The situation of commercially exploited fish stocks in the Baltic sea is largely a consequence of fishing by all the Baltic Sea states. Despite Poland’s adhesion to the requirements of the Common Fisheries Policy (CFP), ICES data show that Baltic fish stocks have often been overfished in the past and one cannot rule out similar situations in the future. One of the reasons may be the maladjustment o fishing quota to reality. Excessive fishing mortality may lead to, and has often led to a deterioration of the other stock parameters, i.e. spawning stock biomass and fish age/size distribution to subGES levels. It should be assumed that without measures jointly undertaken and implemented by all the states in order to rebuild the stocks, achievement of GES with regard to Descriptor 3 will not be possible. Another important factor affecting the condition of commercial stocks is eutrophication in its various manifestations. Poland is responsible for a large part of the input of nutrients, but results of calculations carried out both by HELCOM and by the updated PoM team indicate clearly that achieving GES with regard to Descriptor D5 in Polish Marine Waters will not be possible without the reduction of nutrient loads by other Baltic Sea states. Consequently, without the effort of other states it will not be possible to improve environmental conditions, critical especially for the restoration of Baltic Sea cod stocks.

While it may be expected that properly designed and implemented measures within the framework of CFP will be enough to relatively quickly achieve GES with regard to sprat and herring stocks, in the case of cod it is becoming increasingly clear that the ban on fishing which has been in place for the past few years is not a sufficiently strong impulse to allow swift regeneration of the population. It should be accepted that restoration of GES with regard to cod stocks will likely require an improvement of the environmental conditions, including an improvement in the oxygenation of water below the halocline in cod spawning grounds. This in turn will most likely be possible not earlier than several years after external nutrient loads to the Baltic Sea are reduced to the required levels. In other words, even if the external loading was immediately reduced to Maximum Allowable Input levels, the condition of cod spawning grounds would not improve quickly enough for the species to achieve GES by 2027. Taking into account the time that will actually be needed to reduce external nutrient loads, cod may be expected to reach GES only after 2050 unless, by that time, this is made impossible by climate change which is a threat to this species.