Norwegian Acoustic Survey Of North East Arctic Cod On The Spawning Grounds Off Lofoten

No abstracts are to be cited without prior reference to the author.An acoustic survey of the spawning stock of North East Arctic Cod off Lofoten has beenperformed annually in March-April since 1982. The estimates for 1985-1997 have beenrecalculated and mean length and weight at age are shown together with the abundance indices(both numbers and biomass). The abundance indices for each age are compared with VPA resultsfrom a reasonably converged part ofthe series. It is shown that the VPA tuning assumption ofconstant log catchability at age should not be used for this survey series. As the survey producesabundance indices for the mature part of the cod stock these indices should be corrected withproportions mature before they are used in traditional assessment methods estimating year dassstrength.