Flounder is a right eyed demersal flatfish found in European coastal waters and estuaries. Unlike many fish species which spawn in inshore waters, the flounder spends most of its life in coastal waters but moves into deeper open water to spawn. Flounder colouration is variable but is usually a dark green-brown on the upper surface and can have orange spots like plaice. Prey consists mainly of invertebrates such as crustaceans, annelids and molluscs as well as small fish found in coastal waters. Males reach sexual maturity at approximately 11 cm (2-3 years), and females at 17 cm. Flounder feed during daylight hours, locating their prey visually with adults targeting mobile prey, while juveniles have been shown to have a preference for sedentary prey close to the bottom where they tend to stay resulting in less competition for food between adults and juveniles.
Flounder are known to have limited ranges for each population resulting in high dependence on sufficient quantity and quality of estuarine and mudflat habitats for them to inhabit. However in these habitats, larval and juvenile flounder are thought to be a key prey for other small fish and crustaceans such as brown shrimp. Larvae immigration into estuaries in early May also forms an important food source for coelenterates in the plankton.
Click here to read the KEIFCA Species Management Plan for Flounder