Polar bears were hunted heavily in Svalbard, Norway throughout the 19th century and to as recently as 1973, when the conservation treaty was signed. 900 bears a year were harvested in the 1920s and after World War II, there were as many as 400–500 harvested annually. Some regulations of hunting did exist. In 1927, poisoning was outlawed while in 1939, certain denning sights were declared off limits. The killing of females and cubs was made illegal in 1965. Killing of polar bears decreased somewhat 25–30 years before the treaty. Despite this, the polar bear population continued to decline and by 1973, only around 1000 bears were left in Svalbard. Only with the passage of the treaty did they begin to recover.