近海渔业资源严重衰退的情况下,进行鱼、虾、蟹、蜇等经济品种的增殖放流是修复渔业资源、提高海洋捕捞产量和效益最有效的途径。近年来,山东省乳山市不断增加放流品种,扩大放流规模,社会效益非常显著,达到了渔业增效、渔民增收的良好效果。今年乳山市的增殖放流数量又创新高,共放流苗种近1.2亿尾(只),其中中国对虾3 200多万尾,日本对虾6 500多万尾,梭子蟹500多万只,海蜇1 200多万只。通过回捕调查,产量提高35%~58%,经专家论证,乳山近海渔业资源增殖放流的潜力巨大,有关部门研究决定,明年将进一步增加放流的品种和数量。乳山市增殖放流数…     

渤海对虾渔业的最佳开捕期、过度捕捞和渔业管理问题

我们将模型Y/R=(?)用于研究秋汛对虾渔业不同的开捕期和捕捞死亡对世代相对产量(Y/R)的影响。根据渤海对虾渔业的实际情况,在限定捕捞死亡F_旬≤0.3(捕捞力量约相当于1,000对标准机帆船)的条件下,获得最大世代相对产量的最佳开捕期为9月21日。当前秋汛渤海对虾渔业的捕捞力量(约1,700—1,800对标准机帆船)太大,额外消耗能源和渔业经济效益很差。秋汛对虾渔业有明显的生长型捕捞过度的倾向。秋汛对虾渔业管理主要是开捕期与捕捞力量的管理和合理分配资源问题。限定虾流网、机帆船和机轮拖网三种主要网具的数量和它们的开捕期,是合理利用和分配资源的有效途径。     

黄海北部放流虾的死亡特征和去向的研究

描述了黄海北部中国对虾放流虾的死亡特征和去向,结果是机械死亡7.8%,突然死亡16.8%,纳潮死亡7.0%,自然死亡14.4%,8月15日前的非法捕捞死亡10.0%,合计56%。到开捕时放流虾存活的数量约为放流量的10.5%,总计为66.5%,有33.5%的放流虾去向不明。如果将20%的计量误差考虑在内,约有14%的放流虾去向不明。在渔汛期间,存活到开捕时的放流虾,约有82%被捕捞,自然死亡11%,余7%游出黄海北部。     

浙北近海曼氏无针乌贼增殖放流效果评估

为修复浙北近海曼氏无针乌贼(Sepiella maindroni)资源,2013—2016年实施了大规模放流,累计增殖放流受精卵7835×104粒,同期还开展了跟踪监测调查。本研究利用放流前后的定点资料和补充采样数据,估算了生长参数和死亡系数等指标,并构建资源评估模型,模拟分析了渔获产量和残存率的变化趋势。结果表明,2013—2016年浙北海域放流曼氏无针乌贼极限体长为138 mm,年生长系数K为2.354,t0为–0.05237 a,年总死亡系数Z为2.83,年自然死亡系数M为1.74,年捕捞死亡系数F为1.09;现行捕捞强度下,每投放1×104粒受精卵,可形成137.3 kg产量,同时还补充了502 ind性成熟个体,增殖放流在一定程度上起到了种群修复和增产增收的目的。评估结果显示,将开捕时间推迟2个月,捕捞产量可增加10.0%,发育至性成熟个体增加27.5%;捕捞强度也是影响放流效果的重要因素之一,若将年捕捞死亡系数降至0.76,捕捞产量最高可达155.6 kg,发育至性成熟个体增加29.4%。最后,针对研究结果提出提高曼氏无针乌贼放流效果和合理利用资源的建议。     

三疣梭子蟹摄食来源与食物竞争的研究方法

三疣梭子蟹(Portunus trituberculatus)是山东沿海的重要经济种类,在过度捕捞和环境变化影响下,资源已大幅衰退。为恢复三疣梭子蟹资源量,山东省自2005年开始实施大规模增殖放流工作。截止2019年,累计放流37亿尾,回捕产量超过16万t,取得了良好的经济效益、社会效益。三疣梭子蟹和日本鲟(Charybdis japonica)均属十足目、梭子蟹科,两者食性相近,在黄渤海均有分布。了解三疣梭子蟹的食物来源和食物竞争状况,是科学确定放流最佳数量的重要基础,是增殖放流迫切需要解决的关键问题之一.     

山东半岛南部海域三疣梭子蟹增殖放流群体回捕率

根据2010年和2011年5-8月在山东半岛南部海域对三疣梭子蟹(Portunus trituberculatus)增殖放流前后分别进行的每年3个航次的对比调查结果,定量分析了三疣梭子蟹自然群体和增殖放流群体的数量,并根据三疣梭子蟹放流苗种数量和放流后捕捞产量,对三疣梭子蟹增殖放流群体回捕率进行分析.研究结果表明,2010年5月山东半岛南部海域三疣梭子蟹增殖放流前自然群体资源量很少,相对资源密度为0.90 ind/(站.h);在5-6月共放流苗种11 015.13万只,放流后10d左右资源量增加为26.08 ind/(站.h),放流群体所占的比例为96.55％;8月进行调查的相对资源密度为1.70 ind/(站.h),当年生群体数量占所有群体数量的比例为64.29％;9月、10月、11月秋汛期间捕捞产量为3 108 t,捕捞个体平均质量为232.3 g,增殖放流群体回捕率为7.54％.201 1年5月山东半岛南部海域三疣梭子蟹增殖放流前自然群体相对资源密度为1.70 ind/(站.h);在5-6月共放流苗种13 132万只,放流后10d左右资源量增加为29.15 ind/(站.h),放流群体所占的比例为94.17％;8月进行调查的相对数量为1.00 ind/(站.h),当年生群体数量占所有群体数量的比例为70.00％;9月、10月、11月秋汛期间捕捞产量为2 896 t,回捕个体平均质量为226.0 g,增殖放流群体回捕率为6.43％.除2011年胶州湾海域由于富营养化水质较差,以及其他因素对黄家塘湾海域的影响导致这两个放流点放流群体回捕率偏低外,2010年和2011年山东半岛南部放流海域整体水质良好,水温、透明度、盐度、营养盐比例、生物饵料等均比较适中,属于放流环境条件较佳的海域,比较适合三疣梭子蟹生长,放流群体回捕率整体上处于较高水平.     

2016年河北省海域中国对虾增殖放流效果评估与效益分析

采用定时、定点现场调查监测与社会调查相结合方法,对2016年河北省放流的中国对虾进行了三个航次的跟踪调查和社会调查,根据捕获的中国对虾数量及其生物学测定结果,结合对丰南、秦皇岛、黄骅海域渔船实际捕获中国对虾数量调查结果,进行中国对虾增殖放流效果评估与效益分析,2016年中国对虾产量为2 517t,其中放流中国对虾产量2 391t、产值4.598亿元、投入产出比为1∶1.5,回捕率4.5%。2016年中国对虾增殖放流效果初步显现,捕捞渔民收入增加,促进了渔区社会稳定,经济效益、社会效益和生态效益显著。     

秋汛渤海对虾渔业的最大经济效益

调整秋汛对虾渔业开捕期和捕捞力量，以获得世代最大产量，已有许多讨论。这是以一个简单生物项为秋汛对虾渔业的管理目标。生物项作为管理目标是不够的。它的内容，它的系统范围都太小，不能与广泛的社会利益相适应。在渔业管理决策时，必需要考虑经济与社会等有关的因素。包括渔业经济效益，能源消耗、就业等等内容。本文将讨论秋汛对虾渔业的最大经济效益等因素，提供一些科学证据，供决策参考。     

黄海北部中国对虾增殖

根据１９８５￣１９９２年黄海北部中国对虾幼虾放流前后相对资源量资料,估算放流虾在混合虾群中占的平均比例约为９２％,平均回捕率９．２％。放流量（Ｘ）与放流后相对资源量（Ｙ）的关系为Ｙ＝２４．１０Ｘ－１．００３Ｘ＾－２,Ｒ＝０．８９８。经Ｆ－检验相关显著。结果表明：中等放流量才能获最好增殖效果;与最大渔获量相应的放流量约１６亿尾;与最大相对资源量相应的放流量约１２亿尾。描述了放流虾的死亡特征,并估算了     

Stock enhancement programme for black sea bream, Acanthopagrus schlegelii (Bleeker), in Hiroshima Bay, Japan: a review

This paper reviews the stock enhancement programme for black sea bream ( Acanthopagrus schlegelii ) in Hiroshima Bay. This bay is one of the biggest production areas for black sea bream in Japan, accounting for about 10% of the total catch of the species in this country in 2004. After intensive fishing pressure caused a drastic decline in the catch of the species in this bay in the 1970s, a stock enhancement programme was conducted in its northern part since 1982 to restore the depleted population. The number of black sea bream juveniles released in 1996 surpassed 9 million, representing the third main species stocked in Japan. Almost 1.4 million of these juveniles were released into Hiroshima Bay. The fast acclimatization of hatchery-reared juveniles released into the bay may have contributed to the recovery of landings in the late 1980s and 1990s. However, this recovery was accompanied by a reduction in the market price of black sea bream. Further studies to assess the effectiveness of the stock enhancement programme as well as the carrying capacity of Hiroshima Bay to maintain the stock of black sea bream at a stable, healthy level are desirable. The necessity of evaluating the secondary effects derived from using a reduced number of breeders as well as finding new markets are suggested.     

The enhancement of abalone stocks: lessons from Japanese case studies

The dramatic declines in abalone Haliotis spp. fishery production have been documented all over the world. Release of hatchery‐reared juveniles into natural habitats has been considered as one measure to sustain and/or augment the current fishery production of abalone, as well as to restore collapsed abalone stocks. However, attempts at abalone release programmes have only been undertaken at experimental scales, except for Japan, where large‐scale stock enhancement programmes for abalone have been undertaken since late 1960s. To evaluate the potential of stock enhancement for abalone, we analysed the release surveys of 13 case studies in Japan in terms of the overall recapture rate (number of recaptures through a lifetime/number of juveniles released), yield per release (YPR, yields from released individuals), the economic efficiency of releases (ratio of income from recaptured abalone to release cost) for each release year, and the contribution of hatchery releases to total catches for each fishing year. The average estimates for overall recapture rates (0.014–0.238) and YPR (3.1–60.3 g/individual) varied between locations and release years. The economic efficiency was estimated at 0.4–6.2. The released abalone contributed 6.9–83.5% to total catches. Hatchery releases could augment total production at some locations, but the success of release programmes would be limited by the carrying capacity at release areas, because density‐dependent mortality occurred following releases in some cases. Throughout Japan, the annual catch of abalone has continuously declined from ～6500 t in 1970 to ～2000 t in the mid‐1990s, despite the increase in the number of hatchery releases. Based on the estimates for YPR, the magnitude of the abalone releases on a national scale has not been sufficiently large to sustain the total production of Japanese abalone, which has primarily fluctuated according to the abundances of wild populations. Our results suggest that releases should be targeted at local populations in regions where stock enhancement is predicted to have the greatest chance of success, and the magnitude of releases should be considered carefully and determined for each region by taking the local carrying capacity into account. We also address the future prospects of abalone stock enhancement.     

Forecasting the genetic influences of red drum stock enhancement in South Carolina

The South Carolina Department of Natural Resources (SCDNR) began stocking red drum, Sciaenops ocellatus (Linnaeus), in 1989 to augment the abundance of juveniles available for recreational harvest in South Carolina estuaries. While stock enhancement can help supplement wild populations under high fishing pressure, releasing hatchery‐raised fish into the wild also presents the risk of decreased genetic diversity. An individual‐based model (IBM) was developed to forecast the genetic influences of stocking on the wild spawning population to inform responsible stocking strategies. Model results indicated the SCDNR red drum stock enhancement programme should maintain mean contributions of stocked fish no greater than 30% per year class over a 45‐year stocking period, coupled with at least 10 effective breeders in the hatchery replaced annually, to maintain current levels of genetic diversity estimated in the wild population. The IBM is a useful tool for hatchery managers to guide responsible stock enhancement.     

基于渔船捕捞行为特征的远洋延绳钓渔场捕捞强度计算

渔场捕捞强度信息可以为渔业资源评估和管理提供帮助。本研究结合2017年10—11月船舶自动监控系统(AutomaticIdentificationSystem,AIS)信息和同期中国中西太平洋延绳钓渔船捕捞日志数据,通过挖掘延绳钓渔船作业航速和航向特征,建立渔场作业状态识别模型,提取渔场捕捞强度信息。以3～9节为航速阈值和0°～10°及300°～360°为航向阈值,渔船作业状态识别准确率为68.29%。阈值识别和日志记录的捕捞强度信息在空间上相关性很高(0.96),基于AIS信息挖掘的渔船捕捞强度空间分布特征和实际非常相似。阈值识别和日志记录的捕捞强度信息在空间上与单位捕捞努力量渔获量(catch per unite of effort, CPUE)、渔获尾数、渔获重量和投钩数的空间相关系数均大于0.62,基于AIS信息挖掘的渔船空间捕捞强度也可替代用于渔业资源分析。     

Determination of fisheries benefits from floodplain riverine systems in Bangladesh: a mathematical programming approach

Abstract. A non-linear programming model was developed to determine the benefits obtainable from the inland capture fisheries of Bangladesh. Functions and parameters of a base model were estimated by deriving non-linear catch-effort and cost functions as well as rice responsive demand functions using both primary and secondary data. Results of LP (linear programming) solution of the base model suggest that the inland fisheries of Bangladesh are capable, under optimal conditions, of generating a total net benefit of Bangladesh Taka (BDT) 1383 million per annum (US$1 = BDT38), most of which (96%) accrues as producer surplus. Under the optimal allocation of total fishing effort the model shows a 13% reduction in overall fish catch with 54% less effort. Sensitivity analysis, through variations of fishing effort, shows that the incorporated variables (e.g. catch, cost, benefit and shadow price) change in line with theoretical expectations. The implication of these results for management is that a reduction in effort would be required in order to generate a greater net economic benefit from the riverine fisheries. Such reduction should be specific to individual fishery and/or fishing grounds.     

基于系统动力学模型的渔业资源增殖放流效应分析

文章从系统动力学角度出发,着眼于动态系统的整体统筹,综合考虑渔业、生态和社会三方面要素,对山东省中国对虾（Penaeus chinensis）增殖放流渔业进行了系统动力学建模仿真,并通过对预测结果的比较分析,探讨了合理的放流量、捕捞努力量等决策变量,以期为渔业决策者提供有益的参考。文中提出的方法亦可用于对渔业资源生物量、产量、社会效益、生态效应的评估和预报。     

A Genetic Assessment of a Red Drum,Sciaenops ocellatus,Stock Enhancement Program

The South Carolina Department of Natural Resources began a stock enhancement research program for red drum, Sciaenops ocellatus, as a possible management strategy for augmenting the availability of juveniles for recreational harvest in South Carolina estuaries. Between 1999 and 2011, approximately 6 million juveniles and 260 million larvae were stocked into the Charleston Harbor (CH) estuary, and proportions of stocked fish were found through standardized sampling as high as 49.6% within a subadult year‐class and up to 12% within the spatially separate spawning population. This study evaluated the genetic influences of stocking on the spawning population, using microsatellite loci, and examined any changes in genetic diversity metrics over the course of the stock enhancement program. Percent contribution of stocked fish among subadult and adult collections was compared against measures of genetic diversity. No statistically significant correlations were found among genetic diversity metrics, suggesting that responsible stocking of red drum as small juveniles has not altered the genetic diversity of adults spawning offshore the CH. Life‐history characteristics likely play a large role in mitigating changes in genetic diversity, despite high contributions of stocked fish in some years, because red drum exhibit a long adult life span and benefit from overlapping generations.     

浙北沿岸大黄鱼放流增殖的初步研究

为了恢复浙江渔场大黄鱼资源，1998—2002年，浙江省在浙江北部沿岸海域进行了大黄鱼增殖放流可行性研究。通过5年来的放流试验表明，在浙北沿岸进行大黄鱼放流是完全可行的，放流鱼能够在放流区域附近海域存活、生长，并进行索饵、产卵洄游，同时形成了一定数量的捕捞群体，放流鱼回捕率较高，放流效果较好。文章对试验放流过程中出现的问题进行了探讨和分析，为今后进一步大规模放流提出了建议。