نتایج جستجو برای: Trophic level

تعداد نتایج: 1093170  

Journal: :علمی شیلات ایران 0
آرزو وهاب نژاد a. vahabnezhad موسسه تحقیقات علوم شیلاتی ایران، تهران صندوق پستی: 6116-14155 امین اله تقوی مطلق s.a. taghavi motlagh موسسه تحقیقات شیلات ایران ، تهران صندوق پستی 6116-14155 جواد شعبانی javad shaebani پژوهشکده میگوی کشور، بوشهر صندوق پستی: 1347

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...

Journal: :international journal of environmental research 2014
f. abdolahpur monikh m. hosseini j. kazemzadeh khoei a.f. ghasemi

in this study, three stations of the north persian gulf were analyzed in order to determinethe effect of trophic levels on the concentration of harmful pahs in fish and sediment. in all cases,similar distributions were observed in which benzo(a)pyrene largely predominated andbenzo(b)fluoranthene and pyrene were the second major compounds in fish tissues. the predominantcomponents of pahs in sed...

Ali Reza Rastgoo, M.S Mortazavi S.M.R Fatemi T Valinassab

The feeding habits and trophic level of Himantura gerrardi were studied according to sex and size classes utilizing 80 individuals obtained using bottom trawl between May and December 2014 from Oman Sea. Collected specimens were divided in three size classes (small 58 cm) based on disk width (DW). Preys were identified in seven main zoological categories, where crustacean and polychaetes were t...

Fatemi, S.M.R., Mortazavi, M.S., Rastgoo, A.R., Valinassab, T.,

The feeding habits and trophic level of Himantura gerrardi were studied according to sex and size classes of 80 individuals obtained using bottom trawl between May and December 2014 from the Oman Sea. Collected specimens were divided into three size classes (small<38 cm, medium 38-58 cm and large>58 cm) based on disk width. Prey was identified in seven main zoological categories, where crustace...

In the present study, a trophic structure model for some fish species of the northern Oman Sea is developed through using mass balance modeling software, Ecopath with Ecosim (EwE). In this model, we simulated 16 functional groups spread across an area of 3998.20 km2 from 2017 to 2018. Mean trophic level in the area of the present study was 3.49. Values calculated for system omnivory and connect...

Journal: :The Paleontological Society Special Publications 1992

2002
Simon Jennings John K. Pinnegar Nicholas V. C. Polunin Karema J. Warr

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...

Journal: :Current Biology 2017
Nicholas A.J. Graham Tim R. McClanahan M. Aaron MacNeil Shaun K. Wilson Joshua E. Cinner Cindy Huchery Thomas H. Holmes

The distribution of biomass among trophic levels provides a theoretical basis for understanding energy flow and the hierarchical structure of animal communities. In the absence of energy subsidies [1], bottom-heavy trophic pyramids are expected to predominate, based on energy transfer efficiency [2] and empirical evidence from multiple ecosystems [3]. However, the predicted pyramid of biomass d...

Almasieh Almasieh, Mehdi Khoshnamvand, Shahram Kaboodvandpour,

Background: Present study was conducted to measure the level of total mercury (tHg) in sediments, benthos and benthivorous fish (i.e., common carp) for determining Biota (Benthos)-Sediment Accumulation Factor (BSAF), as well as Biomagnification Factor (BMF) of tHg between two trophic levels of benthos and benthivorous fish caught from Sanandaj Gheshlagh Reservoir (SGR) in the west of Iran. Met...

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