نتایج جستجو برای: fishing effort ratio
تعداد نتایج: 627264 فیلتر نتایج به سال:
Bottom trawling is one of the most efficient fishing activities, but serious and persistent ecological issues have been observed by fishers, scientists and fishery managers. Although China has applied the Beidou fishing vessel position monitoring system (VMS) to manage trawlers since 2006, little is known regarding the impacts of trawling on the sea bottom environments. In this study, continuou...
To gauge the collateral impacts of fishing we must know where fishing boats operate and how much they fish. Although small-scale fisheries land approximately the same amount of fish for human consumption as industrial fleets globally, methods of estimating their fishing effort are comparatively poor. We present an accessible, spatial method of calculating the effort of small-scale fisheries bas...
Co-management agreements, whereby community rules for the management of local floodplain lake fisheries are legalised and enforced by the government, have become common in the lower Amazon. Agreements are intended to limit exploitation, in particular by commercial boats, to raise stock abundance and fisheries productivity for the benefit of local subsistence-oriented fishers and for conservatio...
Levels of fishing effort are defined as being excessive where they result in depletion of commercially valuable stocks and so threaten sustainable harvests. In many parts of Southeast Asia, this threat has been realized by the rapid expansion of commercial fisheries and the consequent increase in fishing effort. Southeast Asian fisheries are described as having a dualistic structure with distin...
We present a stock-effort dynamical model of a fishery subdivided into fishing zones. The stock corresponds to a fish population moving between these zones, on which they are harvested by fishing fleets. We consider a linear chain of identical fishing zones. Fish movements between the zones, as well as vessels displacements, are assumed to take place at a faster time scale than the variation of...
A stochastic age-structured population model was developed to explore biologically favourable levels of effort and closing periods within the sardine pelagic fishery in the eastern Mediterranean Sea. Results suggested that the developed age-structured model captured the observed biomass fluctuations and catches reasonably well and represents the first comprehensive investigation of alternative ...
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