Lake Kununurra was formed through the building of the Kununurra Diversion Dam (KDD). This cut the migratory pathways for catadromous fish, such as barramundi, moving from the Ord River estuary system upstream into much of the freshwater environment of the river. However due to the design nature of the dam’s water release points, the downstream flow of fish was less inhibited. As a result, trapped populations of those impacted fish either moved downstream for breeding purposes or lived out their lives in the dam and slowly died off. The result was the gradual loss of some fish species to the upper regions of the river. In 1972, the Ord Dam was constructed about 55km upstream of the KDD, forming what is now known as Lake Argyle.