Ismael Kimirei

Tanzania Fisheries Research Institute | TARIFI · Dar es Salaam

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global...

Freshwater biodiversity, from fish to frogs and microbes to macrophytes, provides a vast array of services to people. Mounting concerns focus on the accelerating pace of biodiversity loss and declining ecological function within freshwater ecosystems that continue to threaten these natural benefits. Here, we catalog nine fundamental ecosystem servi...

Environmental pollution through accumulation of metals in estuarine, coastal, and marine waters is a worldwide issue. Most contaminants originate inland and pass through these environments before dispersing into the ocean. The objectives of this study were to determine metal concentration levels of Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn...

Top predators have oversized impacts on food webs and ecosystem dynamics, and introducing a novel predator to a naive environment can have dramatic consequences for endemic biodiversity. Lake Tanganyika is unique among African lakes in the diversity of the pelagic top predators in the genus Lates , where four species are endemic to the lake. Using...

Understanding the trends and impacts of anthropogenic activities in the water basins and catchments is key to the effective management and conservation of aquatic environments. This study analyses the land use and land cover (LULC) changes in the Nkangabile catchment and their impacts on water quality in the Nyegezi Bay of Lake Victoria, Tanzanian...

Microbial trait variation along environment gradients is crucial to understanding their ecological adaptation mechanisms. With the increasing availability of microbial genomes, making full use of the genome-based traits to decipher their adaptation strategies becomes promising and urgent. Here, we examined microbial communities in water and sedimen...

Cichlid fishes inhabiting the East African Great Lakes, Victoria, Malawi, and Tanganyika, are textbook examples of parallel evolution, as they have acquired similar traits independently in each of the three lakes during the process of adaptive radiation. In particular, “hypertrophied lip” has been highlighted as a prominent example of parallel evol...

Cichlid fishes inhabiting the East African Great Lakes, Victoria, Malawi, and Tanganyika, are textbook examples of parallel evolution, as they have acquired similar traits independently in each of the three lakes during the process of adaptive radiation. In particular, “hypertrophied lip” has been highlighted as a prominent example of parallel evol...

Middle and Late Holocene sediments have not been extensively sampled in Lake Tanganyika, and much remains unknown about the response of the Rift Valley’s largest lake to major environmental shifts during the Holocene, including the termination of the African Humid Period (AHP). Here, we present an integrated study (sedimentology, mineralogy, and ge...

Within 15,000 years, the explosive adaptive radiation of haplochromine cichlids in Lake Victoria, East Africa, generated 500 endemic species. In the 1980s, the upsurge of Nile perch, a carnivorous fish artificially introduced to the lake, drove the extinction of more than 200 endemic cichlids. The Nile perch predation particularly harmed piscivorou...

Cichlid fishes inhabiting the East African Great Lakes, Victoria, Malawi, and Tanganyika, are textbook examples of parallel evolution, as they have acquired similar traits independently in each of the three lakes during the process of adaptive radiation. In particular, "hypertrophied lip" has been highlighted as a prominent example of parallel evol...

Nonpoint source pollution (NPS) has become the most important reason for the deterioration of water quality, while relevant studies are often limited to African river and lake basins with insufficient data. Taking the Simiyu catchment of the Lake Victoria basin as the study area, we set up a NPS model based on the soil and water assessment tool (SW...

Ocean acidification, deoxygenation, and warming are three interconnected global change challenges caused by increased anthropogenic carbon emissions. These issues present substantial threats to marine organisms, ecosystems, and the survival of coastal communities depending on these ecosystems. Coastal upwelling areas may experience significant decl...

High mountain freshwater systems are particularly sensitive to the impacts of global warming and relevant environmental changes. Microorganisms contribute substantially to biogeochemical processes, yet their distribution patterns and driving mechanism in alpine streams remain understudied. Here, we examined the bacterial and fungal community compos...

As the second deepest lake in Africa, Lake Tanganyika plays an important role in supplying fish protein for the catchment’s residents and is irreplaceable in global biodiversity. However, the lake’s water environment is threatened by socioeconomic development and rapid population growth along the lake. This study analyzed the spatial scale effects...

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,...

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...

Lake Tanganyika’s pelagic fish sustain the second largest inland fishery in Africa and are under pressure from heavy fishing and global warming related increases in stratification. The strength of water column stratification varies regionally, with a more stratified north and an upwelling-driven, biologically more productive south. Only little is k...

The factors that govern the geographical distribution of nitrogen fixation are fundamental to providing accurate nitrogen budgets in aquatic environments. Model-based insights have demonstrated that regional hydrodynamics strongly impact nitrogen fixation. However, the mechanisms establishing this physical-biological coupling have yet to be constra...

As the second deepest lake in Africa, Lake Tanganyika plays an important role in supplying fish protein for the catchment’s residents, and is irreplaceable in global biodiversity. However, the lake's water environment is threatened by socio-economic development and rapid population growth along the lake. This study analyzed the spatial scales effec...

Lake Tanganyika is one of the most important lakes in the world because it supports millions of people who rely on its resources and its exceptional biodiversity. However, the lake currently suffers from a range of anthropogenic stressors, including water pollution and sedimentation, resource, biodiversity decline, habitat loss (both physical and f...

The long-term sustainability of the African Great Lakes is strongly connected to the management and monitoring of their coastal areas. Yet, the communities that live in these areas are rarely involved in monitoring and have limited influence on key management issues. Furthermore, regulatory activities and knowledge sharing in these transnational ec...

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...

The use of fish dorsal muscles in stable isotope studies, which is an invasive method that results in fish deaths, limits their applicability for rare and endangered fish species, as well as when large sample sizes and replicates are required, prompting research into feasible non-lethal sampling methods. The possibility of employing fin clippings (...

Urban nitrogen discharge has become an important factor leading to urban water environment deterioration, water crisis, and frequent air pollution. Human consumption is the driving force of nitrogen flow and the core of urban nitrogen research. Based on the process of nitrogen flow in the urban human system, combined with the relevant United Nation...

Freshwater biodiversity, from fish to frogs and microbes to macrophytes, provides a vast array of services to people. Mounting concerns focus on the accelerating pace of biodiversity loss and declining ecological function within freshwater ecosystems that continue to threaten these natural benefits. Here, we catalog nine fundamental ecosystem servi...

Ocean acidification (OA) is a profound change in ocean chemistry due to anthropogenic carbon dioxide (CO 2) emissions. The ocean represents 72 per cent of the Earth's surface and contains about 99 per cent of the available surface water. In response to the accumulation of CO 2 in the atmosphere, the ocean is currently absorbing about one-third of a...

The report summarizes the results of ocean acidification monitoring in the Western Indian Ocean region (Kenya, Mauritius, Mozambique, Seychelles, South Africa and Tanzania) that was supported by WIOMSA, Swedish International Development Cooperation Agency and institutional partners in the WIO region. The research provides a baseline that will foste...

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...

Heterotrophic respiration of organic matter (OM) is thought to dominate over aquatic primary production (PP) in most freshwater lake ecosystems. This paradigm implies that lateral transport of OM from the terrestrial biosphere subsidize the major fraction of aquatic respiration and that many lakes are a net source of carbon dioxide (CO2) to atmosph...

Several studies in Lake Tanganyika have effectively employed traditional methods to explore changes in water quality in open waters; however, coastal monitoring has been restricted and sporadic, relying on costly sample and analytical methods that require skilled technical staff. This study aims in validating citizen science water quality collected...

Natural lakes are thought to be globally important sources of greenhouse gases (CO2, CH4, and N2O) to the atmosphere although nearly no data have been previously reported from Africa. We collected CO2, CH4, and N2O data in 24 African lakes that accounted for 49% of total lacustrine surface area of the African continent and covered a wide range of m...

Anthropogenic pollution plays an important part in deteriorating the water quality of rivers all over the world, especially in urban areas of Africa where water quality monitoring is still seriously constrained by the limited test facility and capability. In this study, for evaluating the impact of urbanization on the river water quality, we invest...

East African lakes include the most productive and alkaline lake group in the world. Yet, they generally receive fewer nutrient inputs than the densely populated subtropical and temperate lakes in the northern hemisphere. In these lakes with insufficient supplies of inorganic nitrogen, the mineralization of benthic organic matter could play an impo...

Tanzania is the only country bordering all three transboundary East African Great Lakes, i.e., Lake Victoria, Lake Tanganyika, and Lake Nyasa (Lake Malawi). This study investigated the spatiotemporal variability of basic physicochemical parameters of nearshore surface waters in Mwanza Gulf (Lake Victoria), Kigoma Bay (Lake Tanganyika), and Wissmann...

A lack of understanding the fate of highly toxic organic micropollutants (OMPs) in the equatorial lakes of Tanzania hinders public awareness for protecting these unique aquatic ecosystems, which are precious water resources and stunning wildlife habitats. To address this knowledge gap, the occurrence of 70 anthropogenically-sourced OMPs, including...

The cover image is based on the Viewpoint A global agenda for advancing freshwater biodiversity research by Alain Maasri et al., https://doi.org/10.1111/ele.13931. Image Credit: Solvin Zankl. image

Conventional water quality monitoring has been done for decades in Lake Tanganyika, under different national and international programs. However, these projects utilized monitoring approaches, which were temporally limited, labour intensive and costly. This study examines the use of citizen science to monitor the dynamics of coliform concentrations...

Extensive research has been conducted at Lake Tanganyika to understand its vulnerability to a warming climate and fishing pressure. However, much of this work has been restricted to the more accessible northern basin. Studies from a limited geographic region of the lake are insufficient to explain whole-lake dynamics of the world’s longest lake (~...

Understanding genetic connectivity plays a crucial role in species conservation decisions, and genetic connectivity is an important component of modern fisheries management. In this study, we investigated the population genetics of four endemic Lates species of Lake Tanganyika (Lates stappersii, L. microlepis, L. mariae and L. angustifrons) using r...

The significance of large tropical lakes as environmental reservoirs of Vibrio cholerae in cholera endemic countries has yet to be established. By combining large scale plankton sampling, microbial culture and ultrasensitive molecular methods, namely Droplet Digital PCR (ddPCR) and targeted genomics, the presence of Vibrio cholerae was investigated...

Lake Tanganyika’s pelagic fish sustain the second largest inland fishery in Africa and are under pressure from heavy fishing and global warming related increases in stratification. Only little is known about whether basin-scale hydrodynamics – including a more stratified north and an upwelling-driven south – lead to regional fish populations with v...

Extensive research has been conducted at Lake Tanganyika to understand its vulnerability to a warming climate and fishing pressure. However, much of this work has been restricted to the more accessible northern basin. Studies from a limited geographic region of the lake are insufficient to explain whole-lake dynamics of the world's longest lake (*...

In Lake Tanganyika, blooms of nitrogen-fixing (diazotrophic) cyanobacteria emerge, when the upper water column re-stratifies after a period of upwelling and convective mixing. During this seasonal transition, diazotrophic cyanobacteria exploit the abundant phosphate and fix nitrogen after other phytoplankton taxa have consumed the available nitrate...

Mangroves are among the most productive coastal ecosystems; however, they are prone to anthropogenic pollution due to their land-sea interface position. We used stable nitrogen isotopes and spectrophotometric nitrate analysis to study the anthropogenic pollution in five mangrove ecosystems in Tanzania, including two polluted (Mzinga and Kizinga), o...

Life history traits are important factors in shaping gene flow within species, and these traits can thus be determinants of whether a species exhibits genetic homogeneity across its range, or considerable population structure. Furthermore, understanding genetic connectivity plays crucially into species conservation decisions, and genetic connectivi...

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pres...

Freshwater biodiversity is declining dramatically, and the current biodiversity crisis requires defining bold goals and mobilizing substantial resources to meet the challenges. While the reasons are varied, both research and conservation of freshwater biodiversity lag far behind efforts in the terrestrial and marine realms. We identify fifteen pres...

Lake Tanganyika (LT) is the largest tropical freshwater lake, and the largest body of anoxic freshwater on Earth’s surface. LT’s mixed oxygenated surface waters float atop a permanently anoxic layer and host rich animal biodiversity. However, little is known about microorganisms inhabiting LT’s 1470 meter deep water column and their contributions t...

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...

Climate and vegetation influence weathering rates and processes; however, evaluating the effects of each and feedbacks between systems, has yet to be accomplished for many types of landscapes. A detailed understanding of how these processes interact to shape landscapes is particularly crucial for reconciling future scenarios of changing climate, wh...

Climate warming coupled with local disturbances within lakes are an accelerating global problem. This issue is acute at Lake Tanganyika (eastern Africa), where warming and overfishing have resulted in declining rates of pelagic fish catches and structural damage to diverse littoral cichlid communities. This deteriorating has fueled demand for alter...