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1.
传统的渔业资源评估方法对数据有一定的要求，而现有的许多渔业缺乏相关数据，造成了渔业评估和管理上的障碍。特别是自然死亡率，由于观测和计算的困难，研究中一般通过经验公式等方法进行假话，而不同来源的数据和估算方法的结果存在较大差异，可能导致在渔业资源评估和管理中很大的不确定性。本研究以蓝点马鲛（Scomberomorus niphonius）为例，利用MSE比较了22种基于有限数据的渔业管理规程（MP），筛选出DCAC、SPMSY、curE75、minlenLopt1 4种对于M不确定性较为稳健的的管理方法，并针对不同年代的自然死亡率以及通过不同计算方法得出的自然死亡率对这4种MP进行了管理策略评价。结果表明：M自1980s至今的不同年代间有显著降低趋势，该变化对MP管理效果产生了较强影响。随着M降低，种群B>0.5BMSY的概率显著上升，而过度捕捞可能性在不同MP间有方向性的差异。M变化对对curE75、minlenLopt1的长期产量的影响较小，而对DCAC、SPMSY的AAVY<15%的可能性变化较大，即降低产量的波动。不同M估算方法的估计值相差不大，对MP管理影响不明显。综合结果来看，Cur75受自然死亡率不确定性影响较小，对于渔业资源的开发和保护两个方面有着最好的权衡，最适用于我国蓝点马鲛渔业的管理。 相似文献
2.
Feeding activities provide necessary nutrition and energy to support the reproduction and development of fish populations. The feeding ecology and dietary plasticity of fish are important factors determining their recruitment and population dynamics. As a top predator, Japanese Spanish mackerel(Scomberomorus niphonius) supports one of the most valuable fisheries in China. In this study, the feeding ecology and diet composition of Japanese Spanish mackerel spawning groups were analysed based on samples collected from six spawning grounds along the eastern coastal waters of China during spring(March to May) in 2016 and 2017. Both stomach contents and stable isotope analysis were conducted. Stomach content analysis showed that spawning groups of Japanese Spanish mackerel mainly fed on fish, consuming more than 40 different prey species. Diets were significantly different among sampling locations. The most important prey species were Stolephorus in Fuzhou, Japanese anchovy Engraulis japonicus in Xiangshan, Euphausia pacifica in Lüsi, sand lance Ammodytes personatus in Qingdao and Weihai, and Leptochela gracilis in Laizhou Bay. Stable isotope analysis showed that the trophic level of Japanese Spanish mackerel was relatively high and generally increased with latitude from south to north. In the 1980 s, the diet of Japanese Spanish mackerel was dominated solely by Japanese anchovies in the eastern coastal waters of China. The results in the present study showed that the importance of Japanese anchovies declined considerably, and this fish was not the most dominant diet in most of the investigated waters. Both the spatial variations in diet composition and changes in the dominant diet over the long term indicated the high adaptability of Japanese Spanish mackerel to the environment. Combining the results of stomach analysis and stable isotope analysis from different tissues provided more comprehensive and accurate dietary information on Japanese Spanish mackerel. The study provides essential information about the feeding ecology of Japanese Spanish mackerel and will benefit the management of its populations in the future. 相似文献
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-This paper presents the use of the hydrographic factors in short-term fishery forecasting of the spawning migration stock of the Spanish mackerel and salinity describes more concretely the correlativity of water temperature, salinity and air temperature with the fishing season in spring. The data have been collected from the hydrographic environmental investigation at the fixed position on the sea and the telegraph recordings of the drift net operation in the spring fishing season during the period of April and May from 1972 to 1980. The correlation coefficients of various factors with the data of the fishing season have been calculated by using the monadic regression method.The main reference targets of the forecasting are: (1) By using the upper-layer water temperature as the forecasting factor at the beginning of the fishing season, the accuracy is high; (2) the distribution and location of the isotherm of the upper-layer water at 10°C at the beginning of April are used as an important factor for d 相似文献
5.
渤海蓝点马鲛食物链结构的研究 总被引：2，自引：0，他引：2
从60年代起,我国开始进行鱼类食性的研究(杨纪明、郑严,1962;杨纪明、林景祺，1966),并且开始以食性分析的方法,对特定海区内的鱼类食物关系进行研究(邓景耀等,1986;张其永等,1981),这为海洋食物链研究提供了初步资料。但至今尚未见有单种鱼食物链结构的研究报道。
蓝点马鮫 Scomberomorus niphonius (Cuvier et Valenciennes)为暖水性、洄游性、中上层鱼类。通常每年6月进入渤海产卵,11月前后离开渤海,向深海做越冬洄游(韦晟,1980)。蓝点马鲛作为渤海的重要经济鱼类之一,近些年来资源量一直保持相对稳定(韦晟,1982;朱德山、韦晟,1983)。进行蓝点马鲛的食物链研究,一方面有助于进行蓝点马鮫资源的预测、增殖及管理,另一方面对阐明渤海生态系统中的能量转换也具有一定意义。本文试图对蓝点马鲛食物链结构问题进行讨论。 相似文献
6.
This paper shows how post-oil spill management measures can affect the general pattern of fishing effort exerted on two particular species of great commercial value in northern Spanish fisheries: anglerfish (Lophius piscatorius and Lophius budegassa) and mackerel (Scomber scombrus). Data time series of catches and fishing efforts were analysed corresponding to the area and time period affected by the oil spill fishing restrictions (December 2002–June 2003) and similar previous and post-spill periods. This was done to detect shifts that could be due to either the oil spill per se or the management measures taken to minimise pollution effects. Then, analyses and simulations with Arcview GIS module FAST (Fishing Activity Simulation Tool v. 1.1) were carried out with the aim of studying the fishing effort spatial distribution. Changes were observed in the Catch Per Unit Effort (CPUE) of anglerfish and mackerel by area or fishery unit. Results show a spatial displacement of fishing effort to other fishing areas in the case of anglerfish, and the transfer of fishing effort between different fishery units in the case of mackerel. Although both effects were caused primarily by the management measures in force after the oil spill, they are considered side or collateral effects. The management measures that have to be taken after any disaster should also consider these kinds of ancillary effects as well as evaluating the likely positive or negative impact of these side effects. 相似文献
7.
Fish biomass is a critical component of fishery stock assessment and management and it is often estimated from ocean primary production（OPP）. However, the relationship between the biomass of a fish stock and OPP is always complicated due to a variety of trophic controls in the ecosystem. In this paper, we examine the quantitative relationship between the biomass of chub mackerel（Scomber japonicus） and net primary production（NPP） in the southern East China Sea（SECS）, using catch and effort data from the Chinese mainland large light-purse seine fishery logbook and NPP derived from remote sensing. We further discuss the mechanisms of trophic control in regulating this relationship. The results show a significant non-linear relationship exists between standardized CPUE（Catch-Per-Unit-Effort） and NPP（P〈0.05）. This relationship can be described by a convex parabolic curve, where the biomass of chub mackerel increases with NPP to a maximum and then decreases when the NPP exceeds this point. The results imply that the ecosystem in the SECS is subject to complex trophic controls. We speculate that the change in abundance of key species at intermediate trophic levels and/or interspecific competition might contribute to this complex relationship. 相似文献
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《African Journal of Marine Science》2013,35(1):307-315
The hake resource is the most important commercial fish species in the demersal sector of Namibia's fisheries, both in terms of annual catch and contribution to Gross Domestic Product (GDP). The fishery now spans four decades. In the 1960s and 1970s, hake were exploited heavily by mainly foreign fleets, total catches peaking at more than 800 000 tons in 1972. The first control measures, the use of a minimum mesh size of 110 mm and the allocation of quotas to each member country participating in the hake fishery, were implemented by the International Commission for the Southeast Atlantic Fisheries in 1975. In 1990, the Namibian Government took action to control fishing activities in Namibian waters, and the enactment of its Fisheries Policy (1991) and Sea Fisheries Act of 1992 provided for the control measures to be taken. The conservative management strategy adopted between 1990 and 1993 resulted in gradual increase in hake biomass, but thereafter the stock declined. The hake fishery is currently managed on the basis of a total allowable catch that takes into consideration the rate of increase or decrease in the size of the resource. Since 1990, the demersal trawl fishery has accounted for approximately 90% of the total hake catch. The resource is subjected to both directed fishing and bycatch, the latter taken in directed fisheries for species such as horse mackerel, monkfish and sole. 相似文献
10.
《Marine Policy》2014
This paper uses a quarterly, game-theoretic model of the Northeast Atlantic mackerel to study the fishing strategies of five players: the EU, Norway, the Faeroe Islands, Iceland, and the international fishery on the high seas. Data on the spatial distribution of fish catches (1977–2011) are used to model changes in the distribution of the mackerel stock. The Nash equilibrium solutions predict a severe decimation of the stock through overfishing, either by parties (Iceland, the Faeroe Islands) that refuse to cooperate or by a general absence of cooperation. There is a wide discrepancy between this prediction and reality, as the stock seems, at most, only moderately overexploited, despite non-cooperation by Iceland and the Faeroe Islands. It is conjectured that these parties, and others, may engage in a degree of quasi-cooperation that falls somewhat short of full cooperation but avoids the extreme destruction of the Nash equilibrium. This tacit cooperation can be seen as being maintained by a mutually assured destruction of the fisheries of all parties in case they go to the logical extremes of non-cooperation. 相似文献
11.
东海南部海洋净初级生产力与鲐鱼资源量变动关系的研究 总被引：6，自引：3，他引：3
海洋初级生产力决定海洋渔业资源的潜在产量,我国应用海洋初级生产力方法估算渔业资源量亦已取得不少研究成果,但海洋生态系统中的营养控制机制复杂多样,将影响海洋初级生产力与鱼类资源量的关系。本文利用中国大型灯光围网渔业在东海南部渔场的鲐鱼(Scomber japonicus)捕捞数据与海洋净初级生产力的遥感资料分析了鲐鱼资源量变化与净初级生产力的关系,探讨了其生态系统营养控制机制。研究结果表明,净初级生产力与标准化CPUE(Catch Per Unit Effort)不存在显著的线性关系(P>0.05),但呈显著非线性关系(P<0.05),且这种非线性关系表现为倒抛物线,即鲐鱼资源量随净初级生产力的增加而提高,但当净初级生产力进一步增加,鲐鱼资源量则呈下降趋势。净初级生产力与标准化CPUE呈显著的倒抛物线关系表明生态系统存在上行控制机制,但并非受该机制完全控制。种间竞争或浮游动物资源量的变动均可能引起鲐鱼资源的相对丰度与净初级生产力呈倒抛物线关系。 相似文献
12.
当前,对渔业资源评估模型的诊断与选择,主要依赖于模型对观察数据的拟合度,很少评价模型的预测能力、并将其作为评价渔业资源评估与管理质量的依据。为此,本文利用后向预报方法评价了印度洋黄鳍金枪鱼(Thunnus albacores)资源评估模型的预测能力,并在此基础上分析了印度洋黄鳍金枪鱼的资源评估与管理质量。研究表明,在利用贝叶斯剩余产量模型对印度洋黄鳍金枪鱼进行资源评估时,存在如下问题:(1)拟合较好的模型其预测能力较差;(2)利用不同时段数据拟合模型时,采用DIC(Deviance Information Criterion)选择的最佳模型缺少稳定性;(3)不同模型估计的TAC (Total Allowable Catch)存在较大差异。据此可以判断,利用贝叶斯剩余产量模型对印度洋黄鳍金枪鱼进行资源评估与管理效果较差。本研究结果表明:(1)利用后向预报方法可评价模型的预测能力、DIC选择模型的稳定性,从而能在一定程度上判断模型模拟的种群演化动态是否正确、资源评估结果是否存在问题;(2)利用后向预报方法可揭示评估结果的不确定性及其可能引起的渔业管理风险,从而有利于避免渔业管理风险、实现渔业管理目标。 相似文献
13.
Interdecadal variability of anchoveta abundance and overcapacity of the fishery in Peru 总被引：2，自引：0，他引：2
Pierre Fron Marilú Bouchon Christian Mullon Christian García Miguel
iquen 《Progress in Oceanography》2008,79(2-4):401
Paleontological and historical stock abundance estimates indicate that pelagic fish populations inhabiting upwelling ecosystems undergo large interdecadal variations in abundance with amplitudes equal to, if not larger than, the interannual variability. The interdecadal variability is characterized by periods of high and low abundance, termed “pseudo-cycles”, because of their irregular periodicity. Fisheries targeting small pelagic fish suffer from overall overcapitalization, like many other fisheries, but also from an additional overcapitalization problem: a phase displacement between rapid fish population decreases and a slower disinvestment which follows. This lag produces economic hardship.Here we document the fish:fishery relationship for the Peruvian anchoveta. Anchoveta pseudo-cycles of 20 to >100 years are observed, with the present stock abundance most likely located near upper part of the cycle. Fleet overcapacity expressed as the proportion of unused present capacity is estimated at 72% and processing overcapacity at 89%. A simple bio-economic model demonstrates the risks associated with the pseudo-periodicity in fish stock abundance in conjunction with fishery investment, open access, and overcapacity: a timing bomb for the fishing sector. The lag between disinvestment and decrease in fish abundance is quantified. A reduction of the fishing and processing capacity and measures to decrease the investment lag are recommended to limit the social, economical and political tensions that will result from the expected decrease in stock abundance. Finally, some management options to reduce these risks are discussed. 相似文献
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We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978–2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts. 相似文献
16.
The South African midwater trawl fishery targets adult horse mackerel Trachurus capensis. The bulk of the catch is taken by a single freezer-trawler, the biggest fishing vessel operating in South African waters. As fishing takes place off the south coast in ecologically sensitive areas, there are concerns about the potential impacts of this fishing operation on non-target species. Fishing behaviour and bycatch of this fishery from 2004 to 2014 were investigated by analysing observer records with regard to catch composition, volume and temporal and spatial patterns. The midwater trawl fishery was estimated to have caught 25 415 tonnes annually, with a bycatch of 6.9% of the total catch, by weight. There are species overlaps with various fisheries, namely the demersal trawl, small-pelagic, line, shark longline and squid fisheries, yet the total bycatch estimates from this fishery are generally small relative to catches taken in the target fisheries. Bycatch species with the highest average annual catches were chub mackerel Scomber japonicus, redeye roundherring Etrumeus whiteheadi, ribbonfish Lepidopus caudatus and hake Merluccius spp. Large-fauna bycatch species included sunfish Mola mola as well as a number of CITES II- and IUCN-listed species, such as Cape fur seal Arctocephalus pusillus, dusky shark Carcharhinus obscurus, smooth hammerhead shark Sphyrna zygaena and thresher sharks Alopias spp. The 97.9% observer coverage is high and the 6.9% bycatch rate low compared to other South African fisheries; however, due to the large size of the individual hauls (average of 46.3 t), the average sampling rate of 1.56% is low. Our analyses suggest that bycatch in the South African midwater trawl fishery has been lower than in other South African fisheries and similar fisheries elsewhere, but due to the combination of high catch volumes and low sampling rates, estimation errors for rare species are high and there is a substantial risk of incidental unmonitored bycatch of rare large fauna and aggregations of small fauna. This could be mitigated by spatio-temporal management of this fishery, to avoid fishing in high-risk areas, and the introduction of an electronic monitoring programme. 相似文献
17.
《African Journal of Marine Science》2013,35(1):433-447
Research surveys of Cape horse mackerel Trachurus trachurus capensis abundance on the south coast of South Africa are complicated because changes in the species' vertical and horizontal distribution limit the value of stock assessments based a single survey method. Annual bottom trawl surveys conducted in spring provide estimates of the abundance of fish close to the bottom over trawlable grounds. Between 1991 and 1994, hydroacoustic surveys conducted in spring have been used to estimate the pelagic portion of the stock, as well as the portion over untrawlable grounds. These two research datasets, as well as data from purse-seine, mid water and bottom trawl commercial landings, are reviewed to elucidate distribution patterns of horse mackerel and their migratory and spawning strategies. The problems and advantages of bottom trawl and acoustic surveys are discussed in the context of fluctuations in estimates of the size of the stock between 1991 and 1994 and the prevailing environmental conditions. It is concluded that combined acoustic and bottom trawl surveys are the only effective means of surveying horse mackerel, and that effort should be concentrated east of 22°E to assess the spawner stock. It is suggested that research effort directed at improving understanding of exchanges between West Coast (including Namibia) and South Coast population of horse mackerel, as well as of the role of vertical migrations in modulating these exchanges, would be beneficial. 相似文献
18.
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
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小黄鱼是我国近海四种最重要的经济鱼类之一，在过去的几十年中小黄鱼种群及其两个地理亚种群经历了巨大的变化。小黄鱼的种群动力学研究，对于维持这一重要渔业的可持续管理是至关重要的。目前仅有的两个小黄鱼种群动力学模型只涵盖了较短的时间，且没有关注其空间差异。本文研究了1968年至2015年间黄渤海和东海小黄鱼的种群动力学模型，包含和不包含空间分层结构的两种贝叶斯模型被用于分析其种群动力学的大尺度空间异质性。本文分析了不同的假设，来研究小黄鱼种群动力学潜在的变化趋势。研究结果表明小黄鱼种群动力学特征具有明显的时间和空间变化。种群的增长速度从20世纪八十年代开始增加，而可捕系数从1981年到2015年增加了两倍多。与黄渤海亚种群相比，东海的小黄鱼亚种群生长速度更快，遭受的捕捞压力也更大。基于最大可持续产量MSY的参考点表明，无论是整个小黄鱼种群还是两个亚种群，近年来都有非常高的过度捕捞风险。因此我国小黄鱼的渔业管理急需更加保守的管理策略，同时考虑其地域差异。本文所用的方法可以应用于其他种类的资源评估和渔业管理，尤其是具有空间异质性和数据有限的种类。 相似文献
20.
Evaluation of the Effect of Marine Ranching Activities on the Tongyeong Marine Ecosystem 总被引：1，自引：0，他引：1
Using ecosystem models (Ecopath, Ecosim, and Ecospace), we assessed the structure and function of the Tongyeong marine ranching ecosystem and compared changes in various ecosystem components before and after marine ranching activities. An ecosystem structure model, Ecopath, was used to estimate the changes in biomass and trophic level of major species or groups, the relative contribution of target species or groups to the total flow of energy (throughput), and niche overlaps and impacts of competition between major species or groups. It showed that the Tongyeong ecosystem had 4 trophic levels. A large amount of energy flows occurred at trophic levels 3 and 4, and jacopever rockfish (Sebastes schlegelii) and black rockfish (S. inermis) that were target species for stock enhancement belonged to trophic level 3, indicating that those two species played an important role in the ecosystem. Using an ecosystem dynamic model, Ecosim, the mechanism of dynamic changes in the quantity of target species or groups was investigated to identify the effects of stock enhancement activities and impacts of fishing intensity. After marine ranching activities, the biomass of two target species had increased, while those of most other fish groups decreased. Assuming that fishing mortality was double the current level, the biomass of most fish groups decreased but jacopever rockfish maintained its current stock level due to excessive stock enhancement and low fishing mortality in recent years. An ecosystem space model, Ecospace, was employed to simulate the temporal and spatial dynamics of the biomass of organisms in order to examine how resource enhancement activities have changed the distribution and abundance of target species or groups in the ecosystem. The distribution pattern of jacopever rockfish and black rockfish showed stronger aggregations around reefs and rocky areas with high stock densities after ranching. However, most of the other fish groups exhibited lower densities in the marine ranching area, while they showed higher densities outside the marine ranching area. Thus, it would be necessary to take appropriate holistic management actions based on the ecosystem-based approach to keep the ranching ecosystem healthy and to maintain the fishery production of the ecosystem at the maximum sustainable level. 相似文献