Oncorhynchus gorbuscha
| Pink salmon | |
|---|---|
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| Male ocean phase pink salmon | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Salmoniformes |
| Family: | Salmonidae |
| Genus: | Oncorhynchus |
| Species: | O. gorbuscha |
| Binomial name | |
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Oncorhynchus gorbuscha (Walbaum, 1792) |
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Pink salmon or humpback salmon (Oncorhynchus gorbuscha) is a species of anadromous fish in the salmon family. It is the smallest and most abundant of the Pacific salmon. The scientific species name is based on the Russian common name for this species gorbúša (горбуша), which literally means humpie.
In the ocean, pink salmon are bright silver fish. After returning to their spawning streams, their coloring changes to pale grey on the back with yellowish-white belly (although some turn an overall dull green color). As with all salmon, in addition to the dorsal fin, they also have an adipose fin. The fish is characterized by a white mouth with black gums, no teeth on the tongue, large oval-shaped black spots on the back, a v-shaped tail, and an anal fin with 13-17 soft rays. During their spawning migration, males develop a pronounced humped back, hence their nickname "humpies". Pink salmon average 4.8 pounds (2.2 kg) in weight. The maximum recorded size was 30 inches (76 cm) and 15 pounds (6.8 kg).
Pink salmon in their native range have a strict two year life cycle, thus odd and even-year populations do not interbreed. In the state of Washington, Pink salmon runs occur on odd years. Adult pink salmon enter spawning streams from the ocean, usually returning to the stream where they originated. Spawning occurs between late June and mid-October, in coastal streams and some longer rivers, and in the intertidal zone or at the mouth of streams if hyporheic freshwater is available. Using her tail, the female digs a trough-shaped nest, called a redd (Scandinavian word for "nest"), in the gravel of the stream bed, where she deposits her eggs. As she expels the eggs, she is approached by one or more males, which fertilize them as they fall into the redd. Subsequently, the female covers the newly deposited zygotes, again with thrusts of her tail, against the gravel at the top of the redd. The female lays from 1000 to 2000 eggs in several clutches within the redd, often fertilized by different males. Females guard their redds until death, which comes within days of spawning. In dense populations, a major source of mortality for embryos is superposition of redds by later-spawning fish. The eggs hatch from December to February, depending on water temperature, and the juveniles emerge from the gravel during March and April and quickly migrate downstream to estuaries, at about one-quarter gram in weight. The fish achieve sexual maturity in their second year of life. They return to freshwater in the summer or autumn as two-year-old adults. Pink and chum salmon sometimes interbreed in nature to form the hybrid known as the miko salmon; the hybrids are sterile.
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Wikipedia