Olive flounder
The olive flounder, bastard halibut, Japanese flounder or Korean halibut is a temperate marine species of large-tooth flounder native to the North-western Pacific Ocean. It is the highest valued finfish in the world, known to be excellent for aquaculture due to a rapid growth rate and popularity in Japan and Korea.
Names
In Japanese, olive flounder is called hirame. In Korean, it is called gwangeo. In Chinese, it is called yaping or biankouyu.In English, it is often referred to as "Japanese flounder" or "Korean flatfish" when mentioned in the context of those countries.
Description
It reaches a length of and a weight of. In 2017 its genome and transcriptome was sequenced as a model to study flatfish asymmetry.Biology
Habitat and diet
The olive flounder is often found in soft and muddy offshore, coastal areas where the water level goes down to 100 m in depth. The temperature of water in these areas range from 21–24 °C or 69–75 °F. Some flounder have been found in the Mariana Trench.Olive flounder typically eat fish spawn, crustaceans, polychaetes, and small fish.
Life cycle
Olive flounder spawn anytime from January through August in shallow water, roughly about 70 cm in depth. The egg and larvae remain that way for about 24–50 days after hatching. Once they begin their metamorphosis process, they move towards more sandy areas and feed on shrimp. After achieving metamorphosis, the flounder move offshore and begin feeding on bigger fish in order to grow to their adult size.Young olive flounder first hatch with a "normal" morphology like other fish, but then after 24 to 50 days after hatching they turn onto their side. Their previous side now becomes their belly or their underside and then their eye and nostril move towards what is now considered the back. This process is typically called the "metamorphosis."