Characterisation of the Amateur Fishery for Kahawai (Arripis Trutta) in NZ

2004
Funding: $6,390


(including support from Massey University and Stanford University)

Researchers:
Paul Taylor, Dieter Ayers,
Bruce Hartill, Dave Fisher

Kahawai are highly valued by recreational and customary fisheries in many areas of New Zealand from the Far North to half way down the South Island. It is the second largest recreational fishery in the country, after snapper.

The Ministry were about to introduce kahawai to the Quota Management System (in 2004) without any study bring together all the information on the amateur fishery of Kahawai. The NZ Marine Research Foundation funded this study to fill that gap.

Approximately 70% of the recreational catch in area 1 (North Cape to Cape Runaway) is taken from private boats, mostly by fishers using baited hook and jigging methods, with around 20% of the catch taken by shore based fishers.

The main source of data on recreational fishers in area 1 is that collected during boat ramps surveys, which have been conducted intermittently since 1991. These data are used to characterise the recreational fishing season, the methods used and number of kahawai landed by fishers using hook & jig and trolling methods. Since 2001, boat ramp surveys have been conducted annually in KAH 1 to specifically collected length and age information for recreational fishers. Kahawai grow rapidly, attaining a length of around 15 cm at the end of their first year, and maturing after 3–5 years at about 35–40 cm, after which their growth rate slows.

There are two species of kahawai in New Zealand. By far the most common is Arripis trutta. There is also a Northern kahawai, Arripis xylabion, which grow considerably larger than kahawai. They are found around the Kermadec Islands and seasonally in the Far North but little is known about the biology of this species.

Further research:

The Ministry paid for a full characterisation of all New Zealand kahawai fisheries in 2005. Hundreds of pages of evidence on kahawai fisheries was produced on both sides of the Kahawai Legal Challenge which was in the High Court in 2006, Appeal Court in 2007 and Supreme Court in 2009. An age structured stock assessment in KAH 1 (area 1) was completed in 2009. This was revised and updated in 2015.