Pink Salmon – Oncorhynchus gorbuscha
Adults: Distribution and shape of spots on tail: spots are dark, elongate and occur on both lobes of the caudal fin; spotting occurs above the lateral line only on the body. Males develop a large hump on their back as they mature. Both sexes change colour in fresh water: darkening of the head and back, silver/white flanks, with purple blotches below the lateral line.
Fry: Pink fry are small with bright silver flanks, an iridescent green back and no lateral parr marks
Pink Salmon spawn in most rivers and streams along British Columbia’s coast. Typically these runs spawn within 100km from the ocean, however in the Skeena system some pink salmon travel as far as the Babine counting fence to spawn (480km from the ocean). In the Lakelse watershed, Pink salmon utilize Coldwater Creek, Hatchery Creek (Granite Creek), Herman Creek, Lakelse River, Schulbuckhamd Creek (Scully Creek), Williams Creek and White Creek for spawning.
Northern pink salmon populations tend to enter fresh water earlier and spawn earlier than than southern populations. Northern populations enter fresh water as early as July and spawn in September and October. Females choose the spawning site with preference to clean coarse gravel with sub-gravel flow. The digging of a redd and spawning behaviour of the female are similar to other salmonines. Virtually all native populations of pink salmon mature and return to spawn at the age of two. However, there is great variability in the size, shape, and colour of the males. A nest-digging female may be accompanied by up to ten or more males, with the largest most dominant male closest to the female. When the female is ready to spawn the dominant male takes position and fertilizes the eggs. The remaining males follow closely behind releasing sperm. Female pink will remain with their nest until they die. However male pinks are polygamous and continue to move around the spawning grounds before dying.
The eggs incubate in the gravel overwinter. Depending on water temperature the eggs hatch after 1.5 to 3 months and emergence occurs between 3 to 5 months after hatching. Pink fry spend the least amount of time in freshwater in comparison to other Pacific Salmon. Downstream fry migration occurs as early as February and last until May.
Age, Growth, and Maturity
Pink fry are about 30-35 mm long when they enter estuaries. Once in the ocean pink fry grow rapidly, reaching 27 to 34 cm in length by the end of their first growing season. Pink salmon migrate to the northwest reaching the Gulf of Alaska in the fall or winter before returning. Pink return to their natal stream to spawn in their second year at 45 to 55 cm in length.
Although most pink fry migrate immediately to the ocean upon emergence, many populations with longer migrations will feed on larvae and pupae of chironomids on their way to the ocean. In the ocean fry remain in shallow water and feed on copepods until they reach about 5 to 8 cm in length. At this time pink move offshore and begin feeding on fish,squids,amphipods, and copepods.
McPhail, J.D. (2007). The Freshwater Fishes of British Columbia. Edmonton, Alberta: The University of Alberta Press.