Recent changes in the spatial and temporal distribution of the krill fishery in Area 48: the role of sea ice and voluntary restricted zones

CCAMLR is currently developing a new management approach for the krill fishery in Area 48, with a parallel initiative underway to designate an MPA in planning domain 1 (Subareas 48.1 and 48.2). In the meantime, the fishing industry agreed to voluntary closed areas (voluntary restricted zones, VRZs) in the vicinity of penguin colonies during the summer breeding season in Subarea 48.1, with one year-round VRZ. Here we investigate recent changes in the spatial and temporal distribution of the krill fishery and consider those changes in the context of sea ice and the introduction of the VRZs in 2018/19. The krill fishery catch has increased since 2009, with that increase largely due to increases in catches in Subarea 48.2 (South Orkneys). Coupled with that increase, fishing effort has concentrated in Subarea 48.2 during the austral summer (December-February), when central-placed foragers, such as penguins and seals are constrained in their foraging areas and have high food demand. The shift to a summer fishery in 48.2 has been driven by a concurrent switch to autumn/early winter fishing in Subarea 48.1 since 2017. The change in fishing distribution may be linked to sea ice changes, with fishing in 48.1 less disrupted by sea ice in winter than 48.2, but has been reinforced by the introduction of the VRZs. The VRZs, which are in force from December until the end of February, restrict krill fishing in the primary fishing grounds in 48.1 and hence vessels prefer to fish in 48.2 when they are in force. The concentration of fishing in 48.2 during the summer season is a cause for concern, particularly as catches are taken from small areas to the north of the South Orkney Islands, which are home to important breeding colonies of krill-dependent predators. This also demonstrates that any introduction of closed areas must consider the impacts of displaced fishing effort and that a holistic approach to all subarea catch limits is required when considering any revision to the krill management measures.