Yellowfin sole

The yellowfin sole (Limanda aspera) is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on soft, sandy bottoms at depths of up to 700 m, though it is most commonly found at depths of around 91 m. Its native habitat is the temperate waters of the northern Pacific, from Korea and the Sea of Japan to the Sea of Okhotsk, the Bering Sea and Barkley Sound on the west coast of Canada. Males grow up to 49 cm in length, though the common length is around 33.5 cm. The maximum recorded weight is 1.7 kg, and the maximum recorded lifespan is 26 years.

Description
The yellowfin sole has a deep body, with a small mouth, moderately large and closely situated eyes, and a slightly pronounced snout. The upper side of the body is olive to brown in colour, with dark mottling, and dorsal and anal fins are yellowish on both sides of the body, with faint dark bars and a narrow dark line at the base. Scales are rough on both sides of the body.

Taxonomy
The yellowfin sole was originally described as Pleuronectes asper by Pallas in 1814, and subsequently as Limanda asprella by Hubbs in 1915.

Role in ecosystem
The yellowfin sole occupies a moderately high trophic level in the food chain. The diet of the yellowfin sole consists mainly of zoobenthic organisms, including polychaetes and amphipods such as hydroids, worms, mollusks, and brittle stars. Yellowfin sole are known to be prey fish for sculpin, Pacific halibut, Pacific cod, and arrowtooth flounder.

Reproduction
Female yellowfin sole reach reproductive maturity when they reach around 30 cm in length (usually around 10.5 years old), and spawn following migration to shallow waters during spring and summer. Yellowfin sole have high reproductive potential, with females producing 1 to 3 million eggs.

Commercial fishing
Yellowfin sole is fished commercially, primarily by demersal trawl fishing. Having recovered from high fishing rates in the 1960s and 1970s, it is currently not considered to be overfished, and the biomass of yellowfin sole in the Bering Sea is estimated to be high and stable, above its target level. Catch has averaged 94,000 tons from 1998 to 2010, with the 2008 catch of 148,894 tons representing the highest annual catch in 11 years. Landings are limited by crab and halibut bycatch limits. As of 2021 there were two MSC certified commercial fisheries in the northern Pacific.

It is additionally the subject of a fishery off of Sakhalin Island, where population fluctuations associated with cyclic change in water temperature have been amplified by overexploitation in the first two decades of the 2000s, prompting regulatory changes in 2014.