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171.
172.
Ecosystems have been viewed both as chaotic, untamed nature, and as mechanical systems with predictable equilibrium states. A developing concept of ecosystems as “complex adaptive systems” lies between these extreme concepts, with recognizably patterned but not fully predictable behavior. Sustainability has also been redefined as humans have exploited and often depleted desirable natural resources. Fisheries management desires sustainable yield, but must rethink this concept within the ecosystem context. The most powerful union of “ecosystem” and “sustainability” acknowledges the defining characteristics of complex adaptive systems with the objective of identifying and sustaining healthy relationships within and between ecosystems, economies, and society. 相似文献
173.
The principal inshore fishery in the southwest Irish Sea is currently for whelk Buccinum undatum, which expanded in the 1990s and yielded almost 10,000 t in 2003. The fleet exploiting it consisted largely of old boats many of which previously used a variety of gears but which cannot any longer compete with more modern towing craft. Whelk is the only target species for the majority. The fishery is in open access and is not regulated and the paper examines the consequences of this for the fishers, particularly the problems associated with maintaining a way of life traditionally associated with remuneration by share rather than wage. Lack of regulation, it is argued, encourages a short term, opportunistic harvesting regime, which is not conducive to maintain a biologically sustainable fishery. 相似文献
174.
Study on the phytoplankton · in a large reservoir 总被引:3,自引:0,他引:3
A comprehensive study on the community structure and function of the phytoplankton in Taipinghu Reservoir, the largest reservoir
(9400 ha) in Anhui Province, China, was carried out during 1985–1986. A total of 175 species of algae belonging to 8 phyla
and 87 genera was noted. The composition of phytoplankton was dominated by species of Chlorophyta, Cyanophyta and Bacillariophyta.
The species number, cell density and biomass of the three groups were respectively 88%, 86.5% and 78.9% of the total phytoplankton.
The weighted annual average biomass was 1.52 mg/L and cell density was 1.43×106 ind/L. The growth maximum was observed in summer. Diatoms were abundant in the region adjoining a river. A large number of
flagellated algae such asEuglena andChromulina occurred in the artificial fish culture bay.
It can be inferred from the algal composition and total nitrogen concentration (1.48 mg/L) that this reservoir is a mesotrophic
water body that had undergone slight natural eutrophication.
Presented are an equation for the relation between cell density and biomass of algae and a newly developed method based on
the energy flow principle in ecology for theoretically estimating algal fishery potential. The algae volumes of 128 species
were measured for calculating the biomass. 相似文献
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176.
海洋渔业资源过度利用的原因分析 总被引:2,自引:0,他引:2
海洋渔业对我国海洋经济的发展起着举足轻重的作用,但在海洋渔业迅速为我们创造巨大财富的同时,却遭到了掠夺性地捕捞,使海洋渔业资源陷入了日益枯竭的境地。通过分析后认为由于海洋渔业资源产权不明晰, 具有公共资源的性质,所以人们在对海洋渔业资源利用时会产生负的外部性和使用者之间的博弈行为,这成为海洋渔业资源过度利用的主要原因。 相似文献
177.
浅谈南海渔业管理对策 总被引:2,自引:0,他引:2
夏章英 《广东海洋大学学报》2005,25(2):1-5
南海渔业资源衰退的主要原因是捕捞过度和海洋生态环境破坏。由于海洋生态过程是动力学过程,很多生态因素的变化会相应引起生态过程的变化,同时生态动力学过程的因素又是多方面的,因此南海渔业资源的管理和生产方式应该从过去的开发型管理向着管理型管理方向转变。这种管理方式涉及面较广,必须实施从渔业资源管理、渔业水域管理、渔业水域周围环境管理到加强对渔船与船员管理、捕养并重、健全法制、强化治政队伍与执法力量配置以及开展国际渔业合作等管理措施。 相似文献
178.
179.
本文介绍了基于ArcGIS平台的渔业信息化管理平台的建设目标,阐述了系统的设计架构与建设内容,并简要分析了系统的关键技术及应用实践。 相似文献
180.
随着近几年南极磷虾渔业的快速发展,南极海洋生物资源养护委员会(CCAMLR)正在抓紧建立反馈式管理(FBM)机制,以预防和控制磷虾渔业对南大洋局部生态系统可能产生的负面影响,介绍了CCAMLR南极磷虾渔业反馈式管理的基本概念和理论框架,梳理了反馈式管理工作开展的具体进程;侧重阐述了近期反馈式管理的两类模式策略,分析了反馈式管理关注的科学问题和基础理论、方法;提出我国渔业相关机构应积极储备科学数据和理论,参与反馈式管理建设,以适应未来南极磷虾渔业新的管理模式,促进我国南极磷虾渔业的可持续发展。 相似文献