CHAPTER ONE

1.1 Background of the Study

Freshwater crustaceans, such as crabs, shrimps, and crayfish, play vital roles in aquatic ecosystems. They contribute to nutrient cycling, serve as prey for fish and birds, and support the food web. These organisms are sensitive to water quality, making them good indicators of aquatic health (Brito et al., 2018).

Water pollution has become a major threat to freshwater ecosystems. Pollutants include heavy metals, pesticides, industrial effluents, and domestic waste. These substances enter rivers, lakes, and ponds, altering physical and chemical properties of water. Contaminated water affects crustaceans’ growth, reproduction, and survival. High pollutant concentrations can cause mortality, reduce feeding efficiency, and disrupt molting cycles.

Studies have shown that water pollution not only harms crustaceans but also reduces biodiversity and alters ecosystem balance. Crustaceans in polluted waters exhibit slower growth and lower reproductive success compared to those in clean water. Despite this, limited local studies exist on how pollution impacts freshwater crustacean populations. Understanding these effects is crucial for environmental management and sustainable aquaculture.

1.2 Statement of the Problem

Water pollution continues to threaten freshwater ecosystems globally. Freshwater crustaceans are highly vulnerable because they directly interact with water for feeding, respiration, and reproduction. Pollutants reduce their growth, survival, and population density. Despite their ecological importance, there is limited research on the effect of water pollution on freshwater crustaceans in many regions. This knowledge gap hinders effective environmental monitoring and conservation planning.

1.3 Aim of the Study

The aim of this study is to investigate the effect of water pollution on the growth and survival of freshwater crustaceans.

1.4 Objectives of the Study

The specific objectives are to:

1. Identify freshwater crustacean species in selected water bodies.

2. Assess water quality parameters, including pH, turbidity, and pollutant concentration.

3. Determine the growth rate and survival of crustaceans in polluted and unpolluted sites.

4. Evaluate the relationship between water quality and crustacean health.

1.5 Research Questions

The study seeks to answer the following questions:

1. What freshwater crustacean species occur in the study area?

2. How do water quality parameters differ between polluted and unpolluted sites?

3. How does water pollution affect the growth and survival of freshwater crustaceans?

4. What relationship exists between water quality and crustacean health?

1.6 Significance of the Study

This study provides valuable information for environmental managers, aquaculture practitioners, and conservationists. It helps identify the impact of pollution on freshwater crustaceans and supports strategies for water quality improvement. The findings will guide sustainable management of aquatic ecosystems and promote awareness of pollution impacts. Additionally, the study contributes to scientific knowledge on crustacean ecology and environmental monitoring.

1.7 Scope of the Study

The study focuses on selected freshwater bodies that are exposed to varying degrees of pollution. It examines the growth and survival of crustaceans and evaluates water quality parameters. The study does not include marine crustaceans or genetic analysis. Seasonal variations in water quality are also not considered due to time limitations.

1.8 Operational Definition of Terms

Freshwater Crustaceans: Aquatic animals with exoskeletons living in rivers, lakes, or ponds, such as crabs and shrimps.
Water Pollution: The introduction of harmful substances into water bodies, affecting the ecosystem.
Growth Rate: The increase in size or weight of organisms over time.
Survival: The ability of organisms to live and reproduce in a given environment.
Water Quality: The physical, chemical, and biological characteristics of water that affect living organisms.