نتایج جستجو برای: fish harvesting
تعداد نتایج: 131730 فیلتر نتایج به سال:
Overfishing can lead to the reduction or elimination of fish populations and the degradation or even destruction of their habitats. This can be prevented by introducing Marine Protected Areas (MPA’s), regions in the ocean or along coastlines where fishing is controlled. MPA’s can also lead to larger fish densities outside the protected area through spill-over, which in turn may increase the fis...
An economic anylysis was made to determine the cost of fish production in the floodplains at Daudkandi Upazilla in Comilla district during the period form January to April, 2007. Survey method was followed to collect data from 20 floodplain aquaculture projects. The projects record books and personal interviews of the NGOs and Fisheries officers were the main instruments of data collection. Sta...
this study aimed to investigate the concentrations of two heavy metals, lead and cadmium, in the water of zayandehroud river which is surrounded by zarinshahr rice farms. water was sampled from a depth of 30 cm during june, july and august 2015, i.e. during the process of planting, growing and after harvesting, in three stations. water was collected from three points; 20m before the farms, besi...
Rapid life-history changes caused by size-selective harvesting are often interpreted as a response to direct harvest selection against large body size. However, similar trait may result from harvest-induced relaxation of natural for size via density-dependent selection. Here, we show evidence such favouring large-bodied individuals at high population densities, in replicated pond populations me...
Fish is the primary dietary source of omega-3 long-chain polyunsaturated fatty acids, which are necessary for healthy prenatal development and linked to reducing cardiovascular disease risk. The type and quantity of seafood that individuals choose to eat can impact both their health and the long-term sustainability of the world’s fisheries. An interdisciplinary team of researchers wants consume...
Fish is the primary dietary source of omega-3 long-chain polyunsaturated fatty acids, which are necessary for healthy prenatal development and linked to reducing cardiovascular disease risk. The type and quantity of seafood that individuals choose to eat can impact both their health and the long-term sustainability of the world’s fisheries. An interdisciplinary team of researchers wants consume...
Modelling population dynamics in ecological systems reveals properties that are difficult to find by empirical means, such as the probability a will go extinct when it is exposed harvesting. To study these properties, we use an aquatic system containing one fish species and underlying resource our models. In particular, class of stage-structured with without starvation. models, resilience, reco...
A field survey through questionnaire was conducted in rice-prawn (Macrobrachium rosenbergii)-fish culture ghers six villages of Khulna, Satkhira and Bagerhat districts south-west Bangladesh during March to December, 2008 assess present practices. About 10-25% the total area land converted for building canals dikes remaining were used rice cultivation. Boro with prawn fish appeared have positive...
Harvesting has been implicated in destabilizing the abundances of exploited populations. Because selective harvesting often targets large individuals, some studies have proposed that populations experience demographic shifts toward younger, smaller individuals and become more sensitive to environmental fluctuations. The theory consumer–resource dynamics applied address impacts simple modular fo...
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