So how do they get here? There are several ways but just think, right now you could be drinking coffee from South America while wearing clothes made in South East Asia, and reading this on a device made in the USA or China. Your lifestyle is only possible due to thousands of container ships ploughing across our oceans on a daily basis, taking products around the world from one port to another. But often, that’s not all they’re carrying....
We humans have proved we can thrive anywhere on the planet. But we're not the only species capable of doing so. Having conquered the earth and sea, we are now transporting other resilient, adaptable, non-specific species around the world which are wreaking havoc in the absence of predators or pathogens.
Each day some 3000 species are transported in ship ballast or on ships’ hulls. Ballast water is taken on board when the ship is empty, and discharged usually in port when the ship is loaded. [Title picture courtesy of CSIRO]
This water can contain millions of creatures and pathogens, including, for example, cholera. Although most perish on route, some survive and find the waters where they are discharged to their advantage where they thrive to the detriment of native species.
Of the 54 invasive non-native invertebrate species identified by Buglife as currently posing the greatest threat to biodiversity in Britain, 23 (43%) may have been, or could in future be, introduced via ballast water.
Shipping patterns are undergoing changes and expanding in volume, frequency and coverage. The opening of new, northern shipping routes due to the the reduction of Arctic ice cover raises the threat of ballast water introductions from previously blocked geographical areas, augmenting the continuing arrival of species along established commercial shipping routes.
Yet our knowledge of marine invasive non-native species is extremely limited and there are few marine species-specific risk assessments. It is practically impossible to eradicate marine and aquatic invasive non-native species once they have established. It is thus imperative that we do our utmost to prevent their arrival and export in the first place to avoid large scale negative impact on native biodiversity and the economy.
We need to have strict controls in place to limit the spread of invasive non-native species by ballast water, not only into British waters but to avoid transfer from British waters elsewhere. We have the mechanism to do this through the International Maritime Organisation Ballast Water Management Convention, and yet the UK refuses to ratify it.
Many of Europe’s large maritime economies have ratified this Convention, including Holland, Germany, France and Denmark. The International Maritime Organisation has addressed most of the UK’s sticking points so the UK should now follow suit. This would enable the Convention to come into force worldwide, providing valuable pathway control for marine, coastal and estuarine invasive non-native species.
You can help to slow down invasive species more generally by making sure you know what you grow in your garden, especially if you have a pond, and by making sure you clean, check, dry fishing and boating equipment etc you use around water.
Government Affairs Officer
Wildfowl and Wetlands Trust
Aspects of this blog were originally published on Wildfowl and Wetlands Trust's website
The opinions expressed in this blog are the author’s and not necessarily those of the wider Link membership
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