نتایج جستجو برای: trophic index
تعداد نتایج: 410552 فیلتر نتایج به سال:
Competition between marine mammals and fisheries for marine resources-whether real or perceived-has become a major issue for several countries and in international fora. We examined trophic interactions between marine mammals and fisheries based on a resource overlap index, using seven Ecopath models including marine mammal groups. On a global scale, most food consumed by marine mammals consist...
Response of Trophic Groups of Macrobenthic Fauna to Environmental Disturbance Caused by Fish Farming
Sediment dynamics and the hydrodynamics of the environment cause the complexity and variability in animal-sediment relationship, both in spatial and temporal. This study is focused on the response of macrobenthic fauna to environmental disturbance caused by fish farming using their trophic structure. Their changes in trophic structure can be used as an indicator of disturbance. Eight control si...
23 24 Understanding how marine ecosystems are structured and how they function is a 25 scientific challenge. Nowadays, to learn about ecosystem trophic dynamics ecologists use 26 two complementary methodological approximations, mass-balance ecosystem models and 27 isotopic tools. However, despite the wide applications of these methodologies, the 28 comparison and combination of both are still s...
The current study deals with the physicochemical characterization, temporal variability and trophic state evaluation of a post glacial mountain lake in eastern Himalaya during the period of 2014-2016. Notable seasonal variations are recorded for physicochemical parameters of lake water. The values for electrical conductivity, total suspended solids, total dissolved solids, total alkalinity and ...
Exploited ecosystems are characterised by exports of secondary production from each fished trophic level that reduce the energy available for upper levels at the ecosystem scale, thus impinging on overall secondary production. Depletion in secondary production is proposed here as a proxy for quantifying the ecosystem effects of fishing. Theoretical analysis of trophic web interactions permits t...
Models of biomass size spectra assume that organisms with higher body mass feed at higher trophic levels, but explicit empirical tests of this pattern are rare. We used nitrogen stable isotopes (δ15N) as an index of the trophic level in a benthic fish and invertebrate size-spectrum, and demonstrated that body mass was positively and significantly related to trophic level. This pattern was consi...
Ciénaga de Mallorquín is a coastal lagoon designated as a RAMSAR site due to its ecological regional and international importance. In this work, the environmental fluid dynamics code explorer modeling system was implemented to determine the spatio-temporal distribution of temperature, dissolved oxygen, chemical oxygen demand and nutrient levels, and assess the trophic status of Ciénaga de Mallo...
Investigating the relations and mechanisms of coexistence among sympatric species is essential to comprehend their ecological roles in the food webs. In the present study, the diet and trophic interactions of 5 abundant teleost species coexisting in the northern Oman Sea were examined using stomach contents analyses. The cumulative prey curves showed that the sample size of each studied species...
Exploited ecosystems are characterised by exports of secondary production from each fished trophic level that reduce the energy available for upper levels at ecosystem scale thus impinging on overall secondary productions. Depletion in secondary production with respect to the unfished state is here proposed as a proxy for quantifying ecosystem effects of fishing. Theoretical analysis of trophic...
In order To increase the knowledge of Saurida tumbil biology and ecology, an investigation of food habits of this species was conducted from October 2010 to September 2011 in Bushehr coastal waters, Persian Gulf. 485 fish stomach contents were studied. In this study the frequency of occurrence of prey, feeding intensity index, the index is empty stomachs, the mean Trophic levels and the rate of...
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