Tracking snapper in the Gulf
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.