UPDATE: Lack of evidence blocks MSC investigation into toothfish mislabelling claims
Sep 23, 2011
The MSC has not been able to pursue its investigation into Dr Peter Marko’s allegations of supply chain breaches for certified South Georgia toothfish products.
Following the publication of their paper (Marko et al., Current Biology, Volume 21, Number 16, R622), the investigation team approached Dr Marko and co-authors, Holly Nance and Kimberley Guynn, with four requests for the sampling information necessary to establish whether or not the products tested in their investigation were, in fact, mislabelled. The information required is:
• Place of sampling;
• Date and time of sampling;
• MSC Chain of Custody (Logo License) certificate number;
• Product form.
To date, none of the data requested have been supplied, although the team has been informed that some of the data required will be made available in the future.
Dr David Agnew, MSC Standards Director, said: “We take supply chain integrity extremely seriously and we’re very disappointed that, over a month after we undertook to investigate these mislabelling claims, we have been unable to progress our investigation due to lack of sampling data from this study.
“Without such data, we are unable to make a judgment about whether product substitution has taken place at some point, leading to mislabelling. Once we have these data, we will conduct a full review and present the outcome.”
Nevertheless, the MSC takes this opportunity to publish its 2009 study on the verification of toothfish supply chain integrity, which found no evidence for mislabelling. The Marko et al.study used toothfish sampled in 2008.
MSC’s data from 2009 toothfish sampling generates confidence in supply chain
In 2009 MSC obtained samples of toothfish product deriving from certified supply chains and non-certified supply chains and examined their likely origin using genetic analysis. The work was undertaken by Tepnel Life Sciences under contract to MSC. Sampling was conducted following standard protocols defined by the laboratory and by MSC, and included recording of all relevant data. The laboratory was not informed which samples were from MSC certified chains.
The analytical method chosen was mitochondrial DNA sequencing of three mitochondrial gene regions (ND2, 12S and the control region), which is a more robust method than the RFLP (Restriction Fragment Length Polymorphism) approach used by Shaw et al. (2004) and Marko et al. (2011). Furthermore, rather than using existing studies for the reference sample, which, as acknowledged by Marko et al. (Supplementary information) might contain unknown biases, new reference samples were collected from known Falkland Island and South Georgia populations. The study was conceived as part of a wider product integrity study, so sample sizes were necessarily limited to 10 MSC-labelled fish, 2 non-MSC labelled fish, and 26 fish from each of the reference populations.
The most promising gene region for discrimination between toothfish from the two populations was 12S. In the 12S gene region 96.1% of samples from the two populations showed opposing sequence haplotypes (96% of South Georgia showed a ‘TG’ haplotype, 96% of Falkland Island samples showed an ‘AC’ haplotype). All of the MSC labelled fish possessed the TG haplotype, and both of the non-MSC possessed the AC haplotype. Full results will be available on request.
Current Biology claims unsupported by published data
Dr Agnew went on to say, “Even with this more robust methodology, our study found some AC haplotypes in the South Georgia reference population and some TG haplotypes in the Falkland Islands reference population. This is consistent with previous studies (Shaw et al., 2004), that have shown very high genetic separation between these two populations given their proximity, but still some residual gene flow.
“Thus it is not possible with population level genetic studies such as described in Marko et al. (2011) to attribute individual fish to specific populations. The categorical statement in Marko et al. (2011) that ‘not all MSC certified Chilean sea bass came from the certified fishery’ cannot be supported by their study. Furthermore, without exhaustive sampling of reference populations it is not possible to state that fish possessing previously unidentified holotypes (such as holotypes I and J in Marko et al., Supplementary information) did not arise from the South Georgia source population.”
MSC remains open to further investigation of Marko claims
Although the MSC is confident that its sampling in 2009 did not identify any likelihood of product substitution, monitoring the integrity of supply chains remains a priority for the MSC and will continue in the future. Amy Jackson, Deputy Standards Director and the MSC lead on supply chain integrity, said: “Despite the age of the findings published by Marko et al., should relevant and comprehensive data be supplied by Dr Marko and his colleagues, the MSC will still undertake to investigate them”.