Identification of potential target levels for Central Baltic Sea fishing mortalities, taking multispecies interactions into account: Extended abstract

The main biological interactions between Baltic cod, herring and sprat have been modelled in a stochastic multispecies (SMS) model. Based on this, a simple approach has been developed to quantify candidates for FMSY proxies (fishing mortality that produces the maximum sustainable yield) in a multispecies context. Multispecies FMSY is higher for cod than single‐species FMSY values,
due to cannibalism. The actual FMSY for herring and sprat, and cod’s influence on prey yield, depend on assumptions about density‐dependent growth and spatial overlap between predator and prey. The results are ready for implementation in management, however, the multispecies aspects depend on predation data mainly from the 1980s and there is an urgent need to update the
information base. The current productivity regime and spatial distribution of fish stocks in the Baltic is different from the earlier period when predation data was collected. Also, prey‐to‐predator feedback mechanisms should be more understood before implementation in management