Conservation of the resources of the African great lakes: why?

The purpose of our Symposium is to analyse the nature of the resources of the Great African lakes, their utilisation and the need to conserve them, and to determine ways to convince policy makers and economists dealing with their management

Identification of characteristic zooplankton species in the Kinyankonge River basin, Burundi

The objective of this study is to determine the zooplankton species that characterize the Kinyankonge River basin in Burundi. Thus, zooplankton was sampled monthly over a period of 18 months (from July 2015 to June 2016, then from January 2017 to June 2017) at seven stations. The Indicator Value (IndVal) of the identified zooplankton species and the coverage of stations were determined. The results showed that three species characterized significantly the most upstream station whereas the water of the irrigation channel was characterized by 4 species. The waters of the Nyabagere tributary and the wastewater treatment plant are characterized by 1 and 5 species, respectively. Furthermore, the dry season was characterized by 4 singletons and 13 pairs of species, while the rainy season was characterized by 11 pairs of species. Moreover, the group of upstream stations was characterized by 5 species while 3 species characterized the group of downstream stations. These species highlighted by the indicator value method can be used to characterize stations in the Kinyankonge River and provide information on seasonal changes

Les poissons du bassin de la rivière Ulindi, à l’Est de la République Démocratique du Congo : revue de la littérature

Cette revue de la littérature sur les poissons du bassin hydrographique de la rivière Ulindi à l’Est de la République Démocratique du Congo a été réalisée dans le but d’avoir une idée sur l’état des connaissances actuelles de son ichtyofaune en vue de définir les orientations pour leurs études ultérieures dans cette région non encore prospectée en profondeur et dont la plupart des rivières se trouvent actuellement menacées par des activités anthropiques. Cette étude présente une vue globale des rivières du Bassin de la rivière Ulindi avec une liste systématique non exhaustive d’environ 31 espèces de poissons appartenant à 17 genres, 9 Familles et 4 ordres, basée sur la méta-analyse des différentes études taxonomiques de l’ichtyofaune du Bassin de la Rivière Ulindi, réalisées depuis l’époque coloniale du Congo-Belge jusqu’en 2019. Les résultats de cette étude constituent une aide-mémoire pour les services publics en charge de la gestion de l’environnement dans la gestion de la biodiversité ichtyologique de cet écosystème à intérêt socio-économique considérable dans la région, d’une part et une liste de contrôle aux scientifiques pour des études ultérieures.Mots clés : Ichtyofaune, Ulindi, République Démocratique du Congo, revue de la littérature, liste de contrôle.   English Title: Fishes from the Ulindi river basin, East of the Democratic Republic of Congo: review of the literatureThis review of the literature on fish in the Ulindi river basin in the east of the Democratic Republic of Congo was carried out with the aim of gaining an idea of the state of current knowledge of its fish fauna in order to define guidelines for their further studies in this region not yet explored in depth and most of the rivers of which are currently threatened by anthropogenic activities. This study presents a global view of the rivers of the Ulindi river basin with a non-exhaustive systematic list of approximately 31 fish species belonging to 17 genera, 9 Families and 4 orders, based on the meta-analysis of the various taxonomic studies of the ichtyofauna of the Ulindi river basin, carried out since the colonial times of the Belgian Congo until 2019. The results of this study constitute a baseline for the public services in charge of environmental management in the management of the ichthyological biodiversity of this ecosystem with considerable socio-economic interest in the region, on the one hand and a checklist to scientists for further studies.Keywords: Ichtyofauna, Ulindi, Democratic Republic of Congo, literature review, checklist. &nbsp

Reproduction de Bagrus bajad (Fabricius, 1775, Bagridae) du Lac Albert, Bassin du Nil, République Démocratique du Congo (RDC)

Le Bagrus bajad figure parmi les espèces des poissons très pêchées dans les cours d’eau tropicaux d’Afrique dont les informations sur la reproduction sont rares. Quelques paramètres de reproduction de Bagrus bajad du Sud-ouest du Lac Albert ont été étudiés durant cette recherche. Les échantillons ont été collectés entre décembre 2019 et décembre 2020 au moyen des éperviers, des palangres et des filets maillants de maille standard (20,2, 25,4 et 30,5 mm). Au total, 520 spécimens dont 283 femelles et 237 males ont été étudiés. Les informations sur le sex-ratio, le stade de maturité sexuelle, le rapport gonadosomatique, le rapport hepathosomatique, la fécondité et le facteur de condition ont été analysés. L’étude a révélé l’égalité entre les mâles et les femelle parmi les individus, même si les femelles étaient supérieurs aux mâles (1: 0,84; p-value<0.05). Tous les poissons étudiés ont présenté tous les stades de maturité sexuelle (I, II, III, IV, et V). Les matures (III, IV et V) ont une plus grande proportion (III, IV et V) par rapport aux immatures (I et II). Les mâles ont une taille de première maturité sexuelle de 43.5 cm contre 44 cm pour les femelles. Les valeurs mensuelles des indices gonadosomatiques et celles des stades gonadiques macroscopiques prouvent que B. bajad a trois périodes de fraie au cours de l’année : (i) Janvier-Avril ; (ii) Juin-Août et (iii) Octobre-Novembre alternées par une période d’un mois de repos en mai, septembre et décembre. La fécondité absolue est de 525 à 34440 ovocytes mais n’est pas significativement corrélées avec la longueur totale (R2=0,002) et le poids (R2=0,12). Les connaissances de la présente étude constituent une base fondamentale pour assurer la surveillance des risques d’épuisement du stock potentiel cette espèce et orienteront les décideurs à développer des politiques et stratégies efficaces garantissant l’exploitation et la conservation rationnelle de cette espèce.   Bagrus bayad is one of the highly fished fish species in tropical African rivers for which information on reproduction is scarce. Some reproduction parameters of B. bayad from the southwest of Lake Albert were studied. The samples were collected between December 2019 and December 2020 using cast nets, longlines, and standard mesh gillnets (20.2, 25.4, and 30.5 mm). A total of 520 specimens including 283 females and 237 males were examined. Information on sex ratio, stage of sexual maturity, gonadosomatic ratio, hepatosomatic ratio, fecundity, and condition factor was analyzed. The study revealed equality between males and females among individuals, although females were superior to males (1:0.84; p-value<0.05). All fish investigated showed all stages of sexual maturity (I, II, III, IV, and V). The mature (III, IV and V) have a greater proportion (III, IV and V) compared to the immature (I and II). Males have a size at first sexual maturity of 43.5 cm against 44 cm for females. The monthly values of gonadosomatic indices and those of macroscopic gonad stages show that B. bajad has three spawning periods a year: (i) January-April; (ii) June-August and (iii) October-November, alternated by a one-month rest period in May, September, and December. Absolute fecundity varies between 525 and 34440 oocytes but is not significantly correlated with total length (R2=0.002) and weight (R2=0.12). Knowledge from this study constitutes a fundamental basis for ensuring the monitoring of the risks of depletion of the potential stock of this species and will guide decision-makers in developing effective policies and strategies guaranteeing rational exploitation and conservation of this species

Monogenean parasites of sardines in Lake Tanganyika : diversity, origin and intraspecific variability

publishedVersio

Weak population structure and recent demographic expansion of the monogenean parasite Kapentagyrus spp. infecting clupeid fishes of Lake Tanganyika, East Africa

Author's accepted version (postprint).This is an Accepted Manuscript of an article published by Elsevier in International Journal for Parasitology on 08/04/2020.Available online: https://www.sciencedirect.com/science/article/pii/S0020751920300606?via%3DihubLake Tanganyika, East Africa, is the oldest and deepest African Great Lake and harbours one of the most diverse fish assemblages on earth. Two clupeid fishes, Limnothrissa miodon and Stolothrissa tanganicae, constitute a major part of the total fish catch, making them indispensable for local food security. Parasites have been proposed as indicators of stock structure in highly mobile pelagic hosts. We examined the monogeneans Kapentagyrus limnotrissae and Kapentagyrus tanganicanus (Dactylogyridae) infecting these clupeids to explore the parasites’ lake-wide population structure and patterns of demographic history. Samples were collected at seven sites distributed across three sub-basins of the lake. Intraspecific morphological variation of the monogeneans (n = 380) was analysed using morphometrics and geomorphometrics of sclerotised structures. Genetic population structure of both parasite species (n = 246) was assessed based on a 415 bp fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Overall, we observed a lack of clear geographical morphological differentiation in both parasites along a north–south axis. This lack of geographical population structure was also reflected by a large proportion of shared haplotypes, and a pattern of seemingly unrestricted gene flow between populations. Significant morphological and genetic differentiation between some populations might reflect temporal differentiation rather than geographical isolation. Overall, the shallow population structure of both species of Kapentagyrus reflects the near-panmictic population structure of both host species as previously reported. Morphological differences related to host species identity of K. tanganicanus were consistent with incipient speciation at the genetic level. Both parasite species experienced a recent demographic expansion, which might be linked to paleohydrological events. Finally, interspecific hybridisation was found in Kapentagyrus, representing the first case in dactylogyrid monogeneans.acceptedVersio

ICDP workshop on the Lake Tanganyika Scientific Drilling Project: a late Miocene–present record of climate, rifting, and ecosystem evolution from the world's oldest tropical lake

The Neogene and Quaternary are characterized by enormous changes in global climate and environments, including global cooling and the establishment of northern high-latitude glaciers. These changes reshaped global ecosystems, including the emergence of tropical dry forests and savannahs that are found in Africa today, which in turn may have influenced the evolution of humans and their ancestors. However, despite decades of research we lack long, continuous, well-resolved records of tropical climate, ecosystem changes, and surface processes necessary to understand their interactions and influences on evolutionary processes. Lake Tanganyika, Africa, contains the most continuous, long continental climate record from the mid-Miocene (∼10 Ma) to the present anywhere in the tropics and has long been recognized as a top-priority site for scientific drilling. The lake is surrounded by the Miombo woodlands, part of the largest dry tropical biome on Earth. Lake Tanganyika also harbors incredibly diverse endemic biota and an entirely unexplored deep microbial biosphere, and it provides textbook examples of rift segmentation, fault behavior, and associated surface processes. To evaluate the interdisciplinary scientific opportunities that an ICDP drilling program at Lake Tanganyika could offer, more than 70 scientists representing 12 countries and a variety of scientific disciplines met in Dar es Salaam, Tanzania, in June 2019. The team developed key research objectives in basin evolution, source-to-sink sedimentology, organismal evolution, geomicrobiology, paleoclimatology, paleolimnology, terrestrial paleoecology, paleoanthropology, and geochronology to be addressed through scientific drilling on Lake Tanganyika. They also identified drilling targets and strategies, logistical challenges, and education and capacity building programs to be carried out through the project. Participants concluded that a drilling program at Lake Tanganyika would produce the first continuous Miocene–present record from the tropics, transforming our understanding of global environmental change, the environmental context of human origins in Africa, and providing a detailed window into the dynamics, tempo and mode of biological diversification and adaptive radiations.© Author(s) 2020. This open access article is distributed under the Creative Commons Attribution 4.0 License

Diet composition of young and adult Northern Grey-headed Sparrow Passer griseus and adult Southern Red Bishop Euplectes orix in Burundi

peer reviewedWe studied the diet composition of Northern Grey-headed Sparrow Passer griseus and Southern Red Bishop Euplectes orix in four localities of the Rusizi Plain, northwest Burundi. We analyzed crop contents of 100 adults from each of the two species and the composition of food brought by parents to nestlings of the sparrow at ten nests. In all four sites, the sparrow’s diet consisted primarily of rice. The bishop also fed mostly on rice grains but also ate Lepidoptera caterpillars, some other insects and wild grass seeds such as Panicum sp. and Brachiaria sp. For adults of both bird species, there was no significant variation in diet throughout the year. However, the diet of young sparrows was much more diverse and changed from the day of hatching until fledging. On the day of hatching, chicks ate mainly caterpillars but by the tenth day, food items comprised one third caterpillars, one third Orthoptera and the rest of other insects including Odonata, Dictyoptera, Isoptera and adult Lepidoptera. After this and until fledging, the chicks were fed increasingly on rice seeds. Simultaneously, the proportion of caterpillars taken gradually decreased until none was fed to the nestlings at the end of the nestling period. The items brought by parents also varied with time of day, with caterpillars and grasshoppers in higher proportions in the morning, decreasing around mid-day and then increasing in the evening