DescriptionOncorhynchus gorbuscha
(Pink Salmon)
(Other common names: Humpback Salmon, Humpie)
Figure 12.3
DescriptionLength: 76 cm.
Mouth: large, terminal, directed upwards and forward; upper jaw reaches the posterior edge of orbit; snout is rounded and narrow; lips are fleshy; teeth small and weak, except in breeding males where the mouth becomes enlarged with well-developed teeth, the upper jaw becomes hooked downwards.
Body: elongate; caudal peduncle compressed; caudal fin slightly forked; adipose fin slender; 24-35 gill rakers over the first gill arch; breeding males develop a predorsal fin hump.
Color: metallic blue to green above; silvery to white below; large dark oval spots on back, adipose fins, and caudal fin; in breeding males, the dorsal surface becomes dark, the sides are red with green spots. Females are olive with dusky stripes.
Depth: pelagic schooling; 0-250 m.
Habitat: open Pacific offshore waters and coastal streams.
Season: spawns in the fall (September-October); eggs hatch in the spring and young spend first summer in river/estuarine systems, moving into deeper offshore waters in the fall; spend 18 months at sea then return to rivers to spawn.
Diet: juveniles/young eat crustaceans (e.g., copepods, euphasiids), salps, insects, forage fish (e.g., herring, hake); adults eat crustaceans (e.g., copepods, euphasiids), squid, forage fish species.
Predators: larger fish species including other salmon (on young), sea birds, marine mammals.
Distribution: North Pacific: southern California to Alaska to Bering Sea to the Arctic Ocean to Russia and Japan.
Scale
DescriptionRelative Size of Scale: small.
Position of Scale on Body: >150 on the lateral line (Hart, 1973).
Overall Scale Shape: circular to somewhat oval, the posterior field can be rounded but the edge is often irregular.
Focus and Circuli: focus is clearly defined and often centralized between the fields; often just anterior to the interface of the posterior field. The circuli are concentric with the scale outline. Circuli are both continuous and discontinuous in the lateral and anterior fields. The posterior field is clear and circuli are absent.
Radii: absent.
Remarks: Mosher (1969) reported that there will be only one "winter zone" or year mark; circuli (discontinuous) and radial striations sometimes present in the posterior field; and six complete circuli below the focus. According to Bilton et al., (1964) at the base of the anterior field the circuli break up into "ladder-like" and sometimes "globular" reticulation; greater than seven broken circuli in the posterior field; and no freshwater year bands.
