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This study aimed to assess the impact of the cage fish farming on the water quality in two selected bays of the Bukavu basin, Lake Kivu; from February to December 2021. Physicochemical parameters including pH, Temperature, EC, TDS, Salinity, DO, Transparency were sampled in situ using a COMBO HI 98129 multi-parameter probe, PCE-PHD1 probe and a Black & White Secchi disk; water at different depths was collected with the aid of a Van-Dorn Sampler; nutrients namely PO43−, NH4+, NO2−, SiO2, and Chl_a were analysed using the UV-VIS spectrophotometer. The results revealed that water pH, temperature, TDS, salinity and transparency significantly (p ≤ 0.05) varied between the selected sites. Water at the cage sites contained significantly (p ≤ 0.05) much higher concentrations of PO3 − 4, NH4+, NO2−, SiO2 and Chl_a than in control site. In overall, these results suggest that cage fish farming changed water quality in the selected bays. Therefore, the study recommends that measures should be taken to regulate cage fish farming and related activities and deforestation around Bukavu basin to avoid advert conditions.

Objectif: Cette etude vise l’inventaire des macroinvertebres du Lac Vert pour faciliter sa conservation et le suivi regulier des changements que subit ce lac, sa biodiversite et ses services ecosystemiques surtout parce que les macroinvertebres sont des veritables bioindicateurs des changements. Methodologie et Resultats: Les macroinvertebres aquatiques ont ete recolte par la methode homme surface (Touzin, 2008; Melhaoui et Berrahou, 2009). a l’aide d’un filet troubleau dans 4 sites choisis en fonction des activites anthropiques, du type de substrat et de la vegetation riveraine. Dix (10) Ordres repartis en 22 Familles et 26 Genres avec 1635 individus ont ete inventories. Les analyses statistiques ont montre que les indices de Shannon et d’Equitabilite n’ont pas de difference significative (Kruskal-Wallis, ddl = 3, Chi² = 4,15 et p-value = 0,25) entre les sites mais les sites Rutanda-Busara different des autres en terme de Richesse Specifique (p-value = 0,005). Conclusion et application des resultats: Le Lac Vert regorge une diversite des macroinvertebres aquatiques importante par rapport aux lacs Kivu, Edouard, Tanganyika et Albert. Une abondance des Coleopteres et Mollusques a ete trouvee rapprochee par une flore importante, cas des macrophytes et du phytoplancton. Les activites anthropiques sont les principaux facteurs influencant la diversite des macroinvertebres dans cet ecosysteme. Cette etude ouvre une question scientifique sur differents aspects de la recherche sur la taxonomie, l’ecologie et structure fonctionnelle des invertebres aquatiques de cet ecosysteme pour une etude approfondie dans ce domaine. Ceci ferait de ce lac un bon jardin zoologique et botanique au bienetre de l’humanite. Mots cles: Macroinvertebres Aquatiques, Shannon, Equitabilite, Richesse Specifique, Lac Vert English Abstract Objective: This study aims to inventory the macroinvertebrates of Lac Vert to facilitate its conservation and regular monitoring of the changes that this lake, its biodiversity and its ecosystem services undergoe mainly because macroinvertebrates are absolute bioindicators of changes. Methodology and Results: Aquatic macroinvertebrates were collected by the human surface method using a trickle net in 4 sites chosen according to human disturbance, type of substrate and surrounding vegetation. Ten (10) Orders divided into 22 Families and 26 Genera with 1635 individuals were inventoried. Statistical analyses showed that the Shannon and Equitability indices have no significant difference (Kruskal-Wallis, ddl = 3, Chi² = 4.15 and p-value = 0.25) between the sites but the sites Rutanda-Busara different from others in terms of specific wealth (p-value = 0.005). Conclusion and application of results: The Lac Vert lake has a large diversity of aquatic macroinvertebrates compared to lakes Kivu, Edouard, Tanganyika and Albert. An abundance of Coleoptera and Molluscs was found to be close to a flora composed of macrophytes and phytoplankton. Human disturbance activities are the main factors which act on the diversity of macroinvertebrates in this ecosystem. This study opens a scientific question on different aspects of the research on the taxonomy, ecology and functional structure of aquatic invertebrates of this ecosystem for an in-depth study in this field. This would make this lake a good zoological and botanical garden for the welfare of humanity. Keywords: Aquatic Macroinvertebrates, Shannon, Equitability, Specific Wealth, Lake Vert