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    Revisiting krill ageing method using eyestalk cuticles

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    Document Number:
    S. Kawaguchi, T. Barnes, N. Waller, B. Farmer, D. Hayes, R. Kilada, C. Reiss, G. Zhu, B. Krafft, A.-L. Agnalt, T. Ichii and T. Matsuda
    Submitted By:
    Dr So Kawaguchi (Australia)
    Approved By:
    Dr Dirk Welsford (Australia)
    • The development of a consistent and reproducible ageing method for krill is critical for improving the precautionary management of krill fisheries.
    • The only method to date that has shown promise in the determination of the absolute age of krill is that of Kilada et al. (2017), which involves thin sectioning of the eyestalk cuticle.
    • The mechanisms controlling the generation and retention of growth bands in the cuticle through multiple moulting processes is poorly understood, and is in fact a point of contention among crustacean researchers.
    • Since the interpretation of growth bands in thin eyestalk sections is also difficult, inter-laboratory calibration of this method should be conducted as a matter of priority.
    • It is also important to discuss and agree on terminology on the structures that are kept through moulting and what are the structures that we can read growth bands from.
    • We propose that an inter-laboratory calibration should be undertaken as a community effort supported by CCAMLR, in a series of workshops led by a qualified scientist, and using known age krill.