- Other Habitat Features
- Range depth
- 1280 (high) m
- 4199.48 (high) ft
- Average depth
- 366 m
- 1200.79 ft
- Sexual Dimorphism
- sexes alike
- Range mass
- 600 to 800 g
- 21.15 to 28.19 oz
- Range length
- 30.5 to 91 cm
- 12.01 to 35.83 in
- Average length
- 61 cm
- 24.02 in
- Mating System
- polygynandrous (promiscuous)
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- broadcast (group) spawning
- Breeding interval
- spawn once yearly
- Breeding season
- March to August in eastern Bering Sea and January to March in Aleutian Basin
- Range number of offspring
- 100,000 to 1,000,000
- Range time to hatching
- 9 to 28 days
- Range age at sexual or reproductive maturity (female)
- 3 to 4 years
- Range age at sexual or reproductive maturity (male)
- 4 to 5 years
Besides the energy put into gamete production and spawning, (Love, 1996)makes no investment in its offspring.
- Parental Investment
- no parental involvement
The mortality coefficient for (Bailey, et al., 1999)is 0.3 on the eastern Bering Sea shelf (0.3 implying that that the annual natural morality rate is 30%) and 0.2 on the Aleutian Basin. usually lives from 12 to 16 years. The oldest ever reported was 31 years old (Bailey 1999).
- Range lifespan
- 31 (high) years
- Range lifespan
- Typical lifespan
- 12 to 16 years
- Typical lifespan
- Average lifespan
- 17 years
- Average lifespan
No information on the home range ofcould be found.
Communication and Perception
Limited information pertaining to the communication and perception of (Bailey, et al., 1999)exists. Most schooling fish, however, use visual cues for schooling and feeding (Bailey 1999).
- Communication Channels
copepods, while older tend to eat larger food items such as adult Acartia and Pseudocalanus. In winter, adult pollock feed mostly on fishes and euphausiid krill. In spring, feed on Appendicularia. In summer, the diet consists of euphausiids and copepods and in autumn, they feed on mainly euphausiids (Kooka 1998). Large have a diet rich in small pollock (specifically in the eastern Bering Sea) and shrimp. In areas where the juvenile population is extremely large, such as in the eastern Bering Sea, cannabalistic adults prey on the juveniles. Smaller-sized individuals are more likely to consume copepods and euphausiids (Avdeev 2001). (Avdeev, G.V and Avdeev, 2001; Bailey, et al., 1999; Kooka, 1998)feeds on both fish and invertebrates (Bailey 1999). The diet of this fish varies by developmental stage, season, and body size. Larvae tend to consume zooplankton such as larval
- Animal Foods
- aquatic crustaceans
- other marine invertebrates
northern rockfish, polka-dot snailfish, and atka mackeral. One-year-olds are preyed on by greenland turbot, plain sculpin, and arrowtooth flounder. Those that are two years old are hunted by greenland turbot, bigmouth sculpin, sablefish, pacific cod, plain sculpin, pacific halibut, and great sculpin. Adult fall prey to yellow irish lords and plain sculpin (Cohen 1990; Kooka 1998). In the Gulf of Alaska, is the primary prey of stellar sea lions (Cohen 1999). (Cohen, et al., 1990; Kooka, 1998; Love, 1996)larvae are preyed on by
- Known Predators
- greenland turbot (Reinhardtius hippoglossoides)
- plain sculpin (Myoxocephalus jaokin)
- arrowtooth flounder (Atheresthes stomias)
- bigmouth sculpin (Hemitripterus bolini)
- sablefish (Anoplopoma fimbria)
- pacific cod (Gadus macrocephalus)
- pacific halibut (Hippoglossus stenolepis)
- great sculpin (Myoxocephalus polyacanthocephalus)
- yellow irish lords (Hemilepidotus jordani)
- stellar sea lions (Eumetopias jubatus)
In the Bering Sea,plays a key role as both predator and prey. The reproductive success of stellar sea lions is dependent on (Avdeev 2001).
Predator-prey interactions forfluctuate with seasonal conditions. One-year-old pollock occupy different areas depending on temperature. This change in local abundance affects the annual populations of other species in the region.
When infected with the parasitic copepod Haemobaphes diceraus, there is a decrease in the body weight of as well as an increase in the weight of its spleen. If is infected during the juvenile stage of development, it suffers from delayed maturity, and if it is infected as an adult, it experiences a decrease in reproductive success (Bailey 1999). (Avdeev, G.V and Avdeev, 2001; Bailey, et al., 1999)
- Ecosystem Impact
- keystone species
- a parasitic copepod (Haemobaphes diceraus)
Economic Importance for Humans: Positive
This species is a valuable fish for fisheries on the Russian, Japanese, and Korean coasts. The fish is sold frozen, as fillets, fish sticks, surimi, and roe in Japan (Love 1996). The desire for this fish has gone up in recent years; however, it still lacks appreciation on the North Californian coast where its abundance is high. In addition to being used for food, it is also utilized for fish meal and industrial products. (Love, 1996)
- Positive Impacts
Economic Importance for Humans: Negative
There are no adverse effects of (Kooka, 1998)on humans (Kooka 1998).
This species is not threatened and is not listed on the 2004 IUCN Red List of Threatened Species nor is it listed as endangered by the U.S. Fish and Wildlife Service. The most important site of reproduction for this species, the Shelikof Strait in the Gulf of Alaska, has an annual period of time in which fishing is prohibited. This enforced fishing restriction was put in place to prevent potential decreases in this species due to this region having such a large (Bailey, et al., 1999; Bailey, et al., 1999)density during spawning season (Bailey 1999).
Allison Poor (editor), University of Michigan-Ann Arbor.
Parisa Ijadi-Maghsoodi (author), University of Michigan-Ann Arbor, Kevin Wehrly (editor, instructor), University of Michigan-Ann Arbor.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
- Pacific Ocean
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
- bilateral symmetry
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
the nearshore aquatic habitats near a coast, or shoreline.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.
- external fertilization
fertilization takes place outside the female's body
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- keystone species
a species whose presence or absence strongly affects populations of other species in that area such that the extirpation of the keystone species in an area will result in the ultimate extirpation of many more species in that area (Example: sea otter).
having the capacity to move from one place to another.
specialized for swimming
- native range
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).
an animal that mainly eats fish
the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
- saltwater or marine
mainly lives in oceans, seas, or other bodies of salt water.
- seasonal breeding
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
associates with others of its species; forms social groups.
uses touch to communicate
uses sight to communicate
animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)
Avdeev, G.V, G., E. Avdeev. 2001. Patogenic [pathogenic] influence rendered by parasitic copepod Haemobaphes diceraus on Alaska pollock. Zoological Record Plus, 128(1): 287-292, 336, 342.
Bailey, K., D. Powers, J. Quattro, G. Villa, J. Traynor, G. Walters. 1999. Population Ecology and Structural Dyamics of Walleye Pollock. Pp. 581-590 in T Loughlin, K Ohtani, eds. Dynamics of the Bering Sea. Fairbanks, Alaska: University of Alaska Sea Grant.
Cohen, D., T. Inada, T. Iwamoto, N. Scialabba. 1990. "Theraga chalcogramma" (On-line). Accessed October 12, 2005 at http://www.fishbase.org/Summary/SpeciesSummary.php?id=318.
Harmann, A. 2005. "A Biophysical Model of Shelikof Strait" (On-line). Accessed October 16, 2005 at http://www.pmel.noaa.gov/foci/spem-ibm.html.
Kooka, K. 1998. Vertical distribution and prey of walleye pollock in the northern Japan sea. Fisheries Sciecne, 64 (5): 686-693.
Love, M. 1996. Probably more than you want to know about the fishes of the Pacific coast.. Sante Fe, California: Really Big Press.