Knowra Freshwater fish Freshwater fish Freshwater fish are fish that spend some or all of their lives in rivers, lakes, streams, or other low-salinity inland waters. Their physiology and life cycles vary widely, including species that migrate between fresh and salt water.
Osmoregulation : The regulation of water and dissolved substances in an organism’s body. Freshwater fish constantly manage water entering their bodies and salts leaving them.
Gill : A respiratory organ that extracts dissolved oxygen from water and releases carbon dioxide. Gills exchange gases while helping regulate ions in freshwater.
Salmon : A group of fish whose species include migratory forms that reproduce in freshwater. Salmon demonstrate how a freshwater spawning phase can be linked to ocean growth.
Freshwater aquaculture : The farming of aquatic organisms in inland freshwater systems. It raises fish for food while creating questions about feed, water quality, and escapees.
Freshwater pollution : The contamination of rivers, lakes, and other inland waters by harmful substances or energy. Pollutants can impair fish health, reproduction, and access to suitable habitat.
Freshwater ecosystem : An ecological community and its physical environment in inland waters. Fish depend on interactions among organisms, water conditions, and habitat structure.
Fish migration : Regular movement by fish between habitats for feeding, reproduction, or survival. Seasonal and life-stage movements connect feeding grounds with spawning sites.
European eel : A migratory eel that grows in European inland and coastal waters and reproduces in the Sargasso Sea. Its life cycle links freshwater habitats to a distant ocean spawning ground.
Inland fisheries : The capture and management of fish from inland waters. These fisheries provide food and livelihoods but depend on healthy fish stocks.
Eutrophication : The enrichment of water with nutrients that can cause excessive plant and algal growth. Nutrient loading can deplete oxygen and trigger fish kills.
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