Blue cod

Scientific name:	Parapercis colias
Other names:	kopukopu, paakirikiri, paatutuki, raawaru (Maori), New Zealand cod, sand perch, taragisu (Japan)

Best or alternative choice

Blue cod caught by pots are a good seafood choice, and the best region is Southland. Blue cod caught by trawling is ranked red, worst seafood choice and should be avoided.

Description

Blue cod is an endemic bottom dwelling species that is relatively common throughout New Zealand but is most abundant south of Cook Strait.

Blue cod is caught using bottom trawls and pots. Potting is the better method than trawling, with less environmental impact such as benthic impact and protected bycatch. Other concerns are the unknown sustainability of current catch limits, which are significantly greater than yield estimates based on past average catches, the combined commercial and recreational catches, plus limited research. There are concerns over the impact of bottom trawling on long-lived, slow-growing fragile corals and sponges. Large and heavily baited pots can also damage seafloor species when dropped on sensitive habitats.

Certification

Not certified under any scheme.

Economic value

New Zealand markets plus exports to China, Australia, Singapore and Hong Kong of about $409,000 in 2015.

Asssessment output

Regional and or fishing method differences

Blue cod was assessed as bottom trawl-caught and pot-caught, and also for regional differences. Blue cod caught by pots were the most sustainable and are a good seafood choice, rating amber. The best regional pot-caught blue cod was lower South Island. Trawl-caught blue cod ranked red, a worst seafood choice which should be avoided.

Status of seafood stocks - sustainability of catches

Score:	D
Population size:	Unknown
Annual catch limit:	Limit set at 2,332 tonnes since 2011-12 with reductions in Southland and West Coast North Island quota areas, taking these area catch limits closer to actual catches.
Recorded catch:	Reported landings of 2,198 tonnes in 2014-15, the third lowest in 10 years. BCO 5 makes up about 50% of the reported catch.
Stock trends:	BC03: Unlikely to be below 20%Bo and biomass has likely increased since 2008-09. BCO4: Current catches are unlikely to be causing a decline. BCO5: “The current catch and TACC are unlikely to cause the stock to decline.” Other areas: Unknown.
MSY Status:	Uncertain
*The Ministry of Primary Industries assessment plenary report includes:*	“For BCO 1 and 8 recent commercial catch levels are considered sustainable.” For BCO3: “Overfishing is About as Likely as Not to be occurring.” Unlikely to be below 20%Bo and biomass has likely increased since 2008-09. BCO4: “The current catch and TACC are unlikely to cause the stock to decline.” Very unlikely to be below the soft limit (20%Bo). BCO5: B₂₀₁₃ was estimated to be 39.4% of Bo. BCO5 biomass is expected to stay steady over the next 5 to 10 years at the 2012 TACC which approximates that 2012 catch. BCO7: Stock status in relation to targets and limits is unknown. “It is unknown whether biomass will continue to decline under current management controls.” (MPI 2016, p 157-167)

Biological characteristics - risk of overfishing and ability to recover

Score:	C
Distribution:	Blue cod is a bottom dwelling species found mainly inshore off southern New Zealand and the Chatham Islands to depths of 150m. The main fisheries occur off Southland and the Chatham Islands with smaller but significant fisheries off Otago, Marlborough Sounds and Wanganui.
Maximum age (years):	32
Age at sexual maturity:	2-6 years. All blue cod start life as females, with some changing into males when older.
Growth rate:	Moderate
Reproductive output:	Medium to high
Age exploited:	Enter commercial fishery at 2-6 years.
Ability to recover:	Moderate

Fishing method impacts including non-threatened species bycatch & habitat damage

Score:	Pot – B, trawl – E
Fishing method(s):	Blue cod is caught using trawl nets and potting. The pot fishery dominates southern waters: about two-thirds in Canterbury/Otago, all of the Chathams, and all Southland region fishing. The trawl fishery is mainly bycatch by the inshore trawl fleet in BCO 3 and BCO 7 – which includes targeting flatfish, red cod and tarakihi.
Habitat damage:	Pot: Is a relatively selective method with little habitat impact unless heavy baited pots are placed on fragile reefs or corals, sponges or bryozoans. Trawl: Damage to seafloor communities when caught by bottom trawl. Trawlers impact on benthic species by scraping and damaging the seabed and associated species. Given the low observer coverage the benthic impacts of inshore bottom fishing has been poorly documented. Impacts include habitat modification, loss of biodiversity, loss of benthic productivity and modification of important breeding and juvenile fish habitat.
Habitat of particular significance:	hasn’t been defined in New Zealand.
Bycatch:	Pot: Bycatch in pots is very low. Apart from area BCO5 there are no limits on the size of mesh used in pots. This increases the chance of small fish being caught. Trawl: Inshore trawls have a wide range of non-threatened species bycatch.
Ecological effects:	The combined effects of a loss of large blue cod which are easily caught in fisheries, the bycatch caught in trawl fisheries, and the serial depletion of blue cod may all be having a degree of adverse impacts on the wider marine ecosystem.

Protected species or threatened species bycatch

Score:

Pot – A, trawl – D

Bycatch:

Pot: Bycatch of protected species is very low.

Trawl: Inshore trawl fisheries have an estimated seabird bycatch of 4370 seabirds (this includes cryptic mortality of birds that strike the trawl warps and are not recovered in the nets). Species reported include white-capped albatross, Salvin’s albatross and white-chinned petrels. Fur seal captures have also been estimated in the inshore trawl fisheries at about 20 per year.

Unit of seafood stock arrangement

Score:	C
Management component:	Single species. It is likely that there are several populations within each current management area, especially where there are inlets and sounds.

Effectiveness of management, monitoring, & research

Score:	D
Quota Management Species:	Yes, since 1986.
Catch limits:	Yes
Management plan:	There is no approved inshore plan.
Stock assessment:	No quantitative stock assessment for any areas.
Research:	Research has focused on developing stock assessments based on potting.
Observer coverage:	Potting is unobserved. About 1.5% for the inshore trawl fishery over the last 5 years but it is not spatially or temporally representative of the fishing effort.

Fisheries map

Taken from the Ministry for Primary Industries’ Plenary report for fisheries management.

References

Report from the Fishery Assessment Plenary, May 2016: stock assessments and yield estimates. Part 1: Introductory Section to Hoki, Science Group, Ministry for Primary Industries; Ministry for Primary Industries (2016) Aquatic Environment and Biodiversity Annual Review 2015. Compiled by the Fisheries Management Science Team, Ministry for Primary Industries. 682p. The Guidebook to New Zealand Commercial Fish Species, 2007 Revised Edition, The New Zealand Seafood Industry Council Ltd. Seafood New Zealand, 2016. New Zealand Seafood Exports to December 2015. 133p. H J Cranfield, G Carbines, K P Michael, A Dunn, D R Stotter, D J Smith (2001) Promising signs of regeneration of blue cod and oyster habitat changed by dredging in Foveaux Strait, southern New Zealand. New Zealand J of Marine and Freshwater Research, 2001, Vol. 35. Thompson, F.N.; Berkenbusch, K.; Abraham, E.R.(2013). Marine mammal bycatch in New Zealand trawl fisheries, 1995–96 to 2010–11. New Zealand Aquatic Environment and Biodiversity Report No. 105. 73p.