Blue cod
Introduction
Blue cod was introduced into the Quota Management System (QMS) in 1986. The commercial fishing year for blue cod is 1 October to 30 September the following year.
Fisheries New Zealand advise that national, annual landings of blue cod of up to 2400 tonnes (t) were reported in the 1930s and landings over 1500 t were sustained in the 1950s and 1960s.
Total landings averaged 574 t in the 1970s and reached 1546 t in 1985, prior the introduction of blue cod into the QMS in 1986. Historically, the largest catches of blue cod were taken in Blue cod 5 (BCO 5).
Biology
Blue cod are most abundant south of Cook Strait and around the Chatham Islands. Growth rates are likely influenced by a range of factors including sex, habitat quality and fishing pressure.
Blue cod have been known to change sex, from female to male, when individuals reach a large size. Research shows that blue cod males grow faster and larger than females. The maximum recorded age for blue cod is 32 years.
The average size of blue cod is 30-40cm, but can reach 60cm. Blue cod can weigh 1-3 kilos and can be found in depths to 150 metres.
Stock status
Fisheries New Zealand report that for Blue cod 1 and 8 recent commercial catch levels are considered sustainable. There is not much known about the status of the other stocks aside from Blue cod 5 (BCO 5).
FNZ assessed BCO 5 in 2020 and noted the biomass has been decreasing since about the year 2000. They estimate the BCO 5 stock size to be around 36% of estimated unfished biomass.
Catches
Table 1: Total Allowable Catches (TACs), Total Allowable Commercial Catches (TACCs) and allowances for blue cod, in tonnes (t).
| Fishstock | Recreational allowance | Māori customary allowance | Other mortality | TACC | TAC |
| BCO 1 | 2 | 2 | – | 46 | 50 |
| BCO 2 | – | – | – | 10 | 10 |
| BCO 3 | – | – | – | 163 | 163 |
| BCO 4 | – | – | – | 759 | 759 |
| BCO 5 | 191 | 2 | 20 | 1239 | 1452 |
| BCO 7 | 177 | 27 | 69 | 70 | 343 |
| BCO 8 | 188 | 2 | 2 | 34 | 226 |
| BCO 10 | – | – | – | 10 | 10 |
| TOTAL (t) | 558 | 33 | 91 | 2331 | 3013 |
Blue cod is an iconic species, important to recreational, Māori customary and commercial fishing interests.
In 1986 there was no requirement to set a Total Allowable Catch (TAC) or allowances for blue cod. In 1986 the Blue cod 7 Total Allowable Commercial Catch (TACC) was set at 110 tonnes which then increased over time to 136 t. In 1996 the TACC was reduced to 70 t. In 2003 a TAC was set and allowances were set aside for non-commercial fishing interests in BCO 7, these have remained unchanged since.
Between 2002 and 2011 the TACC in Blue cod 5 was 1548 t. In 2012 the BCO 5 TACC was reduced to 1239 t, and has remained unchanged since. Commercial catch in BCO 5 is mostly taken by the target cod pot fishery operating in Foveaux Strait and around Stewart Island, with some taken from Fiordland.
Blue cod is identified as a taonga species, a treasure, in the Te Waipounamu Iwi Form Fisheries Plan. No quantitative data on historical or current blue cod customary catch is available however there is evidence that blue cod was a significant part of early Māori’s diet.
Blue cod are recognised as the most important finfish for recreational fishers in Marlborough, Canterbury, Otago, Southland and the Chatham Islands. They are usually caught by rod and reel and to a lesser extent by longlining, set nets, potting and spearfishing. Recreational harvest from the Marlborough Sounds has been limited over time due to regulatory closures and strict harvesting controls.
The National Panel Survey estimated total recreational harvest for blue cod for the 2017-18 fishing year was 293 tonnes with most catch taken from BCO 3, 5 & 7. The most frequent bag size was two fish (34%) and 19% of survey respondents took a bag of one fish per day.
Management controls
There is a range of measures used to control recreational harvest of blue cod including minimum size limits, method restrictions and daily bag limits. These controls vary between areas. There have been several temporary and seasonal closures in the Marlborough Sounds and Fiordland.