Norwegian acoustic survey of North East Arctic cod on the spawning grounds off Lofoten
Original version
This report is not to be cited without prior reference to the authorAbstract
An acoustic survey of the spawning stock of North East Arctic Cod off Lofoten has been
performed annually in March-April since 1982. The estimates for 1985-1997 have been
recalculated 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 results
from a reasonably converged part of the series. It is shown that the VPA tuning assumption of
constant log catchability at age should not be used for this survey series. As the survey produces
abundance indices for the mature part of the cod stock these indices should be corrected with
proportions mature before they are used in traditional assessment methods estimating year class
strength.