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    Implementing the risk assessment in Subarea 48.1 at a scale relevant to fishery operations

    Request Meeting Document
    Document Number:
    WG-EMM-2022/17
    Author(s):
    V. Warwick-Evans, M. Collins and P. Trathan
    Submitted By:
    Dr Vicky Warwick-Evans (United Kingdom)
    Approved By:
    Dr Chris Darby (United Kingdom)
    Abstract

    The Risk Assessment (RA) provides a framework by which to identify the optimum management units to spatially and temporally subdivide the catch limit for the krill fishery, with the aim of reducing risks to the ecosystem. It is a data limited approach that will allow CCAMLR to implement precautionary management to address spatial and temporal aggregation of fishing effort and provides a vital short-term, step forwards in CCAMLR’s ambition to manage the fishery at scales relevant to ecosystem function and operation.

    One of the key assumptions of the RA is that the catch within each management unit is harvested equally from across that management unit however, historical fishing patterns show the fishery actually concentrates at a finer scale. As such, we have implemented the risk assessment at a scale more closely aligned with the scale which we believe the fishery would operate under different management scenarios.

    Additionally. in order to assess whether there is a scenario where the fishery is not forced into either the outer management units, or into the Bransfield and Gerlache Straits, we also implemented the RA omitting the use of the scaling factor for fisheries desirability, instead using the direct measure of the proportion of catch previously taken in each management unit.

    The current pattern of fishery operation resulted in one of the highest risks. The lowest risk scenarios were those whereby management of the fishery were based on the US AMLR survey strata, but split further into additional management units. The next joint lowest risk scenarios were also based on the US AMLR survey strata, but with extra management units added. In most cases there was very little difference in risk or in the proportion of catch assigned to each management unit whether the fishery desirability was scaled or unscaled.

    The RA provides a short-term solution to manage the fishery at a smaller scale, however, for future iterations it is vital that some of the limitations to this approach are addressed. We emphasize that ongoing and additional monitoring of both krill and krill predators, to fill in seasonal and spatial gaps, and to regularly review any change in dynamics, is vital to further develop advice and understand the potential impacts of the fishery.