~ 328 ~ International Journal of Fisheries and Aquatic Studies 2021; 9(1): 328-332 E-ISSN: 2347-5129 P-ISSN: 2394-0506 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.549 IJFAS 2021; 9(1): 328-332 © 2021 IJFAS www.fisheriesjournal.com Received: 28-11-2020 Accepted: 30-12-2020 Amadou Guissé Laboratory of Biological, Agronomic and Food Sciences and Complex Systems Modeling of the Gaston Berger University of Saint-Louis, Senegal Farokh Niass Laboratory of Biological, Agronomic and Food Sciences and Complex Systems Modeling of the Gaston Berger University of Saint-Louis, Senegal Corresponding Author: Amadou Guissé Laboratory of Biological, Agronomic and Food Sciences and Complex Systems Modeling of the Gaston Berger University of Saint-Louis, Senegal Weight-length relationship and condition factor of Sarotherodon melanotheron (Rüppell, 1852) in the special wildlife reserve of Gueumbeul (RSFG) in Senegal Amadou Guissé and Farokh Niass DOI: https://doi.org/10.22271/fish.2021.v9.i1d.2420 Abstract The Special Wildlife Reserve of Gueumbeul (RSFG) consists of a water reservoir (the basin) frequented by a diversity of fish and migratory birds. The most represented in terms of abundance is the species Sarotherodon melanotheron. The objective of this study was to determine the relations weight-length and to characterize the condition factor of S. melanotheron, in the basin of Gueumbeul. A total of 628 fish were sampled including 364 males, 178 females and 86 immature individuals from March 2019 to February 2020. The total length (TL) of S. melanotheron specimens sampled in the Gueumbeul reserve ranged from 6.1 cm to 17.6 cm with an average of 11.08 ± 1.82 cm and the weight (W) from 4.8 g to 103 g with an average of 27.25 ± 12.09 g. The results of the weight-length analyses gave values of 2.69 and 2.77 for the regression coefficient (b) for males and females respectively, and 2.72 and 2.76 for the dry and wet seasons. This reflects negative allometric growth in both sexes (male and female) and by season (dry and wet season). No statistically significant difference was noted for dry and wet season b values for S. melanotheron in the Gueumbeul basin, unlike condition factors between males and females and between dry and wet season where significant differences in K values were noted. Keywords: length-weight relationship, condition factor, Sarotherodon melanotheron, Gueumbeul basin, Saint-Louis 1. Introduction Most African aquatic ecosystems are currently affected by climate change and the development of anthropogenic activities, the main ones being the scarcity of rainfall leading to long droughts, industrial deforestation, construction of hydroelectric dams and irrigation of agricultural land, overexploitation due to fishing and various forms of pollution [1] . All of these phenomena and practices are exerting increasing pressure on exhaustible natural resources and endangering aquatic fauna, especially fish in various hydrosystems [1] . However, the protection of aquatic ecosystems with a view to rational management of its biodiversity is currently becoming a major concern for all scientific communities and non-governmental organizations. Among the aquatic organisms taken from the various African water bodies and rivers, fish constitute the major part. The weight-length relationship is an important tool in biology, physiology, ecology and fish stock assessment [2-4] . Indeed, this tool is a widely used approach in fisheries management and environmental monitoring programmes in many respects, as it provides information on the status of fish stocks in an aquatic ecosystem [5] to allow morphological comparisons of populations in different regions [6, 7] . This relationship also allows the study of ontogenetic allometric changes in fish growth [8] . Furthermore, the condition factor is also a morphometric index frequently used to assess the physiological condition of fish based on the principle that individuals of a given length with a higher mass are in better condition [9] . Growth is a fundamental characteristic of all living organisms and the growth pattern and growth rates are very species-specific [10] and vary from one aquatic ecosystem to another within the same species. Growth can be isometric when the organ grows at the same rate as the rest of the body, whereas allometric growth occurs when an organ grows at a different rate