The decline of the native fishes of lakes Victoria and Kyoga (East Africa) and the impact of introduced species, especially the Nile perch, Lates niloticus, and the Nile tilapia, Oreochromis niloticus

1990 ◽  
Vol 27 (2) ◽  
pp. 81-96 ◽  
Author(s):  
Richard Ogutu-Ohwayo
Keyword(s):  
East Africa ◽  
Introduced Species ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Nile Perch ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Lates Niloticus ◽  
Native Fishes ◽  
The Impact

scholarly journals The impact of stocking density and dietary carbon sources on the growth, oxidative status and stress markers of Nile tilapia (Oreochromis niloticus) reared under biofloc conditions

2020 ◽  
Vol 16 ◽  
pp. 100282 ◽  
Author(s):  
Mohamed A.A. Zaki ◽  
Ahmed N. Alabssawy ◽  
Abd El-Aziz M. Nour ◽  
Mohammed F. El Basuini ◽  
Mahmoud A.O. Dawood ◽  
...  
Keyword(s):  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Carbon Sources ◽  
Stocking Density ◽  
Oxidative Status ◽  
Stress Markers ◽  
Nile Tilapia Oreochromis Niloticus ◽  
The Impact

scholarly journals Molecular genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus, L. 1758) in East African natural and stocked populations

2019 ◽  
Author(s):  
Papius Dias Tibihika ◽  
Manuel Curto ◽  
Esayas Alemayehu ◽  
Herwig Waidbacher ◽  
Charles Masembe ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
East Africa ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Anthropogenic Activities ◽  
Genetic Erosion ◽  
Gene Pools ◽  
East African ◽  
Nile Tilapia Oreochromis Niloticus

Abstract Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.

scholarly journals Molecular genetic diversity and differentiation of Nile tilapia (Oreochromis niloticus, L. 1758) in East African natural and stocked populations

2019 ◽  
Author(s):  
Papius Dias Tibihika ◽  
Manuel Curto ◽  
Esayas Alemayehu ◽  
Herwig Waidbacher ◽  
Charles Masembe ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
East Africa ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Anthropogenic Activities ◽  
Genetic Erosion ◽  
Gene Pools ◽  
East African ◽  
Nile Tilapia Oreochromis Niloticus

Abstract Background The need for enhancing the productivity of fisheries in Africa triggered the introduction of non-native fish, causing dramatic changes to local species. In East Africa, the extensive translocation of Nile tilapia (Oreochromis niloticus) is one of the major factors in this respect. Using 40 microsatellite loci with SSR-GBS techniques, we amplified a total of 664 individuals to investigate the genetic structure of O. niloticus from East Africa in comparison to Ethiopian and Burkina Faso populations. Results All three African regions were characterized by independent gene-pools, however, the Ethiopian population from lake Tana showed to be more divergent than expected suggesting that it might be a different species. In East Africa, the genetic structure was congruent with both geographical location and anthropogenic activities. O. niloticus from Lake Turkana (Kenya) was isolated, while in Uganda, despite populations being rather similar to each other, two main natural catchments were able to be defined. We show that these two groups contributed to the gene-pool of different non-native populations. Moreover, admixture and possible hybridization with other tilapiine species may have contributed to the genetic divergence found in some populations such as Lake Victoria. We detected other factors that might be affecting Nile tilapia genetic variation. For example, most of the populations have gone through a reduction of genetic diversity, which can be a consequence of bottleneck caused by overfishing, genetic erosion due to fragmentation or founder effect resulting from stoking activities. Conclusions The anthropogenic activities particularly in the East African O. niloticus translocations, promoted admixture and contact with the native congenerics which may contribute to outbreeding depression and hence compromising the sustainability of the species in the region.

Survival, growth and reproduction of non-indigenous Nile tilapia, Oreochromis niloticus (Linnaeus 1758). I. Physiological capabilities in various temperatures and salinities

2011 ◽  
Vol 62 (5) ◽  
pp. 439 ◽  
Author(s):  
Pamela J. Schofield ◽  
Mark S. Peterson ◽  
Michael R. Lowe ◽  
Nancy J. Brown-Peterson ◽  
William T. Slack
Keyword(s):  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Global Climate ◽  
Thermal Refugia ◽  
Coastal Watersheds ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Saline Waters ◽  
Coastal Landscapes ◽  
Native Fishes ◽  
Growth And Reproduction

The physiological tolerances of non-native fishes is an integral component of assessing potential invasive risk. Salinity and temperature are environmental variables that limit the spread of many non-native fishes. We hypothesised that combinations of temperature and salinity will interact to affect survival, growth, and reproduction of Nile tilapia, Oreochromis niloticus, introduced into Mississippi, USA. Tilapia withstood acute transfer from fresh water up to a salinity of 20 and survived gradual transfer up to 60 at typical summertime (30°C) temperatures. However, cold temperature (14°C) reduced survival of fish in saline waters ≥10 and increased the incidence of disease in freshwater controls. Although fish were able to equilibrate to saline waters in warm temperatures, reproductive parameters were reduced at salinities ≥30. These integrated responses suggest that Nile tilapia can invade coastal areas beyond their point of introduction. However, successful invasion is subject to two caveats: (1) wintertime survival depends on finding thermal refugia, and (2) reproduction is hampered in regions where salinities are ≥30. These data are vital to predicting the invasion of non-native fishes into coastal watersheds. This is particularly important given the predicted changes in coastal landscapes due to global climate change and sea-level rise.

scholarly journals Genetic structure and gene flow in an endangered native tilapia fish (Oreochromis esculentus) compared to invasive Nile tilapia (Oreochromis niloticus) in Yala swamp, East Africa

2010 ◽  
Vol 12 (1) ◽  
pp. 243-255 ◽  
Author(s):  
Paul O. Angienda ◽  
Hyuk Je Lee ◽  
Kathryn R. Elmer ◽  
Romulus Abila ◽  
Eliud N. Waindi ◽  
...  
Keyword(s):  
Gene Flow ◽  
Genetic Structure ◽  
East Africa ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Nile Tilapia Oreochromis Niloticus
Sign in / Sign up

Export Citation Format

Share Document