Salmonids

Salmonids are a family of ray-finned fishes, Salmonidae, in the order Salmoniformes. The group includes several genera and is traditionally divided into subfamilies such as Salmoninae (true salmons and trouts), Thymallinae (graylings), and Coregoninae (whitefishes). The most familiar species include the Atlantic salmon (Salmo salar), the Pacific salmon (Oncorhynchus species such as O. kisutch, O. tshawytscha, O. nerka, O. gorbuscha), the brown trout (Salmo trutta), the rainbow trout or steelhead (Oncorhynchus mykiss), and various lake-dwelling chars and whitefishes (Salvelinus and Coregonus).

Life history among salmonids is diverse. Many species are anadromous, migrating from the ocean into freshwater to spawn, while others are landlocked and complete their life cycle in rivers or lakes. Spawning typically occurs in cold, well-oxygenated waters, often on gravel beds. Eggs hatch into alevins, which rely on yolk sacs before emerging as fry. Growth stages proceed through juveniles to adults; in some species, individuals die after spawning (semelparity), while others may spawn multiple times.

Ecology and habitat requirements emphasize cool, clean water and access to migratory corridors. Dam construction, habitat degradation, pollution, climate change, and invasive species can threaten populations by limiting migration or altering life-supporting conditions.

Economic and conservation aspects center on the significance of salmonids for commercial and recreational fisheries and for aquaculture, especially Atlantic salmon and rainbow trout. Conservation status varies by species, with management focusing on habitat protection, sustainable harvests, mitigation of barriers to migration, and careful use of hatcheries to minimize genetic and ecological impacts.