New Zealand EEZ southern blue whiting pelagic trawl

MSC status

Certified as sustainable in April 2012. 

Summary

Species:  Southern blue whiting (Micromesistius australis)
Location:  NZ EEZ
Fishing methods:  Pelagic trawl
Vessels:  16
Number of fisheries: 1

More about whiting

Southern blue whiting is a schooling species that is predominantly found in sub-Antarctic waters. Early growth has been well documented with fish reaching a length of about 20 cm FL after one year and 30 cm FL after two years. Growth slows down after five years and virtually ceases after ten years. The ages and lengths at maturity, and at recruitment into the fishery, vary between areas and between years. In some years a small proportion of males mature at age 2, but the majority do not mature until age 3 or 4, usually at lengths of 33–40 cm FL. The majority of females also mature at age 3 or 4 usually at lengths of 35–42 cm FL. 

Southern blue whiting are highly synchronised batch spawners. Four spawning areas have been identified on Bounty Platform, Pukaki Rise, Auckland Islands Shelf, and Campbell Island Rise. The Campbell Island Rise has two separate spawning grounds, in the north and the south respectively. Fish appear to aggregate to spawn first to the southern ground but thereafter spawn also on the northern ground. Spawning on Bounty Platform begins in mid August and finishes by mid September. Spawning begins 3–4 weeks later in the other areas, finishing in late September/early October. Spawning appears to occur at night, in mid-water, over depths of 400–500 m on Campbell Island Rise but over shallower waters elsewhere. The four spawning areas are treated as separate stocks.

More about the fishing methods

Catches of southern blue whiting are taken mostly by semi-pelagic trawls. The trawl vessels deploy high aspect ratio multipurpose doors, which allow bottom or midwater operation. Vessels predominantly use Furuno CN22/24 electronic net-monitoring systems, which capture data on the headline height, the distance between the groundrope and the seabed, and water temperature, and transmit this data in real time through an acoustic link to the vessel’s bridge to assist with the deployment in the water column. Some of the fleet use Scanmar or Simrad net monitoring equipment to measure door spread and catch sensors to assess codend “fullness”, but none use trawl sonar as cabled systems are illegal in New Zealand waters, to prevent seabird mortalities.The midwater trawls come in a wide range of sizes measured by either headline length or headline opening (opening from 25-75m) and can be used in pelagic or semi-pelagic mode. Regulations prescribe a minimum mesh size of 60 mm for cod end for trawls in the southern blue whiting fisheries.

Fishery tonnage

Estimated catches for 2003-4 (Tonnes):

Bounty Platform - 3812
Campbell Island Rise - 28,718
Pukaki Rise - 163

Commercial market

Similar to other NZ deepwater finfish species, southern blue whiting is taken commercially and the majority is exported (>90%). The main export markets are Europe, Japan, Russia and Spain.

Actual eligibility date

October 2011