Collection of kingfish heads and lengths is being finalised in Northland/ Hauraki Gulf.  We have exceeded the target number of otoliths and lengths for this region.  Thanks to those fishers in the region who have participated.

Bay of Islands Yellowtail Tournament

A very successful BOI Yellowtail Tournament has almost got the Northland sample up to the target level. A total of 226 lengths were collected and 48 sets of otoliths extracted. Great work Kaye and thanks to all the skippers and helpers who lent a hand.

Northland/HGulf progress

Collection of kingfish heads and lengths is being finalised in Northland/ Hauraki Gulf.  We have exceeded the target number of otoliths and lengths for this region.  The number of otoliths collected in each length class is shown below.  There is good coverage for fish up to 1100 mm in length and a few larger fish.

The intention was to get 5 samples to age per size class (blue line on graph). Some of the larger fish have been hard to land in a measurable state because of attention from sharks. There is still some data to come in from some fishers – please contact us with your data sheets and heads.

Bay of Plenty progress

Winter is a slow time to collect data from the Bay of Plenty.  We have more than 260 BOP lengths in the database, but are looking for as many more as possible in the next two months.  We aim to have a BOP sample that matches what we have retrieved from Northland/Hauraki Gulf. 

Please let us know if you have data sheets or labelled heads of BOP fish that are larger than 750 mm.
 

Age, length and weight

We know that kingfish weight can vary with condition. However, kingfish length is more reliably correlated with age.  This is one very good reason that fisheries scientists use length rather than weight when characterising fish populations. 

Below, is a graph showing the best information currently available at the moment, for New Zealand kingfish reproduction, age and growth. It shows 50% of the female kingfish attain reproductive maturity at 950mm fork length (red line). These fish will be about 9 years of age. In contrast, 50% of male kingfish will attain maturity at 820mm or about 7 years old.  The green line gives an average weight (read against the right hand scale) of 10 kg for females and 7 kg for males when they first mature.

Current indications are that there are plenty of adult kingfish in the wider New Zealand region and that egg production is not limiting the potential of this fishery.