The health of our marine environment plays a key role in the health of the economy, and has a direct effect on our own health and well being.
In terms of economy, fisheries has a direct and obvious link with the marine environment, but indirectly tourism is also intrinsically linked with healthy seas and wildlife. Beaches, penguins, albatrosses and whales make up a large chunk of what the Falklands has to offer tourists.
Marine biosecurity is concerned with preventing pests, diseases and invasive species from harming our marine environment. There are three main sea routes by which harmful organisms can enter the Falklands; ship’s ballast water, hull fouling organisms and terrestrial organisms hitching a ride on the vessels themselves.
We know of two marine invasive species already established in the Falklands, but there are likely to be others which we have yet to identify. Ciona intestinalis is a sea squirt which is abundant in Stanley Harbour, cloaking FIPASS and other underwater structures. More widespread is Chaetopetrus variopedatus or the parchment worm—the empty ‘paper’ tubes are commonly seen washed up on beaches all over the Falklands. Both species probably arrived as hull fouling organisms on ships or yachts decades or perhaps even centuries ago.
With a huge number of vessels from all over the world visiting the Islands it is only a matter of time before we are exposed to new harmful organisms. However, we are working on ways to avoid those introductions, and to minimise the impacts of marine invasive species when they do arrive.
The problem with marine invasive species is that they are extremely difficult, if not impossible to get rid of once they are established. Therefore it is essential that we do what we can to prevent the introduction of these organisms in the first place.
Hoping for the best…
There are all kinds of new technologies emerging for the safe treatment or flushing of ballast water from ship’s hulls, from continuous flushing methods to using ozone or ultraviolet light to sterilise ballast water before it is discharged, but until these are incorporated into the design of all vessels we must rely on robust marine policies such as IMO ballast water regulations to ensure that ships flush their ballast tanks prior to arrival in our coastal waters.
Not all vessels exchange ballast water to maintain stability, but all vessels and underwater structures are prone to fouling. The fact that both of our known invasive species probably arrived here as hull fouling organisms backs up the evidence to suggest that hull fouling is an equal or higher risk pathway compared with ballast water exchange for the introduction of non native species.
Even well maintained hulls may host marine invasive species in niche areas where antifouling is hard to apply or is quickly eroded away. These areas include the propeller, rudder and any inlet/outlet pipes, and by default these are the areas hard to inspect and identify the presence of non native species.
It can be difficult to separate native species from introduced non-native species because we do not yet have a thorough understanding of what species are naturally present. However, the Shallow Marine Survey Group (SMSG) has gone some way to fill these knowledge gaps and their ongoing surveys have led to a better understanding of the diverse marine life in our near shore environments.
The DoA—Biosecurity in collaboration with SMSG and with support from Premier Oil, have embarked on a monitoring project to establish a baseline of marine species and to act as an early warning for incursions of new non-native species.
We have deployed settlement plate arrays around Stanley Harbour which provide a suitable place for marine organisms to colonise. Through regular monitoring we are building up a picture of what species we currently have, and will therefore be in a better position to identify new non-native species when they appear. Specialist software is used to analyse photographs of the plates, allowing us to calculate species richness, evenness and diversity.
Sea temperature loggers record temperature every 30 minutes giving us a very accurate picture of how environmental conditions correlate with recruitment of organisms on the plate. Ultimately these data will be of value in understanding and managing the spread of non native organisms.
When the plates have become completely encrusted with growth they are replaced, and the full ones are sent away for genetic analysis. This technique allows for the detection of species that may be more cryptic and difficult to identify.
Preparing for the worst…
But what do we do if marine invasive species arrive?
Unless we have early warning it is unlikely that we will be able to eradicate new marine invasive species. Management will be key and to this end the Department of Agriculture has been working closely with Dr iLaria Marengo and Dr Amelie Auge from the South Atlantic Environmental Research Institute (SAERI) in a pilot study mapping the areas most at risk from the introduction of non native species (NNS) and the likely dispersal routes around the Islands in the event of those NNS becoming established. The study formed part of the Darwin Plus funded Marine Spatial Planning project and was in collaboration with the IMS-GIS Data Centre.
More than a thousand vessels of various types enter the Falklands Exclusive Economic Zone each year. Some pass by on their way to other destinations but many are bound for the Falklands. SAERI used data gathered by Customs to plot the origin of these vessels. The results show just how well connected the Falklands are and the pathways by which organisms might arrive here.
SAERI pulled together information from various sources including AIS data showing vessel positions and locations of known ecologically sensitive areas such as seabird and wildlife colonies, to identify the places that were most at risk from the introduction of NNS, both in terms of likelihood of introduction and the likelihood that they would impact on native species should they become established there.
Unsurprisingly, being the busiest first port of entry to the Falklands, Port William and Stanley Harbour were the most at risk of introduction of NNS. This is verified to some extent with both known marine invasive species being present in these areas.
Once areas at risk of introduction from international vessels were identified, diffusion methods (ways the NNS could be spread within the Falklands) were considered. These factors allowed other areas to be identified as areas prone to the secondary spread of NNS and therefore highlighted the pathways that could be managed to prevent this spread.
Although this was only a pilot study and there remains a lot of work to do to refine this model, it illustrates how marine spatial planning and GIS will allow us to contingency plan for such events and react more efficiently to incursions of NNS helping safeguard the Falkland Islands environment and economy.
These tools will allow us to put in place management procedures, if necessary, to limit the spread of NNS around the islands should they become established, and help minimise their impacts on the environment and potential conflicts with current and future marine related industries.