Thousands of people fish the Goulburn River every year, and many like to eat the fish they catch.
So for every fish taken out of the Goulburn, another has to be put back — by nature or by humans. Before the river was regulated with weirs and dams, native and introduced fish could breed naturally. But many species — like Murray cod and trout — need to migrate upstream to breed, and some need water warmer than the water that comes out of Lake Eildon.
So fish are bred artificially and let go into Lake Eildon, the Eildon pondage, and the river for people to catch.