Comparison of Catch and Survey Data for Assessing Northern Shrimp (Pandalus borealis) from Arnarfjordur (NW-Iceland) Using a Stock Production Model

Özet

Catch Per Unit Effort (CPUE) data and survey biomass indices of Arnarfjordur (NW-Iceland) shrimp stock (Pandalusborealis) were used as tuning series for a Surplus Production Model (SPM) fitted using three different types of software. It isobserved that many of the model assumptions in the SPM are violated in this analysis. The average estimation of MSY, $\;B_{MSY}$and $\;F_{MSY}$ among the software platforms were 776 t, 2977 t and 0.18 respectively for survey series, and 1109 t, 2195 t and 0.51respectively for CPUE series. The interaction of relative fishing mortality over relative biomass for survey data is relativelymore realistic based on empirical observation where fishing intensity, predation by cod and effect of physical parameters onthe shrimp stock were revealed by many researchers. It is concluded that survey or fisheries independent data is more reliablethan catch data or fisheries dependent data.