KEY POINTS:
Shark expert Malcolm Francis will try and tag a great white shark tomorrow off the Kapiti Coast, but admits the job's easier said than done.
Dr Francis, a fisheries scientist from the National Institute of Water and Atmospheric Research (Niwa), is leading an expedition to attach electronic monitoring tags after a cluster of shark sightings on the coast north of Wellington.
However, tagging the sharks was not always an easy process, Dr Francis said.
"We have to attract them to the boat, then we use a long pole that has a sort of needle tip on it, and we have a little plastic anchor on a tag and that slides over the needle tip.
"When it's close enough and at, hopefully, the right angle, with the dorsal fin nearby, you use the pole to stab the anchor just under the skin as it swims by."
He said although shark's skin was fairly soft and the anchor usually went in pretty easily, it did not always work out.
"You've got to have a cooperative shark and everything's got to work just right."
Attracting a shark to the boat - by throwing a burley mixture and dead fish over the side - was sometimes difficult, Dr Francis said, and often it depended on the day.
"We had one expedition to the Chathams a couple years ago where we saw sharks just about every day, but we couldn't get them anywhere near the boat and, despite having a week on the water, we didn't tag anything.
In contrast, he said they had tagged seven sharks in the space of three days on an earlier trip to the exact same spot .
Accompanying Dr Francis on the trip are a group of men who had a run in with a great white shark whilst diving off the Kapiti Coast on Saturday.
The shark, which was about four metres long, circled their boat for more than an hour.
Other big shark sightings have been reported by fishermen and surfers around Kapiti Island and off shore at Peka Peka, at least one of which was at the same time as the divers had their close encounter.
Tagged sharks have been known to travel thousands of kilometres and to depths of more than 900m.
In December a 4.4m female great white, nicknamed Kerri, set a distance record for a New Zealand shark by swimming more than 3000km to Australia's Great Barrier Reef after being tagged off Stewart Island in March.
Tags, which record location, depth and temperatures, are released after a pre-determined time. The tag then floats to the surface and transmits data to a satellite, which emails the results to scientists' computers.
There have been about 45 unprovoked shark attacks recorded in New Zealand since 1852, nine of which were fatal.
- NZPA
