Thursday, October 15, 2009

Case #2 NZ Hoki fishery

Certified as sustainable by Marine Stewardship Council in March 2001 and recertified sustainable in October 2007

Fishing methods for NZ hoki include mid-water trawling and bottom trawling. The fishery is managed as one quota management system (QMS) stock although it comprises two stocks, an eastern stock and a western stock. The quota has decreased regularly over the last 10 years from 250kt to the current level of 90kt as a consequence of decreases in biomass.

The 2009 hoki stock assessment results published by the NZ Ministry of Fisheries show that the eastern stock is in the target zone of 35-50% B0 (B0=unexploited or virgin biomass). The western stock however declined to the overfished or depleted zone of 20%B0 for a number of years in the mid-2000s and has only just reached the bottom of the target zone in the last two years.

Based on this slight recovery a quota increase has been proposed for the next fishery year. The NZ Harvest Strategy Standard requires that the risk of a fishery causing the stock to fall below the “soft limit” (20%B0 for hoki) should be less than or equal to 10%. Given the uncertainties in the assessment this has clearly not been the case in the recent past for the western stock. So technically the western stock was being unsustainably fished for part of the period it has been certified as sustainable by MSC.

Depending on the magnitude of the quota increase it seems possible that the western hoki stock could once again fall below the target zone and be at a risk of >10% of being in the overfished or depleted zone again. Is it premature to consider the NZ hoki fishery “sustainable”? What are your views?

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