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1.
剩余产量模型在不同渔业中的应用 总被引：4，自引：0，他引：4
剩余产量模型因其简单和所需数据较少的特点为渔业资源评估广泛采用.本文应用目前常用的四种剩余产量模型对五种渔业下的渔业生物种群及北大西洋箭鱼种群xiphias gladius评估效果作了比较.四种剩余产量模型在渔业1中的评估效果较好,而在渔业2中的效果较差;Schnute模型在充分捕捞的渔业,如渔业3、4、5,尤其是在低生物量的渔业3中评估效果较好,但不适合评估未充分捕捞的渔业.Walters-Hilborn模型(W-H模型)适用于各种渔业,尤其是渔业1、4、5.在过度捕捞渔业中如渔业3、4,模型对参数q的估计较其它参数接近真值.在北大西洋箭鱼(xiphias gladius)渔业的评估中,W-H模型对MSY的估计约为14000吨,接近于Prager(1996)的结果. 相似文献
2.
《中国海洋大学学报(自然科学版)》2021,(11)
中国近海大多数渔业都属于数据有限渔业,用对数据要求较高的复杂模型无法对这些渔业资源做出有效评估,因此用数据有限评估模型评估渔业资源的研究具有重要意义。本文使用经典剩余产量模型(CEDA和ASPIC)和两种新型有限数据评估模型(贝叶斯Schaefer剩余产量模型(BSM)和蒙特卡洛MSY估算模型(CMSY)),评估了黄渤海鳀鱼(Engraulis japonicus)、东海带鱼(Trichiurus lepturus)和南海金线鱼(Nemipterus virgatus)这三种重要渔业资源的生物学参考点和资源现状。研究表明:黄渤海鳀鱼MSY估计值为80×10~4～83×10~4 t,生物学参考点F/F_(MSY)估计值小于1.0而B/B_(MSY)略小于1.0,表明这种渔业捕捞强度适中但资源尚未得到完全恢复。东海带鱼MSY估计值为58×10~4～64×10~4 t,F/F_(MSY)估计值大于1.0而B/B_(MSY)估计值小于1.0,表明这种渔业存在过度捕捞且资源已经衰退。南海金线鱼MSY为30×10~4～32×10~4 t,F/F_(MSY)估计值大于1.0而B/B_(MSY)估计值小于1.0,表明这种渔业存在过度捕捞且资源已经衰退。以上4种模型均可适用于中国近海数据有限的渔业资源,但两种经典剩余产量模型对三种渔业数据的拟合不够稳定(相关系数R~2波动较大),因此取BSM和CMSY模型的评估结果作为重要参考,但这两种有限数据评估模型的拟合效果尚需进行深入研究。 相似文献
3.
鱼类自然死亡率的估算及其影响因子的探讨 总被引：6，自引：1，他引：5
为探讨鱼类自然死亡率参数,文中讨论了1种通过资源量和渔获量数据估算鱼类自然死亡率(M)的方法。蒙特卡罗模拟分析显示当资源量的白色噪音,即变异系数(CV)水平小于大约10％时自然死亡率的估计值基本上是准确的;捕捞死亡率的变化对自然死亡率估计的影响不大。文中构造了长寿命自然死亡率小和短寿命自然死亡率大的2个鱼类种群,模拟结果表明这种方法更适用于寿命短而自然死亡率大的种群。另外该方法在黄海鲲鱼(Engraulis japonicus)渔业数据上的应用同样得到了良好的结果。 相似文献
4.
渔业产量和资源生物量数值模型及相关因子的初步研究 总被引：2，自引：0，他引：2
对于渔业的中长期预报计算,是渔业种群补充的关键问题。本文在单位补充量产量和单位补充量生物量模型中加入了亲体一补充模型即密度相关过程,并引入了白色噪音以模拟环境变化。结果表明：本研究(1)可以明确地给出渔业种群崩溃的可能性,估计出达到崩溃时的捕捞死亡率;(2)可以估计最大持续产量的绝对值;(3)引入的白色噪音可以模拟环境变化对产量与捕捞死亡率和产量与亲体生物量关系曲线的影响。虽然亲体补充关系仍多是个假设,补充与亲体之间存在的补偿机制需要进一步的研究。 相似文献
5.
根据已开发鱼类种群的自然死亡率（M）在鱼类资源评估中的重要作用,讨论了1种应用实际种群分析（VPA）（亦即世代分析方法）估算鱼类自然死亡率的方法.文中假设了捕捞努力量（E）已知和未知2种情况,并同时求出了其他种群参数,如可捕系数,补充量等.在蒙特卡罗模拟分析中,假设了4种模拟渔业（管理良好的渔业,掠夺式渔业,恢复性渔业和稳定性渔业）对该方法进行了验证.并将von-Bertalanffy生长方程（VBGF）引入VPA模型来估算鱼类的自然死亡率.当CV等于20%时,在4种模拟渔业中鱼类各龄自然死亡率（Ma）的EP均小于10%.在已知单位捕捞努力量渔获量数据时,计算北大西洋长鳍金枪鱼（Thunnus alalunga）的M等于0.119,这个结果比先前假定的值（0.3）小,但考虑到该鱼种所承受的高的捕捞压力作者认为该估计值是合理的. 相似文献
6.
大多数渔业种类由于数据缺乏,无法使用传统的渔业资源评估方法开展评估和管理。越来越多的研究采用CMSY等基于有限数据的评估方法,但CMSY方法在渔获量数据时间序列长度有限、存在误差等情况下的评估可靠性尚有待验证。本研究运用CMSY方法对黄海3种产量较高的经济鱼类开展资源评估,探索渔获量数据时间序列长度、不同渔业发展阶段,以及观测误差水平对评估结果的影响。结果表明,鲐、带鱼和银鲳在2000年后均出现产量高于最大可持续产量(MSY)的情况,资源处于过度利用状况(B/BMSY<1、 F/FMSY>1),近10年来开发强度降低,但生物量仍处于较低水平(B/BMSY<1)。评估模型的回溯性分析结果差异较小,表明评估结果稳定。从数据长度上看,使用遍历产量上升和下降过程的长时间序列数据,其评估结果更为稳定。在观测误差大于20%的情况下,模型对MSY和BMSY出现高估,但结果仍较为稳健。在CMSY方法的应用中应注意选取长时间序列的产量数据,在评估结果不确定性高的情况下应采取相对保守的渔业管理措施。 相似文献
7.
鱼类种群行为及其与环境变化的关系 总被引：1，自引：1，他引：0
任何渔业的重要生物特征是鱼类种群的变动.经典的鱼类种群动态模型是以稳定的种群行为为基础的.作者阐述了鱼类种群的行为,并划分为三种类型: (1)稳定型:种群在较稳定产量上维持较长时间(反应系数0.02).(2) 周期型:种群表现出周期性的高产量和低产量(反应系数0.22).(3) 不稳定型:种群产生高产量后无可挽回地崩溃了(反应系数0.3).在环境变化较大时,白色噪音水平(变动系数)增加至35%,稳定型种群变为不稳定型.在白色噪音水平(变动系数)增加至20%时,周期型种群变为不稳定型. 相似文献
8.
应用渔业体长分析方法ELEFAN和SLCA估算鱼类生长参数的研究 总被引：3，自引：0，他引：3
本文应用蒙特卡罗模拟方法,通过假设不同的生长参数、样本大小和白噪音水平,模拟出不同假设条件下的鱼类种群时间序列的体长频数分布,再应用体长分析方法ELEFAN(e-lectronic length-frequency analysis)与SLCA(Shepherd's length-composition analysis)估算模拟数据的生长参数K和L∞。用总生长特征φ估算求得生长参数的可靠性。模拟结果表明在大多数情况下ELEFAN比SLCA更能准确稳定地估计生长参数。生长速率和极限体长越大,φ估计值的精确度越高。当体长的白噪音水平小于20%时,估计结果较准确。当样本小于60时,样本越大估计结果越准确;当样本大于60时,样本增大对结果影响不大。应用本文的方法估计西非科特迪瓦的法荷水库的长臂虾(Macrobrachium vollenhovenii)真实渔业数据也得到了较好的结果。 相似文献
9.
基于CEDA和ASPIC软件的南大西洋长鳍金枪鱼渔业资源评估研究 总被引：2，自引：0，他引：2
《海洋湖沼通报》2015,(3)
剩余产量模型是最简单和应用最广泛的渔业资源评估模型之一。CEDA(catch-effort data analysis)和ASPIC(a surplus-production model incorporating covariates)是使用非平衡剩余产量模型对渔业产量和捕捞努力量数据进行分析的计算机软件。根据中国台湾延绳钓渔业的单位捕捞努力量渔获量(CPUE)数据,利用CDEA和ASPIC软件对南大西洋长鳍金枪鱼(Thunnus alalunga)渔业进行研究。结果显示,CEDA中使用对数正态误差假设的Fox模型产生了最大的R2值以及最接近ASPIC分析结果的种群参数值,但是CEDA得到的R2值低于ASPIC。CEDA对不同初始B1/K值的反应比ASPIC敏感。ASPIC中Logistic产量模型对不同初始B1/K值的反应比Fox模型更加灵敏。CEDA和ASPIC得出的最大可持续产量基本一致。 相似文献
10.
以盐城保护区核心区为例,利用2002年野外高程测量数据,运用Kriging和TIN两种不同思想的插值方法对研究区DEM的构建与精度评估两个问题展开研究.研究结果表明:1)Kriging插值验证显示:均差接近于0,均方根标准误差接近于1.证明采用Kriging插值同时考虑数据本身约束性条件的模型是可行的.同时,运用等高线和等高点数据生成的TIN,效果同样比较理想.2)对两种DEM进行了精度评估,数据显示误差都在可控范围之内.其中Grid-DEM的绝对误差最大值为0.162 m,平均绝对误差为0.063 m,平均相对误差为4.20％;而TIN-DEM的最大值仅为0.028 m,平均绝对误差和平均相对误差只有0.005 m和0.36％.3)在对两种DEM的比较中发现:无论是绝对误差还是相对误差,Grid-DEM都要远高于TIN-DEM,两者最大值相差0.134 m;在受人类干扰较强以及经常受潮汐影响而处于不断变化的区域,Grid插值要明显差于TIN插值.但从DEM表面整体光滑度来看,Grid-DEM却要优于TIN-DEM. 相似文献
11.
《Marine Policy》2013
The importance of local communities relying on fisheries is constantly emphasised in the European Union's Common Fishery Policy. Previous studies have analysed fishery employment for the entire EU based on statistical figures aggregated by administrative units at the regional or provincial level. This paper adopts a geographical approach to identify EU coastal communities relying on fisheries using accessibility analysis, principles at the basis of gravity models and disaggregated population and employment statistics. The dependency on fisheries is calculated comparing estimated employment from fisheries at each port with general employment in the areas of accessibility surrounding the port. By considering spatially disaggregated statistics the importance of fishing activities for specific local communities emerges more clearly in respect of previous studies. The map of fisheries dependent coastal communities identifies in 2010, 388 communities, out of 1697, with dependency ratios above 1%. Around 54% of total fishery employment is estimated in these areas. In terms of policy support, identifying and mapping these local fishing coastal communities is of key importance considering the strong priority assigned by the new European Union's Common Fishery Policy to fishery management at the regional level. 相似文献
12.
China and Vietnam have recently signed two bilateral agreements to deal with maritime issues in Beibu Gulf. One is the maritime boundary delimitation agreement, and the other the fisheries agreement. The two parties have also formulated a supplementary protocol to the latter agreement. All of them have entered into force on 30 June 2004. This article introduces the new arrangements for fisheries management initiated by the two countries, focusing especially on the Joint Fishery Committee established by the two parties, the contracting waters covered by the fisheries agreement, and the conservation and management measures for the Gulf's fisheries. The challenges likely confronted by China after this institutional change takes place are analyzed. A brief comparison is drawn among the three effectual fisheries agreements signed by China, respectively, with Japan, South Korea and Vietnam. Finally, as for the future of fisheries management in the Gulf some recommendations are made. 相似文献
13.
Oregon's Developmental Fisheries Program is designed to encourage the commercial exploration and development of State managed underutilized fishery resources. A key program strategy is allocating relatively secure harvest rights to pioneering entrepreneurs when a fishery successfully transitions from “developing” to “developed” status. Since the program's inception in 1993, two fisheries, sardine and bay clam, have moved from undeveloped to developed status. Case studies of these fisheries show that many challenges impact the success of the Developmental Fisheries Program including difficulties in designing and allocating asset rights, establishing operational program guidelines, selecting measurable targets that meet legislative standards for a developed fishery, and financing developmental fisheries management practices. Developmental fisheries strategies used in other regions and countries are summarized. Recommendations are made for improving Oregon's Developmental Fishery Program including establishing clear objectives and timelines for the Program and identifying appropriate renewal requirements for permits and other developmental incentives on a fishery-by-fishery basis. 相似文献
14.
The use of ITQ management in multi-species fisheries has been the subject of much debate and the complexities and difficulties of managing multi-species fisheries are well known. A major problem is that the species mix in fishery catches may not necessarily match the mix in combined TACs or in quota holdings. While a number of solutions have been proposed or implemented to improve transferability of quota and other incentives to reduce over-quota fishing and discarding, it is surprising that there has been little focus on TAC-setting itself and coordinating this across multiple species/stocks as a means of dealing with some of these issues. In this paper, data were analysed from the trawl sector of the Australian Southern and Eastern Scalefish and Shark Fishery to determine the relationship between primary species and companion species and the implications this has for TAC setting. The primary species is the species being considered when setting an individual species TAC. The companion species are ones that should also be considered when setting the TAC of the primary species, because a considerable proportion of the primary species catch is taken as a companion species non-target catch. The target species in each fishing operation was determined and was used to characterize recent multi-species catch data into primary and companion components. This approach provides an empirical means to examine the impact of individual species TAC decisions across all of the quota species in a fishery. 相似文献
15.
《Marine Policy》2017
Excess capacity is a major concern for fisheries management worldwide. It is often argued that Individual Transferable Quota (ITQ) systems will enhance efficiency and alleviate problems of excess capacity. While improvements in efficiency have been observed, most empirical studies have found only modest changes in excess capacity as a result of such systems. Using a database of compulsory log-book information for the Tasmanian Rock Lobster Fishery in Australia, from January 2000 to December 2013, this study presents the first analysis to investigate the dynamic behaviour of both excess capacity and efficiency (i.e. technical and scale efficiency) in an industrialised fleet after the introduction of quota management. The analysis revealed weak evidence for a prolonged adjustment in the fishery following the introduction of an ITQ system. In addition, no marked changes in excess capacity were observed over the study period; and furthermore, there was no evidence for an increase in excess capacity during a period of non-binding Total Allowable Catch (TAC) when race to fish behaviour increased in the fishery. The results suggest a limited ability of the ITQ system to alleviate levels of excess capacity in fisheries in the long-term. 相似文献
16.
To sustain fishery development and ensure the supply of fish, the role that a sustainable development indicator system plays in the evaluation of fishery management performance is becoming increasingly important. A sustainable indicator system based on the Pressure–State–Response (PSR) framework was developed for local fisheries in Gungliau, Taiwan, between 1995 and 2003. Factor analysis and canonical correlation analysis were also applied to aggregate indicators and analyse the linkage of indicators. The most serious problem facing fishery system in Gungliau is conflicting local and higher levels of enforcement that result in the problems of effort, harvest and fleet age composition related to the pressure component. Fishery resources and the state of ecosystem were also affected by marine environmental change, especially by El Ñino. Consequently, fishermen adjusted their effort and investment to the variation of Fishery resources, leading Gungliau fisheries to unsustainability. 相似文献
17.
18.
《Marine Policy》2014
The applicability of catch shares programs is evaluated for the various fisheries of the Western Pacific Fishery Management Council region in each of the archipelagoes. Implementation of Catch Shares programs in the region is problematic, but would require better data to be done fairly and equitably. Catch shares are currently under initial consideration for the Hawaii and American Samoa longline fisheries and the Hawaii Deep 7 bottomfish fishery. It is argued that current conditions in all the other small boat fisheries in the region make them inappropriate for catch shares management. Overfishing and the “race for fish” are not yet an issue for these fisheries and some are underdeveloped. Catch share programs can cause significant negative social consequences for Western Pacific communities because data on fishermen's participation, catch histories, and motivations to fish for cultural needs is not adequate for any initial allocation scheme to be developed equitably. The prevailing Western Pacific cultural value of sharing the fish by gifting portions, sharing the catch widely and sharing fishing opportunities widely is in clear conflict with the individualized commercial profit motive philosophy of fisheries that are appropriate for catch shares. The small boat fisheries lack adequate monitoring and enforcement, and do not have a total allowable catch or quota. Nor do they usually have a demonstrated need for one. Preliminary community outreach by Council staff and community discussion of catch shares shows a general lack of information yet a potential for strong resistance to the imposition of catch shares. 相似文献
19.
《Marine Policy》2013
Fishery managers are faced with the challenge of maintaining sustainable fisheries at the lowest possible cost while conforming to international and national obligations. Given that fisheries range from low to high value, there is a real need to understand how to trade ecological and economic risks, and the various costs associated with their management, against the benefits from catch. Key to this is an understanding of (a) the costs corresponding to a given level of acceptable risk, or conversely, (b) the change in risk given a change in cost investment. This paper first defines biological, economic and ecosystem risk at a whole-of-fishery level, and then develops a simple model to quantify the trade-offs between risk, cost and catch. Using as case studies Australia's federally managed fisheries that range from data-rich to data-poor, risk was quantified for target species in terms of both their limit and target reference points (defined as “biological risk” and “economic risk”, respectively), and for ecosystems in terms of overall ecological impact (defined as “ecosystem risk”). A statistical linear model was used to quantify the risk–cost–catch frontier for each of the three forms of risk. The most parsimonious models were statistically significant for each. However, the management and research costs were mostly positively correlated with risk, indicating that these tended to be reactive to risk, as opposed to risk decreasing in response to increased costs. The only model where this was not the case was for the ecosystem risk, which is probably because these risks have only recently been assessed and the management response to these risks across all the fisheries has so far been limited. For target species risks, it was not possible to develop a model for proactive use. However, the method itself has merit and, if the costs were defined to a greater level of resolution, and/or a time-dynamic modelling approach considered, these issues could potentially be addressed. 相似文献
20.
《Marine Policy》2001,25(1):33-42
This paper describes the process by which the groundfish resources off Alaska are being transformed from essentially open access to more manageable common property resources. Selected common property institutions that were created or developed in these fisheries are described in terms of the problems they were designed to solve, their success or lack of success in doing so, and the factors that influenced both emergence and success of these institutions. The institutions discussed include the North Pacific Fishery Management Council, the Community Development Quota system, the Pollock Conservation Cooperative, and the cooperative bycatch control system known as Sea State used by the factory trawler fleets. Conclusions applicable to other fisheries and other common property resources are then drawn from the analysis of these common property institutions in the Alaskan groundfish fisheries. 相似文献