Yellowfin Sole Research
The yellowfin sole (Limanda aspera) is one of the
most abundant flatfish species in the eastern Bering Sea and is the target
of the largest flatfish fishery in the United States. They inhabit the EBS
shelf and are considered one stock. Abundance in the
Aleutian Islands region is negligible. Yellowfin sole are distributed in North
American waters from off British Columbia, Canada, (approx. lat. 49° N)
to the Chukchi Sea (about lat. 70° N) and south along the Asian coast to
about lat. 35°N off the South Korean coast in the Sea of Japan.
Adults exhibit a benthic lifestyle and occupy separate winter, spawning and summertime
feeding distributions on the eastern Bering Sea shelf. From over-winter grounds
near the shelf margins, adults begin a migration onto the inner shelf in April
or early May each year for spawning and feeding. The directed fishery typically
occurs from spring through December. Yellowfin sole is managed as part of the
shallow-water flatfish complex in the Gulf of Alaska.
Yellowfin sole are a relatively slow growing and long-lived fish species.
Yellowfin sole concentrate on the outer shelf in the winter, and move to very
shallow waters (<30 m) to spawn and feed in the summer. Prey includes benthic
infauna and epifauna, euphausiids, and fish.
Females reach 50% maturity at 30 cm (about 10.5 years old) and are highly fecund,
producing one to three million eggs. Spawning occurs in June and July in shallow
waters of Bristol Bay to Nunivak Island. Annual natural mortality of adults
has been estimated to be about 10% (M = 0.12). Yellowfin sole begin to recruit
to trawl fisheries at age 6, but are not fully recruited to all gear types
until about age 13. Maximum age for this species is 31 years. The stock has
recently been at high population levels due to good recruitment in the early
1970's and low exploitation. Biomass is projected to decline slowly in coming
years.
Yellowfin sole are targeted primarily by trawl catcher-processors. Seasons
are generally limited by seasonal apportionments of halibut. Fishing occurs
throughout the shelf area. Yellowfin sole were overexploited by foreign fisheries
in 1959-1962, when catches averaged about 400,000 t. As a result of reduced
abundance, annual catches declined to about 100,000 t through the late 1960's
to 50,000 t in the 1970's. Abundance increased in the 1980's, resulting in
increased catch by foreign and joint-venture operations. The fishery became
fully domestic in 1991.
During 2006, pollock made up 71.4% of the average groundfish catch off Alaska. The pollock catch for 2006 was 1.56 million metric tons (t), down approximately 0.4% from 2005.
The next major species, Pacific cod, accounted for 239,427 t or 10.9% of the total 2006 groundfish catch. The Pacific cod catch was down about 5.4% from a year earlier.
The 2006 catch of flatfish, which includes yellowfin sole, rock sole, and arrowtooth flounder was 231,343 t, up about 10.1% from 2005.
Other important species are sablefish (0.7%), rockfish (1.9%), and Atka mackerel (2.9%).
- MOLES, A.
2004. Parasites of juvenile yellowfin sole and rock sole in southeast Alaska. Northwest Sci. 78(4):339-343.
- NICHOL, D. G., and E. I. ACUNA.
2001. Annual and batch fecundities of yellowfin sole, Limanda aspera, in the eastern Bering Sea. Fish. Bull., U.S. 99:108-122. (.pdf, 348kb) Online.
- NICHOL, D. G.
1998. Annual and between-sex variability of yellowfin sole, Pleuronectes asper, spring-summer distributions in the eastern Bering Sea. Fish. Bull., U. S. 96:547-561. (.pdf, 925). Online.
- JOHNSON, S. W., S. D. RICE, and D. A. MOLES.
1998. Effects of submarine mine tailings disposal on juvenile yellowfin sole (Pleuronectes asper): A laboratory study. Mar. Poll. Bull. 36:278-287.
- Additional publications, posters, and reports.
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(Sources: Groundfish
of the Bering Sea and Aleutian Islands Area: Species Profiles 2001 and
the 2005 North Pacific Groundfish Stock
Assessment and Fishery Evaluation Reports for 2006.)
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