DOI: https://doi.org/10.36347/sajb.2025.v13i12.001

Pages: 1567-1573

The assessment of the effect of mercury on the growth of Micralestes eburneensis in the Cavally River, specifically in the Zouan-hounien department, involved determining the length-weight relationship and the average mercury content in the specimen's tail. The length-weight relationship was calculated using the formula P = a × Lsb. The mercury content in the tail was determined using atomic absorption spectrometry. A total of 320 specimens were collected from four sampling stations: three (Bakatouo (SB), Daapleu (SD), and Floleu (SF)) subject to gold panning, and one (Niampleu (SN)) not subject to it. Sampling was conducted monthly from February to May 2024. The results showed negative allometric growth of M. eburneensis in the Cavally River for the studied stations (SD: b=1.96; SN: b=1.25; SF: b=2; and SB: b=2.9). The highest median value (3.8) of the condition factor was obtained at the Niampleu station, which was not subject to gold panning, and the lowest median values (0.96 to 2.76) were recorded at the stations subject to gold panning. Analysis of the mercury content of the sampled individuals showed that all samples analyzed had total mercury levels below the World Health Organization (WHO) standard of 0.5 mg kg⁻¹ wet weight. The results of the Spearman correlation analysis between the condition factor, standard length, fish weight, and mercury level showed a negative correlation between these parameters and the mercury level. Thus, the pressures of illegal gold mining lead to a biological weakening of populations and highlight the need for rigorous ecological management to preserve the health of the Cavally River and this endemic species.