Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and cond...Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and condition factor of Oriochromis niloticus in Korir and Lailay Wukro Dams, Northern Ethiopias. The study was conducted by deploying two gill net, every month in the littoral and pelagic zones of the two dams from August 2011 to May 2012. A total of 524 O. niloticus, 278 from Lailay Wukro and 246 from Korir dams were collected. The monthly catch per unit effort （CPUE） showed significant variation among months, the highest catch was in May and the least was in January 2012 （P 〈 0.000）. Catches of fish encountered higher in the littoral （69.1%） than in the pelagic zones （30.9%） （P 〈 0.000）. The condition factor of O. niloticus in the two reservoirs remains high, in Korir 2.05 and in Lailay Wukro 1.65 （P 〈 0.000）. In these small tropical dams, O. niloticus mature as they are smaller in size （Ls0： TL average 22.5 cm）. The ratio of male to female was 1.3：1 （P 〈 0.016）. The two dams have favorable condition for high production of O. niloticus. This high potential for fish production in the dams may be sustainable if the local authorities set a regulation to control the illegal fishing activity.展开更多
Gypsy moth, Lymantria dispar （L.） is one of the most widespread defoliators of deciduous and larch forests in Kazakhstan. Preferred host plants, flying capacity of females and neonate caterpillars, preferred places ...Gypsy moth, Lymantria dispar （L.） is one of the most widespread defoliators of deciduous and larch forests in Kazakhstan. Preferred host plants, flying capacity of females and neonate caterpillars, preferred places for egg laying, major factors of mortality and other characteristics vary considerably between different populations of the pest. According to several year researches on gypsy moth, in Kazakhstan, the main biological characteristics of this pest in the regions were investigated. Results of research showed that gypsy moth exists in central and northern of theses regions. From biological and geographical aspects, gypsy moth which there is in Kazakhstan is close to the same species from Siberia western regions. The pest lays on the different heights of trees trunk. It was found that the number of eggs in each egg mass and egg masses laid by the pest are different. The lack of egg eaters and the over- reproduction of the pest at the natural conditions have resulted in the development of bacterial and viral diseases in the populations of this pest from the regions of Kazakhstan to Siberia west.展开更多
The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants s...The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants such as doum and diss, had been found. Chamaerops humilis, xerophyte plant, with special morphologic and botanic character presents a resistance of these climatic. The authors have proposed study of fauna closly linked to this plant. A faunistic inventory was realized in the Mansourah area （region of Tlemcen）. Four stations have been described. Collecting sample was performed during June 2003-Mar. 2004, replying on sixteen （16） prelevements. The number of species were estimated of about 136, in which 111 are Arthropoda, the Entomofauna represented by 97 species and the other inventory are Arachnida by 8 species and Myriapoda by 6 species. 18 species are related to Gastropoda. The vertebrates are few. The importance of different groups＇ recolted on the Chamaerops humilis in the four stations is done particular to the insects. Analysis factorial correspondence （A.F.C） show different grouping of animal species.展开更多
Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high p...Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches,at least for a short period.This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment.The ingestion rate of the average-sized medusae Chrysaora cf.caliparea is well balanced in nature,which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources.Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured.A full understanding of predation mechanics awaits further investigation of both predator and prey behavior.However,because of the scarcity of long-term quantitative population data most insights have to be made indirectly.Nevertheless,low abun-dance of Chrysaora cf.caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to con-siderably affect the zooplankton population,especially copepods.The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters,which is especially crucial for understanding the process of ecological recovery of coastal water environment.展开更多
文摘Several dams have been constructed in Ethiopia, East Africa to support electricity and/or irrigation. Fishes were introduced to some of these dams. Thus, the objective of this study was to assess the dynamics and condition factor of Oriochromis niloticus in Korir and Lailay Wukro Dams, Northern Ethiopias. The study was conducted by deploying two gill net, every month in the littoral and pelagic zones of the two dams from August 2011 to May 2012. A total of 524 O. niloticus, 278 from Lailay Wukro and 246 from Korir dams were collected. The monthly catch per unit effort （CPUE） showed significant variation among months, the highest catch was in May and the least was in January 2012 （P 〈 0.000）. Catches of fish encountered higher in the littoral （69.1%） than in the pelagic zones （30.9%） （P 〈 0.000）. The condition factor of O. niloticus in the two reservoirs remains high, in Korir 2.05 and in Lailay Wukro 1.65 （P 〈 0.000）. In these small tropical dams, O. niloticus mature as they are smaller in size （Ls0： TL average 22.5 cm）. The ratio of male to female was 1.3：1 （P 〈 0.016）. The two dams have favorable condition for high production of O. niloticus. This high potential for fish production in the dams may be sustainable if the local authorities set a regulation to control the illegal fishing activity.
文摘Gypsy moth, Lymantria dispar （L.） is one of the most widespread defoliators of deciduous and larch forests in Kazakhstan. Preferred host plants, flying capacity of females and neonate caterpillars, preferred places for egg laying, major factors of mortality and other characteristics vary considerably between different populations of the pest. According to several year researches on gypsy moth, in Kazakhstan, the main biological characteristics of this pest in the regions were investigated. Results of research showed that gypsy moth exists in central and northern of theses regions. From biological and geographical aspects, gypsy moth which there is in Kazakhstan is close to the same species from Siberia western regions. The pest lays on the different heights of trees trunk. It was found that the number of eggs in each egg mass and egg masses laid by the pest are different. The lack of egg eaters and the over- reproduction of the pest at the natural conditions have resulted in the development of bacterial and viral diseases in the populations of this pest from the regions of Kazakhstan to Siberia west.
文摘The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants such as doum and diss, had been found. Chamaerops humilis, xerophyte plant, with special morphologic and botanic character presents a resistance of these climatic. The authors have proposed study of fauna closly linked to this plant. A faunistic inventory was realized in the Mansourah area （region of Tlemcen）. Four stations have been described. Collecting sample was performed during June 2003-Mar. 2004, replying on sixteen （16） prelevements. The number of species were estimated of about 136, in which 111 are Arthropoda, the Entomofauna represented by 97 species and the other inventory are Arachnida by 8 species and Myriapoda by 6 species. 18 species are related to Gastropoda. The vertebrates are few. The importance of different groups＇ recolted on the Chamaerops humilis in the four stations is done particular to the insects. Analysis factorial correspondence （A.F.C） show different grouping of animal species.
基金supported by FAPESP 2003/02433-0,2003/02432-3 and 2010/50174-7)
文摘Chrysaora cf.caliparea,one of the most abundant medusae species in India,seems to be an important predator in the coastal waters of Bay of Bengal.The ability of Chrysaora cf.caliparea to feed at maximum rate in high prey concentrations implies that this jellyfish can efficiently exploit dense prey patches,at least for a short period.This study presents preliminary information regarding digestion and feeding rate upon copepods in a warm water environment.The ingestion rate of the average-sized medusae Chrysaora cf.caliparea is well balanced in nature,which in turn implies that this jellyfish is tuned for optimal utilization of available prey resources.Comparison with earlier research indicates that prey escape speed is one important factor governing which prey will be captured.A full understanding of predation mechanics awaits further investigation of both predator and prey behavior.However,because of the scarcity of long-term quantitative population data most insights have to be made indirectly.Nevertheless,low abun-dance of Chrysaora cf.caliparea in the water column during summer (May 2007) and the overall annual abundance seem not to con-siderably affect the zooplankton population,especially copepods.The present work contributes to the knowledge of prey-predator relationship of the forgotten fauna in Indian waters,which is especially crucial for understanding the process of ecological recovery of coastal water environment.
