One species of New Zealand whitebait can climb waterfalls, scientist Dr Bob McDowell says.
Dr McDowell, who recently retired from the National Institute of Water and Atmospheric Research (Niwa), gave the keynote speech on whitebait at a Greymouth conference on fresh water ecology (limnology) yesterday.
His speech focused on five species of whitebait and factors affecting their migration - the fish return to fresh water after spending their first winter feeding at sea.
He found different rivers, streams and tributaries turned up different whitebait species.
"Fish are choosing where they're going," he said.
For example, koara preferred cold waters and did not like more acidic bush streams.
Dr McDowell said that in addition to his earlier body of work, he had recently made an interesting discovery about koara.
"They have calluses inside their fins, which means they have sharp edges - this explains why they can climb waterfalls."
Conference organiser Philippe Gerbeaux said much of Dr McDowell's research had been conducted in the 1970s and had recently been validated by new research.
Mr Gerbeaux also suggested that lower catches being recorded today were partly the result of overfishing.
Dr McDowell noted that when he worked in South Westland, one man caught 200 kerosene tins of whitebait - worth around $150,000 today.
His key research was undertaken on the Waitoto River, which used to be fished by around 25 people. Dr McDowell said if the 180 who fished it now had done so 30 years ago, they would have heavily depleted the whitebait population in the river.
The limnology conference runs until November 14.
- NZPA
Further reading
nzherald.co.nz/environment
Whitebait can climb waterfalls
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