Thursday, November 15, 2012

Overfished and overfishing are the new sustainable?

In a multi-authored article (22 authors) published online in the open access journal PLOS in August 2012, the claim is made that fisheries certified by the Marine Stewardship council are in better shape than those that are not as well as those that failed the MSC confidential pre-assessment  process. 

Two initial observations: (i) About half of the authors are directly or indirectly associated with MSC.  (ii) Data on those stocks that failed pre-assessment are not available for scrutiny because of a confidentiality agreement.

There are currently 132 MSC certified fisheries, yet the authors of the paper only examine the state of 74 of these (56%).  The required data were not available for the other 58 stocks. This constitutes a potentially biased sample of certified stocks.  It seems likely that those stocks without adequate data could be in worse shape, or at best their status is more uncertain.
Of 74 stocks examined only 32 (43%) had a stock assessment adequate for determining whether overfishing was taking place (fishing mortality or exploitation rate higher than that which would result in maximum sustainable yield or MSY) or whether the stock was overfished (below 50% of the biomass that generates MSY).  It is of considerable concern that fisheries are certified as sustainable on stocks for which such basic information regarding sustainability is lacking.

In addition to the 32 stocks, the authors were able to fit a Schaefer surplus production model to the data, or to combine a Schaefer surplus production model with the existing stock assessment model to estimate MSY related information for 13 additional stocks.  The methods used to fit the model have previously been published.   However, for a number of reasons it is unlikely that their approach would garner support through a peer review process on individual stock assessments; otherwise it would surely already be in use in these assessments.
Of the 32+13=45 stocks for which overfishing and overfished status could be determined, 8 MSC certified stocks are currently subject to overfishing while 4 certified stocks are overfished.  One could thus conclude that the MSC certification definition of sustainable fisheries  includes overfishing and overfished stocks.
Of the 4 overfished MSC certified stocks, only one has had its certification suspended.  The authors point out that the other three are above their respective biomass limit reference point, and therefore above the level where serious and possibly irreversible harm to the stock productivity is considered to occur.  It is arguable whether merely having the stock above the biomass level where serious and potentially irreversible harm occurs is sufficient grounds to consider a fishery sustainable.

Of the MSC certified stocks where overfishing is taking place, 4 are above the biomass that gives MSY which the authors consider to be less of a concern than overfishing on the other 4  certified stocks which have a biomass below the MSY level.   One of these stocks of concern is the South African Deep Water Hake, “poster-child” for a recent MSC-produce dvideo.  North Sea Saithe continues to be certified by MSC even though it is overfished and overfishing is continuing.

Although the authors find that MSC certified fisheries are healthier than those that are not certified or that failed confidential MSC pre-assessment for certification, they also note that this divergence was largely established before MSC certification commenced in 1999.  It is therefore not a consequence of certification.

The main criticism of MSC certification by environmental groups and informed members of the general public is that it sets the sustainability bar too low in some cases.  Stocks on which fisheries are certified as sustainable should be near or above the MSY biomass and should be exploited below the MSY exploitation rate.  They should not include fisheries in which the stock is currently overfished, or where overfishing is taking place, even if it is anticipated that overfishing will cease at some point so that the stock will recover to the MSY level in the future.

Consumer confidence in the MSC brand will be diminished if fisheries are certified in cases where the stock is overfished or overfishing is occurring , or where there are insufficient data to reliably make such a determination.

No comments:

Post a Comment