Oops, You Can't Bring that in - Customs and Quarantine

If you look outside the Museum at the ships tied up along the wharf you may notice the circular, metal discs attached to the top of their mooring lines. If you are wondering what those things are, they are rat guards. According to International Law every ship in the world must carry them and they must be attached to their mooring lines, when in port, to prevent rats getting into or out of them. They are an indicator as to how far customs and quarantine have come over the years. Centuries ago, when European traders began moving out into what was then known as ‘The New World’, there was little concept of the dangers posed by not quarantining your ship to prevent vermin from getting aboard or ashore. In fact, in some places, especially offshore islands, seafarers actually released animals such as pigs and rabbits so that they might breed there and become a source of fresh meat for anyone who subsequently called in. The result of this practice on native flora and fauna was disastrous. Because of the lack of quarantine and vermin control, black rats, domestic mice, cockroaches, moths, wasps - a whole range of potentially harmful creatures - was deposited around the world by visiting ships. Keep in mind that there were several cases of plague in Fremantle between 1900 and 1906.  Rattus rattus is a tough, wily customer and rat guards remain in the first line of defence.