さあ！諸君！捕鯨問題だ！

(つづき)
If one of the main aims for estimating age-dependent
natural mortality is to calculate historical time trends in
recruitment, then the analyses in this paper show that it is
essential to determine the absolute level of natural
mortality, not just how it varies with age. The simulation
studies show that any estimates obtained by the Japanese
research programme, even if continued for more than
thirty years, would not lead to estimates of natural
mortality which would be sufficiently precise for the
reliable determination of historical trends in recruitment or
the refinement of yield prediction.

ACKNOWLEDGEMENTS

The author is grateful for comments on this paper by Dr.
J. G. Cooke, of the Center for Long-term Ecosystem
Research, Moos la, D7809 Winden Im Eltzal, 1, Federal
Republic of Germany; Dr. S. J.Holt, Loc. Acquaioli,
06062 Citta della Pieve (PG), Italy; Dr. D. S. Butterworth,
University of Cape Town, Rondebosch 7700, South
Africa; and an anonymous reviewer.

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(unpublished).
（つづく）