The curse of dirty bottoms

Five cruise ships have been turned away from New Zealand and Australia ports due to fouling. Has shipping underestimated the biodiversity concerns of ports and administrations?

In recent weeks there have been six cruise ships turned away from New Zealand or Australia because of the fear of invasive species attached to the ships hulls.


For the cruise ship companies it is a huge expense to have to change or cancel itineraries, particularly just after the industry has picked up again following the pandemic, for passengers it is an inconvenience, especially if they are on once in a life time holidays hoping to see some of the countries’ best known sites.


For the shipping industry it should be a wakeup call that fouled hulls are seen as as big a risk as ballast water to natural biodiversity.


Coral Princess, Viking Orion, Queen Elizabeth, Seven Sea Explorer, and Oceania Regatta are the five cruise ships that have had to miss ports and idle deep out at sea while divers have spent long dangerous hours in the water scrubbing hull surfaces.


The majority of cruise vessels were left idling for nearly two years during the pandemic with itineraries cancelled as passengers and crews were unable to travel.


With restrictions removed the industry has returned to normal and itineraries are in full swing with operators making the most of the Southern Hemisphere summers.


It now seems that some vessels may have been returned to service without a full consideration of how authorise in some parts of the world perceives the biodiversity risks to their coastal waters.


The stories about the cruise ships comes also weeks after nations attended COP15 on biodiversity in Montreal and agreed the Global Biodiversity Framework with its four overarching global goals to halt human induced extinctions and biodiversity threats. The Convention on Biological Diversity lists Invasive alien species as a direct driver of biodiversity loss.

Is there worse to come?

Tor Ostervold is co-founder and CEO of ECOsubsea a company that has developed a diver-less autonomous hull cleaning system that prevents any removed detritus form falling into the sea.


He has been outspoken about the need for more robust rules to ensure that the industry can be more proactive in addressing the risks. He thinks that shipowners and operators will see more ports take a stringent approach.


“I think this is the start of a new era when it comes to dealing with biofouling, “ he told Fathom World’s Aronnax Podcast.


“Historically, we’ve been dealing with biofouling just because of climate reasons – to save CO2 and basically to save fuel, but what we are seeing now is the other side of the coin that is playing a much bigger role – And that is biodiversity”.


And this he adds has been expected, that industry would talk about biofouling from a fuel saving perspective first, but then from a biodiversity perspective as this latter point is seen by many as a huge treat to mankind.


 “I think this is just the start, I anticipate that it’s going to be a little bit like in the start of COVID It was a few countries starting to talk about that you had to show your COVID passport. But as soon as someone has pointed at a problem, something that a disease that can spread, it very soon happens that the next neighbouring country is also going to ask about the same COVID passport.


With concern growing about biodiversity, and their requirements under the new global biodiversity agreement, the risks are that ports will choose to take a much stricter approach to cleaning and banning it.


The risk then is that vessels are sailing from port to port seeking a cleaning refuge, a story already seen with the DL Marigold in 2017.


The International Maritime Organization’s biofouling guidelines are currently being updated, but many are already calling for them to be made mandatory to ensure there is an opportunity for ports and pot authorities to create a harmonised policy on hull cleaning and risk assessments.

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