Estimation of fishing mortality rates based on the 4 parameter estimation approaches.

Fishing mortality rates estimated for dusky kob (A. coronus) (a) and leerfish (L.amia) (b) according to different assumptions for global parameter minimization. Results assuming constant selectivity (μS and σS fixed over years) are presented in red (approaches ii and iv), whereas those assuming yearly selectivity parameters are in black (approaches i and iii). Dashed lines represent rates assuming the population is at equilibrium (approaches i and ii), whereas solid lines use the “n-fishing years” hypothesis (approaches iii and iv).