About
71
Publications
33,379
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,490
Citations
Introduction
Current institution
Additional affiliations
April 1998 - present
July 2008 - September 2012
Publications
Publications (71)
New species typically evolve over several million years. However, rates of speciation and ecological diversification vary by orders of magnitude across the tree of life, with the fastest shown by some adaptive radiations. Eight hundred endemic species of cichlid fishes emerged and formed entire food webs in Lake Victoria and nearby lakes in East Af...
Understanding people's perceptions of climate change and associated environmental risks is paramount in assessing how individuals respond to climate change. Awareness of the consequences of climate change determines the present and future behaviours and expectations, as well as the actions taken to mitigate the likely impacts. We surveyed the perce...
Management and conservation of species‐rich tropical freshwater systems require reliable information on the diversity and distribution of species present. Here, we used environmental DNA metabarcoding to reveal the diversity of the fishes in the Rufiji River catchment of central Tanzania. Across 174 samples from 49 sites, and using a newly develope...
Discerning ecosystem change and food web dynamics underlying anthropogenic eutrophication and the introduction of non-native species is necessary for ensuring the long-term sustainability of fisheries and lake biodiversity. Previous studies of eutrophication in Lake Victoria, eastern Africa, have focused on the loss of endemic fish biodiversity ove...
The Lake Victoria ecosystem is emblematic of the catastrophic effects that human activities, particularly cultural eutrophication, can have on freshwater biodiversity. However, little is known about the long-term spatial and temporal pattern of aquatic primary paleo-production (PPaq) and producer communities in Lake Victoria and how these patterns...
Octopus cyanea (Gray, 1849), abundant in the South‐West Indian Ocean (SWIO), constitutes a vital resource for both subsistence and commercial fisheries. However, despite this socioeconomic importance, and recent indications of overfishing, little is known about the population structure of O. cyanea in the region. To inform sustainable management st...
Lake Victoria is well known for its high diversity of endemic fish species and provides livelihoods for millions of people. The lake garnered widespread attention during the twentieth century as major environmental and ecological changes modified the fish community with the extinction of approximately 40% of endemic cichlid species by the 1980s. Su...
Preserved assemblages of invertebrate remains in lacustrine sediment reveal temporal variations of community composition and environmental conditions. However, records for large tropical lakes are scarce. Lake Victoria, the largest tropical lake, has a dynamic history of changes in water level, biogeochemistry and fish community composition over th...
This file is the Electronic Supplemental Material (ESM) of this MS:
Plisnier, P.-D., Kayanda, R., MacIntyre, S., Obiero, K., Okello, W., Vodacek, A., Cocquyt, C., Abegaz, H., Achieng, A., Akonkwa, B., Albrecht, C., Balagizi, C., Barasa, J., Bashonga, R.A., Bishobibiri A.B., Bootsma, H., Borges, A.V., Chavula, G., Dadi, T., De Keyzer, E.L.R., Doran,...
There is considerable potential for nuclear genomic material in environmental DNA (eDNA) to inform us of population genetic structure within aquatic species. We tested if nuclear allelic composition data sourced from eDNA can resolve fine scale spatial genetic structure of the cichlid fish Astatotilapia calliptera in Lake Masoko, Tanzania. In this...
To ensure the long-term sustainable use of African Great Lakes (AGL), and to better understand the functioning of these ecosystems, authorities, managers and scientists need regularly collected scientific data and information of key environmental indicators over multi-years to make informed decisions. Monitoring is regularly conducted at some sites...
Reconstructing hydrological variability is critical for understanding Lake Victoria's ecosystem history, the evolution of its diverse endemic fish community, the dynamics of vegetation in the catchment, and the dispersal of aquatic and terrestrial fauna in the East African Rift system during Latest Pleistocene and Holocene times. Whereas consensus...
Tropical freshwater lakes are well known for their high biodiversity, and particularly the East African Great Lakes are renowned for their adaptive radiation of cichlid fishes. While comparative phylogenetic analyses of extant species flocks have revealed patterns and processes of their diversification, little is known about evolutionary trajectori...
Adaptive radiations have been instrumental in generating a considerable amount of life’s diversity. Ecological opportunity is thought to be a prerequisite for adaptive radiation ¹ , but little is known about the relative importance of species’ ecological versatility versus effects of arrival order in determining which lineage radiates ² . Palaeonto...
Although some lineages of animals and plants have made impressive adaptive radiations when provided with ecological opportunity, the propensities to radiate vary profoundly among lineages for unknown reasons. In Africa’s Lake Victoria region, one cichlid lineage radiated in every lake, with the largest radiation taking place in a lake less than 16,...
Seascape configuration is known to influence fish distribution and abundance in coastal waters. However, there is little information regarding how the shape of the coastal seascape influences catches of landed fisheries species, particularly so in the understudied western Indian Ocean (WIO). With focus on big blue octopus (Octopus cyanea), which is...
Over 42 million people rely on Lake Victoria as their primary source of food, employment, and clean drinking water. The lake's fisheries have produced around one million tonnes in recent years, but the lake's growing population has resulted in a lower catch rate per capita. And the lake and its catchment have been negatively impacted by a wide vari...
Studies on marine and coastal habitats in the western Indian Ocean have mostly focused on mangroves, seagrasses and coral reefs but the spatially predominant soft sediment habitats have largely been ignored. It is these habitats that support the commercially important crustacean trawl fisheries and small-scale fisheries which provide socio-economic...
Tropical freshwater lakes are well-known for their high biodiversity, and the East African Great Lakes in particular are renowned for their endemic cichlid fish adaptive radiations. While comparative phylogenetic analyses of extant species flocks have revealed patterns and processes of their diversification, evolutionary trajectories within lineage...
Water quality degradation of urban rivers has become a serious constraint to the sustainable development of big cities in sub-Saharan Africa, and few systematic quantitative studies have been conducted on this issue. Here, we studied three main urban rivers: Mzinga River, Kizinga River, and Msimbazi River in Dar es Salaam, the largest port city on...
Fire regimes differ across tropical and subtropical biomes depending on multiple parameters whose interactions and levels of importance are poorly understood, particularly at multidecadal and longer time scales. In the catchment of Lake Victoria, savanna, rainforest, and Afromontane vegetation have interspersed over the last 17,000 years, which may...
The distribution of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and their fraction characteristics (except Hg) were investigated in surface sediments of the Mwanza Gulf, Lake Victoria. The ecological risks, bioavailability, and mobility of the metals were also evaluated by using enrichment factor (EF), contamination factor (Cf), geo-accumulation index (Igeo...
Temporal octopus closure is an important controller of fishing pressure on near-shore
reef fisheries. For the Comoros, Tanzania and Kenya on the east coast of Africa, the
harvest of octopuses below 1 kg, 500 g and 350 g, respectively, is not allowed. This
regulatory strategy has been in place for decades. However, its practicability is
questionable...
Tanzania is the only country bordering all three trans-boundary East African Great Lakes, i.e., Lake Victoria, Lake Tanganyika, and Lake Nyasa (Lake Malawi). This study investigated the spatio temporal variability of basic physicochemical parameters of nearshore surface waters in Mwanza Gulf (Lake Victoria), Kigoma Bay (Lake Tanganyika), and Wissma...
The haplochromine cichlids of Lake Victoria exhibit the fastest adaptive radiation of vertebrates known. Species identification of these lacustrine cichlids has been subject of debate for many years. Over the past 35 years, environmental perturbations have resulted in phenotypic change and possibly in hybridization, making species delimitation even...
Lakes Victoria, Kyoga, and Nabugabo (“the Lake Victoria region”) are remarkable for hosting one of the largest assemblages of cichlid fishes among the African inland lakes. Here, we review the role and severity of anthropogenic and environmental stressors on the cichlid communities in the Lake Victoria region to understand the mechanisms leading to...
Octopus cyanea is a commercially important cephalopod in the Western Indian Ocean (WIO) region, but scientific information to inform management strategies for the species is limited. A study was conducted in 2014, 2015, 2017 and 2018 to investigate biological parameters including growth, mortality, exploitation rates and recruitment patterns in the...
Background: Researchers in the developing countries often have inadequate scientific writing skills to publish their research in international peer reviewed journals.
Objectives: To improve the research-and proposal-writing skills of researchers and to evaluate the impact of this intervention.
Methods: An off-the-shelf online course (AuthorAID, dev...
Background: Researchers in the developing countries often have inadequate scientific writing skills to publish their research in international peer reviewed journals.
Obj ectives: To improve the research-and proposal-writing skills of researchers and to evaluate the impact of this intervention.
M e th ods: An off-the-shelf online course (AuthorAID,...
Background: Researchers in the developing countries often have inadequate scientific writing skills to publish their research in international peer reviewed journals.
Objectives: To improve the research-and proposal-writing skills of researchers and to evaluate the impact of this intervention.
Methods: An off-the-shelf online course (AuthorAID, d...
Speciation rates vary considerably among lineages, and our understanding of what drives the rapid succession of speciation events within young adaptive radiations remains incomplete1–11. The cichlid fish family provides a notable example of such variation, with many slowly speciating lineages as well as several exceptionally large and rapid radiati...
Phosphorus discharge in urban household consumption system has an important impact on the urban ecological environment, especially the surface water environment. In this study, a framework and its accounting model of phosphorus flow analysis in urban household consumption system by means of SFA (substance flow analysis) was constructed. Based on th...
The ABCD conference format (All continents, Balanced gender, low Carbon transport, Diverse backgrounds) mixes live-streamed and pre-recorded talks with in-person ones to reflect a diverse range of viewpoints and reduce the environmental footprint of meetings while also lowering barriers to inclusiveness.
The ABCD conference format (All continents, Balanced gender, low Carbon transport, Diverse backgrounds) mixes live-streamed and pre-recorded talks with in-person ones to reflect a diverse range of viewpoints and reduce the environmental footprint of meetings while also lowering barriers to inclusiveness.
Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growt...
The Lake Victoria Basin is home to the most extensive wetlands in Eastern Africa and these wetlands support remarkably high levels of floral biodiversity. Freshwater plants have a diverse range of uses, with variations in use depending on the plant part and life stage. Medicinal use of plants is very common in rural communities, as there is often n...
Freshwater ecosystems are among the most threatened on Earth, facing environmental and anthropogenic pressures often surpassing their terrestrial counterparts. Land use and land cover change (LUCC) such as degradation and fragmentation of the terrestrial landscape negatively impacts aquatic ecosystems. Satellite imagery allows for an impartial asse...
Eutrophication is an increasing global threat to freshwater ecosystems. East Africa's Lake Victoria has suffered from severe eutrophication in the past decades which is partly responsible for the dramatic decline in haplochromine cichlid species diversity. However, some zooplanktivorous and detritivorous haplochromine species recovered and shifted...
Stable isotopes are increasingly being used to infer past and present trophic interactions in light of environmental changes. The Lake Victoria haplochromine cichlids have experienced severe environmental changes in the past decades that, amongst others, resulted in a dietary shift towards larger prey. We investigated how the changed environment an...
Textbook examples of adaptive radiation often show rapid morphological changes in response to environmental perturbations. East Africa’s Lake Victoria, famous for its stunning adaptive radiation of cichlids, has suffered from human-induced eutrophication over the past decades. This cultural eutrophication is thought to be partly responsible for the...
This study explored the yield and economic benefits of African sharptooth catfish, Clarias gariepinus, and Nile tilapia, Oreochromis niloticus polyculture, reared in earthen ponds for 270 days integrated with Chinese cabbage, Brassica rapa chinensis, farmed for 45 days to small-scale farmers in Tanzania. An integrated aquaculture–agriculture (IAA)...
Unaffordability of commercial feeds to semi-intensive Nile tilapia, Oreochromis niloticus farmers has led to reliance on supplemental feeding and fertilization for nutrition of their fish without a scientific basis. This study compared the growth, survival, condition factor and yield performance of O. niloticus fed on mixed ingredients (MI) and ric...
Lake Victoria had a fish fauna dominated by 500 + species of haplochromines. In the 1980s, the haplochromines from sub-littoral areas of the Mwanza Gulf vanished almost completely. In the 1990s, a recovery of some haplochromine species was observed. To establish the status of the recovery, we studied their relative abundance and distribution patter...
Prolific breeding and production of high percentage of recruits are main problems in mixed-sex
Nile tilapia (Oreochromis niloticus) culture in earthen ponds. The current study assessed the efficiency of
different sizes of African sharptooth catfish (Clarias gariepinus) in controlling recruitment in mixed-sex Nile
tilapia cultured in tanks and its e...
2014. Coupled human and natural system dynamics as key to the sustainability of Lake Victoria's ecosystem services. Ecology and Society 19(4):
Rapid morphological changes in response to fluctuating natural environments are a common phenomenon in species that undergo adaptive radiation. The dramatic ecological changes in Lake Victoria provide a unique opportunity to study environmental effects on cichlid morphology. This study shows how four haplochromine cichlids adapted their premaxilla...
The introduced Nile perch, Lates niloticus Linnaeus 1758 in LakeVictoria is considered to be a major contributor to the decline of haplochromine species. In the 1990s, the abundance of Nile perch declined and the recovery of some haplochromine species, mainly detritivores and zooplanktivores was observed. However,
the resurgence of detritivores gro...
Climate changes and global warming have severe consequences for aquatic ecosystems. In
East Africa's Great Lakes, environmental perturbations are occurring as a result of global
warming. Lake Victoria, famous for its stunning adaptive radiation of cichlids, has suffered
from cultural eutrophication over the past decades. This eutrophication is thou...
Lake Victoria, by area the largest tropical lake of the world, is well-known for its diverse native fish fauna, which com¬prised about 500 endemic haplochromine cichlid species, two tilapiine species and 46 other species belonging to 12 fami¬lies. During the past decades, the fish species diversity in the lake has declined dramatically due to human...
During the past decades, major anthropogenic environmental changes occurred in Lake Victoria, including increased predation pressure due to Nile perch introduction, and decreases in water transparency and dissolved oxygen concentrations due to eutrophication. This resulted in a collapse of the haplochromine cichlids in the sub-littoral waters of th...
Until the 1970s, the fish fauna of Lake Victoria was dominated by 500+ endemic haplochromine cichlid species in which detritivores was the dominant group followed by zooplanktivores. With the upsurge of Nile perch in the 1980s, a strong decline of haplochromines occurred. During the1990s, a resurgence of some haplochromine species was observed and...
Possible causes of the increased algal
blooms in Lake Victoria in the 1980s have been
disputed by several authors; some suggested a topdown
effect by the introduced Nile perch, whereas
others suggested a bottom-up effect due to eutrophication.
In this article the potential impact is established
of grazing by fish on phytoplankton densities, before...
Haplochromine cichlids used to be the main prey of the introduced Nile perch, Lates niloticus, in Lake Victoria. After depletion of the haplochromine stocks at the end of the 1980s, Nile perch shifted to the shrimp Caridina nilotica and to a lesser degree to its own young and the cyprinid Rastrineobola argentea. In the present study, we investigate...
Cichlid fishes of Lake Victoria are well known for their trophic specializations. In our study area, the sub-littoral waters of the Mwanza Gulf (Tanzania), at least 12 trophic groups coexisted in the 1970s. After the Nile perch upsurge and eutrophication in the 1980s, most cichlids disappeared from the area. During the 1990s, heavy exploitation of...
Ciklidbladet 41 (4): 28-29 (2008) För drygt trettio år sedan startade en grupp biologer från Leidens Universitet i Holland en ekologisk undersökning om de haplochrominer som förekom i de södra delarna av Viktoriasjön. Haplochrominernas Ekologiska Forskargrupp (The Haplochromis Ecology Survey Team (HEST)) och forskare från Tanzanias Fiskeriforskning...
SILnews 51: 12-13 (2007). The recovering cichlid species in Lake Victoria provide interesting data on ecological and morphological responses to the dramatic environmental changes in the lake. In the 1970s, the species feeding on detritus and phytoplankton made up 50% of the haplochromine ichthyomass in sub-littoral waters, and zooplanktivores 25%....
Lake Victoria had a fish fauna dominated by 500+ species of haplochromine cichlids that made up more than 80% of the fish mass. The five main trophic groups caught with bottom trawlers in the sub-littoral areas of the Mwanza Gulf were: detritivores, zooplanktivores, insectivores, molluscivores and piscivores. The detritivores (13+ species) formed t...
The cichlid fish community of East African Lake Victoria comprised numerous specialist feeders. During the 1980s, the upsurge of introduced Nile perch (Lates niloticus) and concomitant environmental perturbations caused the disappearance of about 200 (out of 500+) species. In the sublittoral waters of the Mwanza Gulf (Tanzania), more than 110 speci...
Until the 1970s, the fish fauna of Lake Victoria in East Africa was dominated by about 500 endemic haplochromine cichlid species, which comprised about 80% of the demersal fish mass. The cichlids were extremely diverse ecologically; however, the small diversity in gross morphology and the presence of intraspecific variation made it difficult to dis...
A study conducted during the period of March/April 2002 aimed at measuring physical and chemical parameters in Tanzanian portion of Lake Victoria. Temperature and conductivity values were homogeneous among and within the study stations. Levels of dissolved oxygen (DO) ranged from 4-9 mgl-1 and there was significant difference between stations (P <...
This paper evaluates the impacts of reduction in effort, increase in mesh sizes, and prohibition of illegal fishing gears in selected satellite lakes around Lake Victoria. The study was carried out in six satellite lakes by making investigations on fish collected from experimental and artisanal fisheries. The fishes were analysed for length frequen...
Sediment samples were analyzed for Cd, Cr, Cu, Pb, Hg and Zn by AAS. The highest concentrations (ppm) for Cu (26.1+/-4.8), Hg (0.2+/-0.05), Pb (30.7+/-5.6) and Zn (45.4+/-13.1) were found at approximately 25 m from the shoreline. Generally, heavy metals concentration in the sediment decreased with increasing distance from the shoreline except for C...
The aim of this study was to investigate heavy metal concentrations in suspended particulate matter (SPM), sediment and fish tissues found in Mwanza Gulf in the Tanzania portion of Lake Victoria. Samples were analyzed for Cd, Cr, Cu, Pb, Hg and Zn by AAS. The highest concentrations (ppm) of Cd (0.2 ± 0.04), Cr (35.3 ± 6.5), Cu (3.0 ± 1.3), Pb (4.5...
