Seafood with Concerns Blue cod Scientific name: Parapercis colias Other names: kopukopu, paakirikiri, paatutuki, raawaru (Maori), New Zealand cod, sand perch Ranking: D (Amber - Concerns)

Icon Explanations

The main concerns with this fishery 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. The impact of trawling on long-lived, slow-growing fragile corals and sponges is also of major concern as they are broken when large and heavy baited pots drop onto them in deeper waters. Other concerns the lack of a management plan.

The fishery assessment plenary report states: "For BCO 1,2,3,4,5 and 8 recent commercial catch levels and current TACCs are considered sustainable and are probably at levels that will allow the stocks to move towards size that will support the MSY." But "For BCO 7 it is not known if the combined recreational and commercial catches are sustainable or if they are at levels that will allow the stock to move towards a size that will support the maximum sustainable yield." (MFish 2007, p129)

Market: New Zealand and main exports to Australia, Malaysia, China and Taiwan of about $1 million.

Status and sustainable yield
Status: Uncertain.
Annual catch limit: Set at 2,680 tonnes in 2001-02.
Recorded catch: Reported landings of 2,184 tonnes in 2005-06.
Population size: Unknown.
Stock trends: Unknown but a decline of over 40% in 6 years is indicated in Marlborough Sounds from pot survey and recreational fishers suggested local depletion in parts of BCO3, BCO5 and BCO7. BCO5 productivity appears to be affected by dredging for oysters (Cranfield et al 2001).

Fishing method
Method: Mostly target caught in pots but some are caught on hand lines, and as bycatch of inshore trawl species. Apart from area BCO5 no size limits are required for pot mesh.
Habitat damage: Long-lived, slow growing soft corals, sponges and bryozoans are broken when large heavy baited pots are dropped on them. Trawlers also scrape and damage the seabed.
Bycatch: Shags drown in pots.
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.

Management
Stock assessment: No quantitative stock assessment for any areas.
Management plan: No.
Quota Management Species: Yes, since 1986.

Biology
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): 20
Age at sexual maturity: 2-6 years - all blue cod start life as females, with only some changing into males when they reach a larger size.
Growth rate: Moderate.
Reproductive output: Medium to high.
Age exploited: Enter commercial fishery at 7-12 years.

References: Report from the Fishery Assessment Plenary, May 2007: stock assessments and yield estimates. Part 1: Albacore to Groper, Science Group, Ministry of Fisheries; Guidebook to New Zealand Commercial Fish Species, Revised Edition 1990, NZ Fishing Industry Board. Cranfield H J, 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. NZ J of Marine and Freshwater Research, 2001, Vol. 35.

This page was updated on 4 November, 2005