The destruction of an endemic species flock: quantitative data on the decline of the haplochromine cichlids of Lake Victoria

1992 ◽  
Vol 34 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Frans Witte ◽  
Tijs Goldschmidt ◽  
Jan Wanink ◽  
Martien van Oijen ◽  
Kees Goudswaard ◽  
...  
Keyword(s):  
Endemic Species ◽  
Quantitative Data ◽  
Lake Victoria ◽  
Species Flock ◽  
Haplochromine Cichlids

Assessing Gender Roles in Dagaa Fishery Value Chain among Fishing Communities on Lake Victoria, A Case Study of Lake Victoria Beaches In Siaya County, Kenya

2020 ◽  
Vol 4 (2) ◽  
pp. 13-32
Author(s):  
Albert Ogoma Odhone ◽  
Ishmail Mahiri ◽  
Francis Onsongo
Keyword(s):  
Gender Roles ◽  
Interest Rates ◽  
Value Chain ◽  
Quantitative Data ◽  
Lake Victoria ◽  
Sampling Technique ◽  
Fishing Communities ◽  
Value Chains ◽  
Chain Model ◽  
Cross Sectional

Fisheries in the East Africa region have suffered due to less emphasis given to some fishery specifically Dagaa (Rastrineobolaargentea), whose quantity is the highest of all the species in the Lake Victoria. Despite the importance of this resource in Kenya, there has been a concern of gender parity and inequality in terms of roles played by both gender in harvesting, processing, trading and marketing in the Dagaa fishery. This study analyzed gender roles in Dagaa Fishery Value Chain among fishing communities around Lake Victoria in Bondo Sub County, in Siaya County, Kenya. The study addressed the following objectives: Identified the various roles of men and women in Dagaa Fishery Value Chain, discussed factors influencing gender roles in Dagaa Fishery Value Chain, analyzed the barriers to women’s participation in certain Dagaa Fishery Value Chain and examined the strategies to overcome challenges in gender roles in Dagaa fishery value chain in Bondo Sub-County, Siaya County. The study adopted a cross-sectional research design. This study was guided by two models; gender analysis framework model that was developed by Sarah Longwe and supply chain model. Purposive sampling technique was used to select Bondo Sub-County and fishing community in Bondo Sub-County; random sampling technique was used to select five (5) fish landing sites/beaches where quantitative data were collected from 186 out of the targeted 188 primary respondents, from among the forty-four beaches of Lake Victoria in Bondo Sub-County. Quantitative data was analyzed using SPSS Version 25, and descriptive statistics such as frequencies and percentages were used in presenting analyzed data. The results were presented using tables and charts. The study findings revealed that majority of the boats and fishing gears were owned by men, motorized boats belonged to men while a higher percentage of females still had the paddled boats. While men dominated the fishing of Dagaa, women dominated processing and trading of Dagaa in the beaches. The study noted that men made higher returns than their female counterparts at all levels of Dagaa fishery value chain. The study concluded that there is a still wide disparity among gender roles in Dagaa fishery value chain. Most of the activities in the value chain are still dominated by men. This study recommends that women be encouraged to take part in Dagaa fishery value chains, empowerment of women to take part in transportation and distribution of Dagaa and application of various strategies such as joining SACCOs to access loans at low interest rates, formation of groups for ease of access to credit services and weakening patriarchy to mitigate factors affecting Gender roles in Dagaa fishery value chains.

scholarly journals Guilty as charged: Nile perch was the cause of the haplochromine decline in Lake Victoria

2018 ◽  
Vol 75 (9) ◽  
pp. 1542-1559 ◽  
Author(s):  
Brian E. Marshall
Keyword(s):  
Lake Victoria ◽  
Food Chains ◽  
Nile Perch ◽  
Top Down ◽  
Selective Predation ◽  
Bottom Up ◽  
Haplochromine Cichlids ◽  
Lates Niloticus ◽  
Climatic Event ◽  
Existing Data

Debate on the contribution of Nile perch (Lates niloticus) to the demise of Lake Victoria’s 500+ endemic haplochromine cichlids centers around the “top-down” and “bottom-up” hypotheses. The former suggests Nile perch destroyed the haplochromines, causing the disruption of food chains and nutrient cycling and so initiating the accelerated eutrophication of the lake. The latter proposes that haplochromines suppressed Nile perch by preying on its eggs and fry or competing with juveniles for food. A recent paper argued that accelerated eutrophication caused by a climatic event led to their collapse, allowing Nile perch to explode. However, the Nile perch population grew before haplochromines decreased, and they only collapsed once Nile perch biomass exceeded theirs. The chronology indicates that accelerated eutrophication of the lake followed rather than preceded the haplochromine collapse, suggesting that eutrophication was not its cause. A size-selective predation model developed to support the bottom-up hypothesis is discussed in light of existing data, but does not support the bottom-up hypothesis. It was concluded that the top-down model better fits the data and conforms to the law of parsimony.

scholarly journals Repeated trans-watershed hybridization among haplochromine cichlids (Cichlidae) was triggered by Neogene landscape evolution

2012 ◽  
Vol 279 (1746) ◽  
pp. 4389-4398 ◽  
Author(s):  
Julia Schwarzer ◽  
Ernst Roelof Swartz ◽  
Emmanuel Vreven ◽  
Jos Snoeks ◽  
Fenton Peter David Cotterill ◽  
...  
Keyword(s):  
Nuclear Dna ◽  
Congo Basin ◽  
Alternative View ◽  
Species Flock ◽  
East African ◽  
Haplochromine Cichlids ◽  
Mtdna Haplotypes ◽  
Phylogenetic Hypotheses ◽  
Explosive Speciation ◽  
East African Lakes

The megadiverse haplochromine cichlid radiations of the East African lakes, famous examples of explosive speciation and adaptive radiation, are according to recent studies, introgressed by different riverine lineages. This study is based on the first comprehensive mitochondrial and nuclear DNA dataset from extensive sampling of riverine haplochromine cichlids. It includes species from the lower River Congo and Angolan (River Kwanza) drainages. Reconstruction of phylogenetic hypotheses revealed the paradox of clearly discordant phylogenetic signals. Closely related mtDNA haplotypes are distributed thousands of kilometres apart and across major African watersheds, whereas some neighbouring species carry drastically divergent mtDNA haplotypes. At shallow and deep phylogenetic layers, strong signals of hybridization are attributed to the complex Late Miocene/Early Pliocene palaeohistory of African rivers. Hybridization of multiple lineages across changing watersheds shaped each of the major haplochromine radiations in lakes Tanganyika, Victoria, Malawi and the Kalahari Palaeolakes, as well as a miniature species flock in the Congo basin (River Fwa). On the basis of our results, introgression occurred not only on a spatially restricted scale, but massively over almost the whole range of the haplochromine distribution. This provides an alternative view on the origin and exceptional high diversity of this enigmatic vertebrate group.

scholarly journals Nuclear markers reveal unexpected genetic variation and a Congolese-Nilotic origin of the Lake Victoria cichlid species flock

2003 ◽  
Vol 270 (1511) ◽  
pp. 129-137 ◽  
Author(s):  
Ole Seehausen ◽  
Egbert Koetsier ◽  
Maria Victoria Schneider ◽  
Lauren J. Chapman ◽  
Colin A. Chapman ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Lake Victoria ◽  
Species Flock ◽  
Nuclear Markers ◽  
Cichlid Species
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