Joint EU-Norway request to ICES on options to revise the long-term management plan for herring in the North Sea

ICES has evaluated the biological precautionary reference points to be B_lim= 800 000 t and B_pa = 1 000 000 t. Flim and Fpa are not defined. FMSY (average over ages 2–6) is estimated to be within the range 0.24 to 0.30. The value of Btrigger is conditional on the harvest control rule (HCR) selected.

ICES concludes that all harvest control rule options in the request include precautionary scenarios. Several options are considered to be operational for management of the herring fisheries and could be implemented in a revised North Sea herring long-term management plan.

Some  HCR  options  are  suggested  based  on  their  performance (yield  and  interannual  variability  in  yield)  and applicability  for  management.  These  include  option  1  (numbers  as  in  request),  which  is  an  updated  version  of  the  current  management  plan  with new reference points, and options 3b and 3c, which have the ability quickly to adapt to changes  in  recruitment  and  stock  biomass.  Interannual  quota  flexibility  (request  item  5) is  a  practical  solution  to  facilitate fishery operations and could, therefore, also be considered in the management of these fisheries. However, this feature has only been simulation tested under HCR option 1.

Density-dependent regulatory effects on the stock–recruitment relationship can neither be ruled out nor confirmed.