Differentiated gonochorism in Nile perch<i>Lates niloticus</i>from Lake Victoria, Uganda

Basiita, Rose Komugisha; Aruho, Cassius; Kahwa, D; Nyatia, Edward; Bugenyi, F. W. B.; Rutaisire, J.

doi:10.2989/16085914.2011.559694

Cited by 7 publications

(4 citation statements)

References 22 publications

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“…These include; heavy fishing pressure coupled with climate and ecological pressures which may in part be responsible for the current declines of Nile perch in Lakes Kyoga and Victoria. Results from the present study are consistent with reports that have shown declining numbers of Nile perch in Lakes Kyoga and Victoria despite the increase in fishing effort of the Nile perch amidst climate and ecological pressures [ 13 , 17 , 18 , 20 , 45 , 88 , 89 ]. Nile perch declines were first detected in Lake Kyoga as early as the 1980’s, and predictions of such declines speculated then for Lake Victoria have now been realised [ 88 ].…”

Section: Discussionsupporting

confidence: 92%

“…Although a portion of Nile perch individuals introduced into Lake Victoria were putatively acquired from Lake Turkana, results from the current investigation showed that the Nile perch in Lake Victoria exhibited a very limited genetic signature from Lake Turkana, but had a strong signal from Lake Albert. The very weak signal from Lake Turkana seems to be consistent with the historical stocking records, where only eight individuals were introduced in Lake Victoria at Kisumu Port [ 18 ]…”

Section: Discussionsupporting

confidence: 76%

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Gene flow and genetic structure in Nile perch, Lates niloticus, from African freshwater rivers and lakes

et al. 2018

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BackgroundGeological evolution of the African continent has been subject to complex processes including uplift, volcanism, desert formation and tectonic rifting. This complex geology has created substantial biogeographical barriers, and coupled with anthropogenic introductions of freshwater fishes, has influenced the genetic diversity, connectivity and sub-structuring of the teleost fauna. Nile perch, Lates niloticus, is an iconic fish in Africa and is of high commercial importance, both in the species’ native range and where it has been translocated. However, the species is in decline and there is a need to understand its population genetic structure to facilitate sustainable management of the fishery and aquaculture development.MethodologyNile perch tissue samples were acquired from two West and four East (Lakes; Albert, Kyoga, Victoria and Turkana) African locations. Nineteen polymorphic microsatellite loci were used to study the genetic variation among populations across regions (West and East Africa), as well as between native and introduced environments within East Africa.Principal findings and their significanceResults revealed strong and significant genetic structuring among populations across the sampled distribution (divergence across regions, FCT = 0.26, P = 0.000). STRUCTURE analysis at a broad scale revealed K = 2 clusters, the West African individuals were assigned to one cluster, while all individuals from the East African region, regardless of whether native or introduced, were assigned to another cluster. The distinct genetic clusters identified in the current study between the West and East African Nile perch, appear to have been maintained by presence of biogeographic barriers and restricted gene flow between the two regions. Therefore, any translocations of Nile perch should be carefully considered across the regions of West and East Africa. Further analysis at a regional scale revealed further structuring of up to K = 3 genetic clusters in East African Nile perch. Significantly (P < 0.05) lower genetic diversity based on analysis of allelic richness (AR) was obtained for the two translocated populations of Lake Kyoga (AR = 3.61) and Lake Victoria (AR = 3.52), compared to Nile perch populations from their putative origins of Lakes Albert (AR = 4.12) and Turkana (AR = 4.43). The lower genetic diversity in the translocated populations may be an indication of previous bottlenecks and may also indicate a difficulty for these populations to persist and adapt to climatic changes and anthropogenic pressures that are currently present in the East African region.

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Section: Discussionsupporting

confidence: 92%

Section: Discussionsupporting

confidence: 76%

Gene flow and genetic structure in Nile perch, Lates niloticus, from African freshwater rivers and lakes

et al. 2018

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“…To the right of Lake Albert are the Murchison Falls along the Victoria Nile River, another biogeographical barrier separating the Albertine rift system (includes Lakes Edward, George and Albert) from Lake Victoria. This barrier has been documented as an effective obstacle in preventing, for instance, Nile perch stocks in Lake Albert from migrating into Lakes Kyoga and Victoria (Basiita et al., ; Hopson, ).…”

Section: Introductionmentioning

confidence: 99%

Populations genetically rifting within a complex geological system: The case of strong structure and low genetic diversity in the migratory freshwater catfish, Bagrus docmak, in East Africa

Basiita

Zenger

Jerry

2017

Ecology and Evolution

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The complex geological history of East Africa has been a driving factor in the rapid evolution of teleost biodiversity. While there is some understanding of how macroevolutionary drivers have shaped teleost speciation in East Africa, there is a paucity of research into how the same biogeographical factors have affected microevolutionary processes within lakes and rivers. To address this deficiency, population genetic diversity, demography, and structure were investigated in a widely distributed and migratory (potamodromous) African teleost species, Ssemutundu (Bagrus docmak). Samples were acquired from five geographical locations in East Africa within two major drainage basins; the Albertine Rift and Lake Victoria Basin. Individuals (N = 175) were genotyped at 12 microsatellite loci and 93 individuals sequenced at the mitochondrial DNA control region. Results suggested populations from Lakes Edward and Victoria had undergone a severe historic bottleneck resulting in very low nucleotide diversity (π = 0.004 and 0.006, respectively) and negatively significant Fu values (−3.769 and −5.049; p < .05). Heterozygosity deficiencies and restricted effective population size (N eLD) suggested contemporary exposure of these populations to stress, consistent with reports of the species decline in the East African Region. High genetic structuring between drainages was detected at both historical (ɸST = 0.62 for mtDNA; p < .001) and contemporary (microsatellite F ST = 0.460; p < .001) levels. Patterns of low genetic diversity and strong population structure revealed are consistent with speciation patterns that have been linked to the complex biogeography of East Africa, suggesting that these biogeographical features have operated as both macro‐ and micro‐evolutionary forces in the formation of the East African teleost fauna.

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“…Its use has apparently been extended into studies for domestication of fish species, guiding culturalists to identify sexually mature and ripe individuals for induced spawning (Aruho et al 2013;Rutaisire and Booth 2004). Identification of suitable candidates for induced spawning requires adequate knowledge of the size of the fish with high chances of oocytes that have reached ripening stage ready for ovulation (Basiita et al 2011;Rutaisire et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Optimizing selection of sexually mature Barbus altianalis for induced spawning: determination of size at sexual maturity of populations from Lake Edward and Upper Victoria Nile in Uganda

Aruho¹,

Ddungu²,

Nkalubo

et al. 2018

Fish Aquatic Sci

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Sexual maturity (L 50), the length at which 50% of fish in a size class are mature, is a key aspect of domestication of new fish species because it guides the procedure for identification of appropriate broodstock size for artificial spawning. In this study, the L 50 was determined for 1083 Barbus altianalis samples obtained from Lake Edward and the Upper Victoria Nile. Gonads of freshly killed samples were examined macroscopically and verified with standard histological procedures for the maturation stages that were used to determine L 50. Oocytes and spermatogenic cell sizes were compared for fish obtained from both water bodies. Results indicated that there were no variations in macro gonad features observed for fish from Lake Edward and Upper Victoria Nile. Similarly, there were no significant differences in oocyte sizes (P > 0.05) between the two populations but significant differences in spermatogenic cell sizes were noted (P < 0.05) except for spermatozoa (P > 0.05). This however did not suggest peculiar differences between the two populations for staging the gonads. Consequently, no staging variations were suggested for both populations in determination of L 50. Sexual maturity was found in the same class size of fork length (FL) 20-24.9 cm and 35-39.9 cm for males and females from both water bodies, respectively. At this FL, however, males were too small, and for good selection of vigor broodstocks for spawning and conservation purposes, they are better picked from class size of 30-34.9 cm FL and above. These findings were crucial for integration of appropriate breeding size in spawning protocol by farmers and fisheries scientists conserving wild B. altianalis populations.

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Differentiated gonochorism in Nile perchLates niloticusfrom Lake Victoria, Uganda

Cited by 7 publications

References 22 publications

Gene flow and genetic structure in Nile perch, Lates niloticus, from African freshwater rivers and lakes

Gene flow and genetic structure in Nile perch, Lates niloticus, from African freshwater rivers and lakes

Populations genetically rifting within a complex geological system: The case of strong structure and low genetic diversity in the migratory freshwater catfish, Bagrus docmak, in East Africa

Optimizing selection of sexually mature Barbus altianalis for induced spawning: determination of size at sexual maturity of populations from Lake Edward and Upper Victoria Nile in Uganda

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