Lake Victoria Fishing Research Articles

Prevalence and correlates of HIV infection among adolescents and young people living in fishing populations along Lake Victoria Fishing Communities in Uganda.

Introductionfishing communities in Uganda are key populations for HIV, with persistently higher prevalence and incidence than the general population.Methodsbetween March and August 2014, a cross sectional survey was conducted in 10 fishing communities of Lake Victoria in Uganda. Data was collected on socio-behavioural characteristics using interviewer administered questionnaires and venous blood collected for HIV testing. Prevalent HIV infections among adolescents and young people aged 13 to 24 years was estimated and the factors associated with those infections determined using multi variable logistic regression modelling.ResultsHIV prevalence was 10.8% among the 630 (96.5%) who provided a blood sample. Females were 3.5 times as likely to have HIV infection as males (aOR=3.52, 95% CI: 1.34-9.22). Young people aged 20-24 years were twice as likely to be HIV infected as those aged 13-19 years (aOR=1.77, 95% CI: 0.05-2.10), participants without formal education or those who had studied up to primary level were more likely to be HIV infected than those who had post primary education ((aOR=2.45, 95% CI: 1.19-5.07) or (5.29 (1.35-20.71) respectively). Reporting more than one sexual partner in the past 6 months was associated with HIV prevalent infection than those reporting no sexual partners (aOR=6.44, 95% CI: 1.27-32.83).Conclusionadolescents and young people aged 13-24 years in fishing communities around Lake Victoria, Uganda, have a high HIV prevalence, with females having a three-fold higher level than males. These findings highlight-the need to improve HIV prevention among young females living in these fishing communities.

Late Pleistocene Fish Remains from the Rurubu River, Tanzania

ABSTRACTA collection of fish bones was recovered from upper Pleistocene (Gamblian) deposits near the confluence of the Kagera and Rurubu rivers in Tanzania, west of Lake Victoria. The Rurubu/Kagera bones include two families: the Clariidae (Clarias gariepinus, Clarias sp.) and Cichlidae (tribes Oreochromini, Haplochromini; Oreochromis sp.). Geological, paleontological, and molecular data presented here provide new insights into Pleistocene eastern African biogeography and into the evolution and past affiliations of the Rurubu/Kagera and Lake Victoria fish taxa. The data indicate that the Rurubu/Kagera taxa were descended from Miocene-aged populations in the Congo and/or Nile rivers. Data also suggest that the Rurubu/Kagera haplochromines may have been part of a shared Kagera River/Lake Victoria basin haplochromine clade, whose later members radiated into hundreds of species in Lake Victoria over the past approximately 15,000 years.

The Impact of Intensive Versus Standard Anthelminthic Treatment on Allergy-related Outcomes, Helminth Infection Intensity, and Helminth-related Morbidity in Lake Victoria Fishing Communities, Uganda: Results From the LaVIISWA Cluster-randomized Trial.

BackgroundThe prevalence of allergy-related diseases is increasing in low-income countries. Parasitic helminths, common in these settings, may be protective. We hypothesized that intensive, community-wide, anthelminthic mass drug administration (MDA) would increase allergy-related diseases, while reducing helminth-related morbidity.MethodsIn an open, cluster-randomized trial (ISRCTN47196031), we randomized 26 high-schistosomiasis-transmission fishing villages in Lake Victoria, Uganda, in a 1:1 ratio to receive community-wide intensive (quarterly single-dose praziquantel plus albendazole daily for 3 days) or standard (annual praziquantel plus 6 monthly single-dose albendazole) MDA. Primary outcomes were recent wheezing, skin prick test positivity (SPT), and allergen-specific immunoglobulin E (asIgE) after 3 years of intervention. Secondary outcomes included helminths, haemoglobin, and hepatosplenomegaly.ResultsThe outcome survey comprised 3350 individuals. Intensive MDA had no effect on wheezing (risk ratio [RR] 1.11, 95% confidence interval [CI] 0.64–1.93), SPT (RR 1.10, 95% CI 0.85–1.42), or asIgE (RR 0.96, 95% CI 0.82–1.12). Intensive MDA reduced Schistosoma mansoni infection intensity: the prevalence from Kato Katz examinations of single stool samples from each patient was 23% versus 39% (RR 0.70, 95% CI 0.55–0.88), but the urine circulating cathodic antigen test remained positive in 85% participants in both trial arms. Hookworm prevalence was 8% versus 11% (RR 0.55, 95% CI 0.31–1.00). There were no differences in anemia or hepatospenomegaly between trial arms.ConclusionsDespite reductions in S. mansoni intensity and hookworm prevalence, intensive MDA had no effect on atopy, allergy-related diseases, or helminth-related pathology. This could be due to sustained low-intensity infections; thus, a causal link between helminths and allergy outcomes cannot be discounted. Intensive community-based MDA has a limited impact in high-schistosomiasis-transmission fishing communities, in the absence of other interventions.Clinical Trials RegistrationISRCTN47196031.

Fishing Business Arrangements and Sustainability in Lake Victoria Fishing

Fishing is an important activity for communities living adjacent to rivers and lakes—it is an economic activity that generates income and provides sustenance to those engaged in fishing as an occupation. Majority of the crewmembers of the fishing vessels, though small scale, are not the owner of the vessels. Majority are hired and their payment is made in-terms of the share of the catch. The main fish species are Tilapia, Nile perch (sangara), Dagaa, nembe, gogogo and furu. In this article an attempt is made to analyse the existing production relations between the owners of the vessels and the crewmembers and the concern for sustainability. Our results found that the existing sharing system in Lake Victoria poses a big challenge in as far as sustainability is concerned. Some of the system such as the percentage of catch after deducting operation costs are to some extent seems to be exploitative since majority of the owner of the fishing vessels assign high costs. Hence large percentage of the catch will go to the owner of the fishing vessels. Thus, fishermen are compelled to use any means to ensure that they have enough catch. The most favoured sharing model is the ratio in days, in which case each fishing unit is assigned a day, that’s owners’ day, crews day, and vessels day. Regression results further shows that type of fishing gears, in particular mesh size, net length, Boat size, method of propulsion significantly influence the value of catch and the quantity harvested. Mounting of fishing nets is found to negatively influence the quantity of catch in each fishing trip. Suggesting that given the current stock mounting of nets is not an efficient way of catching large quantity of fish.     Â

A Very High Infection Intensity of Schistosoma mansoni in a Ugandan Lake Victoria Fishing Community Is Required for Association with Highly Prevalent Organ Related Morbidity

BackgroundIn schistosomiasis control programmes using mass chemotherapy, epidemiological and morbidity aspects of the disease need to be studied so as to monitor the impact of treatment, and make recommendations accordingly. These aspects were examined in the community of Musoli village along Lake Victoria in Mayuge district, highly endemic for Schistosoma mansoni infection.Methodology and Principal FindingsA cross sectional descriptive study was undertaken in a randomly selected sample of 217 females and 229 males, with a mean age of 26 years (SD ±16, range 7–76 years). The prevalence of S. mansoni was 88.6% (95% CI: 85.6–91.5). The geometric mean intensity (GMI) of S. mansoni was 236.2 (95% CI: 198.5–460.9) eggs per gram (epg) faeces. Males had significantly higher GMI (370.2 epg) than females (132.6 epg) and age was also significantly associated with intensity of infection. Levels of water contact activities significantly influenced intensity of infection and the highest intensity of infection was found among people involved in fishing. However, organomegaly was not significantly associated with S. mansoni except for very heavy infection (>2000 epg). Liver image patterns C and D indicative of fibrosis were found in only 2.2% and 0.2%, respectively. S. mansoni intensity of infection was associated with portal vein dilation and abnormal spleen length. Anaemia was observed in 36.4% of the participants but it was not associated with S. mansoni infection intensity. Considering growth in children as one of the morbidity indicators of schistosomiasis, intensity of S. mansoni was significantly associated with stunting.ConclusionAlthough organ-related morbidity, with the exception of periportal fibrosis, and S. mansoni infections were highly prevalent, the two were only associated for individuals with very high infection intensities. These results contrast starkly with reports from Ugandan Lake Albert fishing communities in which periportal fibrosis is more prevalent.

Ubiquitous omnivory, functional redundancy and the resiliency of Lake Victoria fish community

The fish community of Lake Victoria, East Africa, has continued to exhibit an intriguing degree of resiliency despite stress from anthropogenic activities. Frequent environmental perturbations include wild fluctuations in fishing pressure, limnological conditions, and lake levels. Surprisingly, many of the endemic and other indigenous fishes have survived, and some have even increased in numbers in recent years. While a positive development, this resiliency is a red flag to scientists because we do not understand it, or know whether it can be expected to continue. Furthermore, besides issues of immediate human well-being, there remain grave concerns about long term resource sustainability. This paper explores possible reasons for ecological resilience in the Lake Victoria fish community, with a focus on omnivory and functional redundancy as possible explanations. The analysis used published data based on both traditional gut content analysis (GCA) and stable isotope analysis (SIA). Trophic plasticity is ubiquitous among the surviving fishes of Lake Victoria. This, combined with an overall simplification of the food web, contributed to the lake community's current resilience.

Lake Victoria Fish Stocks and the Effects of Water Hyacinth

This article analyzes the effects of the invasion of water hyacinth on fishing in Lake Victoria. The authors built two fairly standard Schaefer-type models that have one innovation: They allow the water hyacinth abundance to affect catchability. The authors estimated static and dynamic catch per unit of effort functions for Lake Victoria fisheries, investigating the trend in the lake's stocks during the period 1983 to 2000 and focusing particularly on the effect of the water hyacinth on fish stocks and on catchability coefficients. The results show that although fish stocks have fallen since 1990, this decline appears to have been at least temporarily halted by the declining catchability of fish because of the growing abundance of water hyacinth. The impact of the hyacinth on the catchability of fish was greatest in the Kenyan section of Lake Victoria. Although hyacinth has many negative effects, it effectively hinders fishing and thereby paradoxically stops or at least postpones serious overfishing.

Higher de novo synthesized fatty acids and lower ω3- and ω6-long-chain polyunsaturated fatty acids in umbilical vessels of women with preeclampsia and high fish intakes

Umbilical veins (UV) and arteries (UA) of preeclamptic women in Curaçao harbor lower long-chain polyunsaturated fatty acids (LCP). The present aim was to test these findings in Mwanza (Tanzania), whose inhabitants have high LCPω3 and LCPω6 intakes from Lake Victoria fish. Women with preeclampsia ( n=28) in Mwanza had lower PUFA and higher 20:0 in UV and UA, compared with normotensive/non-proteinuric controls ( n=31). Their UV 22:6ω3, 22:4ω6, LCPω6, ω6, and LCPω3+ω6 were lower, while saturated FA, potentially de novo synthesized FA (Σ de novo) and (Σ de novo)/(LCPω3+ω6) ratio were higher. Their UA had higher 16:1ω7, ω7, 18:0, and 16:1ω7/16:0. Umbilical vessels in Mwanza had higher 22:6ω3, LCPω3, ω3, and 16:0, and lower 22:5ω6, 20:2ω6, 18:1ω9, and ω9, compared to those in Curaçao. Preeclampsia in both Mwanza and Curaçao is characterized by lower LCP and higher Σ de novo. An explanation of this might be placental dysfunction, while the similarity of umbilical vessel FA-abnormalities in preeclamptic and diabetic pregnancies suggests insulin resistance as a common denominator.

Markets, Networks, and Risk: An Analysis of Labor Remuneration in the Lake Victoria Fishing Industry

This study applies concepts from Habermas' Theory of Communicative Action to the problem of identifying the circumstances under which networks replace markets as the primary governance mechanism for economic activities. The suggestion derived from this theory is that markets govern economic activities tied to material phenomena; whereas networks control such activities when they are tied to social relationships. This suggestion is subjected to an empirical test. Labor transactions in the Lake Victoria fishing industry are used to test the hypothesis that risk factors arising from natural contingencies will distribute according to a risk market model, whereas those arising from social relationships will be distributed through a logic of social power tied to networks and identities. The hypothesis is generally supported by data on the effects of kinship and, more strongly, ethnicity.

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

The Lake Victoria fish fauna included an endemic cichlid flock of more than 300 species. To boost fisheries, Nile perch (Lates sp.) was introduced into the lake in the 1950s. In the early 1980s an explosive increase of this predator was observed. Simultaneously, catches of haplochromines decreased. This paper describes the species composition of haplochromines in a research area in the Mwanza Gulf of Lake Victoria prior to the Nile perch upsurge. The decline of the haplochromines as a group and the decline of the number of species in various habitats in the Mwanza Gulf was monitored between 1979 and 1990. Of the 123+ species originally caught at a series of sampling stations ca. 80 had disappeared from the catches after 1986. In deepwater regions and in sub-littoral regions haplochromine catches decreased to virtually zero after the Nile perch boom. Haplochromines were still caught in the littoral regions where Nile perch densities were lower. However, a considerable decrease of species occurred in these regions too. It is expected that a remnant of the original haplochromine fauna will survive in the littoral region of the lake. Extrapolation of the data of the Mwanza Gulf to the entire lake would imply that approximately 200 of the 300+ endemic haplochromine species have already disappeared, or are threatened with extinction. Although fishing had an impact on the haplochromine stocks, the main cause of their decline was predation by Nile perch. The speed of decline differed between species and appeared to depend on their abundance and size, and on the degree of habitat overlap with Nile perch. Since the Nile perch upsurge, the food web of Lake Victoria has changed considerably and the total yield of the fishery has increased three to four times. Dramatic declines of native species have also been observed in other lakes as a result of the introduction of alien predators. However, such data concern less speciose communities and, in most cases, the actual process of extinction has not been monitored.

Species Extinction and Concomitant Ecological Changes in Lake Victoria

Lake Victoria's fish fauna included a large endemic flock of 300+ haplochromine cichlid species. About two-thirds of these species have disappeared or are threatened with extinction. The main cause of this large extinction event is predation by Nile perch, an introduced predator. We describe the decline of the haplochromine species and demonstrate that the rate and sequence of their decline was determined by their relative abundance, their adult size and their habitat overlap with Nile perch. Many non-haplochromine species declined as well, but in contrast, stocks of the native pelagic cyprinid Rastrineobola argentea and the introduced Oreochromis niloticus increased. There are also indications of an increase in phytoplankton, macrophytes, prawns and benthic organisms. Many of these rapid changes in the ecosystem were probably effects of the increase of the Nile perch and the disappearance of the haplochromines. The original fish fauna included many primary and secondary consumers. Currently secondary and tertiary consumers dominate. The food web in the sub-littoral and offshore areas of the lake changed considerably due to the stock replacements.