Salmon in New Zealand with special reference to the quinnat salmon

Abstract

Of the 3 species of salmon successfully acclimatised in New Zealand, the quinnat, Oncorhynchus tshawytscha (Walbaum) is the most widespread. It is found mainly in the east coast rivers of the South Island. Although adults live in the sea and return to freshwater to breed, lake populations have developed either voluntarily or because egress to the sea is blocked by dams. Sea-living adult quinnat salmon return to rivers in summer to spawn in their natal streams and once in freshwater, cease feeding and the gut degenerates. Eggs laid by the females in redds are fertilised by the male, after which both parents die. Most young salmon emerging from the redds migrate downstream but their fate is uncertain. The few remaining feed and grow and migrate to sea in early summer. Examination of the ridges on fish scales reveals information about migration patterns which assists in studies conducted by the Ministry of Agriculture and Fisheries in the Glenariffe Stream. Marking and tagging of smelts is expected to provide information on survival to adult return and on movements of salmon at sea. The quinnat is the salmon species most favoured by anglers and it is also considered to have a commercial future in New Zealand, using the method of ocean ranching.