Plaice and flounder are common flatfish species often confused due to their flattened bodies and similar appearances. Both are demersal fish, meaning they live on the seafloor, with eyes adapted to one side of their head. This article clarifies the specific differences between plaice and flounder.
Distinctive Physical Traits
One of the most immediate ways to differentiate plaice from flounder involves examining their eye placement. While all flatfish undergo a metamorphosis where one eye migrates to the other side of the head, plaice (specifically European plaice, Pleuronectes platessa) are typically right-eyed. Flounders, however, can be either right-eyed or left-eyed, depending on the specific species, though some, like summer flounder, are typically left-eyed, while winter flounder are right-eyed. Plaice also possess a distinct row of bony knobs or ridges located behind their eyes, which is absent in flounder.
Coloration and markings provide further distinctions. European plaice are recognized by their smooth, grey or brown skin adorned with prominent, bright orange or red spots. These spots often develop a white circle around them as the fish ages. Flounder, in contrast, typically exhibit a more mottled or dappled skin pattern that aids in camouflage, and while they can have spots, they are generally not as bright or distinctly orange as those on plaice.
The lateral line also reveals differences. The lateral line of a plaice is relatively straight, while some flounder species may have a more pronounced arch or curve over the pectoral fin. The texture of their skin and scales offers another clue; plaice generally have smooth skin when rubbed from tail to head, unlike some other flatfish like dab which can feel rough. Flounder can have spiny scales, particularly at the base of their dorsal and anal fins.
Habitat and Geographic Range
Plaice and flounder exhibit differing aquatic preferences. European plaice are typically found in sandy sea beds, often hiding themselves within the substrate. They inhabit coastal waters and can migrate to deeper offshore areas, reaching depths of around 200 meters as they mature.
Flounder species show greater adaptability to varying salinity levels. Many flounder species are known for their tolerance to brackish water, and some can even be found in freshwater estuaries. Geographically, European plaice are prevalent in the North Atlantic, particularly around the British Isles and European waters, where they are a significant commercial species. Flounder species are more widespread, with various types found in both the Atlantic and Pacific oceans, including American and Alaska plaice, which are technically types of flounder.
Culinary Considerations
The culinary attributes of plaice and flounder present subtle differences. Plaice is known for its moist, very fine, and delicate texture, which can be almost creamy when prepared correctly. It has a distinctive, mild taste, often described as having an umami-like quality that stands well on its own. Flounder also offers a mild flavor and a delicate, white flesh, comparable to tilapia in texture, but it can be softer and more prone to falling apart if not handled carefully during cooking.
Both flatfish are popular food choices and can be prepared in various ways. Plaice is often pan-fried, baked, or steamed, and its delicate flesh benefits from gentle cooking methods. Flounder is also frequently fried whole, and its mild taste makes it versatile for different culinary applications.
In terms of availability and market value, European plaice is a principal commercial flatfish in Europe. American plaice is a significant commercial catch in North America. Flounder species are also widely available and are a common target for both commercial and recreational fishing, contributing to their presence in fish markets globally.