uniquely significant fresh water fishes of iran are exposure to environmental stress

the native fishes of springs, ghanats and caves of iran are uniquely significant, since they are rear and, because of pollution, dryness, . purposeful or accidental introduction of exotic species and over all, because of industrialization are in danger. the stock of valuable fishes of iran are declining while they have not been completely identified. the stock of these fishes, particularly those of economic value, such as large barbus sp. at western part of iran are declining. in an atempet fishes among the 140 station and average of three unit of effort for catch of fish in every station (total of 400 unit of effort) about 80 specimen of large barbus were caught. fishes were caught by electroshoker and various kind of net with mesh size of2cm to 4 em. the gamasib river was known to have large carp, but this result showed that nowadays the stock of large barbus substantially damaged. the stock of: b. subquincunciatus and b. grypus severely damaged. the purpose of this paper is to describe those factors, which affect the stock and abundance of iranian freshwater fishes, and to suggest measures for the conservation of this fauna. these factors include pre-industrial, and such factors related to industrialization and population increases as devegetation, water abstraction, fishing, pollution and faunal introductions. introduction of new species to increase fish production and exploit the fishery potential of waterbodies, can be great utility; but has many hazardous impacts on native species, biodiversity and ecology of the waterbodies. some aspect of theses impacts are outlined.