(DRAFT) - Taxonomy
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
TAXONOMY
NAME - perch, Pacific Ocean
OTHER COMMON NAMES -
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - ,
ORDER AND SUBORDER - ,
FAMILY AND SUBFAMILY - ,
GENUS AND SUBGENUS - Sebastes,
SPECIES AND SSP - alutus,
SCIENTIFIC NAME - Sebastes alutus
AUTHORITY -
TAXONOMY REFERENCES - 232
Taxonomy - 1 (DRAFT) - Status
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
STATUS
Coded Status
Migrant
Depleted
Existing, FMP exists
See Comments
REFERENCES FOR STATUS - 232
COMMENTS ON STATUS -
Adult Pacific ocean perch do not migrate long distances. Seasonal movements
of perch are largely between deep and shallow bottoms within a limited area
*232*.
Before heavy commercial exploitation began in the early 1960's, Pacific
ocean perch were a dominant groundfish in the Gulf of Alaska. But perch
stocks now have been severely reduced *232*.
Pacific ocean perch within the 200-mi limit are managed by the North Pacific
Fishery Management Council in their groundfish fishery management plans
*232*.
Status - 1 (DRAFT) - Distribution
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - MARINE
REFERENCES FOR HABITAT - 232
LAND USE -
Water
Bays and Estuaries
REFERENCES FOR LAND USE - 232
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine
REFERENCES FOR NWI - 232
COMMENTS ON HABITAT ASSOCIATIONS -
Pacific ocean perch were found in each region but were generally restricted
to outer shelf and upper slope depth zones. Adult Pacific ocean perch are
generally found on the continental slope *232*.
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Anemone (Metridium senile)
Walleye pollock (Theragra chalcogramma)
REFERENCES FOR SPECIES ASSOCIATIONS - 232
COMMENTS ON SPECIES ASSOCIATIONS -
Juveniles inhabit areas where cover and protection among sessile
invertebrates such as the anemone (Metridium senile). Pacific ocean perch
may compete with walleye pollock (Theragra chalcogramma) for food because
they feed on largely the same organisms *232*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 232
LIFESTAGE FOOD FOOD PART
Juvenile Copepods Not Specified
Juvenile Crustaceans Not Specified
General Crustaceans Not Specified
General Osteichthyes Not Specified
Juvenile See Comments; Food See Comments
General See Comments; Food See Comments
REFERENCES FOR GENERAL FOOD - 232
REFERENCES FOR JUVENILE FOOD - 232
COMMENTS ON FOOD -
Juvenile perch of all sizes in Southeast Alaska feed on copepods and
euphausiids. Stocks in the Gulf of Alaska fed almost entirely on
euphausiids, whereas those in the Bering Sea consume fishes, euphausiids,and
other crustaceans *232*.
Types of Feeding Area Used: Schools of feeding perch are found mainly at
depths of 150 to 200 m. Dense concentrations of feeding perch were found in
the western Gulf of Alaska southeast of Kodiak Island, southwest of Shumagin
Islands, and south of Unimak Island *232*.
Factors Limiting Availability of Food: Pacific ocean perch may compete with
walleye pollock (Theragra chalcogramma) for food. Rapid growth and survival
of larval rockfish, as with other ocean fish (such as pollock and Pacific
halibut), is probably dependent on ocean currents and weather conditions
that result in a concentration of available food *232*.
Feeding Behavior: Perch in the Gulf of Alaska feed heavily from May to
September and hardly at all through the rest of the year. The feeding rate
changes during the day, being most intensive at noon and least intensive in
the morning *232*.
COMMENTS ON JUVENILE FOOD -
Juvenile perch of all sizes in Southeast Alaska feed on copepods and
euphausiids *232*.
Food Habits - 1 (DRAFT) - Environment Associations
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Water Depth Preference: 500-1000 ft.
G Water Depth Preference: Specified in Comments
E Bottom Type [Aquatic]: Specified in Comments
BA Bottom Type [Aquatic]: Specified in Comments
E Coastal Features: Specified in Comments
BA Coastal Features: Specified in Comments
J Bottom Type [Aquatic]: Specified in Comments
A Bottom Type [Aquatic]: Specified in Comments
A Water Temperature: Below 15 degrees C
A Water Temperature: Specified in Comments
J Water Temperature: Below 15 degrees C
J Water Temperature: Specified in Comments
G Dissolved Oxygen: Specified in Comments
FA Water Depth Preference: 200-500 ft.
FA Water Depth Preference: 500-1000 ft.
FA Water Depth Preference: Specified in Comments
BA Water Temperature: Specified in Comments
BA Water Depth Preference: 1000-1500 ft.
BA Water Depth Preference: Specified in Comments
J Water Depth Preference: 200-500 ft.
J Water Depth Preference: Specified in Comments
A Water Depth Preference: 1000-1500 ft.
A Water Depth Preference: Specified in Comments
A Water Depth Preference: 500-1000 ft.
A Water Depth Preference: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR JUVENILE ENVIRONMENTAL ASSOC_ - 232
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 232
Environment Associations - 1 (DRAFT) - Environment Associations
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Pacific ocean perch were found in each region where sampling occurred but
were generally restricted to outer shelf and upper slope depth zones.
Adult Pacific ocean perch are generally found on the continental slope at
depths of 200 to 300 m. Large concentrations have been found around
submarine canyons. Nearshore, rocky-bottom coastal areas exposed to open
sea conditions and adjacent bays and straits are probably nursery areas for
Pacific ocean perch. Juveniles inhabit areas where cover and protection
are afforded by cracks and crevices in and under rocks and ledges and among
sessile invertebrates such as the anemone (Metridium senile). Both
juveniles and adults were found only over areas with a hard or firm
substrate, never over muddy substrate. These areas of clean substrate may
be caused by ocean currents and that current, rather than substrate type,
was a controlling factor in Pacific ocean perch habitat. Distribution of
adults may be determined more by food and hydrographic conditions than by
substrate. Water temperature is an important environmental factor
controlling distribution of perch. Adult rockfish live within 4.0 to 6.5
oC and the young (14 to 26 cm) at lower temperatures (2.5 to 3.5 oC). The
vertical distribution of perch in the Gulf of Alaska has been related to
the depth of the layer of oxygen deficiency (where O2 content is less than
1 ml/l). Rockfish concentrations throughout the year remain above this
layer, which varies from 350 m deep in summer to 420 m in winter *232*.
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Adult Pacific ocean perch are generally found on the continental slope at
depths of 200 to 300 m. Large concentrations have been found around
submarine canyons. Adults were found only over areas with a hard or firm
substrate, never over muddy substrate. These areas of clean substrate may
be caused by ocean currents and that current, rather than substrate type,
was a controlling factor in Pacific ocean perch habitat. Distribution of
adults may be determined more by food and hydrographic conditions than by
substrate. Water temperature is an important environmental factor
controlling distribution of perch. Adult rockfish live within 4.0 to 6.5 oC
*232*.
When perch become sexually mature, the perch move into deeper waters (up to
320-370 m or deeper) *232*.
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
Schools of feeding perch are found mainly at depths of 150 to 200 m *232*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
The location of spawning relates to water temperature, with females
spawning in the warmer areas of the gulf. Spawning in the Bering Sea
occurs at depths of 360 to 420 m *232*
Nearshore, rocky-bottom coastal areas exposed to open sea conditions and
adjacent bays and straits are probably nursery areas *232*.
COMMENTS ON JUVENILE ENVIRONMENTAL ASSOC_ -
Juveniles inhabit areas where cover and protection are afforded by cracks
and crevices in and under rocks and ledges and among sessile invertebrates
such as the anemone (Metridium senile). Juveniles were found only over
Environment Associations - 2 (DRAFT) - Environment Associations
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
areas with a hard or firm substrate, never over muddy substrate. These
areas of clean substrate may be caused by ocean currents and that current,
rather than substrate type, was a controlling factor in Pacific ocean perch
habitat. The young (14 to 26 cm) live at lower temperatures (2.5 to 3.5 oC)
*232*.
Sometime during their first year of life, the juvenile perch become
demersal and are found near the ocean bottom in areas 110 to 140 m deep
*232*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
Nearshore, rocky-bottom coastal areas exposed to open sea conditions and
adjacent bays and straits are probably nursery areas *232*.
Environment Associations - 3 (DRAFT) - Life History
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
LIFE HISTORY
Reproductive Habitat: Spawning occurs in the northern Gulf of Alaska, with
densities of larvae being highest in the Yakutat area. High larval
densities are also found in the Kodiak Island area. In the Bering Sea,
spawning takes place south and southeast of the Pribilof Islands. A study
related the location of spawning to water temperature, with females spawning
in the warmer areas of the gulf. Spawning in the Bering Sea occurs at
depths of 360 to 420 m *232*.
Reproductive Seasonality: Pacific ocean perch are ovoviviparous, meaning
they are internally fertilized and give birth to live young. Copulation
takes place October through February, and spawning (release of young) takes
place from March through June. Significant concentrations of larvae have
been reported in the Yakutat region during April and May *232*.
Reproductive Behavior: Mating has not been observed; however, it has been
suggested that males may copulate several times with different females. A
study stated mating and fertilization take place simultaneously; however,
another study stated that fertilization may occur two months after mating
*232*.
Age at Sexual Maturity: Fish from all stocks begin to mature at age 5, and
all individuals are mature at age 9. Fifty percent of the stock is mature
at age 7 *232*.
Frequency of Breeding: Pacific ocean perch breed annually *232*.
Fecundity: Fecundity is higher in Bering Sea stocks (75,000 eggs at age 15,
205,000 at age 20) than in the Gulf of Alaska (33,000 at age 15, 48,000 at
age 20). It is reported that 10,000 to 270,000 larvae may be released
*232*.
Incubation Period: Spawning (release of live young) takes place four to
five months after copulation *232*.
Movements Associated with Life Functions: Larval Pacific ocean perch are
planktonic, with their distribution largely controlled by ocean currents.
Sometime during their first year of life, the juvenile perch become demersal
and are found near the ocean bottom in areas 110 to 140 m deep. When they
become sexually mature, the perch move into deeper waters (up to 320-370 m
or deeper). Adult Pacific ocean perch do not migrate long distances.
Seasonal movements of perch are largely between deep and shallow bottoms
within a limited area *232*.
Natural Factors Influencing Populations: A study noted strong fluctuations
in year class strength. Extreme success of failure of year classes is
apparently characteristic of the species. Female perch in the Gulf of
Alaska cast their larvae in places where water currents are conducive of
high productivity. Weather and current conditions resulting in dispersal of
plankton may have a negative effect on larval pollock survival. It seems
possible the perch larvae are similarly affected. Before heavy commercial
exploitation began in the early 1960's, Pacific ocean perch were a dominant
Life History - 1 (DRAFT) - Life History
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
groundfish in the Gulf of Alaska. But perch stocks now have been severely
reduced, and possibly as a result of release from competition with perch,
pollock have become much more abundant. Pollock and perch feed on largely
the same organisms, and it is possible that competition with pollock will
prevent perch stocks from recovering even if fishing pressure is relieved
*232*.
Human-related Factors Influencing Populations: A summary of possible
impacts from human-related activities includes: alteration of preferred
water temperature, pH, dissolved oxygen, and chemical composition;
introduction of water-soluble substances; increase in suspended organic or
mineral material; alteration of preferred substrate; reduction of food
supply; seismic shockwaves; and human harvest *232*.
LIFE HISTORY CODES -
Dispersion: Clumped
Nest Materials: Gravel
Periodicity: Most active in early summer
Periodicity: Most active in late summer
Breeding/Spawning Season: January
Breeding/Spawning Season: February
Breeding/Spawning Season: October
Breeding/Spawning Season: November
Breeding/Spawning Season: December
Breeding/Spawning Season: March
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Mating System (Single breeding season): Polygamy (mal
Number of Broods/Litters (Reproductive Efforts) Per Ye
Average Number of Offspring/Reproductive Effort: 1,00
Average Number of Offspring/Reproductive Effort: Grea
Gestation/Incubation Period: 3-4 months
Gestation/Incubation Period: 5-6 months
REFERENCES FOR LIFE HISTORY- 232
Life History - 2 (DRAFT) - Management Practices
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Developing/maintaining suitable salinity
Beneficial Developing/maintaining suitable pH
Adverse Salinity alteration
Beneficial Prohibiting harvest of species being described
Adverse Other management practices [specified in comments]
Beneficial Other management practices [specified in comments]
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 232
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 232
COMMENTS ON MANAGEMENT PRACTICES -
Human-related Factors Influencing Populations: A summary of possible
impacts from human-related activities includes: alteration of preferred
water temperature, pH, dissolved oxygen, and chemical composition;
introduction of water-soluble substances; increase in suspended organic or
mineral material; alteration of preferred substrate; reduction of food
supply; seismic shockwaves; and human harvest *232*.
Pacific ocean perch within the 200-mi limit are managed by the North Pacific
Fishery Management Council in their groundfish fishery managements plans
*232*.
Management Practices - 1 (DRAFT) - References
Species perch, Pacific Ocean
Species Id M010240
Date 26 AUG 96
References
232 * State of Alaska Department of Fish, and Game. 1986. Alaska
Habitat Management Guide: Life Histories and Habitat
Requirements of Fish and Wildlife. (ed.). Alaska Department of
Fish and Game Juneau, Alaska:763.
References - 1