Modelling non-stationary natural mortality in catch-at-age models (original) (raw)

2012, ICES Journal of Marine Science

Jiao, Y., Smith, E. P., O'Reilly, R., and Orth, D. J. 2012. Modelling non-stationary natural mortality in catch-at-age models. – ICES Journal of Marine Science, 69: 105–118. Non-stationarity in the natural mortality of many species has been discussed among research scientists, but no generally applicable models/methods have been developed where a statistical catch-at-age (SCA) model framework is used. Using the Atlantic weakfish (Cynoscion regalis) fishery as an example, several SCA models are developed to assess the population dynamics, then compared. Models used included (i) an SCA with constant natural mortality, (ii) an SCA with unknown natural mortality, but with a hierarchical prior distribution from a mixture of distributions based on life-history information, (iii) an SCA with age-specific unknown natural mortality, (iv) an SCA with time-varying natural mortality, following a random-walk process, and (v) an SCA with age-specific time-varying natural mortality. The last t...