The New York Times has a story describing the fight over the management of New Zealand's hoki stocks.
The New Zealand government has been cutting the allowable catch of hoki by substantial amounts, which indicates that overfishing, predominantly by bottom trawling, has harmed the stock, but hasn't formally admitted that there are problems. From about 275,000 tons in 2000 and 2001 (when the fishery was certified) to about 100,000 tons in 2007 and 2008 — a decline of nearly two-thirds.
Complicating the issue, the fishery is certified by the Marine Stewardship Council, which makes it more popular with buyers. In a subtle way, the MSC label also makes it more difficult for environmental groups to raise objections, as its presence indicating a sustainable fishery, tend to take the wind out of the sails. But the fact that Hoki are caught by bottom trawling, a damaging process that impacts deep ocean benthic systems by dredging up the life on the ocean floor e.g. sponges, corals, while catching both the target species and non-target species. Add to this that the catch limits set by the New Zealand government have caused or exacerbated population declines and it's difficult to see how certification has made the transition to sustainability.
It's lending evidence to the emerging idea that despite the fact that many MSC (or certified) fisheries are well managed and do minimise environmental impacts, the seal alone is not sufficient, to demonstrate a sustainable fisheries. The devil is in the details and consumers need to explore the consequences of their seafood choices.
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Just because a catch decline doesn't mean that a stock has been overfished. The New Zealand Seafood Industry agreed to some very painful readjustments when it became clear that the natural fluctuation in the hoki stock was on a downward curve. As a result, the nation's two hoki fisheries are seen as a model of responsible management, something that was echoed most recently by Dr. Boris Worm when he called New Zealand's fisheries, along with Alaska, as the most responsibly managed in the world.
ReplyDeleteFor more on what's really happening in New Zealand visit our Web site at http://www.seafoodindustry.co.nz/nzhoki.
Is there scientific evidence that the hoki population "naturally" fluctuates enough to require a 2/3 cut in the catch limit? If not, then it absolutely is evidence of overfishing. It's still overfishing if fishing exacerbates natural fluctuations - catch limits should be set so as not to add to other stresses on the population.
ReplyDeleteNew Zealand Harvest Strategy Standard of the Ministry of Fisheries specifies an approach for determining whether or not a stock is overfished. The default soft limit is ½ BMSY or 20% B0, whichever is higher. B0 is the estimated unexploited biomass. The soft limit is considered to have been breached when the probability that stock biomass is below the soft limit is greater than 50%. Stocks that have fallen below the soft limit are overfished and should be rebuilt back to at least the target level in a time frame between Tmin and 2 * Tmin with an acceptable probability. Tmin is the theoretical number of years required to rebuild a stock to the target in the absence of fishing. Stocks are considered to have been fully rebuilt when it can be demonstrated that there is at least a 70% probability that the target has been achieved and there is at least a 50% probability that the stock is above the soft limit. The default target is Bmsy. According to the graph at http://www.fish.govt.nz/NR/rdonlyres/3EA98FE0-A946-49D1-8FB5-891A21A8BC13/0/2009HokiStockAssessmentresults.pdf
ReplyDeletethe Eastern Hoki stock is doing ok wherehas the Western Hoki stock declined to the 20%B0 line over 2003-2005 and has subsequently been increasing. One would need to dig further into the assessment to determine whether or not the the soft limit was actually breached with P>50%, triggering the need for a formal, time-constrained, rebuilding plan. The fact that the Western Hoki is clearly not fluctuating around Bmsy in the recent past would cause one to have some reservations with regard to classifying this fishery as sustainable just yet.
An example of an MSC certified fishery that is clearly not sustainble is the South African hake fishery. It comprises and inshore and offshore stock (two different species). The offshore stock was assessed in 2008 to be less than 10% of B0 in a published paper yet the fishery is still on the MSC list of certified fisheries.
Here is another controversial MSC certification - Pacific hake - apparently the adjudicator dismissed an objection that the fishery was not sustainable http://www.canada.com/technology/groups+protest+Pacific+hake+ruling/2066102/story.html
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