The Soles are flatfishes of various families. Narrowly speaking, they are the members of the family Soleidae, but, outside Europe, the name 'sole' is also applied to various other similar flatfish, especially other members of the sole suborder Soleoidei as well as members of the flounder family. The True Sole solea solea is sufficiently broadly distributed that it is not considered a threatened species;

however, overfishing in Europe has produced severely diminished populations, with declining catches in many regions. For example, the western English Channel and Irish Sea sole fisheries face potential collapse according to data in the UK Biodiversity Action Plan.

In European cookery, there are several species which may be considered 'true' soles, but the common or Dover sole Solea solea, often simply called the 'sole', is the most esteemed and most widely available. (Davidson)

The name 'sole' comes from its resemblance to a sandal, Latin solea. In other languages, it is named for the tongue, e.g. German Zunge, Spanish lenguado.

The name 'sole' outside Europe presents a confusing picture. Davidson says:

In North America, the two names [sole and flounder] are applied in what seems like a haphazard manner across the whole range of flatfish.... So on seeing what we call a sole an American would be apt to describe it as a flounder. If served what we call a flounder he would probably wonder why it had been deprived of the more honorific title of sole. The situation is irremediable. (Davidson, 1972, p. 224)

Indeed, in North American restaurants, the name 'sole' is often used to name any small flatfish, especially when filleted.

Worldwide, members of several groups of flatfish are called 'soles'. A complete list can be found using Fishbase's search function. They include:

In the sole suborder Soleoidei:

• The true soles Soleidae, including the common or Dover sole Solea solea. These are the only fishes called 'soles' in Europe.
• The American soles Achiridae, sometimes classified among the Soleidae.
• The tongue soles or tonguesoles Cynoglossidae, whose common names usually include the word 'tongue'.
• Several species of righteye flounder in the family Pleuronectidae, including the lemon sole, the Pacific Dover sole, and the petrale sole.

Threats
Sole, along with the other major bottom-feeding fish in the North Sea such as cod, monkfish, and plaice, is listed by the ICES as "outside safe biological limits." Moreover, they are growing less quickly now and are rarely older than six years, although they can reach forty. World stocks of large predatory fish and large ground fish such as sole and flounder were estimated in 2003 to be only about 10% of pre-industrial levels. According to the World Wildlife Fund in 2006, "of the nine sole stocks, seven are overfished with the status of the remaining two unknown."

This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)