International Journal of Aquaculture, 2026, Vol.16, No.2, 74-89 http://www.aquapublisher.com/index.php/ija 79 subjected to inferential statistical analysis. As such, they are interpreted as indicative of compositional differences rather than statistically confirmed variation. Figure 1 Recovery patterns of fish following exposure to citrus leaf extracts. Table 1 Qualitative phytochemical composition of aqueous citrus leaf extracts Phytochemical Group C. sinensis C. aurantium C. limon Flavonoids Present Present Absent Limonoids Present Present Present Terpenoids Present Absent Absent Phenolic acids Present Absent Present Carotenoids Present Present Absent Coumarins Present Present Present Essential oils Absent Present Present Alkaloids Absent Present Absent Presence and absence are based on qualitative phytochemical screening; no inferential statistical analysis was applied. The variation in phytochemical composition suggests species-specific bioactivity profiles, which may explain differences in anaesthetic potency and physiological responses observed in subsequent experiments. 3.2 Behavioural anaesthetic responses 3.2.1 Behavioural responses of Clarias gariepinus under different extract concentrations Behavioural responses of Clarias gariepinus across increasing extract concentrations are presented (Table 2). A progressive change in behavioural response was observed as concentration increased. At lower concentrations, fish exhibited minimal or mild behavioural changes. As concentration increased, fish showed loss of equilibrium, reduced responsiveness, and eventual immobility. At the highest concentration, extracts of Citrus aurantiumand Citrus limon were associated with cessation of opercular movement, suggesting pronounced respiratory depression. In contrast, Citrus sinensis produced less severe effects under comparable conditions. These observations are descriptive and were not subjected to statistical testing. Consequently, interpretations are limited to observed patterns. Table 2 Behavioural responses of Clarias gariepinus Concentration (mg L⁻¹) C. sinensis C. aurantium C. limon 1000 No observable effect Initial agitation Agitation followed by calming 2000 Slight loss of equilibrium Partial loss of balance Sedation 3000 Loss of equilibrium with gasping Anaesthesia Deep anaesthesia 4000 Prolonged immobility Cessation of opercular movement Cessation of opercular movement
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