From front to back, they have around thirteen dorsal fin spines and between 14 and 17 soft rays that create a round structure that ends where the tail begins.

However, unlike the Pacific Ocean Perch, the Acadian Redfish has orange blotches along its back instead of an olive-green coloration.

The Pacific ocean perch was first formally described as Sebastichthys alutus in 1890 by the American ichthyologist Charles Henry Gilbert with the type locality given as the Santa Barbara Islands off California.

[4] The Pacific ocean perch is found in the North Pacific Ocean where its range extends from Honshu in Japan to Cape Navarin in the Bering Sea, although they are absent from the Sea of Okhotsk, through the Aleutian Islands from Stalemate Bank to Bowers Bank and south along the west coast of North America as far as La Jolla in California.

Although small numbers of Pacific ocean perch are dispersed throughout their preferred depth range on the continental shelf and slope, most of the population occurs in patchy, localized aggregations.

[7] Pacific ocean perch are generally considered to be semi-demersal but there can at times be a significant pelagic component to their distribution.

[citation needed] There is much uncertainty about the life history of Pacific ocean perch, although generally more is known than for other rockfish species.

Once they’ve reached the juvenile stage of their life, they tend to live in rocky areas inshore and can be found on the surfaces of offshore waters for access to food and shelter from predators.

[10] Genetic techniques using allozymes [11] and mitochondrial DNA are capable of identifying larvae and juveniles to species, but are expensive and time-consuming.

[12] Post-larval and early young-of-the-year Pacific ocean perch have been positively identified in offshore, surface waters of the GOA,[13] which suggests this may be the preferred habitat of this life stage.

However, they can become bottom-dwelling fish as early as one year of age, which rejected earlier hypotheses which suggested that they had a 2-3 yearlong pelagic lifestyle.

[18] Research that studied their reproductive seasonality near the Gulf of Alaska found that Pacific ocean perch ovary cells for females began to develop during the months of July through September.

[18] There is also an increase in the size of the ovary through March, a decrease in May as egg laying occurs, and a sharp drop off in June after parturition (Figure 3).

[18] The reproduction of this species was highly synchronous with a prolonged period of development from the onset of yolk formation in July and August to parturition in May.

The spent/resting period of Pacific ocean perch was very short, only about 2 months from the end of May through July, before yolk formation began again.

Larger juveniles and adults fed primarily on euphausiids, and to a lesser degree, copepods, amphipods and mysids.

[21] In the Aleutian Islands, myctophids have increasingly comprised a substantial portion of the Pacific ocean perch diet, which also compete for euphausiid prey.

Consequently, the large removals of Pacific ocean perch by foreign fishermen in the Gulf of Alaska in the 1960s may have allowed walleye pollock stocks to expand in abundance greatly.

Studies of this species and the rougheye rockfish (S. aleutianus) for senescence in reproductive activity of older fish and found that oogenesis continues at advanced ages.

[32] In contrast, preliminary analysis using mitochondrial DNA techniques suggest that genetically distinct populations of Pacific ocean perch exist (A. J. Gharrett pers.

Prior to 1965, the Pacific ocean perch resource in the US Vancouver and Columbia areas of the INPFC were harvested almost entirely by Canadian and United States vessels.

Landings from 1956-65 averaged slightly over 2,000 metric tons (mt) in each of the two INPFC areas included in this assessment, with an overall increasing trend of catch over this period.

Like other Pacific members of the Sebastes genus, it faces significant fishing pressure due to its slow growth rate, delayed maturation age, low yearly population fecundity, and its habit of forming large schools, making them easier to catch.

The second study evaluated alternative trip limits as a management tool for the Pacific ocean perch fishery (Tagart et al. 1980).

Controls on catch of Pacific ocean perch, and assessments of this species off Washington and Oregon have continued to the present day.