A huge, lucrative and increasingly controversial scheme to certify ‘sustainable’ fish has taken another broadside from researchers today.

The Marine Stewardship Council (MSC), an international not-for-profit organization based in London, has to date awarded some 170 fisheries the coveted certification of sustainable food source. Such a seal of approval can in principle command higher prices from environmentally conscious consumers.

In recent years a number of scientists have raised objections about MSC certification for fisheries (see ‘Seafood stewardship in crisis’ and ‘Seafood labelling under fire’). The MSC has established a formal system for reviewing its applications for certification, in which third parties — usually conservation activists — can raise objections.

The new study examined those objections and warns that “contrary to MSC claims, MSC-certified fisheries are not all sustainable”. It raises the possibility that the scheme will come to be regarded as ‘bluewashing’ — analogous to the derogatory term ‘greenwashing’ levelled at companies that attempt to put a sheen of environmental responsibility on their activities.

The MSC has strongly denied the claims in the paper.

Jennifer Jacquet, an environmental-studies researcher at New York University, and her colleagues looked at how the objections related to three guiding principles in the MSC process: sustainability, ecosystem impacts and effective management of fish stocks. In Biological Conservation, they write that “although certified, many fisheries are not seen as abiding by the MSC’s certification principles”.

The team analysed all 19 formal objections made to MSC certifications since the scheme started in 1997 and concludes that the council’s principles are “too lenient and discretionary” and that the organization’s logo “may be misleading both consumers and conservation funders”. Only one of the objections was upheld by the MSC, resulting in denial of a certification.

They cite examples such as certified fisheries having high levels of by-catch of endangered species, having a low stock size and lacking information on crucial details.

In a formal written response to the paper seen by Nature, Nicolas Gutierrez and David Agnew from the MSC write that the authors “appear to misunderstand the intention of the objection procedure”.

They say that although only one stock has not been listed following an objection, many have had new conditions imposed or had improvements to their management recommended as a result. Gutierrez and Agnew also say that the authors have failed to declare personal interests, as more than one-third of the objections analysed were filed by co-authors of the Biological Conservation study or by the institutions that employ them.

“The MSC welcomes independent reviews and constantly seeks advice on programme improvements from a wide range of stakeholders,” say Gutierrez and Agnew. “Unfortunately the conclusions taken by [the new paper] are focused on previous critiques of MSC certified fisheries by environmental groups that have been shown to be untrue, rather than addressing weaknesses and strengths in the objection procedure and the MSC programme as whole.”