New University of Otago research shows whitebait can rapidly switch their life-cycles following significant events, like earthquakes.
Whitebait are the juveniles of five species of Galaxiidae — a family of fish confined to the southern hemisphere.
The fish usually go to sea as juveniles in autumn, and then migrate back into rivers during spring, where they are caught as whitebait.
Senior author and zoology researcher Prof Jonathan Waters said they found whitebait undergo dramatic biological shifts when their paths to the sea become blocked.
‘‘In New Zealand, earthquakes have caused major landslides, which have formed new lakes and prevented whitebait from going to sea.
‘‘Our research shows that whitebait isolated in lakes, can rapidly swap their life-cycles, so they are breeding in spring instead of autumn, to take advantage of increased lake productivity over the summer.’’
Published in the journal Nature Communications, the study compared the genetics of landlocked whitebait with migratory whitebait and found that some of the sea-going fish were ‘‘jackpot’’ individuals carrying the ability to adapt to landlocking.
Lead author and zoology master of science student Ash Iwikau said they found a small part of the whitebait genome, which was crucial for adapting to lake conditions.
‘‘It’s almost as though the fish are pre-adapted to cope with environmental change,’’ she said.
‘‘This research provides unique insights into how genomes can be structured to enable animals to keep pace with ecological change.’’
Co-author and zoology research colleague Prof Gerry Closs said whitebait that lived solely in lakes had evolved to become smaller and weaker than marine whitebait, which needed to be strong swimmers in rough coastal waters.
‘‘Interestingly, our research shows that sea-going whitebait are far more muscular and fast-growing than landlocked whitebait, which may have relevance for future whitebait aquaculture,’’ he said.
