SUMMARY

• Main Authors: North Atlantic, Bluefin Tuna, D S Butterworth, H F Geromont
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.548.5891; http://www.iccat.int/Documents/CVSP/CV052_2001/no_3/CV052031116.pdf

Simulation testing is motivated as an appropriate approach for the necessary process of testing proposed assessment procedures for robustness, in particular to mistaken assumptions about the underlying reality. A simple example is given of the application of the approach to the one/two stock hypotheses for north Atlantic bluefin tuna (Thunnus thynnus). Preliminary but nevertheless suggestive results are obtained that the apparent increase in recruitment to the east, and decrease in the west, indicated by region-specific ADAPT VPA's for the period since 1970 may (at least in part) be an artefact of the distributional shift in catch which followed the imposition of restrictions on the catch in the west in 1982. An addendum which extends results by considering a wider range of ADAPT VPA estimation proceduresstrengthens this conclusion and also points to the sensitivity of estimated recruitment trends to the manner in which F-ratio ()910 / FF + estimation is effected. Some suggestions are made for more refined analyses to address this issue further. RÉSUMÉ Les tests de simulation sont mentionnées comme étant une approche adéquate au processus nécessaire de test des méthodes d’évaluation proposées quant à leur robustesse, notamment