A Study on Haematological Responses of Wallago attu to Seasonal Environmental Changes in the Sai River

Aim: The present study investigates seasonal variations in the hematological profile of Wallago attu in the Sai River in Pratapgarh district, Uttar Pradesh, India, across three sites representing different levels of anthropogenic influence. Study Design: The study was based on field based quantitative analysis. Place and Duration of Study: Three sites were chosen at Sai River in district Pratapgarh, UP, India. The duration of the study was 2 years. Methodology: Fish samples were collected during winter, summer, and rainy seasons. Live fish were transported to the laboratory under optimum conditions and processed immediately for blood sampling and observations. Results: The haematological parameters of Wallago attu exhibited significant variations across the three sampling sites (Site I, Site II, and Site III) and seasons (winter, summer, and rainy), indicating the influence of water quality on fish physiology. A consistent and significant decline in haemoglobin (Hb) and erythrocyte (RBC) count was observed from Site I to Site III in all seasons. In contrast, total leucocyte count (WBC) showed a significant increase at Site III across all seasons, with the highest values observed during summer. ESR values decreased progressively from Site I to Site III in all seasons. PCV values also showed a declining trend from Site I to Site III, with significant reductions in winter and rainy seasons. Mean corpuscular volume (MCV) and mean corpuscular haemoglobin (MCH) showed an increasing trend from Site I to Site III, while MCHC exhibited variable responses but generally decreased in polluted sites (especially during the rainy season). The seasonal fluctuations may be attributed to changes in temperature, dilution effects during rainfall, and variation in pollutant load. Conclusion: Overall, the progressive deterioration in haematological parameters from Site I to Site III clearly indicates that water quality of the Sai River adversely affects the health of Wallago attu. The observed anaemia, altered red cell indices, and elevated WBC counts suggest physiological stress and immune response due to pollution, making these parameters reliable biomarkers for environmental monitoring.