The first recorded attempt to bring salmon and trout eggs the 12 000 miles from England was in 1852. The journey took four months and the eggs were stored in a tub of fresh water that was topped up four times a day. The eggs all died. Subsequent attempts used up to 25 tons of ice to produce cool water which ran over the eggs in trays. However, the ice supply inevitably ran out before the end of the voyage, with fatal results.
Finally, in 1864, salmon and trout eggs from England were packed in moss in boxes and stored in an ice-house aboard ship. While many of the eggs still died, enough remained to produce hatchlings. By 8 June 1864, 300 healthy trout and several thousand salmon were observed in the Salmon Pond in Tasmania’s Derwent Valley. The first fish were released the following year.
While the salmon disappeared and were never seen again, trout appeared to adapt well to local conditions. They were later introduced on the mainland of Australia. The first successful introduction in New South Wales and the Canberra region was in 1888, when a number were released into the Cotter, Naas, Molonglo and Queanbeyan rivers. Trout stocks have been maintained over the years by government-run hatcheries. Rainbow trout, native to North America, were introduced to New South Wales from New Zealand (where they had been previously established) in 1894. Acclimatisation societies then transferred the fish into Victoria and Tasmania.
However, not everyone appreciates the trout. This introduced species has played havoc with Australian ecosystems, putting stress on frog populations by eating their tadpoles, and depleting populations of native fish. The International Union for the Conservation of Nature ranks brown and rainbow trout in the top 100 of the world’s worst invasive alien species.