Abstract A hypothesis was advanced and grounded that the total content of eicosapentaenoic (EPA, ... more Abstract A hypothesis was advanced and grounded that the total content of eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids in fish muscle tissue is associated with the species-specific (taxon-specific) duration of embryo development. A meta-analysis of the original and published data was performed using fishes of the families Coregonidae and Salmonidae as an example. Fishes with longer embryo development times, which are observed at lower temperatures, were found to have significantly higher EPA + DHA contents in muscles as compared with the species that belong to the same families but have shorter embryo development times. This association was explained by the fact that an embryo forms more cells per unit tissue volume at lower temperatures, which requires a greater specific amount of cell membranes and, therefore, greater amounts of EPA and DHA to produce them.
Page 1. Journal of Fish Biology (1999) 54, 417423 Article No. jfbi.1998.0875, available online a... more Page 1. Journal of Fish Biology (1999) 54, 417423 Article No. jfbi.1998.0875, available online at http://www.idealibrary.com on Observations on reproduction of the Lake Tana barbs Y. Y. D MV M, SS ...
There are many locations in Russia where Eurasian beaver (Castor fiber) populations have been res... more There are many locations in Russia where Eurasian beaver (Castor fiber) populations have been restored. As a keystone species, beavers provide wideranging direct and indirect impacts on aquatic ecosystems. In particular, beaver-created ponds provide are sites for spawning and nursery places for tadpoles of the brown frog (genus Rana). Because of such impacts, study techniques for assessing aquatic organisms abundance are being developed. We compared two methods for estimating tadpole abundance: traditional catches by dipnet and electrofishing. Our results show that the dipnet catch data of the shallower ponds with larger water surface area were five times
The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of ... more The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of Mongolian fish. This is connected with new findings as well as the continuing process of invasion of alien species. Climate change and increase of human impact transformed ranges and local distribution of fish during last 30 years. Bias on ratio of ecological guilds, number of pathological findings are increasing, and declining of local diversity, rate of growth and fecundity of many species of fish are observed. In the course of long-term observation was confirmed periodically drying of waters of the Central Asian Lake Valley and temporal extinction of some populations of Altai osmans (genus Oreoleuciscus). The gold mining as a main anthropogenic factor in rivers of Arctic Ocean basin cause substantial silting of the grounds, increase of water turbidity, the lowering of flow velocity and heterogeneity of environment at separate sections led to a drastic fall in number of such species as...
Abstract A hypothesis was advanced and grounded that the total content of eicosapentaenoic (EPA, ... more Abstract A hypothesis was advanced and grounded that the total content of eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids in fish muscle tissue is associated with the species-specific (taxon-specific) duration of embryo development. A meta-analysis of the original and published data was performed using fishes of the families Coregonidae and Salmonidae as an example. Fishes with longer embryo development times, which are observed at lower temperatures, were found to have significantly higher EPA + DHA contents in muscles as compared with the species that belong to the same families but have shorter embryo development times. This association was explained by the fact that an embryo forms more cells per unit tissue volume at lower temperatures, which requires a greater specific amount of cell membranes and, therefore, greater amounts of EPA and DHA to produce them.
Page 1. Journal of Fish Biology (1999) 54, 417423 Article No. jfbi.1998.0875, available online a... more Page 1. Journal of Fish Biology (1999) 54, 417423 Article No. jfbi.1998.0875, available online at http://www.idealibrary.com on Observations on reproduction of the Lake Tana barbs Y. Y. D MV M, SS ...
There are many locations in Russia where Eurasian beaver (Castor fiber) populations have been res... more There are many locations in Russia where Eurasian beaver (Castor fiber) populations have been restored. As a keystone species, beavers provide wideranging direct and indirect impacts on aquatic ecosystems. In particular, beaver-created ponds provide are sites for spawning and nursery places for tadpoles of the brown frog (genus Rana). Because of such impacts, study techniques for assessing aquatic organisms abundance are being developed. We compared two methods for estimating tadpole abundance: traditional catches by dipnet and electrofishing. Our results show that the dipnet catch data of the shallower ponds with larger water surface area were five times
The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of ... more The studies in recent years (2000-2011) have allowed to make more precise the list and ranges of Mongolian fish. This is connected with new findings as well as the continuing process of invasion of alien species. Climate change and increase of human impact transformed ranges and local distribution of fish during last 30 years. Bias on ratio of ecological guilds, number of pathological findings are increasing, and declining of local diversity, rate of growth and fecundity of many species of fish are observed. In the course of long-term observation was confirmed periodically drying of waters of the Central Asian Lake Valley and temporal extinction of some populations of Altai osmans (genus Oreoleuciscus). The gold mining as a main anthropogenic factor in rivers of Arctic Ocean basin cause substantial silting of the grounds, increase of water turbidity, the lowering of flow velocity and heterogeneity of environment at separate sections led to a drastic fall in number of such species as...
Uploads
Papers by Yury Dgebuadze