Four fish species new to the Omo-Turkana basin,with comments on the distribution ofNemacheilus abyssinicus (Cypriniformes: Balitoridae) in Ethiopia

Four fish species,Pollimyrus isidori (Mormyridae),Barbus paludinosus, Labeo forskalii (Cyprinidae), andNemacheilus abyssinicus (Balitoridae), new to the Omo-Turkana basin, were recorded from the Gojeb River, a tributary of the Omo River (south-western Ethiopia). Occurrence of the latter species in the upper reaches of the Blue Nile and of the Omo drainage substantiates the belonging of the upper parts of these water systems to the Abyssinian highlands ichthyofaunal province.     

On estimation of phenetic relationships of Altai Osmans (<Emphasis Type="Italic">Oreoleuciscus</Emphasis>, Cyprinidae) from three lakes in Mongolia by skull characters

By four meristic and 14 morphometric characters of the skull the phenetic relationships of Altai Osmans of the genus Oreoleuciscus from lakes Ust-Nur (the Selenga Basin), Sangiyn-Dalai-Nur (the Khangai Highland), and Orog-Nur (Lake Valley) are estimated. Principal components analysis is performed. No interpopulational differences by the set of meristic characters are found. By the set of morphometric characters the specimens from Lake Ust-Nur in the space of principal components are separated from specimens from two other lakes while the distributions of specimens from Lake Sangiyn-Dalai-Nur and Orog-Nur overlap. With consideration of estimates of similarity in the structure of interpopulational differences it is assumed that separation of the phyletic line common for populations of lakes Ust-Nur and Orog-Nur from the phyletic line of population of Lake Sangiyn-Dalai-Nur preceded separation of phyletic lines of populations from lakes Ust-Nur and Orog-Nur.     

Antimicrobial Activity of Lipid Extracts of Echinoderms in the Nhatrang Bay (South China Sea)

Doklady Biochemistry and Biophysics - The obtained results on the study of the antimicrobial activity of lipid extracts of tissues of starfishes Linckia laevigata and Culcita novaeguineae and sea...     

Morphological Differentiation of Altai Osman Oreoleuciscus humilis (Cyprinidae) in the Tuin-Gol River,Lake Valley,Mongolia

Journal of Ichthyology - Variability of osteological characters of Altai osmans of the genus Oreoleuciscus in the Tuin River is studied. Two morphological forms are discerned on the basis of...     

The influence of Eurasian beaver Castor fiber activity on fish assemblages in small steppe rivers in Russia

In recent decades, the Eurasian beaver (Castor fiber) has once again become the keystone species in small river ecosystems in Russia. In many places, beaver activity has resulted in a significant change in lotic habitats, affecting the diversity, density, and biomass of aquatic organisms, including fish. While many studies have considered the ecosystem impacts of beavers, relatively few have focused on understanding the influence of beaver activity on steppe rivers. We conducted the first quantitative study of beaver impacts on fish assemblages in beaver-influenced and beaver-free sites on two small steppe rivers in the Don River basin in Russia. The presence of beavers altered the habitats in small steppe rivers and affected the diversity, density, and biomass of fish. A comparison of the number of species, density, and biomass of fish in six types of river habitats showed that these parameters were lower in beaver ponds than at riverine sites without beaver activity. Three fish species primarily preferred a single habitat type. Barbatula barbatula was found in riffles, Misgurnus fossilis in old beaver ponds, and Eudontomyzon mariae in abandoned beaver ponds. Beavers impacted fish distribution and density by changing dissolved oxygen, pH, and water current velocity. Overall, our results showed that the presence of beavers led to a temporary homogenization of fish habitats at a local scale in the valleys of small steppe rivers because beavers occupied these rivers only for a short period. However, habitat heterogeneity may increase if the beaver population stays stable or expands in the future.

     

Large African Barbs with Hypertrophied Lips and their Relationship with Generalized Forms of Species of the Genus Barbus (Labeobarbus auctorum)

Journal of Ichthyology - Geographical variation in the large African barbs with hypertrophied lips (morphotype LIP) and in the individuals of the generalized form (GF) is studied in the water...     

The first case of morphological differentiation of Altai Osman <Emphasis Type="Italic">Oreoleuciscus potanini</Emphasis> (Cyprinidae,Actinopterigii) in a river

The variability of osteological characters has been investigated in cyprinid fish of the genus Oreoleuciscus (Potanin Altai osman) from the river Zavkhan; this fish species is endemic for water bodies of Central Asia. Multivariate analysis of 13 quantitative parameters of the size of the cerebral and visceral skull and the pectoral girdle and the construction of ontogenetic channels allowed the detection of morphologically distinct forms in the fluvial habitats. The result obtained provides additional proof of the possibility of sympatric diversification of fish in river ecosystems. One of the two fluvial forms discovered has been shown to be identical (with regard to the osteological characters) to a previously described herbivorous form of O. potanini from the standing water bodies of the Great Lakes Hollow (Western Mongolia).     

Biotic fluxes of matter and energy between aquatic and terrestrial ecosystems

This paper is an introduction to a special issue of the journal. A brief historical delineation of the question of studying interfaces between adjacent ecosystems (ecotones) is presented. High biodiversity of ecotones and their vulnerability to natural and anthropogenic impacts, including invasions of alien species, are noted. It is supposed that there is no contradiction between the ecotone and river continuum concepts. The important ecological role of amphibiotic animals and plants in interactions and functioning of the adjacent ecosystems is emphasized. The issue of studying the quantitative parameters of fluxes of matter and energy between ecosystems in conjunction with their qualitative parameters (chemical elemental and biochemical compositions) is considered in the present paper.