Science Centres: Fisheries

Sleeping snapper. If you catch a tagged snapper, you could be in to win a rod and reel combo. (Photo: Richard Taylor, University of Auckland)

NIWA launched a major study of snapper movements in the Hauraki Gulf this month to help understand what keeps this recreational fishery so productive.

We’re tagging up to 4000 snapper with external streamer tags from two commercial longliners in the inner gulf. Tag returns from recreational and commercial fishers – combined with night surveys of snapper, aerial boat surveys, and boat ramp interviews – will provide information on snapper movements to help us understand what makes the population tick.

In particular, we’re interested in testing the idea that hotspots for snapper (and snapper fishers) are actually population ‘sinks’ – where fish caught are replaced by snapper moving in from surrounding ‘source’ areas.

‘We think that something about the sink areas – for instance, more complex seafloor structure – makes them more attractive to snapper than the source areas’, says project leader Dr Mark Morrison.

Initial results from night counts of sleeping snapper show more snapper in complex seabed habitats, which we’ve surveyed using multibeam bathymetry, digital sidescan sonar, and underwater video.

This research forms part of a wider study investigating the interactions of recreational fishing (in the Hauraki Gulf) and tourism (around the Poor Knights Islands) with their underpinning marine ecosystems. The four-year study is being funded by the Foundation for Research, Science & Technology.  

What to do if you find a tagged fish

• Remove the tag, and call 09 375 2050 (this number is written on the tag).
• You will be asked for the number on the tag, where and when you caught the fish (GPS coordinates would be ideal if you have them), whether you caught it over sand or reef, and what its length was.
• You will then be sent a pre-paid, self-addressed envelope in which to return the tag to NIWA. 

For further information, please contact:

Dr Darren Parsons
NIWA Science
Tel: +64 9 375 4531
Mob: +64 27 288 4956
d.parsons@niwa.co.nz

Dr Mark Morrison
NIWA Science
Tel: +64 9 375 2063
m.morrison@niwa.co.nz