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    Yet further krill yield computations

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    R.B. Thomson and D.S. Butterworth (South Africa)
    Agenda Item(s)

    Preliminary computations are carried out for the krill yield model of Butterworth et al. (1993), adjusted as requested by the fifth meeting of WG-KRILL. This involves modifying the input distributions for the lengths at recruitment and maturity, natural mortality and the extent of recruitment variability. Sensitivity tests are carried out to assess the consequences of avoidance of gravid females by the fishery, and higher natural mortality for younger ages of krill. Results do not differ greatly from those of comparative calculations in Butterworth et al. (1993), except at higher harvesting intensities for which greater resource depletion is indicated. Comparatively greater depletion is also evident for males when gravid females are avoided, and if natural mortality is higher for younger ages.