A sole fish is a type of flatfish that lives half-buried in the muddy bottom of the ocean. As an adaptation, both of the fish's eyes are on the topside of its body. These fish are prized for their flesh, with common sole being the most sought after.
As with all flatfish, the sole is born as a normal-looking fry. As it matures, one of its eyes begins to migrate from one side until it's very close to the other eye. The eyes of the common sole are on the right side of its body. The sole eats marine worms and shrimp.
Right-eyed or left-eyed? Flounder or sole?
Which halibut is really a flounder? And just what is a sanddab?
When it comes to terminology, the huge family of flatfish is more than a little confusing. In the U.S., commercial fishermen catch more than a dozen different flatfish species, some are called flounder, some are called sole, some are called both. But there is one thing most of these fish have in common: sweet, delicate white flesh that chefs and consumers everywhere enjoy. All flatfish belong to the order Pleuronectiformes, which means they have both of their eyes on the same side of their head.
All flatfish start out life looking like normal fish, but after a few weeks, one eye migrates to the other side of their head, their bodies flatten, one side turns dark and one side white and they settle to the bottom. The meat from a flatfish typically varies in color: fillets from the bottom (white) side of the fish will be thinner and whiter, while fillets from the top (dark) side will be thicker and more gray. Even though many of them are called soles, all the flatfish fished commercially in the U.S. are really flounders. There are two flounder families: the right-eyed Pleuronectidae family and the left-eyed Bothidae family. More than a million tons of flounders are landed throughout the world each year.
True soles belong to the Soleidae family. The highest value sole, the true Dover sole, Solea solea, is fished in the eastern North Atlantic off Europe. Small quantities of true Dover are exported to white tablecloth restaurants in the U.S., primarily on the East Coast.
The largest flatfish fishery in the U.S. is for yellowfin sole, Limanda aspera, a small flounder that averages less than a pound. Factory trawlers fishing off Alaska land more than 100,000 tons of yellowfin each year. Almost all of this catch is exported to China, where it is filleted and re-exported back to the U.S. and Canada.
Arrowtooth flounder, Atheresthes stomias, which is found from California to Alaska, is a very large resource. Because it has a soft flesh, fishermen often try to avoid the low-value arrowtooth, especially in Alaska. To make it more marketable, arrowtooth is usually sold on the West Coast as turbot, although it is not related to the true turbot (Psetta maxima) caught off Europe, which is the most expensive flatfish in the world. Arrowtooth can grow quite large, reaching more than 15 pounds. About 5,000 tons of arrowtooth are landed off the West Coast each year. Greenland turbot, Reinhardtius hippoglossoides, which is caught in both the North Atlantic and North Pacific oceans, is not really a turbot either, but instead is a member of the halibut family (outside of North America it is called Greenland halibut or black halibut). To avoid marketing confusion with Pacific halibut, the halibut industry successfully lobbied to have the name of this flatfish changed to turbot.
California halibut, Paralichthys californicus, is actually a left-eyed flounder. This big flounder, which can grow to 40 pounds, is fished in the winter and spring by gillnetters in California and Mexico. A small resource, annual U.S. landings are about 250 tons.
Fluke is a common name for summer flounder, Paralichthys dentatus, a popular East Coast flatfish that occurs from the southern Gulf of Maine to South Carolina. Because it is a closely related species, California halibut may also be called fluke on occasion.
Pacific sanddab, Citharichthys sordidus, is a left-eyed flounder. Although it is found from Baja California to the Bering Sea, this fish is most abundant off the California coast. Although they’re a small fish, usually less than 1/2 pound in size, Pacific sanddab, which are usually marketed pan-ready, are excellent eating.
American plaice, Hippoglossoides platessoides, is a significant flounder resource in the northwest North Atlantic. U.S. catches of plaice, which is also called sandab or dab, average about 5,000 tons. Catches of plaice in Canada have been as large as 60,000 tons, however, in recent years they have been less than 5,000 tons. Depending upon the market, plaice is sold generically as either flounder or sole.
Alaska plaice, Pleuronectes quadrituberculatus, is a medium-sized flounder that produces thick chunky fillets that average 4-6 ounces. Although it is caught mainly as a bycatch by factory trawlers in the Bering Sea, significant quantities of Alaska plaice are “refreshed” by seafood processors in the Lower 48.
Rex sole, Errex zachirus, are found from Baja California to the Bering Sea. Off the West Coast, landings are less than 1,000 tons a year, however, in Alaska they are larger. A small fish normally under 2 pounds, rex sole are one of the better eating flounders and are often sold pan ready.
English sole, Pleuronectes vetulus, is another small flounder resource, which is landed as a bycatch off the West Coast. Annual landings are about 1,000 tons a year. A small fish averaging under a pound in size, English sole produce fillets that average 1 to 2 ounces.
Rock sole, Lepidopsetta bilineata, which is fished in the Bering Sea off Alaska, is the second largest flatfish fishery in the U.S., with average annual catches of about 60,000 tons. Rock sole are fished from mid January to March prior to spawning. Although the primary market is roe-in females for Japan, some male rock sole is exported to China, where it is filleted and exported back to the U.S. Although they can reach a size of 5 pounds, most rock sole are less than 2 pounds and produce fillets between 2 to 4 ounces.
Starry flounder, Platichthys stellatus, is an excellent flounder, which is often caught as a byctach in salmon troll fisheries. A big fish with a firmer texture than other flounders, starry flounders can reach 10 to 15 pounds in size.
