Mathias Nzitiri BWALA 1*, Nafisat ABDULKADIR 2, Ahmed Abbator3, Mohammed Zanna GREMA4, Hassan DAUDA5 & Umate USMAN6
1* National Environmental Standards and Regulations Enforcement Agency (NESREA), Borno State Field Office, Maiduguri, Nigeria
2Department of Ecology, Abubakar Tafawa Balewa University (ATBU), Bauchi, Nigeria
3Department of Botany, Faculty of Life Sciences, University of Maiduguri, Borno State, Nigeria
4Department of Science Laboratory Technology, Federal Polytechnic Monguno, Borno State, Nigeria
5Department of Biology Education, Federal College of Education (Technical), Potaskum, Nigeria
6Department of Fisheries, Faculty of Agriculture, University of Maiduguri, Borno State, Nigeria
*Corresponding author’s Email: mathias.bwala@nesrea.gov.ng, doi.org/10.55639/607.020100127
ABSTRACT
Water quality plays a critical role in aquatic ecosystems, as water pollution can alter physicochemical conditions and negatively affect fish health, growth, reproduction, and survival. This study assessed the influence of physicochemical parameters on biological indices of Oreochromis niloticus and Clarias gariepinus from Biu and Alau Dams, Northeastern Nigeria. Both water and fish samples were collected bi-weekly from the study sites for 3 months. In each dam, a composite of sample from 4 different sampling sites were collected. A total of 48 (6 sampling visits x 4 landing sites per reservoir x 2 fish species per each visit) fish sample for each sampled species were collected. Temperature, EC and TDS were measured in-situ using a handheld device while NO3- and SO4- were analyzed at Public Health Engineering Laboratory, Abubakar Tafawa Balewa University, Bauchi. The result of the study indicates that Alau Dam recorded higher temperature (30.2±1.4 °C), EC (336±23.7 µS/cm), NO3- (27.5±4.8 mg/L), SO4- (12.1±4.3 mg/L), BOD (2.4±0.8 mg/L), and TDS (186.25±12.5 ppm) compared to Biu Dam (24.2±4.7 °C; 72.42±31.1 µS/cm; 13.1±3.6 mg/L; 8.7±4.2 mg/L; 1.1±0.5 mg/L; 111.87±1.2 ppm respectively). Female GSI of O. niloticus was higher in Alau (13.1±8.8%) than Biu (9.4±2.8%), while male GSI of C. gariepinus increased from 3.11±2.8% (Biu) to 4.29±2.1% (Alau). PCA showed 85.5% variance explained by PC1, separating dams spatially. CCA revealed strong associations between EC, NO3-, SO4-, TDS, and reproductive indices. Furthermore, the results also suggest that nutrient-driven environmental gradients were associated with reproductive and physiological indices.
KEYWORDS
Freshwater ecosystem, Water Quality, Aquatic Pollution, Fish Health.