نتایج جستجو برای: cormorant
تعداد نتایج: 329 فیلتر نتایج به سال:
Background and Objectives: The heavy metals pollution in aquatic ecosystems especially mercury, always makes concern about health of aquatic organisms. So, the purposes of this study were determination of total mercury in different tissues of the three species of the most important water birds at north of Iran and comparison with world health standards.Materials and Methods: Generally, 51 birds...
We compared 2 sampling strategies designed to estimate abundance of double-crested cormorants (Phalacrocorax auritus, hereafter cormorants) on aquaculture ponds in western Mississippi. Cormorants are a major predator of cultured channel catfi sh (Ictalurus punctatus) in this region; thus, estimating cormorant abundance is needed to better determine their economic impact. We independently design...
In 1994 and 1995, nesting success of double-crested cormorants (Phalacrocorax auritus) was measured at Cat Island, in southern Green Bay, Lake Michigan, Wisconsin, USA. Sample eggs at pipping and unhatched eggs were collected and analyzed for organochlorines (including total polychlorinated biphenyls [PCBs] and DDE), hepatic microsomal ethoxyresorufin-O-dealkylase (EROD) activity in embryos, an...
Theoretical arguments suggest that increased plant productivity may not only increase consumer densities but also their fluctuations. While increased consumer densities are commonly observed in fertilization experiments, experiments are seldom performed at a spatial and temporal scale where effects on population fluctuations may be observed. In this study we used a natural gradient in soil fert...
Cormorants and other wildlife populations have come in real or perceived conflicts with humans over exploited fish stocks. From gut contents of cormorants, and using an extension of the Catch equation, we estimated the degree of short term competition between great cormorants and coastal fisheries in two areas along the Swedish Baltic Sea. Cormorants consumed 10 and 44%, in respective area, of ...
Biorobotic Waterbird Flipper Locomotion Flipper-propelled locomotion is distinguished by a rhythmic, alternating movement of the flippers, resulting in wave-like motion that propels cormorant forward. In article number 2200380, Jinguo Huang, and co-workers propose processing framework to deliver technological basis for issue flexible flippers confronted with fluid pressures during underwater mo...
In the Laurentian Great Lakes region, the double-crested cormorant (Phalacrocorax auritus) has seen a thousand-fold population increase in recent decades. These large colonies of birds now often conflict with socioeconomic interests, particularly due to perceived competition with fisheries and the destruction of terrestrial vegetation in nesting habitats. Here we use dated sediment cores from p...
Double-Crested Cormorant Distribution on Catfish Aquaculture in the Yazoo River Basin of Mississippi
Estimating the catfish aquaculture production losses that can be attributed to double-crested cormorants (Phalacrocorax auritus) has proved problematic because knowledge of the distribution of cormorants on catfish aquaculture is lacking. We evaluated use versus availability of various production pond types and landscape-scale factors affecting the distribution of cormorants on channel catfish ...
Two free-living seabirds (the African penguin Spheniscus demersus and the bank cormorant Phalacrocorax neglectus) were equipped with stomach temperature-loggers to study body temperature changes during foraging. Body temperature in these endotherms was environmentally and activity-dependent and varied in the case of the cormorant by over 5 degrees C. Considerations of heat flux show that such f...
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