Factors affected the decline rainbow trout rearing in Neour Lake

Neour Lake is a beautiful 250 ha lake locating 78 km north of Ardabil city. This investigstion have been condacted monthly in 2014 to evaluate the cause of trout rearing declining in Neour Lake. The lake was fishless until 1973 when trout were first introduced. The shallow lake (mean depth=3 m) supported a productive benthic fauna in particular amphipod gamaros and probably a high density of large cladocerans and copepods often found in many fishless lakes. The introduced trout grew rapidly and trout rearing/restocking worked well until 2007s, when department of environment experts noticed that growth, survival, and harvest of rainbow trout began to decline. Multiple hypotheses were sugested until in this investigation we find that the invasive species of Carassius gibelio introduced 1n 2002 and successfully established populations over short period which was The principal threat to rainbow trout.the food web investigation in zooplankton and benthic macroinvertebrates resources and amphipod gammarus showed that trout were being out-competed for their prey, zooplankton and benthic invertebrates by invasive C. gibelio.

کلیدواژه ها:

Neour Lake ، Rainbow trout ، Carassius gibelio.