 Since the construction of the Canning Dam , among other drinking water supply dams , water flow into the Canning River has been reduced by up to 96 % . A number of freshwater fish species which are endemic to the south @-@ west of Western Australia are found in the Canning River system , however studies of fish and fish habitats in the area have shown that fish numbers are low due to a loss of habitat and a loss of linkage between breeding areas due to low flows , preventing fish migrating upstream and reaching important breeding and nursery grounds . Stagnant water caused by a lack of water flow has provided a suitable habitat for successful breeding of an introduced pest , the mosquitofish . 
 Since the construction of the Canning Dam , among other drinking water supply dams , water flow into the Canning River <a href='been_done' title='1'><mark>has</mark></a> been reduced by up to 96 % . A number of freshwater fish species which <a href='drop_aux' title='2'><mark>are</mark></a>endemic to the south @-@ west of Western Australia are found in the Canning River system , however studies of fish and fish habitats in the area <a href='been_done' title='3'><mark>have</mark></a> shown that fish numbers are low due to a loss of habitat and a loss of linkage between breeding areas due to low flows , preventing fish migrating upstream and reaching important breeding and nursery grounds . Stagnant water caused by a lack of water flow <a href='been_done' title='4'><mark>has</mark></a> provided a suitable habitat for successful breeding of an introduced pest , the mosquitofish . 
Since the construction of da Canning Dam , among other drinkin water supply dams , water flow into the Canning River done been reduced by up to 96 % . A number of freshwater fish species which endemic to the south @-@ west of Western Australia are found in the Canning River system , however studies of fish and fish habitats in tdaarea done shown dat fish numbers are low due to a loss of habitat and a loss of linkage between breeding areas due to low flows , preventing fish migrating upstream and reaching important breeding and nursery grounds . Stagnant water caused by a lack of water flow done provided a suitable habitat fa successful breeding of an introduced pest , the mosquitofish .