Impact of Aquatic Pollution on Embryonic and Larval Development in Fish: A Comprehensive Review

Abstract

For environmental degradation fish is considered as an early warning system, they are also the biomarkers to measure the specific existence of toxic and carcinogenic components in the environment. Aquatic pollution stemming from industrial, agricultural, and urban activities exerts a profound impact on ecosystems, notably affecting fish reproduction, development, and overall well-being, leading to significant ecological and economic repercussions. The contamination of toxic metals such as copper, zinc, and cadmium severely impact fish embryos, causing delayed hatching, disruptions in development, and heightened mortality rates. These metals disrupt physiological processes, jeopardizing embryonic survival and resulting in organogenesis defects, metabolic imbalances, and altered enzyme activity. Similarly, pesticides, particularly herbicides like Thiobencarb, persist in the environment, perturbing hormonal functions and inducing developmental, behavioural and reproductive alterations in fish, with younger stages being more susceptible than older ones. Microplastics have arisen as a persistent environmental menace, disturbing aquatic ecosystems by affecting fish larvae and embryos. Ingestion of microplastics leads to growth retardation, diminished survival rates, and developmental abnormalities primarily due to metabolic disruptions, oxidative stress, and alterations in gut microbiomes. These consequences underscore plastic pollution's significant ecological and health hazards, disrupting nutrient absorption and impairing long-term survival. Oil spills, which expose organisms to polycyclic aromatic hydrocarbons (PAHs), trigger developmental anomalies, particularly in species like Atlantic cod, resulting in malformations, anaemia, and organ edema. These pollutants notably impact fish embryonic development, causing deformities, delays in development, and increased mortality rates, consequently exacerbating ecosystem well-being. Furthermore, exposure to toxicants disrupts fish behaviour, affecting feeding habits, visual reflexes, and predator avoidance mechanisms through neurotoxic effects and sensory system disturbances. Conclusion: Aquatic pollution poses significant risks to fish health, reproduction, and survival, with widespread implications for aquatic ecosystems.