Length-Weight Relationships and Condition Factors of 15 Fish Species from the Loémé River Basin (Mayombe, Republic of Congo)

Length-weight relationships and condition factors are among the commonly used parameters to link the length of a fish to its weight. The present study was initiated to find out the growth patterns and overweight status of 15 fish species in the Loémé basin in Mayombe, Republic of Congo. In the period from February 2020 to September 2021, sampling was carried out in eight stations, following a standardised capture method using four gillnets of 10, 12, 15, and 25 mm mesh size and a hawk net of 1.90 m radius with 10 mm mesh size. Length-weight relationships were calculated according to P = aLSb and the condition factor, using K = (P/LSb)* 100. A total of 1153 specimens representing 15 species, 10 genera and 6 families were recorded. The number of specimens ranged from 10 to 214 for Chrysichthys auratus and Enteromius camptacanthus, respectively. The allometry coefficient b minimum of 2.697 for Chromidotilapiamelaniae and maximum of 3.589 for Garraornata, with a mean of 3.03 ± 0.2 is significantly not different from 3 at the 0.05 probability threshold and indicates isometric growth for almost all species, except for E. camptacanthus where b = 2.858 was statistically different from 3 at the same threshold. The positive and high values of the coefficients of determination r2 = 0.787-0.989 of the species, obtained during this study, suggest that weight increases with size in the fish of the Loémé basin. The average condition factor varies from 0.524 ± 0.064 for G. ornata to 4.917 ± 0.440 for C. melaniae.