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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 geochemistry) of a radiocarbon-dated sediment core from the Kavala Island Ridge (KIR) that reveals paleoenvironmental variability in Lake Tanganyika since the Middle Holocene with decadal to centennial resolution. Massive blue-gray sandy silts represent sediments deposited during the terminal AHP (~5880–4640 cal yr BP), with detrital particle size, carbon concentrations, light stable isotopes, and mineralogy suggesting an influx of river-borne soil organic matter and weathered clay minerals to the lake at that time. Enhanced by the AHP's warm and wet conditions, chemical weathering and erosion of Lake Tanganyika's watershed appears to have promoted considerable nutrient recharge to the lake system. Following a relatively gradual termination of the AHP over the period from ~4640 cal yr BP to ~3680 cal yr BP, laminated and organic carbon-rich sediments began accumulating on the KIR. δ15Nbulk, C/N, and hydrogen index data suggest high relative primary production from a mix of algae and cyanobacteria, most likely in response to nutrient availability in the water column under a cooler and seasonally dry climate from ~3680 to 1100 cal yr BP. Sediments deposited during the Common Era show considerable variability in magnetic susceptibility, total organic carbon content, carbon isotopes, and C/N, consistent with dynamic hydroclimate conditions that affected the depositional patterns, including substantial changes around the Medieval Climate Anomaly and Little Ice Age. Data from this study highlight the importance of sedimentary records to constrain boundary conditions in hydroclimate and nutrient flux that can inform long-term ecosystem response in Lake Tanganyika. [ABSTRACT FROM AUTHOR]

Components of the lower food web (mussels, Caridina and Omena) were collected from stations from Winam Gulf, Lake Victoria, Kenya in 2022 and 2023 to analyze for stable isotopes and total mercury (THg). Temporal comparisons were made with data generated for the same species in 1998. Values of δ15N in mussels and Caridina were similar (6.89‰ vs. 6.78 ± 0.13‰), while Omena occupied an elevated trophic position (9.97 ± 0.24‰) with minor shifts in δ15N over time. All species had elevated δ13C values in 2022–2023 versus 1998 supportive of enhanced eutrophication in the Gulf. THg concentrations exhibited modest spatial differences between sites (< 2.6 fold), but not between Caridina and Omena. Larger temporal differences were apparent relative to spatial patterns with THg concentrations decreasing in study species by 2.8 to 4.1-fold between years. An exposure assessment indicated that Omena, commonly found in local markets, can be consumed up to 0.74 kg/month without generating excess THg exposures. [ABSTRACT FROM AUTHOR]

Cage aquaculture is quickly expanding in the African Great Lakes Region, with the potential of boosting fish output and acting as a source of food security, poverty reduction, job and wealth creation. However, the proliferation of fish cages in Lake Victoria has come along with sporadic fish kills especially in the shallow zones of the lake in specifically the months of September to November each year and whose documentation is key for future references in case such occurrences reoccur. This paper indicates and discusses results from a rapid assessment of recent fish kills in the years 2021 and 2022 and sheds some light on the possible causes of the fish kills using standard methods and proposes mitigation measures moving forward. Low dissolved oxygen levels (≤ 4.0 mg L-1) instigated by increased eutrophication and upwelling are noted as the main causes of the fish kills. The application of good aquaculture practices for fish cage culture husbandry, application of guidelines as well as fast-tracking and enforcement of regulations will promote sustainable cage farming in such lacustrine systems. [ABSTRACT FROM AUTHOR]

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 ecosystems are strongly limited by funding and infrastructure limitations. Citizen science has great potential to advance both scientific and public understanding of the state of the environment. However, there remains a limited understanding of participants' motivations and expectations, especially in developing countries, where citizen science has great potential to complement regulatory monitoring. The present study explores the motivations of citizen scientists in villages along Lake Tanganyika's northern coast and their potential to take a more active role in lake management. Motivations were examined through qualitative interviews, focus groups, and quantitative surveys with 110 citizen scientists and 110 non-citizen scientists from participating villages. Key motivational factors identified were the desire to contribute to scientific research and local knowledge, as well as aspects of financial compensation. The results confirm that participation in citizen science provides many benefits to participants beyond their role as data aggregators and final knowledge users. However, the incentives to participation varied to those typically considered in citizen science programs conducted in developed countries. To create sustainable long-term community based environmental monitoring, these motivations should be incorporated in the program design and participant recruitment. [ABSTRACT FROM AUTHOR]

Variation in jaw protrusion is critical to cichlid fish trophic diversification. For instance, jaw protrusion distance can influence suction, attack speed, as well as bite force, and jaw protrusion angle is associated with exploiting prey from different substrates. Interestingly, premaxillary ascending process length has been shown to influence the maximum distance some cichlid fishes protrude their oral jaws, but its relationship to jaw protrusion angle is unclear. Using phylogenetic comparative methods, morphometrics, and field measurements in Malawi cichlid species, we tested the relationship between the length of the premaxillary ascending process and two components of jaw protrusion. In Malawi, the premaxilla's ascending process length ranged from 6.9 to 15.2% with respect to standard length. Maximum jaw protrusion ranged from 1.4 to 9.1% of standard length and jaw protrusion angle varied from 17° to 76°. Although jaw protrusion angle was not associated with premaxillary ascending process length, phylogenetically adjusted correlations between the ascending process and maximum jaw protrusion distance were highly significant. Evolutionary change in the premaxilla is likely critical for determining the maximum distance, but not the angle, of Malawi cichlid jaw protrusion. Examinations of this type of potential phenotypic multi-functionality will continue to illuminate the mechanisms contributing to cichlid fish diversity. [ABSTRACT FROM AUTHOR]

We report dissolved CO 2 , CH 4 and N 2 O concentrations in two large East African lakes, Edward (surface area 2,325 km2, average depth of 37 m) and George (surface area 273 km2, average depth of 2 m). Lake George showed modest seasonal and spatial variations, and lower partial pressure of CO 2 (pCO 2) (26 ± 16 ppm, mean ± standard deviation), CH 4 (234 ± 208 nmol/L) and N 2 O saturation levels (%N 2 O) (80 ± 9 %) than Lake Edward (404 ± 145 ppm, 357 ± 483 nmol/L, 139 ± 222 %). Surface waters in both lakes were over-saturated in CH 4 , and Lake George was under-saturated in CO 2 while Lake Edward was slightly over-saturated in CO 2. This difference was related to higher phytoplankton biomass in Lake George than Lake Edward, with average chlorophyll-a concentrations of 177 ± 125 and 18 ± 25 µg/L, respectively. Permanent high cyanobacterial biomass in Lake George led to uniform dissolved CO 2 , CH 4 and N 2 O concentrations. In surface waters of Lake Edward, spatial variations of pCO 2 , CH 4 and N 2 O were related to bottom depth, and locally (in particular in Katwe Bay) also related to the inputs of water from Lake George via the Kazinga Channel, a 40-km natural channel connecting the lakes. Short-term mixing events related to storms increased CO 2 , CH 4 and N 2 O content in surface waters, in particular for CH 4 and N 2 O. This indicates that mixing events in response to storms can create 'hot moments' for CH 4 and N 2 O emissions to the atmosphere in tropical lakes, given the weaker vertical density gradients compared to higher latitude systems. [ABSTRACT FROM AUTHOR]

African cichlids are model systems for evolutionary studies and host-parasite interactions, because of their adaptive radiations and because they harbour many species of monogenean parasites with high host-specificity. Five locations were sampled in southern Lake Victoria: gill-infecting monogeneans were surveyed from 18 cichlid species belonging to this radiation superflock and two others representing two older and distantly related lineages. We found one species of Gyrodactylidae, Gyrodactylus sturmbaueri Vanhove, Snoeks, Volckaert & Huyse, 2011, and seven species of Dactylogyridae. Four are described herein: Cichlidogyrus pseudodossoui n. sp., Cichlidogyrus nyanza n. sp., Cichlidogyrus furu n. sp., and Cichlidogyrus vetusmolendarius n. sp. Another Cichlidogyrus species is reported but not formally described (low number of specimens, morphological similarity with C. furu n. sp.). Two other species are redescribed: C. bifurcatus Paperna, 1960 and C. longipenis Paperna & Thurston, 1969. Our results confirm that the monogenean fauna of Victorian littoral cichlids displays lower species richness and lower host-specificity than that of Lake Tanganyika littoral cichlids. In C. furu n. sp., hooks V are clearly longer than the others, highlighting the need to re-evaluate the current classification system that considers hook pairs III–VII as rather uniform. Some morphological features of C. bifurcatus, C. longipenis, and C. nyanza n. sp. suggest that these are closely related to congeners that infect other haplochromines. Morphological traits indicate that representatives of Cichlidogyrus colonised Lake Victoria haplochromines or their ancestors at least twice, which is in line with the Lake Victoria superflock being colonised by two cichlid tribes (Haplochromini and Oreochromini).

This paper proposes that archives can play an important role in historical climatological research. Major projects in Europe, such as CLIWOC, examine ship logbooks from the era of sail. These sources provide critical weather-related data from the era before scientific climatological measurements and surveys after World War I. Ship logbooks have proved to be crucial sources that have been identified and digitised in major projects such as the CLIWOC project. While CLIWOC has concentrated on the ships concerned of the European maritime powers, their information is of worldwide relevance. This paper then looks at the research that has been undertaken in South Africa and at the sources that have been uncovered by local scientists. The paper also suggests further potential sources within South Africa. Thereafter, the potential sources within the ESARBICA region are suggested with a focus on the African Great Lakes. Finally, an ESARBICA-wide project similar to the CLIWOC and TANAP projects is suggested, and it is proposed that ESARBICA approach IORA for endorsement and funding. [ABSTRACT FROM AUTHOR]

The Winam Gulf in the Kenyan region of Lake Victoria experiences prolific, year-round cyanobacterial harmful algal blooms (cyanoHABs) which pose threats to human, livestock, and ecosystem health. To our knowledge, there is limited molecular research on the gulf's cyanoHABs, and thus, the strategies employed for survival and proliferation by toxigenic cyanobacteria in this region remain largely unexplored. Here, we used metagenomics to analyze the Winam Gulf's cyanobacterial composition, function, and biosynthetic potential. Dolichospermum was the dominant bloom-forming cyanobacterium, co-occurring with Microcystis at most sites. Microcystis and Planktothrix were more abundant in shallow and turbid sites. Metagenome-assembled genomes (MAGs) of Dolichospermum harbored nitrogen fixation genes, suggesting diazotrophy as a potential mechanism supporting the proliferation of Dolichospermum in the nitrogen-limited gulf. Over 300 biosynthetic gene clusters (BGCs) putatively encoding the synthesis of toxins and other secondary metabolites were identified across the gulf, even at sites where there were no visible cyanoHAB events. Almost all BGCs identified had no known synthesis product, indicating a diverse and novel biosynthetic repertoire capable of synthesizing harmful or potentially therapeutic metabolites. Microcystis MAGs contained mcy genes encoding the synthesis of hepatotoxic microcystins which are a concern for drinking water safety. These findings illustrate the spatial variation of bloom-forming cyanobacteria in the Winam Gulf and their available strategies to dominate different ecological niches. This study underscores the need for further use of genomic techniques to elucidate the dynamics and mitigate the potentially harmful effects of cyanoHABs and their associated toxins on human, environmental, and economic health.

Climate change, overfishing, pollution, and habitat degradation are no longer distant threats and demand our collective action. Rising to this challenge, the Aquatic Resources and Blue Economy Conference (ARBEC) held in Kisumu, Kenya served as a call to action for sustainable aquatic practices and protection of blue economy resources. The blue economy holds much promise yet as the global community faces unprecedented environmental challenges, it's potential hinges on our ability to make informed, science-driven decisions. [ABSTRACT FROM AUTHOR]

Lake Victoria has experienced progressive eutrophication which has exacerbated the proliferation of cyanobacterial harmful algal blooms (cHABs). Fueled by anthropogenic nutrient loadings and climate change, these cHABs are increasing in distribution, duration, and frequency, particularly in areas such as the Winam Gulf. With limited resources and infrastructure, local communities have been left vulnerable as they rely on the lake for water for domestic use. Our study presents the results of a localized survey on how small-scale fishing communities perceive and respond to the threat of cHABs in the Winam Gulf of Lake Victoria, Kenya. We used a mixed-methods approach of quantitative and qualitative data-gathering techniques to elucidate the perceptions and consequences of cHABs in local communities. Our results demonstrate most (93.67%) respondents were aware of cHABs in the lake, but were not knowledgeable of cHAB threats to human and animal health. Respondents noted that fish catches decreased during cHABs, with this economic consequence serving as a primary concern of communities. Notably, respondents altered their use of lake water during perceived cHAB events and relied on other means of water treatment or alternative water sources. Overall, cHAB information was self-sourced or passed on from community elders, with no public mechanism for adequate cHAB risk communication. Lake Victoria serves as a critical resource to the Eastern African region and requires a concerted cHAB response effort. Therefore, we recommend the development of a public awareness program to reduce cHAB exposure in these at-risk communities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cichlidogyrus spp. from most East African cichlids are monophyletic. • Host switching followed by duplications is the most frequent coevolutionary event. • Strict specialist species of Cichlidogyrus possess primitive character states. Cichlidogyrus (including Scutogyrus) is the most speciose dactylogyridean monogenean genus known from African and Levantine cichlid fishes (Cichlidae). While its taxonomy is well established, little is known about the phylogenetic relationships and evolutionary history of this ectoparasite, especially from hosts belonging to one of the most impressive vertebrate radiations, the cichlid fishes from the East African Great Lakes and surrounding hydrological systems. Phylogenetic inference based on DNA sequences of the nuclear 18S, internal transcribed spacer 1 and 28S rDNA genes revealed that Cichlidogyrus parasitizing mainly West African cichlid tribes is paraphyletic with respect to species parasitizing hosts belonging to the East African cichlid radiation, which constitute a well-supported monophylum. Members of Cichlidogyrus from tylochromine and oreochromine hosts that colonised Lake Tanganyika only recently, cluster with their non-Lake Tanganyika relatives, indicating that they colonised Lake Tanganyika with their current host species, and did not jump over from any of the many cichlid species already present in the lake. The diversification of Cichlidogyrus in Lake Tanganyika seems to be driven by failure to diverge in old lineages of cichlids, cospeciation in more recently evolved ones, and host switching followed by parasite duplication at the level of the various host tribes. Evaluation of host specificity and structural evolution of haptoral and reproductive organs in Lake Tanganyika Cichlidogyrus revealed that strict specialist species together with larval hook size represent the ancestral state of haptor configuration, suggesting that members of Cichlidogyrus in this system evolved from a very simple form to a more complex one similarly to their West African congeners. Generalist species among Cichlidogyrus with a sclerotized vagina parasitizing ancient Lake Tanganyika lineages seem to have developed a different hook configuration, most probably to ensure successful colonisation of new, phylogenetically unrelated hosts. [ABSTRACT FROM AUTHOR]

Oreochromis is the most important tropical freshwater fish genus for aquaculture purposes, with various introduction and translocation events having played an integral part of its management. Some Oreochromis species such as the Nile tilapia, O. niloticus , are thought to be superior for aquacultural purposes when compared to other species. Hence, understanding the admixed nature of the species within a native system is of key importance for the development of future broodstock. Using a combination of mitochondrial (COI) and nuclear (microsatellites) DNA, we tested for the presence of O. niloticus and O. leucostictus hybrids within the Lake Edward-George system. The present study revealed that, despite their natural overlapping ranges, hybridization between O. niloticus and O. leucostictus appears to be rare within the Lake Edward-George system, suggesting that the native populations of these two species may serve as suitable broodstock to develop future aquaculture strains. Moreover, our study provides the first COI sequences for O. leucostictus from its native range and adds to the growing database of O. niloticus sequences. [ABSTRACT FROM AUTHOR]

Abstract Background Cichlids are a prime model system in evolutionary research and several of the most prominent examples of adaptive radiations are found in the East African Lakes Tanganyika, Malawi and Victoria, all part of the East African cichlid radiation (EAR). In the past, great effort has been invested in reconstructing the evolutionary and biogeographic history of cichlids (Teleostei: Cichlidae). In this study, we present new divergence age estimates for the major cichlid lineages with the main focus on the EAR based on a dataset encompassing representative taxa of almost all recognized cichlid tribes and ten mitochondrial protein genes. We have thoroughly re-evaluated both fossil and geological calibration points, and we included the recently described fossil †Tugenchromis pickfordi in the cichlid divergence age estimates. Results Our results estimate the origin of the EAR to Late Eocene/Early Oligocene (28.71 Ma; 95% HPD: 24.43–33.15 Ma). More importantly divergence ages of the most recent common ancestor (MRCA) of several Tanganyika cichlid tribes were estimated to be substantially older than the oldest estimated maximum age of the Lake Tanganyika: Trematocarini (16.13 Ma, 95% HPD: 11.89–20.46 Ma), Bathybatini (20.62 Ma, 95% HPD: 16.88–25.34 Ma), Lamprologini (15.27 Ma; 95% HPD: 12.23–18.49 Ma). The divergence age of the crown haplochromine H-lineage is estimated to 22.8 Ma (95% HPD: 14.40–26.32 Ma) and of the Lake Malawi radiation to 4.07 Ma (95% HDP: 2.93–5.26 Ma). In addition, we recovered a novel lineage within the Lamprologini tribe encompassing only Lamprologus of the lower and central Congo drainage with its divergence estimated to the Late Miocene or early Pliocene. Furthermore we recovered two novel mitochondrial haplotype lineages within the Haplochromini tribe: ‘Orthochromis’ indermauri and ‘Haplochormis’ vanheusdeni. Conclusions Divergence time estimates of the MRCA of several Tanganyika cichlid tribes predate the age of the extant Lake Tanganyika basin, and hence are in line with the recently formulated “Melting-Pot Tanganyika” hypothesis. The radiation of the ‘Lower Congo Lamprologus clade’ might be linked with the Pliocene origin of the modern lower Congo rapids as has been shown for other Lower Congo cichlid assemblages. Finally, the age of origin of the Lake Malawi cichlid flock agrees well with the oldest age estimate for lacustrine conditions in Lake Malawi.

Evolutionary theory predicts that infection by a parasite that reduces future host survival or fecundity should select for increased investment in current reproduction. In this study, we use the cestode Ligula intestinalis and its intermediate fish host Engraulicypris sardella in Wissman Bay, Lake Nyasa (Tanzania), as a model system. Using data about infection of E. sardella fish hosts by L. intestinalis collected for a period of 10 years, we explored whether parasite infection affects the fecundity of the fish host E. sardella, and whether host reproductive investment has increased at the expense of somatic growth. We found that L. intestinalis had a strong negative effect on the fecundity of its intermediate fish host. For the noninfected fish, we observed an increase in relative gonadal weight at maturity over the study period, while size at maturity decreased. These findings suggest that the life history of E. sardella has been shifting toward earlier reproduction. Further studies are warranted to assess whether these changes reflect plastic or evolutionary responses. We also discuss the interaction between parasite and fishery‐mediated selection as a possible explanation for the decline of E. sardella stock in the lake. [ABSTRACT FROM AUTHOR]

The African Great Lakes (AGL) have rich fisheries and are renowned "biodiversity hotspots". Consequently the AGLand the ecosystem services they provide, underpin the welfare and livelihoods of over 50 million people across 10 countries. Despite the recognized importance of the AGL, these vital ecosystems and their livelihood support systems are threatened by numerous anthropogenic stressors at local, regional, and global scales. Past and continued efforts to address critical challenges on these lakes are often short-term, parochial, disparate, and uncoordinated resulting in a lack of comprehensive and comparable scientific data and inadequate resources to influence evidence-based policy. Over the past two decades, several international workshops, conferences and scientific publications have identified the need for collaboration, knowledge sharing, and harmonization of research and management as key elements to enhance conservation efforts in the AGL. In this commentary, we introduce the African Center for Aquatic Research and Education (ACARE), which aims to strengthen research and provide the scientific evidence needed to make informed decisions related to sustainable fisheries and aquatic resource management in the AGL. To do this, ACARE will administer a highly collaborative network of experts with three long-term goals: (1) strengthen global and regional research partnerships; (2) establish transboundary and inter-jurisdictional lake advisory groups; and (3) build capacity of freshwater scientists through experiential education and public engagement. [ABSTRACT FROM AUTHOR]

The occurrence of toxigenic Vibrio cholerae O1 during a non- outbreak period in Lake Victoria was studied and genetic characteristics for environmental persistence and relatedness to pandemic strains were assessed. We analyzed 360 samples of carps, phytoplankton and water collected in 2017 during dry and rainy seasons in the Tanzanian basin of Lake Victoria. Samples were tested using PCR (ompW and ctxA) with DNA extracted from bacterial isolates and samples enriched in alkaline peptone water. Isolates were screened with polyvalent antiserum O1 followed by antimicrobial susceptibility testing. Whole genome sequencing and bioinformatics tools were employed to investigate the genomic characteristics of the isolates. More V. cholerae positive samples were recovered by PCR when DNA was obtained from enriched samples than from isolates (69.0% vs. 21.3%, p < 0.05), irrespectively of season. We identified ten V. cholerae O1 among 22 ctxA-positive isolates. Further studies are needed to serotype the remaining ctxA-positive non-O1 strains. Sequenced strains belonged to El Tor atypical biotype of V. cholerae O1 of MLST ST69 harboring the seventh pandemic gene. Major virulence genes, ctxA, ctxB, zot, ace, tcpA, hlyA, rtxA, ompU, toxR, T6SS, alsD, makA and pathogenicity islands VPI-1, VPI-2, VSP-1, and VSP-2 were found in all strains. The strains contained Vibrio polysaccharide biosynthesis enzymes, the mshA gene and two-component response regulator proteins involved in stress response and autoinducers for quorum sensing and biofilm formation. They carried the SXT integrative conjugative element with phenotypic and genotypic resistance to aminoglycoside, sulfamethoxazole, trimethoprim, phenicol, and quinolones. Strains contained a multidrug efflux pump component and were resistant to toxic compounds with copper homeostasis and cobalt-zinc-cadmium resistance proteins. The environmental strains belonged to the third wave of the seventh pandemic and most are genetically closely related to recent outbreak strains from Tanzania, Kenya, and Uganda with as low as three SNPs difference. Some strains have persisted longer in the environment and were more related to older outbreak strains in the region. V. cholerae O1 of outbreak potential seem to persist in Lake Victoria through interactions with fish and phytoplankton supported by the optimum water parameters and intrinsic genetic features enhancing survival in the aquatic environment.

Fisheries around the world are declining due to growing anthropogenic pressures including climate change and overexploitation. Understanding how small-scale fishers respond to this unprecedented challenge is critical for developing more effective management strategies in vulnerable socio-ecological systems. While considerable research is focused on adaptation to change in marine contexts, greater attention is urgently needed on regionally important but often neglected inland fisheries. This study analyzes the adaptation intentions of littoral fishers on Lake Tanganyika, a biodiversity hotspot and one of the largest inland fisheries in Africa. Data were collected through in-person surveys of 154 littoral fishers across 11 major landing sites in Tanzania. Based on the Theory of Planned Behavior, we identified and tested 15 individual and site-level factors as potential indicators of adaptation intentions to a hypothetical 50% decline in catch. Our results show that fishers with other (non-fishing) primary livelihoods are more likely to adapt in ways that decrease fishing pressure, increase income, and are supported by family and friends. Homeowners were also more likely to adapt in ways that lessen fishing pressure. Our findings highlight the importance of fostering regional adaptation strategies that increase primary livelihood alternatives and capital outside the fishery, while discouraging investment in adaptations focused on increasing catch amount or fishing income. [ABSTRACT FROM AUTHOR]

The occurrence of toxigenic Vibrio cholerae O1 during a non- outbreak period in Lake Victoria was studied and genetic characteristics for environmental persistence and relatedness to pandemic strains were assessed. We analyzed 360 samples of carps, phytoplankton and water collected in 2017 during dry and rainy seasons in the Tanzanian basin of Lake Victoria. Samples were tested using PCR (omp W and ctx A) with DNA extracted from bacterial isolates and samples enriched in alkaline peptone water. Isolates were screened with polyvalent antiserum O1 followed by antimicrobial susceptibility testing. Whole genome sequencing and bioinformatics tools were employed to investigate the genomic characteristics of the isolates. More V. cholerae positive samples were recovered by PCR when DNA was obtained from enriched samples than from isolates (69.0% vs. 21.3%, p < 0.05), irrespectively of season. We identified ten V. cholerae O1 among 22 ctx A-positive isolates. Further studies are needed to serotype the remaining ctx A-positive non-O1 strains. Sequenced strains belonged to El Tor atypical biotype of V. cholerae O1 of MLST ST69 harboring the seventh pandemic gene. Major virulence genes, ctxA, ctxB, zot, ace, tcpA, hlyA, rtxA, ompU, toxR, T6SS, alsD, makA and pathogenicity islands VPI-1, VPI-2, VSP-1, and VSP-2 were found in all strains. The strains contained Vibrio polysaccharide biosynthesis enzymes, the mshA gene and two-component response regulator proteins involved in stress response and autoinducers for quorum sensing and biofilm formation. They carried the SXT integrative conjugative element with phenotypic and genotypic resistance to aminoglycoside, sulfamethoxazole, trimethoprim, phenicol, and quinolones. Strains contained a multidrug efflux pump component and were resistant to toxic compounds with copper homeostasis and cobalt-zinc-cadmium resistance proteins. The environmental strains belonged to the third wave of the seventh pandemic and most are genetically closely related to recent outbreak strains from Tanzania, Kenya, and Uganda with as low as three SNPs difference. Some strains have persisted longer in the environment and were more related to older outbreak strains in the region. V. cholerae O1 of outbreak potential seem to persist in Lake Victoria through interactions with fish and phytoplankton supported by the optimum water parameters and intrinsic genetic features enhancing survival in the aquatic environment. [ABSTRACT FROM AUTHOR]

The seven African Great Lakes are some of the most critical freshwater, large-lake systems in the world, providing essential services, food, drinking water, and other livelihood support to over 62 million people. Like most freshwater systems around the world, these lakes are strained by anthropogenic stressors, leading to degradation of these biologically important, and human-dependent resources. Despite their importance, these lakes suffer from insufficient research approaches which are short-term, disparate, and unharmonized. Further, a lack of monitoring, data and information exchange, education and training, and gender balance in research, all lead to insufficient knowledge on which to better manage and protect these lakes. While past efforts have resulted in some knowledge accumulation, there is a need for new approaches to understanding and managing these lakes: bottom-up, harmonized, and long-term processes. This paper, and those within this special section of the Journal of Great Lakes Research , highlight new, highly collaborative efforts of freshwater experts representing each riparian country of each African Great Lake through formal advisory groups. These papers are the result of harmonized efforts and collegial agreements as to what issues need to be addressed foremost, written by those on the ground. While each lake has specific, prioritized lists of issues, five overarching issues must be addressed to achieve success on these lakes: providing agency and coordination of African freshwater scientists; increase long-term monitoring; strengthen education and training of existing and future experts; enhance information and data exchange; and ensure stronger gender balance in science and leadership positions. [ABSTRACT FROM AUTHOR]

Abstract In May 2017, the African Great Lakes community convened for a region-wide conference in Entebbe, Uganda. The African Great Lakes Conference (AGLC) focused on 6 regionally-important themes, and 300+ attendees presented over 100 talks and posters. The AGLC culminated in the adoption of a set of Conference Resolutions designed to direct the future of African Great Lakes conservation and management. As an Introduction to this Journal of Great Lakes Research special section on African Great Lakes, we report on the impetus for the African Great Lakes Conference as well as discuss three major advances and investments that were a direct result of conference resolutions adopted at the meeting. First, we present the AGLC Resolutions, a set of management issues and solutions developed at the conference. Second, we discuss the African Great Lakes Conference Fund, a conservation fund that has awarded $500,000 USD to launch four new initiatives. Finally, we describe African Great Lakes Inform, a knowledge management platform designed to promote collaboration in the region. The AGLC in general, and these three major conference outcomes specifically, provide a set of basic building blocks to advance partnerships, research and capacity in the African Great Lakes region. [ABSTRACT FROM AUTHOR]

Abstract The African Great Lakes are under threat from global and local environmental challenges including climatic change, water pollution and overfishing. To address those issues, managers need observations based on regularly monitored environmental indicators. However, environmental monitoring of the African Great Lakes is often lacking or not based on harmonised methods. The present manuscript is a case study based on Lake Tanganyika, impacted by climate change and anthropogenic pressure affecting water quality, fisheries and biodiversity changes. The implementation of environmental monitoring has often not been continuous or standardised among bordering countries. This prevents managers from taking data-based decisions and opens a risky field where speculation may overcome a rational approach. Long-term monitoring observations are essential to guide management measures to adapt to climate changes and decrease, whenever possible, unfavourable human impact on the Great Lake environment. A regionally standardised long-term monitoring programme is proposed. The sustainability of such monitoring requires that it remains inexpensive and focuses on a few essential parameters. Its strength would be its uninterrupted implementation. Setting up a long-term integrated monitoring programme is also a goal of the Lake Tanganyika Authorities (LTA) with mandated national authorities and stakeholders. A Lake Tanganyika Regional Integrated Monitoring Programme (LTRIEMP) needs to be widely encouraged and supported to ensure its sustainability. General principles from the Lake Tanganyika case study could be useful to develop a wider harmonised sustainable long-term regional monitoring network of the African Great Lakes in a multi-lakes collaborative approach. [ABSTRACT FROM AUTHOR]

Abstract Rapid ecological changes in the African Great Lakes (AGL) present lake managers with extraordinary challenges to understand the changes' underlying causes and forecast what they portend for the future. Monitoring and experimental data from the AGL are essential but are limited in duration and continuity. The magnitude of change suggests that a centennial-millennial timescale perspective is needed to identify drivers of change and prepare for changes yet to come. In this review I propose that paleoecological and paleolimnological approaches can provide this perspective. AGL paleorecords have documented the impacts of excess sedimentation, external nutrient loading, and climate change, and can demonstrate the specific ecosystem responses associated with these various drivers. Paleorecords can help us understand how multiple stressors interact and in some cases can falsify specific cause-and-effect hypotheses when the putative causes can be shown to have occurred after the effect started. The number of useful AGL paleorecords is still quite small. Replication is needed to test if patterns seen and hypotheses inferred from single localities are robust for an entire lake, and to understand regional variability within and between lakes. Because many paleorecord methods are quite inexpensive it would be highly desirable if these approaches were incorporated into the routine tool kit of local AGL scientists working in tandem with fisheries and water-quality scientists. Training African lake scientists and conservation biologists to analyze paleorecords should be a high priority for AGL stakeholders interested in the long-term prognoses for the economic and biodiversity resources that they oversee. [ABSTRACT FROM AUTHOR]

Sediment cores and seismic reflection data acquired from the eastern basin of Lake Kivu, Rwanda reveal extensive limnologic variations due to changes in regional climate and basin structure. The eastern basin of the lake contains a sedimentary wedge which is > 1.5 km in thickness on its western side, and basal sediments are estimated to be at least 1.5 million years old. Sediments are likely to be thicker and older than this in the northern, Congolese basin of the lake. Above the ∼300 m iosbath only a thin layer of Holocene sediments are observed indication that this may have been the lake’s high stand prior to that time. There are at least three erosional unconformities interpreted as desiccation or near-desiccation events which are estimated to have occurred at ∼475 ka, ∼100 ka, and ∼20 ka; the two most recent of these low stages likely developed during the African Megadrought and Last Glacial Maximum (LGM) periods. Following the LGM, the water levels rose to form a ∼100 m deep lake with its surface ∼370 m below the current lake level. The lake remained near that level for several thousand years and during this time the Virunga Volcanic Province expanded. At ∼12.2 ka a change to wetter climate conditions rapidly filled the lake to spill out of the Bukavu Bay basin southward toward Lake Tanganyika. Tephra sampled from the cores show that there have been at least 24 large local volcanic events since the early Holocene lake transgression. [ABSTRACT FROM AUTHOR]

Freshwater protected areas are rarely designed specifically for this purpose and consequently their conservation benefit cannot be guaranteed. Using Lake Tanganyika as a test case we investigated the benefits of terrestrial-focussed protected areas on the alpha and beta taxonomic and functional diversity of the diverse endemic rocky-shore cichlid fishes. Lake Tanganyika has limited protected shorelines and continued human population growth in its catchment, which has potential for negative impacts on habitat quality and key biological processes. We conducted 554 underwater surveys across a gradient of human disturbance including two protected areas, along 180 km of Tanzanian coastline, sampling 70 cichlid species representing a diverse range of life-histories and trophic groups. Alpha diversity was up to 50% lower outside of protected areas, and herbivores appeared most affected. Turnover dominated within-locality variation in beta diversity, but the nestedness component was positively related to human disturbance indicating an increase in generalist species outside of protected areas. Within protected areas the decline in zeta diversity (the expected number of shared species across multiple surveys) was best described by power law functions, which occur when local abundance is predicted by regional abundance; but declined exponentially in unprotected waters indicating a dominance of stochastic assembly. Despite not being designed for the purpose, the protected areas are clearly benefitting cichlid taxonomic and functional diversity within Lake Tanganyika, probably through local reduction in sediment deposition and/or pollution, but as cichlids can be poor dispersers protected area coverage should be expanded to benefit isolated communities. [ABSTRACT FROM AUTHOR]

2014 was a hopeful year for the Democratic Republic of Congo (DRC). The M23 movement had been defeated in military operations in which one of the last peacekeeping experiments, the UN Force Intervention Brigade, had played a decisive role. A third UN stabilization plan, the ‘islands of stability’ was proposed to continue the stabilization of a country considered in a post-conflict phase. However, the number of internally displaced persons (IDPs) has almost tripled in the country since 2007. This article will argue that DRC is still immersed into an old social conflict that existed before the Congo Wars and the roots of which are not being addressed. It will argue that the United Nations Organization Stabilization Mission in the Democratic Republic of the Congo (MONUSCO) and the ‘islands of stability’ strategy can address some of the secondary causes of the Congo conflict, such as its internationalization, the presence in DRC of foreign armed groups or the ‘blood minerals’, but cannot address its primary causes: land struggles, an old cycle of violence and the fragmentation of the Congolese society and political elite that is jeopardizing the restoration of the state authority. The huge dimensions of each of these factors make the Congo conflict ‘one of the most complex and intricate environments ever faced by a peacekeeping mission’, for which MONUSCO’s mandate, resources and stabilization strategy do not seem powerful enough. When the UN organized the 2006 elections legitimized a ‘spoiler state’, the bottleneck of all the reforms needed to stabilize the country. The UN fell thus into a trap and became part of the conflict. Lessons learned should be taken for future UN operations.

Research on cichlid fish has revealed remarkable cross-species variation in social and reproductive behavior. Recently, several species of African cichlids have been shown to produce acoustic signals, typically in conjunction with the visual behavioral displays associated with mate choice and competition. However, the recent research conducted on cichlid sound production has focused largely on polygynous cichlids with female care and on species from Lake Malawi and Lake Victoria. In this study, we examined whether sound production occurs in a group-living, cooperative, biparental cichlid species, Neolamprologus pulcher, endemic to Lake Tanganyika, the oldest of the African Great Lakes. Neolamprologus pulcher is a highly social cichlid that lives in complex groups that are socially stratified. We investigated whether N. pulcher performed acoustic signals to each other either during competitive resource contests between size-matched males, or during courtship between male and female breeding pairs. Although the fish displayed prototypical visual displays of aggression, submission, and courtship in the appropriate context, we found no evidence of vocal sound production. Our findings suggest that cichlid sound production was not essential for the evolution of complex social behavior. [ABSTRACT FROM AUTHOR]

Abstract: To assess the long-term water quality changes in Lake Malawi, paleolimnological reconstructions of four radiometrically dated sediment cores collected in 1997/98 along a longitudinal transect of the lake were based on preserved diatom assemblages, as well as stratigraphies of organic carbon, total nitrogen, total phosphorus and biogenic silica concentrations. Population growth, deforestation and intensive agriculture, especially in the southern catchments, have accelerated soil erosion causing rivers to transport greater sediment and nutrient loads into Lake Malawi. Southern cores contain evidence of nutrient enrichment starting around 1940, as indicated by increased silica, carbon and nitrogen influxes. By 1980, increased rates of sedimentation, phosphorus influx, diatom influx, and relative abundances of eutrophic diatom taxa are attributable to accelerated nutrient enrichment accompanying soil erosion. The succession of diatoms in southern Lake Malawi begins with dominance by Aulacoseira nyassensis and Fragilaria africana, followed by a shift in 1980 towards Stephanodiscus, Cyclostephanos and Nitzschia, diatom taxa that have reduced silica requirements. Paleoecological results indicate that patterns of diatom assemblage change are not uniform lake-wide. Evidence of eutrophication extends to central Lake Malawi, but is not observable in the paleo-record from the deeper northern basin. The recent cultural eutrophication of the southern lake has impacted the biogeochemical cycling of silica, the available silica to phosphorus ratios, and the diatom communities of a large portion of Lake Malawi. These results provide a warning that eutrophication of this great lake is underway and will continue unless changes are made to current land use practices within the lake''s catchment. [Copyright &y& Elsevier]

The lower jaw (LJ) provides an ideal trophic phenotype to compare rates and patterns of macroevolution among cichlid radiations. Using a novel phylogeny of four genes ( ND2, dlx2, mitfb, and s7), we examined the evolutionary relationships among two of the most phylogenetically disparate cichlid radiations: (i) the Central America Heroines; and (ii) the East African Lake Malawi flock. To quantify jaw morphology, we measured two LJ lever systems in approximately 40 species from each lineage. Using geologic calibrations, we generated a chronogram for both groups and examined the rates of jaw evolution in the two radiations. The most rapidly evolving components of the LJ differed between the two radiations. However, the Lake Malawi flock exhibited a much faster rate of evolution in several components of the LJ. This rapid rate of divergence is consistent with natural selection, promoting unparalleled trophic diversification in Lake Malawi cichlids. [ABSTRACT FROM AUTHOR]

Abstract: We identified an objective set of 25 commonly available ecosystem metrics applicable across the world''s large continental freshwater and brackish aquatic ecosystem. These metrics measure trophic structure, exploited species, habitat alteration, and catchment changes. We used long-term trends in these metrics as indicators of perturbations that represent an ecosystem not in homeostasis. We defined a healthy ecosystem as being in a homeostatic state; therefore, ecosystems with many changing trends were defined as more disturbed than ecosystems with fewer changing trends. Healthy ecosystems (lakes Baikal, Superior, and Tanganyika) were large, deep lakes in relatively unpopulated areas with no signs of eutrophication and no changes to their trophic structure. Disturbed ecosystems (lakes Michigan, Ontario, and Victoria) had shallow to moderately deep basins with high watershed population pressure and intense agricultural and residential land use. Transitioning systems had widely varying trends and faced increasing anthropogenic pressures. Standardized methodologies for capturing data could improve our understanding of the current state of these ecosystems and allow for comparisons of the response of large aquatic ecosystems to local and global stressors thereby providing more reliable insights into future changes in ecosystem health. [Copyright &y& Elsevier]

The European integration process has altered the conditions under which national foreign policies in Europe are made. Departing from this assumption, this article explores whether and under what conditions a small EU member state can influence European foreign policy. To this end, the role that Belgium has played in the construction of European foreign policy towards the African Great Lakes is examined. This article argues that a small EU member state can significantly influence European foreign policy, resulting in reinforcement of its national foreign policy. Yet this influence is conditioned by two intertwined factors: the nature of EU involvement; and the characteristics of the Union's foreign policy system. Depending on these elements, a small member state can supersede the quantifiable notion of 'smallness' and actively shape the construction of European foreign policy. [ABSTRACT FROM AUTHOR]

This paper is based on five years of research around the shores of Lake Victoria carried out by the lake's Fisheries Research Institutes in collaboration with the Lake Victoria Fisheries Research Project. Based on this experience, the authors identify a series of difficulties, which impedes the effective management of the lake's fisheries. These relate to profound weaknesses in the current state-administered management of the lake along with difficulties transferring regulatory power to fishing communities, and problems establishing an adequate 'co-managerial' framework for the development and implementation of managerial action. The authors propose a management structure based on three levels of administration which have at their core 'beach committees,' and which serve as forums for negotiated managerial outcomes. [ABSTRACT FROM AUTHOR]

There is a global dimension to lake management in Africa and elsewhere that will require a concerted action not only from individual riparian states, but also from regional, continental and global communities. The current global lake threats arise from climate change, regional land degradation and semivolatile contaminants, and share the common feature that the atmosphere is the vector that spreads their impacts over large areas and to many lakes. The Great Lakes of Africa (Malawi, Victoria and Tanganyika) are particularly sensitive to these problems because of their enormous surface areas, slow water flushing rates, and the importance of direct rainfall in their water budgets. Their response times might be slow to yield a detectable change and, unfortunately, their recovery times might also be slow. It is possible for atmospheric effects to act antagonistically to the impacts of catchment change, but antagonistic effects could become synergistic in the future. Improved understanding of the physical dynamics of these lakes, and development of models linking their physical and biogeochemical behaviour to regional, mesoscale climate models, will be necessary to guide lake managers. [ABSTRACT FROM AUTHOR]

Food web structure of the pelagic community in Lake Tanganyika was studied using the stable nitrogen and carbon isotopes 15 N and 13 C. Size-fractionated seston, zooplankton, shrimps, medusae and fish were sampled in the northern part of Lake Tanganyika. Picoplankton fractions as well as cyanobacteria-dominated nano/microplankton fractions had very low nitrogen isotope signatures typical for nitrogen-fixing organisms. Fractions containing mainly dead organic matter (and associated bacteria) or nano/microalgae (chlorophytes and diatoms) had δ 15 N 2 to 4‰ higher. The low δ 15 N signatures of small cyclopoids and shrimps suggest they are feeding on nitrogen-fixing cyanobacteria (picoplankton or larger forms), while the higher δ 15 N signature of larger copepods suggest mixed feeding on large algae and small zooplankton and/or cyanobacteria. Medusae were slightly enriched in δ 15 N relative to large copepods. Among fish, the signatures of Stolothrissa and small Lates stappersi suggested feeding on large copepods, while Limnothrissa and larger Lates were slightly more enriched, indicating partial piscivory. The enrichment of 13 C between the putative trophic levels (2 to 3‰) was higher, while that of 15 N (2 to 3‰) was lower, than usual in isotope studies. Our results indicate that picocyanobacteria and possibly also larger cyanobacteria are important producers in the pelagic food web of Tanganyika. [ABSTRACT FROM AUTHOR]

Caridina nilotica, a freshwater atyid prawn, is a vital component of the Lake Victoria ecosystem. Despite its important role in the food web leading to Nile perch, the diet of Caridina is not well understood. Caridina freshly collected from the inshore littoral and offshore plankton of Lake Victoria were cultured individually under laboratory conditions on (A) decomposing hydrophytes, (B) living hydrophytes, (C) planktonic algae, (D) zooplankton and (E) 35-µm filtered lake water (a 'starvation' control). Inter-moult intervals (IMI, days), size-standardized moult intervals (MI, days mm-1), per moult growth increments (PMI, mm) and survivorship (%) were monitored daily for up to 5 weeks. Significant effects of both food type and shrimp source on MI were revealed by ANOVA. MI increased progressively from treatment A to D, and was shorter in offshore than littoral shrimps. Food influence on IMI was confirmed by ANCOVA. PMI values were close to the limits of detection, but were generally in line with MI responses. PMI values were marginal in treatments A and B, and negligible or negative in treatments D and especially E. Survivorship values, although confounded by non-dietary factors, were generally consistent with dietary influences on MI, although values obtained for treatment E were inconsistently high for true starvation. Disparate responses between inshore and offshore shrimps hint at possible ecotypic differentiation, or perhaps the existence of cryptic species. Stable isotope analyses (SIA, δ13C and δ15N signatures) of cultured shrimps were further consistent with their utilization of food type A but not D. SIA signatures of feral shrimps maintained in situ in enclosure bags with three separate potential fresh hydrophyte food sources (Vossia cuspidata, Cyperus papyrus, and Eichhornia crassipes) reflected Caridina's probable dietary reliance on decomposed organic matter with accompanying bacterial exudates. Collections of feral shrimps from various locations yielded parallel SIA results. No support for zooplanktivory by shrimps occupying either inshore littoral/benthic or offshore planktonic habitats is provided by the δ15N signatures obtained from our data, which support Caridina's primary role as a detritivore. [ABSTRACT FROM AUTHOR]

Approaches to the provision of advice on fishery management are changing from reliance on single species stock assessments to multi-species, multi-gear, and ecosystem approaches. Many of these new approaches may, however, be too expensive to apply to small-scale fisheries in developing countries. The fish stocks of Lake Malawi/Nyassa are currently managed by restrictions on fishing gears, fishing areas, and fishing times. Catch statistics and an annual frame survey of fishing effort provide input data for stock assessment studies that are used to derive these recommendations. This management approach is ineffective with several important fish stocks in decline, reports of local species extinctions, and changes in community structure as a result of the disappearance of larger, more valuable species. Failure to enforce management regulations results partly from an imbalance of economic and human resource allocation between the collection of monitoring data, timely analysis of that data, production of workable recommendations, and enforcement of these recommendations. We recommend redressing the imbalance through a reduction in the scale of catch surveys so that resources can be redirected towards data processing, timely provision of advice, management actions, and enforcement. A number of further modifications are recommended to improve and better match the levels of precision of catch and effort data. The implications of current moves away from "state-led" management to "community-based" management are discussed briefly. [ABSTRACT FROM AUTHOR]

In the surface sediments below the oxic-anoxic interface in meromictic Lake Malawi, there is little or no evidence of biological activity. As the water depth increases, even in sediments within the oxic zone microbial activity, as measured by [sup 14]C leucine incorporation, decreases; the benthic invertebrates decrease in biomass and diversity; and the amount of detrital material remaining in the sediments increases from <1% at 10 m to >14% at 125 m. This relationship with depth could be owing to several factors. At shallower depths, there is terrestrial material available for bacteria to use, as well as detrital material derived from autochthonous production. This detrital material can be degraded in the sediments by the benthic invertebrates, which release dissolved organic carbon and smaller particles through excretion that bacteria can use. As the water depth increases, the bacteria in the water column are able to degrade much of the planktonic debris, leaving the more refractory carbon particles to settle to the sediment. It appears that when there are enough benthic invertebrates, there is still substantial bacterial activity. As the depth increases, the benthic invertebrates disappear and, although there is still detrital carbon available, the bacteria appear unable to utilize it. We suggest that the benthic invertebrates are essential to the processing of detrital carbon and a shift in the degree of anoxia within the lake could seriously alter the cycling of carbon. [ABSTRACT FROM AUTHOR]

Lake Malawi is home to more than 450 species of endemic cichlids, which provide a spectacular example of adaptive radiation. To clarify the phylogenetic relationships among these fish, we examined the presence and absence of SINEs (short interspersed repetitive elements) at orthologous loci. We identified six loci at which a SINE sequence had apparently been specifically inserted by retroposition in the common ancestor of all the investigated species of endemic cichlids in Lake Malawi. At another locus, unique sharing of a SINE sequence was evident among all the investigated species of endemic non-Mbuna cichlids with the exception of Rhamphochromis sp. The relationships were in good agreement with those deduced in previous studies with various different markers, demonstrating that the SINE method is useful for the elucidation of phylogenetic relationships among cichlids in Lake Malawi. We also characterized a locus that exhibited transspecies polymorphism with respect to the presence or absence of the SINE sequence among non-Mbuna species. This result suggests that incomplete lineage sorting and/or interspecific hybridization might have occurred or be occurring among the species in this group, which might potentially cause misinterpretation of phylogenetic data, in particular when a single-locus marker, such as a sequence in the mitochondrial DNA, is used for analysis. [ABSTRACT FROM AUTHOR]

African cichlid fishes have undergone outbursts of explosive speciation in several lakes, accompanied by rapid radiations in coloration and ecology. Little is known about the evolutionary forces that triggered these events but a hypothesis, published by Wallace Dominey in 1984, has figured prominently. It states that the evolution of colour patterns is driven by sexual selection and that these colour patterns are important in interspecific mate choice, a combination which holds the potential for rapid speciation. Here we present phylogenetic analyses that describe major events in colour evolution and test predictions yielded by Dominey’s hypothesis. We assembled information on stripe patterns and the presence or absence of nuptial coloration from more than 700 cichlid species representing more than 90 taxa for which molecular phylogenetic hypotheses were available. We show that sexual selection is most likely the selection force that made male nuptial coloration arise and evolve quickly. In contrast, stripe patterns, though phylogenetically not conserved either, are constrained ecologically. The evolution of vertical bar patterns is associated with structurally complex habitats, such as rocky substrates or vegetation. The evolution of a horizontal stripe is associated with a piscivorous feeding mode. Horizontal stripes are also associated with shoaling behaviour. Strength of sexual selection, measured in terms of the mating system (weak in monogamous, strong in promiscuous species), has no detectable effects on stripe pattern evolution. In promiscuous species the frequency of difference between sister species in nuptial hue is higher than in pair bonding and harem forming species, but the frequency of difference in stripe pattern is lower. We argue that differences between the two components of coloration in their exposure to natural selection explain their very different evolutionary behaviour. Finally, we suggest that habitat-mediated selection upon chromomotor flexibility, a special form of phenotypic plasticity found in the river-dwelling outgroups of the lake-dwelling cichlids, explains the rapid and recurrent ecology-associated radiation of stripe patterns in lake environments, a new hypothesis that yields experimentally testable predictions. [ABSTRACT FROM AUTHOR]