Spatially explicit fisheries simulation models for policy evaluation   总被引：3，自引：0，他引：3  

Dominique Pelletier  & Stéphanie Mahévas 《Fish and Fisheries》2005,6(4):307-349

This paper deals with the design of modelling tools suitable for investigating the consequences of alternative policies on the dynamics of resources and fisheries, such as the evaluation of marine protected areas (MPA). We first review the numerous models that have been developed for this purpose, and compare them from several standpoints: population modelling, exploitation modelling and management measure modelling. We then present a generic fisheries simulation model, Integration of Spatial Information for FISHeries simulation (ISIS‐Fish). This spatially explicit model allows quantitative policy screening for fisheries with mixed‐species harvests. It may be used to investigate the effects of combined management scenarios including a variety of policies: total allowable catch (TAC), licenses, gear restrictions, MPA, etc. Fisher's response to management may be accounted for by means of decision rules conditioned on population and exploitation parameters. An application to a simple example illustrates the relevance of this kind of tool for policy screening, particularly in the case of mixed fisheries. Finally, the reviewed models and ISIS‐Fish are discussed and confronted in the light of the underlying assumptions and model objectives. In the light of this discussion, we identify desirable features for fisheries simulation models aimed at policy evaluation, and particularly MPA evaluation.  相似文献   

Environmental 'loopholes' and fish population dynamics: comparative pattern recognition with focus on El Niño effects in the Pacific   总被引：1，自引：2，他引：1  

Andrew Bakun  Kenneth Broad 《Fisheries Oceanography》2003,12(4-5):458-473

  相似文献   

Relationships among long'term fisheries abundances, hydrographic variables, and gross pollution indicators in northeastern U.S. estuaries     

KENNETH A. ROSE  J. KEVIN SUMMERS 《Fisheries Oceanography》1992,1(4):281-293

Categorical time series regression was applied to 55 fish stocks in the Potomac, Hudson, Narragansett, Delaware, and Connecticut estuaries for the period 1929–1975. Interannual variability in catch per unit effort (CPUE) was related to CPUE, hydrographic variables, and pollution variables, lagged back in time to represent the conditions contributing to the multiple ages comprising each fishery. Hydrographic variables included water temperature and flow in the estuary– and, for offshore spawning stocks, wind direction and magnitude–during the months of spawning and early life stage development. Pollution variables included measures of dissolved oxygen conditions in the estuaries, volume of material dredged, and sewage loading (or human population). Lagged CPUE, hydrographic variables, and pollution variables all played important roles in explaining historical variability in CPUE. Lagged CPUE was significant in 45 of 55 stocks generally accounting for 5–35% of the variability. Lagged hydrographic variables were significant in 53 of 55 stocks, explaining an additional 5–40% of the variability unaccounted for by lagged CPUE. Lagged pollution variables were significant in 35 of 55 stocks, generally accounting for an additional 5–30% of the variability not explained by lagged CPUE and hydrographic variables. Results did not exhibit expected patterns of consistency in the importance of lagged CPUE for a species across estuaries or consistency in the importance of pollution variables across estuaries. Results did exhibit the expected north-to-south longitudinal pattern in the importance of timing of the hydrographic variables, the months of importance being one or two months later in more northerly estuaries. Higher-order interaction effects were important in almost all stocks that were well-modeled by categorical time series regression. Of the 30 stocks with final regression models having R² > 0.55, 26 stocks involved significant interaction effects, five had only significant interaction effects (no significant main effects), and 20 stocks had significant interactions involving variables not significant as main effects. The difficulties involved in analyzing long-term trends in fish populations and partitioning variability between natural and anthropogenic sources are discussed.  相似文献   

A review of interactions between cetaceans and fisheries in the Azores     

Mónica A. Silva  Miguel Machete  Dália Reis  Marco Santos  Rui Prieto  Carla Dâmaso  João Gil Pereira  Ricardo S. Santos 《水产资源保护:海洋与淡水生态系统》2011,21(1):17-27

  相似文献   

Diagnosis and management of small-scale fisheries in developing countries   总被引：2，自引：0，他引：2  

Neil L Andrew  Christophe Béné  Stephen J Hall  Edward H Allison  Simon Heck  & Blake D Ratner 《Fish and Fisheries》2007,8(3):227-240

Small‐scale fisheries (SSF) make important but undervalued contributions to the economies of some of the world’s poorest countries. They also provide much of the animal protein needed by societies in which food security remains a pressing issue. Assessment and management of these fisheries is usually inadequate or absent and they continue to fall short of their potential as engines for development and social change. In this study, we bring together existing theory and methods to suggest a general scheme for diagnosing and managing SSF. This approach can be adapted to accommodate the diversity of these fisheries in the developing world. Many threats and solutions to the problems that beset SSF come from outside the domain of the fishery. Significant improvements in prospects for fisheries will require major changes in societal priorities and values, with consequent improvements in policy and governance. Changes in development policy and science reflect these imperatives but there remains a need for intra‐sectoral management that builds resilience and reduces vulnerability to those forces beyond the influence of small‐scale fishers.  相似文献   

Impact of stocking on yield in small reservoirs in Andhra Pradesh, India     

V. V. Sugunan  & P. K. Katiha 《Fisheries Management and Ecology》2004,11(2):65-69

The relationships between surface area, stocking density and fish yield in 40 small reservoirs in India between 1994 and 1999 were examined. A significant positive correlation (r = 0.6) was found between stocking density and fish yield. Area was negatively correlated with stocking density (r = ?0.57) and fish yield (r = ?0.62), but its correlation with efficiency of stocking was not significant for all the size groups of small reservoirs.  相似文献   

Are the long‐term fluctuations in Atlantic bluefin tuna (Thunnus thynnus) population related to environmental changes?     

Christelle Ravier  Jean-Marc Fromentin 《Fisheries Oceanography》2004,13(3):145-160

We tested whether synchronous, long‐term fluctuations in Atlantic bluefin tuna (Thunnus thynnus) trap catches, collected from the ancestral Mediterranean and Atlantic trap fishery, might be related to large‐scale environmental change. Nine time series of trap catches of more than 80 yr long were compared with long time series of three preselected environmental variables, i.e. the North Atlantic Oscillation (NAO), the Length of the Day Index (LOD, a proxy of the atmospheric circulation index) and the temperature. Spectral analyses of trap catches, LOD and temperature displayed similar spectra with peaks at low frequencies, whereas those of the NAO exhibited a broad band spectrum. Regression analyses and tests of correlation did not reveal any clear relationship between trap catches on the one hand and NAO and LOD on the other hand. In contrast, long‐term fluctuations in trap catches appear to be closely and negatively related to long‐term trends in temperature. Underlying processes that could explain such a relationship are discussed, with special focus on changes in migration patterns of the Atlantic bluefin tuna.  相似文献   

环境友好型虾夷扇贝捕捞网具优化设计与试验     

李明智  何瑞麟  陈海泉  刘鹰  张光发  孙玉清 《农业工程学报》2022,38(11):21-30

目前中国虾夷扇贝网具存在捕捞效果差、海底生境影响严重等问题,该研究基于水下视频监控技术,设计了水压板导流与随动式惊扰相结合的拖曳网架结构。采用FLUENT软件对改造后捕捞网具的水下拖曳水动力特性进行分析得出,在拖曳水深在30~50 m、拖曳速度为1.8 m/s、网口高度为350 mm时,采用22.5°～30°负迎角弧式水压板,可减轻顶部湍流对底栖鱼类的兼捕影响,且随动式惊扰装置满足作业要求,此时拖曳稳定绳长约为156.80～261.34 m、稳定角度为11.03°、稳定拖曳力为2275.83 N。通过海上捕捞对比试验得出,在拖曳速度为1.5、1.8和2.0 m/s时,改造后捕捞网具与生产用捕捞网具在捕捞量方面无显著差异（P>0.5）,在碎贝量和底栖鱼类兼捕量方面显著降低（P<0.5）。单网平均捕捞量的偏差率分别为6.30%、0.59%和5.55%,单网平均碎贝量的偏差率分别为90.63%、84.78%、85.29%,单网底栖鱼类平均兼捕量的偏差率分别为78.57%、81.25%、84.85%。且在拖曳速度为1.8 m/s时,与生产用网具相比,单网平均捕捞量偏差率最低,单网平均碎贝量的偏差率最低,底栖鱼类平均兼捕量显著减少,符合环境友好型捕捞网具设计要求。  相似文献   

The role of catchment scale environmental management in freshwater fish conservation   总被引：8，自引：0，他引：8  

M. J. Collares-Pereira  & I. G. Cowx 《Fisheries Management and Ecology》2004,11(3-4):303-312

  相似文献   

Fisheries of two tropical lagoons in Ghana, West Africa     

H. R. Dankwa  J. M. Shenker  & J. Lin  P. K. Ofori-Danson  Y. Ntiamoa-Baidu 《Fisheries Management and Ecology》2004,11(6):379-386

Abstract  The fisheries of two coastal lagoons, Keta and Songor, were studied as part of Ghana Coastal Wetlands Management Project (GCWMP) aimed at sustainable exploitation of wetland resources. Fish samples were obtained with seine nets and cast net as well as from local fishermen. Water quality parameters (pH, dissolved oxygen, temperature and turbidity) were similar in the two lagoons, except for salinity, which was significantly different ( P  < 0.001). Despite their close geographical proximity, the two lagoons supported different fish assemblages with the blackchin tilapia, Sarotherodon melanotheron Rüppell, and the redchin tilapia, Tilapia guineensis (Bleeker), being the most important commercial fishes in both lagoons. The number of individuals for each species in Songor Lagoon were far more abundant, with densities several orders of magnitude higher than in Keta Lagoon. However, both species were significantly larger ( P  < 0.01) in the latter [15–121 and 25–157 mm standard length (SL)] than in the former lagoon (30–102 and 15–95 mm SL) for S. melanotheron and T. guineensis respectively. Over-fishing, use of small-size mesh nets, limited mixing of marine and fresh water were some of the factors limiting fish production in both lagoons.  相似文献