Marine protected Areas are widely used to safeguard marine ecosystems across Europe. This study investigated the effect of a partially protected areas (PPA) off the coast of Norway on a population of cod (Gadus morhua). The PPA reduced the number of deaths due to fishing, increased survival and stimulated movement to surrounding areas. The authors say that preventing fishing altogether would increase survival even further and recommend no-take zones in areas where populations are severely reduced.

http://ec.europa.eu/environment/integration/research/newsalert/pdf/marine_protected_areas_increase_survival_of_atlantic_cod_430na1_en.pdf