Seafood with Concerns Silver warehou Scientific name: Seriolella punctata Other names: Spotted warehou Ranking: D (Amber - Concerns)

Icon Explanations

The main concerns with this fishery are: the unknown sustainability of current catch levels and limits, overfishing of current catch limits, the lack of current or reference biomass estimates, the uncertainty about stock boundaries, problems over past mis-reporting of silver warehou as white warehou, the absence of a quantitative stock assessment and the lack of a management plan. Trawling impacts on seabed habitats and communities is also of concern, as is seabird, marine mammal and non-target fish bycatch associated in fisheries in which this species is a bycatch.

The fishery assessment plenary report states: No estimates of current or reference biomass are available. SWA1: "Estimates of average fishing mortality from catch curve analysis were lower than the assumed rate of natural mortality and therefore the stocks are likely to be above Bmsy. SWA3 and 4: The sustainability of current TACCs and recent catch levels for all fishstocks is not known, and it is not known if they will allow the stocks to move towards a size that will support the maximum sustainable yield." (MFish 2007, p826).

Market: Export value of about $23 million with the main market being Japan.

Status and sustainable yield
Status: Unknown.
Annual catch limit: Set at 10,380 tonnes in 2003-04.
Recorded catch: Reported landings of 11,138 tonnes in 2005-06.
Population size: Unknown.
Stock trends: Unknown.

Fishing method
Method: Trawling.
Habitat damage: Impact of trawling on bottom dwelling species.
Bycatch: Silver warehou is a bycatch in hoki, arrow squid, barracouta and jack mackerel fisheries including marine mammals and seabirds.
Ecological effects: Impact of trawling on benthic species and diversity.

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

Biology
Distribution: Found mainly on the Chatham Rise, outer Canterbury Bight, South Island west coast and the shelf south east of Stewart Island at depths of 200-800m.
Maximum age (years): 23
Age at sexual maturity: 3-4
Growth rate: Relatively fast to mature.
Reproductive output: Medium to very high.
Age exploited: 3-4

References: Report from the Fishery Assessment Plenary, May 2007: stock assessments and yield estimates. Part 3: Pilchard to Yellow-eyed Mullet. Science Group, Ministry of Fisheries; Guidebook to New Zealand Commercial Fish Species, Revised Edition 1990, NZ Fishing Industry Board.

This page was updated on 9 November, 2007