This title might seem like a uniquely Japanese question. However, in neighboring countries like Korea and China, flounder (karai) and halibut (hirame) are also commonly eaten, and efforts are being made to cultivate them.
In many other countries, however, these fish are not distinguished and are often lumped together as “flatfish.”
One reason is the broad range of species covered by the English term “flounder.” For instance, many species like flounder, plaice, halibut, lemon sole, common dab, Pacific Dover sole, and fluke are all grouped under “karei.” Even the names alone can be confusing.
The common method to distinguish hirame and karei is the rule that when placed belly-side down (the white side), the hirame faces left and the karei faces right. However, there are exceptions like Numagarei (Starry flounder).
Species in the Pleuronectidae family, whose eyes are on the right side, are known as “righteye flounders,” while those in families such as Paralichthyidae and Bothidae, with eyes on the left, are called “lefteye flounders.”
Similarities and Differences Between Karei and Hirame
Both karei and hirame belong to the order Pleuronectiformes and share very similar shapes and colors. They both have flat bodies, are asymmetrical, and possess the unique characteristic of having both eyes on one side of their body.
What is Karei?
Flounder encompasses a vast number of species with a wide distribution range. In Japanese coastal waters alone, approximately 40 species have been identified, including Magarei (Yellow striped flounder), Meitagarei (Ridged-eye flounder), Ishigarei (Stone flounder), and Makogarei (Marbled flounder). The species caught also vary by region.
As they are relatively inactive fish, their flesh is characterized as soft and rich in fat. They feed on small fish, ragworms, and small crustaceans, resulting in a small mouth shaped like a “pursed mouth.” Additionally, their eyes are located on the right side of their body.
While fresh specimens can be eaten as sashimi, they generally have a slight distinctive flavor. Therefore, they are typically enjoyed cooked through methods like simmering, frying, deep-frying, or drying.
What is Hirame?
Compared to karei, hirame has fewer species and a narrower distribution, making it relatively rare. Its scientific name is Paralichthys olivaceus, and it is a premium fish found in the coastal waters of Japan and Korea.
Hirame has well-developed muscles for agile movement, resulting in firm flesh. It has a large mouth and sharp teeth for catching small fish and crustaceans, and its eyes are located on the left side of its body.
When eaten raw, it has a crisp, firm texture that turns tender and flaky when cooked. It’s known for its mild flavor and delicate umami. It is popular as a premium ingredient for sushi and sashimi, and in French cuisine, it is also used in main dishes like meunière.
Its peak season runs from late autumn to early spring, with the winter variety, “Kanbirame,” boasting particularly rich fat content and exceptional flavor.
Conclusion
While karei and hirame may look similar, they have distinct differences in taste, texture, and ecology. In Japan, summer Makogarei (Marbled flounder) and winter Bastard halibut (Hirame) are considered premium fish, highly prized in sushi restaurants and traditional Japanese restaurants. Understanding these differences enhances the enjoyment of dining at sushi establishments.