Small silvery fish that occurs off beaches, in estuaries, lowland rivers and some lakes. Known only in New Zealand and Australia. Average size 6-10 cm.
This fish is the key to the Taupo (and other central North Island of New Zealand) trout fisheries.
Smelt were first introduced into Lake Taupo in 1934 to provide an alternative food source for the ailing trout population. Gone were the halcyon days of huge trout and twice in the preceding years the condition and size of the trout had crashed as the population of native fish, and the koura (freshwater crayfish), collapsed under the predatory pressure. On the first occasion, authorities allowed controlled netting in an attempt to reduce the size of the trout population and between 1913 and 1920, 103,000 trout were sold at markets in Wellington and Auckland to defray expenses.
The trout population made a remarkable recovery and the mid 1920s probably reflect the best years of the Taupo fishery, as epitomized in Zane Grey's writings. However, the recovery was short-lived and by the 1930s it was again apparent that the trout population had outgrown its food supply. Coincidentally, a similar situation was also occurring in Lakes Tarawera and Okataina and smelt which had been successfully released into Lake Rotorua in 1907 were in turn released into these lakes.
Within two years a huge turnaround occurred in the size and condition of the trout and so, not surprisingly the release of smelt from Lake Tarawera into Lake Taupo was trialled. Releases of smelt continued at intervals through to October 1939 and by 1940 smelt were clearly established in the lake. By 1942 smelt were a large part of the diet of Taupo trout which has remained unchanged today. In turn, trout size stabilized and their condition returned as the population finally achieved some sort of balance.