نتایج جستجو برای: cyprinids
تعداد نتایج: 265 فیلتر نتایج به سال:
Habitat fragmentation and flow regulation are significant factors related to the decline and extinction of freshwater biota. Pelagic-broadcast spawning cyprinids require moving water and some length of unfragmented stream to complete their life cycle. However, it is unknown how discharge and habitat features interact at multiple spatial scales to alter the transport of semi-buoyant fish eggs. O...
The first outbreaks of a disease connected with high mortality of common carp and koi carp caused by koi herpesvirus (KHV) were reported in 1998 in Israel and in the United States. Since then, several cases have been confirmed all over the world. At present, this viral disease is considered to be one of the most risky factors affecting populations of common carp and koi carp. Affected fish beco...
Antiviral type I interferons (IFNs) have been discovered in fish. Genomic studies revealed their considerable number in many species; some genes encode secreted and non-secreted isoforms. Based on cysteine motifs, fish type I IFNs fall in two subgroups, which use two different receptors. Mammalian type I IFN genes are intronless while type III have introns; in fish, all have introns, but struct...
The intracardiac nervous system represents the final common pathway for autonomic control of the vertebrate heart in maintaining cardiovascular homeostasis. In teleost fishes, details of the organization of this system are not well understood. Here we investigated innervation patterns in the heart of the goldfish, a species representative of a large group of cyprinids. We used antibodies agains...
Several hypotheses concerning the dominance of percids under mesotrophic lake conditions were tested in five lakes of intermediate trophic state, situated in northeastern Germany. In contrast to prediction, the fish communities in four lakes were dominated by cyprinids (roach, Rutilus rutilus and bream, Abramis brama), while percids (Eurasian perch, Percafluviatilis) dominated in one lake only....
Myxobolus bilobus n. sp. (Myxozoa) is described from golden shiner Notemigonus crysoleucas in Algonquin Park, Ontario, Canada. Plasmodia develop at the distal end of gill filaments, where they form a novel-shaped plasmodium made up of 2 side-by-side hemispheres joined at a central pore. Surrounding gill tissue is vacuolated, necrotic, and hemorrhagic. Spores of M. bilobus n. sp. resemble those ...
found in iran, alburnoides bipunctatus and alburnus filippii. the chromosomes of these species were compared using giemsa staining and silver-staining (ag) techniques to describe the karyotypes. both species possess 2n = 50 chromosomes with no detected sex heteromorphism. the karyotypes were distinct, composed of 7 pairs of metacentric, 10 pairs of submetacentric, and 8 pairs of subtelo-acrocen...
River damming promotes profound changes in aquatic biodiversity, including the facilitation of biological invasions, with subsequent impacts on native communities. The Eurasian otter (Lutra lutra) is a generalist predator that often incorporates new prey types when they become available. We studied short- and long-term effects river trophic ecology across riverine landscape gradient, from flood...
Knight et al. (2013a) clarified the identity of Barbus mussullah Sykes, the type species of Hypselobarbus Bleeker, showing it to represent a lineage clearly distinct from Tor Gray (type species Tor hamiltonii Gray (= Cyprinus tor Hamilton)). They showed the two species to be distinguished by a suite of characters, with Hypselobarbus lacking the distinctive median fleshy lobe of the lower lip (p...
The reproductive biology of the only known intact species flock of large cyprinids, the 16 Labeobarbus species of Lake Tana (Ethiopia), has been extensively studied for the past two decades. Seven species of Labeobarbus are known to migrate >50 km upstream into tributary rivers for spawning during the rainy season (July to October), whereas eight other species are absent from these rivers and p...
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