Is current management of the Antarctic krill fishery in the Atlantic sector of the Southern Ocean precautionary?

This paper is a revised version of WG-EMM-15/28, which uses a question and answer format to explain the management of the Antarctic krill (Euphausia superba) fishery in the subareas 48.1 to 48.4, and current knowledge about the state of the regional krill stock. The revisions provide a new, precautionary assessment of exploitation rate in this fishery. The effective regional catch limit (or “trigger level”), established in 1991, is 0.62 million tonnes year^-1, equivalent to ~1% of the regional biomass estimated in 2000. Additional subarea catch limits were established in 2009. There is some evidence for a decline in the abundance of krill in the 1980s, but no evidence of further decline over more recent decades. Biomass indices from local monitoring programmes established in the 1990s and 2000s also show no evidence of a further decline. Extrapolation from these local monitoring programmes provides conservative estimates of the regional biomass in recent years. This suggests that the trigger level would be equivalent to a long-term exploitation rate (catch divided by biomass) of <7%, which is below the 9.3% level considered precautionary for Antarctic krill. However, the permitted exploitation rate in each subarea, derived from the subarea catch limit, appears to exceed this level in up to 20% of years due to high variability in krill biomass indices. The actual exploitation rate in each subarea has remained <3% because annual catches have been <50% of the regional trigger level since 1991. The subarea catch limits help prevent higher exploitation rates.  The CAMLR Commission also needs to manage the risk of adverse impacts on the ecosystem which might occur as a result of climate change or concentrated fishing in sensitive areas. Frequent assessment of the krill stock will enhance the Commission’s ability to manage these risks. Continuing the local monitoring programmes will provide valuable information on krill variability, but more information is required on how the monitored biomass relates to biomass at the subarea scale. The most effective means to acquire this information is likely to be through the use of fishing vessels to collect data.