During open discussions at the Third International Symposium on Krill (St Andrews, Scotland, June 2017) attended by representatives of the Association of Responsible Krill harvesting companies (ARK), the Marine Stewardship Council (MSC) and CCAMLR, it became apparent that no bycatch of Ice krill (Euphausia crystallorophias) had been reported from fishing vessels targeting Antarctic krill (E. superba). Furthermore there seemed to be little confidence amongst participants that under present observer practice any such bycatch would be detected – this despite the fact that fishers are obligated as a condition of their fishing permits to report all bycatch. Since the present-day Antarctic krill fishery operates in geographic areas that overlap with the known range of Ice krill, that Ice krill and Antarctic krill can occupy similar depths in the water column, and that both species are morphologically similar, the possibilities of bycatch and the failure to detect it cannot be dismissed. Here we analyse publicly-available aggregated decadal-scale krill catch data to evaluate the likelihood that Ice krill will have been included in the reported Antarctic krill catch. We conclude that the likelihood is effectively 100%. The MSC asserts that “bycatch and discards remain[ed] significant to ensuring sustainability. They are considered a waste of resources and contradictory to the overall concept of responsible fisheries” (https://improvements.msc.org/ database/discards; our emphasis). Stemming from this, the MSC now (as of April 2015) requires “fisheries to regularly review alternative mitigation measures to minimise mortalities of unwanted catch”. The krill fishery prosecuted by Aker Biomarine (a member of the Association of Responsible Krill harvesting companies; our emphasis) achieved MSC re-certification in August 2015 (https://www.msc.org/newsroom/news/ msc-labelled-aker-biomarine-krill-products-are-from-a-sustainable-and-well-managed-fishery), but it is not apparent if the probability of bycatch of Ice krill was considered for this re-certification. In the absence of any data, or clear statement, on Ice krill bycatch, it is difficult to reconcile the MSC’s statement (ibid.) that the Aker Biomarine “fishery remains excellent in its performance against MSC standards”. As part of the ongoing MSC assessment of the Deris S.A. – Pesca Chile Antarctic krill fishery (https://fisheries. msc.org/en/fisheries/deris-s.a.-pesca-chile-antarctic-krill-fishery/) and the scheduled re-assessment of Norway’s Aker Biomarine Antarctic krill fishery (https://fisheries.msc. org/en/fisheries/aker-biomarine-antarctic-krill/@@view; due before June 2020) we suggest that due consideration be given to the possibility of under-recording of bycatch of Ice krill in the Antarctic krill fishery, and to associated measures to address this situation.