The first scientifically recognised occurrence of a non-indigenous marine species being transported in ships water occurred in the North Sea in 1903, with the Asian phytoplankton Odontella appearing. The issue became more prevalent with the increase in shipping in the late 20th century and the issue was raised for the first time at the IMO in 1988.[5] Following several years of development, the Convention was adopted by the International Maritime Organization in 2004.[2] To enter into force, the Convention required ratification by a minimum of 30 States, representing 35% of world merchant shipping tonnage, subject to which it would enter into force 12 months later.[6] On 8 September 2016, Finland acceded to the Convention, bringing the contracting states to 52 and the combined tonnage of States to 35.14%.[6] This triggered the applicability of the entry into force date of the Convention, which occurred on 8 September 2017.[6][7][8] Since Finland's accession, a number of States have continued to ratify the treaty. By November 2018 there were 78 contracting States, representing 77.19 per cent of world merchant shipping tonnage.[9] By September 2020, 79 countries had joined the Convention.[10]