نتایج جستجو برای: fish distribution
تعداد نتایج: 706269 فیلتر نتایج به سال:
Glochidia are the larval stage of freshwater unionid mussels that parasitize the fins and gill apparatus of fish. A total of 22 fish species were examined for the presence of glochidia whose distribution on individual hosts was studied on three common fish species, the roach Rutilus rutilus (L.), perch Percafluviatilis L. and bitterling Rhodeus sericeus (Pallas). Between 1997 and 1999, the fish...
Freshwater fish biodiversity is a precious natural asset in terms of economic, cultural and scientific interest. And yet, the inland freshwater ecosystem in Malaysia is declining at a far greater rate than terrestrial ecosystems in the tropics. What happened, and what is being done to address the crisis? This paper extracts findings from the latest literature and explores overarching issues per...
Cover U often thought to be an important habitat characteristic for juvenile stream salmonids. In addition to providing protection from predators, cover may be associated with reduced food availability. Thus, an individual's use of cover is likely to reflect a trade-off between the conflicting demands of growth and survival. We measured die influence of cover on foraging-site selection in group...
Defining the oceanic habitats of migratory marine species is important for both single species and ecosystem-based fisheries management, particularly when the distribution of these habitats vary temporally. This can be achieved using species distribution models that include physical environmental predictors. In the present study, species distribution models that describe the seasonal habitats o...
The Yellow River, one of the very few in the Earth, originated from many dispersive palaeolakes. Taking this unique advantage, we examined the roles of palaeolake isolation vs. geological processes vs. climate in determining current fish biogeographic pattern. We reviewed available data on fish species and their geographical distribution in the river, as well as palaeolake development, geologic...
Salmonid farming affects both the environment and other industries, with impacts of wild fish attracted to fish farms being a major concern. Here, we summarized existing knowledge on the impacts of such aggregations around open-cage salmonid farms in Norway on the environment and human activities and on the interactions of these impacts. Waste fish feed is considered the major cause for the att...
this paper provides information on the geographic distributions of two cyprinid species: hemiculter leucisculus (basilewsky, 1855) and alburnus caeruleus heckel, 1843, in the world and the entire drainage systems in iran. the new distribution records were taken from maroon river (jarrahi river system) and chardaval river (karkheh river system), both in tigris river basin showing wide and narrow...
The objective of this study was to determine the distribution of selected metal concentrations (Cd, Pb, Cr and Fe) in the muscles of five fish species (Sander lucioperca, Liza auratus, Alosa caspia, Cyprinus carpio and Liza saliens) from Gorgan Bay the south-eastern Caspian Sea, in order to assess health risk to the human via fish consumption by graphite furnace atomic absorption spectrophotome...
Reaction norms for age and size at maturation describe the probability of immature fish maturing at a certain age and size. Knowledge of such reaction norms is increasingly important, both for observing and understanding changes in maturation and for calibrating sizeand age-structured population models. Estimating the reaction norms for age and size at maturation by logistic regression requires...
—Stream fish are expected to be influenced by climate change as they are ectothermic animals living in lotic systems. Using fish presence–absence records in 1,110 stream sites across France, our study aimed at (1) modeling current and future distributions of 35 stream fish species, (2) using an ensemble forecasting approach (i.e., several general circulation models [GCM] × greenhouse gas emissi...
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