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Danube River (danube + river)
Selected AbstractsTracing recent invasions of the Ponto-Caspian mysid shrimp Hemimysis anomala across Europe and to North America with mitochondrial DNADIVERSITY AND DISTRIBUTIONS, Issue 2 2008Asta Audzijonyte ABSTRACT The mysid crustacean Hemimysis anomala (,bloody-red shrimp') is one of the most recent participants in the invasion of European inland waters by Ponto-Caspian species. Recently the species also became established in England and the Laurentian Great Lakes of North America. Using information from mitochondrial cytochrome oxidase I (COI) gene sequences, we traced the invasion pathways of H. anomala; the inferences were enabled by the observed phylogeographical subdivision among the source area populations in the estuaries of the Ponto-Caspian basin. The data distinguish two routes to northern and western Europe used by distinct lineages. One route has been to and through the Baltic Sea and further to the Rhine delta, probably from a population intentionally introduced to a Lithuanian water reservoir from the lower Dnieper River (NW Black Sea area) in 1960. The other lineage is derived from the Danube delta and has spread across the continent up the Danube River and further through the Main,Danube canal down to the Rhine River delta. Only the Danube lineage was found in England and in North America. The two lineages appear to have met secondarily and are now found intermixed at several sites in NW Europe, including the Rhine and waters linked with the man-made Mittellandkanal that interconnects the Rhine and Baltic drainage systems. [source] Food Habits of Four Bottom-Dwelling Gobiid Species at the Confluence of the Danube and Hron Rivers (South Slovakia)INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 4-5 2007k Adámek Abstract Since 1997, three new Neogobius species (Neogobius kessleri, N. fluviatilis and N. melanostomus) have been regularly recorded in the Slovak part of the Danube River, formerly inhabited only by one native gobiid species (Proterorhinus marmoratus). The study of their food habits proved that the amphipod Corophium curvispinum, chironomid larvae and pupae, caddis fly larvae (Hydropsyche sp.) and mayfly nymphs (Ephoron virgo, Potamanthus luteus) were the most important food items contributing to the similarity of the diets of the gobiid species. Fish (0+ Zingel zingel and Sander lucioperca) appeared in the diet of N. kessleri only. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Taxonomic status of salmonids in the Bulgarian stretch of the Danube River and their bionomic strategyJOURNAL OF APPLIED ICHTHYOLOGY, Issue 5 2008J. Hol Summary Analysis of salmonid fish samples from the Bulgarian stretch of the Danube resulted in the conclusion that this river segment is inhabited by the Black Sea salmon Salmo labrax Pallas, 1814 and not by the huchen Hucho hucho (Linnaeus, 1758), as originally believed. Occurrence of huchen in this stretch of the Danube River is improbable. It has also been suggested that the anadromous Black Sea salmon population does not exist. It remains to be determined if the salmon occurring in the Danube River and along the coast of the Turkish, Bulgarian, Romanian and Ukrainian coasts of the Black Sea represent the black trout, i.e. the brook form of the Black Sea salmon washed down from the tributaries or the specific potamodromous river form. [source] Morphometrics of two morphs of sterlet, Acipenser ruthenus L., in the middle course of the Danube River (Serbia)JOURNAL OF APPLIED ICHTHYOLOGY, Issue 2 2008D. Ognjanovi Summary Two morphs of the sterlet, Acipenser ruthenus, were clearly recorded in two samplings from the middle course of the Danube River in Serbia. The pooled samples comprised 47.9% pointed-snout morphs and 52.1% blunt-snout morphs. The most obvious differences were snout shape and length, mainly the differences in the snout area in front of the barbels. In addition to this snout difference, the two morphs also differed with regard to head lengths and the pre-ocular, pre-dorsal and post-dorsal areas. The determination of morphs is not exclusively related to either location or body size as sources of this mode of variability, although it seems that it is easier to detect these in larger size sterlet. [source] About the oldest domesticates among fishesJOURNAL OF FISH BIOLOGY, Issue 2004E. K. Balon Domestication of mammals such as cattle, dogs, pigs and horses preceded that of fishes by at least 10 000 years. The first domesticated fish was the common carp Cyprinus carpio. Initially it was held as an exploited captive and did not undergo major changes in body shape or colour variations. About 2000 years ago, wild common carp were most abundant in the inland delta of the Danube River. These fish were torpedo shaped, golden-yellow in colour and had two pairs of barbels and a mesh-like scale pattern. Large schools of them thrived and reproduced on the flood plains of the Danube. The Romans kept fishes in specially built ponds at that time. The common carp was an ideal candidate and its rearing became more popular in medieval times. Common carp culture gradually became the most profitable branch of agriculture in central Europe and many special ponds were built. Soon common carp were being produced in pond systems including spawning and growing ponds. Unintentional artificial selection had taken place between the 12th and mid-14th century, and deep bodied and variously scaled or scaleless domesticated forms appeared in nearly every pond system. Some colour aberrations appeared in the 1950s in Japan, which, as koi, became the most expensive of fish. Common carp were not originally domesticated in China but wild ,chi'Carassius auratus occasionally appeared as a xanthic form that, as the goldfish, has been known since 960 A.D. By the 1200s the fish were used as ornamental animals in the garden pools of rich landowners. Circa 1276 to 1546, the Chinese began keeping golden chi in aquarium-like vessels and soon rich and poor alike became breeders of the fancy domesticated goldfish. The variously shaped monstrosities and colour aberrants were freaks but they became very fashionable at that time and still are. Domesticated goldfish monstrosities were first exported from China to Japan and much later to Europe and around the world. More recently other species have been domesticated by aquarists, such as the guppy Poecilia reticulata or the neon tetra Paracheirodon innesi. Other fishes kept as ornamentals, like swordtails Xiphophorus hellerii and platies Xiphophorus maculatus, the discus and angelfishes (Cichlidae), as well as those cultured for food like the rainbow trout Oncorhynchus mykiss, channel catfish Ictalurus punctatus or sturgeons (Acipenseridae) are merely exploited captives. [source] | |||||||||||||