Stock assessment of D. eleginoides in Subarea 48.3 using dynamic production models

Dynamic production models (DPM) have been proposed for D. eleginoides stock assessment in subarea 48.3. This type of the models differ from the models currently used by CCAMLR Working group on fish stock assessment as they do not require certain initial data and parameters (natural mortality, age selectivity, recruitment estimates, mean weight at age) In the calculations with DPM (with Schaefer and Fox production functions) were used: total yield for a series of years and abundance index describing interyear biomass dynamics (standardized catch per unit effort for 1986- 2001) and fishing effort estimates by years of fishing.
Both models showed that the D. eleginoides stock status at the initial period of intensive fishery was at the level of 22-24 thousand tons. In 1989-1990 stock size increased (to ~31 thousand tons) and then gradually declined, having reached the minimu m size of 12 thousand tons in recent years.
The trends in biomass dynamic estimated by DPM are very similar with trends from dynamic age-structured production model ( ASPM) (Gasiukov, Dorovskich, 2000): DPM and ASPM display more then twofold decline of total biomass since 1990 until now.