Perch

perch a name applied to various fish, notably Perca fluviatilis, a moderate-sized (maximum length 50 cm/20") Eurasian river and lake fish which has been widely introduced elsewhere for the benefit of anglers and because it is considered to be a good food fish. The yellow perch of N. America is almost indistinguishable from the European perch, but often classified separately as P. flavescens.

The name perch has been applied, by extension, to other species, freshwater or marine, which display characteristics (e.g. two distinct dorsal fins) similar to those of P. fluviatilis, especially members of the very large family Percidae. However, the English-speaking colonists who encountered fish in other continents and often had the privilege of bestowing common names on them were not, understandably, as systematic as ichthyologists would have been in their use of the name perch. Thus the climbing perches of Africa and Asia would not, ideally, be called perches at all. And the name ‘sea perch’ has been bestowed in such a seemingly random fashion that it has little meaning except in a local context. Morone americana, called sea perch (or white perch) in N. America, belongs to the grouper family, Serranidae. On the other hand Sander vitreus, which does belong to the family Percidae, is not called perch but walleye (although S. lucioperca is called pike-perch). Examples of such inconsistencies, inevitable since perchlike fish are so numerous, could be multiplied many times.