Kingfish monitoring

Introduction

Kingfish are a popular and challenging target species for many recreational fishers. They form a valuable component of the charter boat business with clients coming from around New Zealand and the world to test their angling skills against these hard fighting fish. Now there is growing demand for guided fly fishing trips sight fishing for kingfish in shallow water.

In New Zealand most popular fish stocks are monitored using commercial catch history and catch rates. However, most of commercial catch of kingfish is taken as small component of longline, trawl and setnet fishing targeting other species.  Kingfish is in the unique position of having a higher documented recreational landed catch (around 740 tonnes a year nationwide) than annual commercial landed catch (around 250 tonnes).

Only the recreational fishery targets kingfish and catches the full size range available. NIWA investigated the options for monitoring kingfish stocks and as a result the Ministry for Primary Industries (MPI) funded projects to monitor the size and age structure of the charter boat kingfish catch in north eastern New Zealand every five years.

Catch sampling

In 2009–10 a total of 2091 kingfish were measured aboard charter and selected private boats and 460 were aged.   All fish were assigned an age based on their length. East Northland had a lot of five year old fish and very few teenagers. In the Bay of Plenty six year olds formed the largest age class and there were more older fish.  The oldest fish aged was a 170 cm fish caught at White Island which was 24 years old.  The oldest and largest fish sampled in East Northland was a 156 cm fish (41.6 kg) caught in Bream Bay aged at 22 years.

The estimates of fishing mortality that year lead MPI to conclude that kingfish in the Bay of Plenty where fully exploited and over fishing was occurring in East Northland.  The 2010 NZSFC club records howerver, showed increasing availability and catch of mid-sized kingfish from 80 to 105 cm, probably from good spawning success in 2004 and 2005.  This pulse of fish could be the start of the stock rebuild we were all hoping for after the management decisions in 2003. 

Thanks to the cooperation of the Bay of Islands Swordfish Club and anglers in the Yellowtail International Tournament, researchers have been able to measure a good number of kingfish in July each year since 2010. Annual updates provided to the club and tournament fishers about this monitoring work features below.

The project estimating the size and age of kingfish in north eastern New Zealand was repeated in 2014-15 and a link to the full report is below.

Commercial kingfish catch

Warming ocean waters, particularly in the Tasman Sea in recent years, have seen an increase in trawl bycatch of kingfish on the west coast of the North Island and the top of the South Island.

Commercial catch rate data has been analysed and increases in the Total Allowable Catch have been proposed in 2020. Read more here.

Kingfish monitoring reports

Reports

Kingfish news