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481.
Jeffrey E. Moore Bryan P. Wallace Rebecca L. Lewison Ramúnas Žydelis Tara M. Cox Larry B. Crowder 《Marine Policy》2009
This paper reviews the available information (observer programs, estimates, statutes, regulations) for bycatch of marine mammals, sea turtles, and seabirds in fisheries of the United States. Goals of the review were to evaluate the state of knowledge of bycatch and the role of existing protective legislation in shaping bycatch management for different taxa. Pressing issues are identified, as well as knowledge gaps and policy limitations that hinder multi-species bycatch reduction. The USA has made important progress toward reducing bycatch in its fisheries, but the efficacy of its management has been limited somewhat by a focus on taxon- and fishery-specific regulation and the lack of consistent mandate across taxa for taking a cumulative perspective on bycatch. Applying consistent criteria across taxa for setting bycatch limits (e.g., extending the approach used for marine mammals to sea turtles and seabirds) would be the first step in a multi-species approach to bycatch reduction. A population-based multi-species multi-gear approach to bycatch would help identify priority areas where resources are needed most and can be used most effectively. 相似文献
482.
Community-based coastal resource management (CBCRM) is a major conservation and fisheries management strategy in the tropics. In this study, the performance of 16 CBCRM programs in the Philippines was assessed using a meta-analysis of eight indicators that represented the perceptions of local resource users. Overall, the CBCRM programs in the Philippines were perceived to have a significant positive impact. However, the performance of each of the indicators was mixed. Although the CBCRM programs were perceived to be effective in empowering the local fishing communities, their perceived impact on improving the state of the local fisheries resources remained limited. This highlights the importance of incorporating ecological and socio-economic considerations in setting fisheries management regimes. 相似文献
483.
Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today. 相似文献
484.
Coinciding with increased numbers of global marine reserves, communities in the Pacific islands are establishing unprecedented number of periodically-harvested and indefinitely-closed marine reserves. An integrated ecological and social comparative methodology is used to examine the motivations and outcomes of reserves in Vanuatu. Communities establish permanent reserves due to concerns about human impacts on reefs, while others establish periodic reserves in response to declining resources. Local knowledge suggests that both reserve types are effective, although validation by underwater surveys was inconclusive. Community support for both reserve types is strong, suggesting that the marine reserve phenomenon in Pacific will continue. 相似文献
485.
2006年1月~10月福建闽东大嵛山附近海域游泳动物调查研究结果表明,该海域的游泳动物有97种,其中鱼类51种(软骨鱼1种,硬骨鱼类50种),隶属于9目24科42属;甲壳类42种,隶属于2目15科20属;头足类4种,隶属于3目3科3属.暖水性种类为33种,占鱼类总种数的64.7%;暖温性鱼类18种,占鱼类总种数的35.3%,未出现冷温性和冷水性鱼类.种类数的季节变化依次呈夏季〉冬季〉秋季〉春季.生物量的季节变化,依次呈夏季〉秋季〉春季〉冬季;而生物量尾数的季节变化,依次呈夏季〉春季〉秋季〉冬季.平均单位网次渔获生物量和密度分别为9.53kg/h和1 319 ind/h.生物量优势种和密度优势种分别为大黄鱼和中华管鞭虾.扫海面积法估算年平均现存资源量为57 370 ind/km^2和404.51kg/km^2.同时,本文对该海域游泳生物的资源结构现状与历史调查数据作了对比分析,并讨论了多样性结构与生物量的季节性变化规律.结果表明,该海域渔业资源有严重衰退的现象,多样性结构与生物量的季节性变化并不具有必然的一致性. 相似文献
486.
根据2006~2007年南海北部海区4季的调查资料,分析该海区软骨鱼类的种类组成和资源密度的分布.结果表明,软骨鱼类有32种,分隶于9目17科,优势种为斑鳐、曾氏兔银鲛、褐黄扁缸、橙黄鲨;渔获率D断面最高(10.19kg/h),B断面最低(4.52kg/h);渔获率有明显的季节变动,夏季最高(12.16kg/h),秋季最低(3.71kg/h),平均渔获率为7.05kg/h;密集分布于180m和140m水深处;其年均资源密度为94.00kg/km^2.文中并讨论合理利用和保护该类群的措施. 相似文献
487.
488.
Fuzzy comprehensive evaluation model for water resources carrying capacity in Tarim River Basin, Xinjiang, China 总被引:12,自引:0,他引:12
This paper explores the method of comprehensive evaluation of water resources carrying capacity and sets up an evaluation model applying the fuzzy comprehensive evaluation method. Based on the data of nature, society, economics and water resources of the Tarim River Basin in 2002, we evaluated the water resources carrying capacity of the basin by means of the model. The results show that the comprehensive grades are 0.438 and 0.454 for Aksu and Kashi prefectures respectively, where the current water resources exploitation and utilization has reached a relative high degree and there is only a very limited water carrying capacity, 0.620 for Kizilsu Kirgiz Autonomous Prefecture, where water resources carrying capacity is much higher, and in between for Hotan Prefecture and Bayingolin Mongolian Autonomous Prefecture. As a whole, the comprehensive grade of the Tarim River Basin is 0.508 and the current water resources exploitation and utilization has reached a relative high degree. Thus, we suggest that the integrated management of the water resources in the basin should be strengthened in order to utilize water resources scientifically and sustainably. 相似文献
489.
490.
白银市农业气候资源特征及开发应用 总被引:4,自引:0,他引:4
白银市农业气候资源具有日照充足,降水少而变率大,气象灾害种类多、危害重的特点。提出了气候资源开发与应用的途径。 相似文献