Zonal Attachment

Zonal attachment is the share of a shared fish stock that occurs within a country’s exclusive economic zone, proposed as the scientific basis for splitting quota between coastal states. It allocates catch by where the biomass actually sits across jurisdictions, in contrast to the EU relative-stability key fixed on historic catch. The UK pressed for zonal attachment in post-Brexit EU negotiations: a 2020 study found UK zonal attachment exceeded its quota share for 12 of 14 major stocks. Because fish distributions shift with warming, zonal-attachment estimates change over time, which complicates fixed long-term allocations.