11th International Congress on
Marine Corrosion and Biofouling
University of San Diego, California
22 July to 26 July 2002

Invasive Species in Fouling

Chris Swanson,
Editor, CQD Journal

A new nightmare for shippers, ports & harbors: the coming problem of ship-fouling and biological invasions.

Three years ago, CQD Journal for the Maritime Environment Industry wrote about two researchers who were studying invasive species (CQD Journal Vol. 5.4 - June, 1999).  Unlike many similar researchers at the time, Dan Minchin and Stephan Gollasch were not studying invasive species in ballast water.  They were looking at another hitherto unlooked at phenomenon, exotic invaders coming from the fouled hulls of ships.

A lot more people are beginning to follow Minchin & Gollasch's example.  Thanks to the efforts of Eric Holms of the U.S. Navy's Surface Warfare Center, Dorn Carlson, of NOAA/SeaGrant and Richard Everett of the U.S. Coast Guard's Environmental Standards Division, a group of international experts, Minchin included, spent July 25^th and 26^th discussing Ship Fouling and Biological Invasions at the Congress on Marine Fouling in San Diego.

Ship fouling is certainly not a new phenomenon to shippers, it is the bane of Masters aboard ships throughout the globe.  Historical records have shown that many of the harbor flora and fauna that we now call native came from non-local ports.  But recent events, including a coming ban on what was the most effective killer of hull bio-foulers (organotin biocides), have brought international scientists to start to aggressively research this hot topic.  Thanks to sponsorship funds from the US Coast Guard, NOAA/SeaGrant and the office of Naval Research, the special two-day session on Invasive Species in Biofouling allowed these scientists to get together to outline what the future portends. 

Robert Whitlatch of the Univ. of Connecticut provided a quick lesson in biofouling organisms as they pertain to ships and shipping.   He explained some of the reasons that biofoulers successfully attach on ships and invade harbors. 

According to Whitlach one of the critical points to scientists is, we do not know how many individuals of a potentially invading species are needed to successfully establish in a new port.  This poses a Shipper's Dilemna.  An owner may be proud to have a ship that is 99% fouling free, but this may not be good enough for scientists.   In biological terms 1% fouling may be all that is needed to allow an exotic invader to get through. 

Ship owners should be warned.  Whitlach noted that the difficulties with managing invasive species in ballast water are nothing compared to the difficulties in managing invasions via ship fouling.

Case studies of significant environmental and economic damage were reported about invasive species that arrived from ships via biofouling.  John Lewis spoke about problems in Australian ports with a number of species.  Chris O'Brien told of the environmental rescue efforts surrounding the sinking of a fishing vessel in New Zealand.  Various international experts from Hawaii (Godwin) to the South Pacific sited many other examples of seaweeds, barnacles, mussels, sponges and other fouling organisms causing damage in ports of the world.

The question in many people's minds is – what do we know about this problem?  Is this a distinctive problem from ballast water invasive species, or can it be handled by the same management practices?

Greg Ruiz of the Smithsonian Environmental Research discussed historical comparisons made between ballast water and hull fouling.  From what his investigations have shown so far, we know dangerously little.  The need for new research on this subject is pressing.

Initial priorities may be to identify where the greatest threats lie.  Barbara Hayden has performed some initial work on the types of vessels that pose the highest risk of bringing in exotic invaders.  Scott Godwin's observations in Hawaii support other reports of the dangers from slower moving vessels such as barges and drydocks. 

Finally, Dan Minchin wrapped up the discussions with his expert observations about merchant shipping and invasive species.  Coupled with regulatory changes in approved antifouling materials, aquatic invasions from fouling organisms on a ship's hull will very likely rise in the near future.  We are certainly heading towards a new and potentially significant environmental problem, one in which ship owners and the world must soon be made aware of.

Robert Whitlatch – On the Ecology and Natural History of Macrofaunal Organisms Fouling Vessel Surfaces

Email: Robert.whitlatch@uconn.edu

From the University of Connecticut, Whitlatch gave an overview of fouling communities that invade and establish in new habitats.  His outline covers three distinct questions that are on the minds of shippers and others.

1) What lets species successfully foul a vessel surface?

• Populations hang out in areas where ships hang out.
• Spores/larvae always seem to be available.
• Harbor areas lack predators; a ship hull is a refuge from predators such as crabs or shrimps.
• Harbors tend to keep larvae/species within their waters.
• Most fouling larvae are present during slack water and before noon.
• Plenty of organic material is available for food.
• There is a huge variety of fouling species, hence there are many different means of securing and creating a community on any particular ship's hull.

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Email: ruiz@serc.si.edu

Ruiz and his research team at the Smithsonian Environmental Research Center (SERC) are working on similarities and differences between two major vectors for exotic species invasions from ships – ballast water and hull fouling.  Ballast Water has received much international attention, is it possible that hull fouling could represent a similar or perhaps worse threat of exotic species?

Ruiz's group estimates that the surface area of hulls arriving from foreign ports into the United States is estimated at about 438 million meters squared per year.  That is comparable to an area 1.5 times the size of Vermont.  Every vessel on the ocean has a hull, but not every vessel de-ballasts.  Based only on scale, hull fouling represents a much larger potential threat than does ballast water, according to Ruiz.

How does the scale of hull area correlate with invasive potential?  Ruiz and others do not yet know.

The SERC group decided to look at the history of invasive species over the last few centuries to determine where most exotic species came from.  They concluded that fouling probably contributed a larger number of species than did wet ballast, but the research is still very uncertain.  In the final analysis, we really do not know the relative importance of hull fouling vs. ballast water invasive potential, says Ruiz.

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John A. Lewis – Hull fouling as a vector for the introduction of exotic marine species to Australia

Email: j.lewis@dsto.defence.gov.au

People have come to recognize danger species from ballast water such as the zebra mussel.  What about hull fouling?  Anyone hear of the Mediterranean Fan Worm, Japanese Kelp or Broccoli Weed?

John Lewis of the Defense Science & Technology Organization (DSTO), representing the Australian Navy, investigated these and other fouling related species that have already caused environmental and economic harm around the globe.  His case studies cause shudder when we see pictures of boat bottoms entirely engulfed in marine fouling.

Lewis showed examples of severe fouling invasions in the Port of Cairns, Australia and other similar ports.  Among other exotics, the Asian green-lipped mussel (Perna viridis) was discovered in a number of marinas.  Aggressive actions were taken to eliminate the mussel or identify the marinas where it had established.  In one case, a heavily fouled fishing vessel was destroyed and a marina was temporarily quarantined to halt further infestations.

The Australian government is reviewing hull fouling as a potential threat of non-indigenous species.  Current actions, according to Lewis include effective antifouling, good maintenance practices and regulation of laid up and derelict vessels.  In-water hull cleaning has been largely banned throughout Australia.

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Email: Chris.obrien@fish.govt.nz

People looking for an example of a severe biofouling threat have only to check with O'Brien and his team at the Ministry of Fisheries, New Zealand.  Their actions regarding the grounding of the Seafresh I show that New Zealand is serious about acting against potential hull fouling invasions.

In March 2000, the fishing vessel Seafresh I sank off a remote southern island of New Zealand.  Although the vessel had just come out of dry dock where its hull was completely cleaned, divers investigating the boat found two small plants of the species Undaria pinnatifida.  Non-native to New Zealand, Undaria is a highly invasive seaweed.

Based on the threat of only those two plants found, O'Brien and the Ministry of Fisheries placed orders to have the vessel lifted from the sea bottom and moved to an open ocean location.  Officials were sure that if the vessel was left where it was, undaria would invade and cover the pristine surroundings where the boat had sank.

Due to rough seas and very poor weather, the salvage effort to move the ship failed.  Seafresh I settled further onto the sea floor making removal impossible. Afraid of undaria invasions, O'Brien ordered monthly underwater and shoreline inspections. 

O'Brien's worries proved correct. By January 2001, divers had removed over 500 undaria plants that had sprouted from the vessel.  Underwater torches were used wherever the seaweed was discovered to sterilize and kill any remaining traces.  Shoreline inspections fortunately did not find any instances of the exotic invader.

In the end, the surveillance effort seems to have worked.  No undaria plants have been discovered and the pristine setting of the islands remains intact.  At a final cost of $3.5 million dollars, the case of the Seafresh I shows that hull fouling can indeed pose severe economic and environmental risks.

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Email: sgodwin@bishopmuseum.org

Godwin works for the Bishop museum of Hawaii.  Native species in the isolated native Hawaiian environment are highly vulnerable to invasions.  Marine and port authorities often call upon his team to identify exotics that may pose a threat to the native species. 

Within this capacity, Godwin performed an informal study where he determined that overseas barge traffic and floating dry docks pose significant potential invasion risks to Hawaii.  These slow moving structures are often highly fouled and can deposit many non-indigenous species of fauna and flora.  Godwin said he observed an exotic plant spawning from underneath a floating barge.  A few weeks later a population of the plant was found attached to a nearby structure;  he believes they came from the same barge.

Unscheduled and "odd-ball" events pose an even greater danger, says Godwin.  Maritime authorities in Hawaii refused to allow a floating dry dock from South America to enter into their ports.  The dry dock was not scheduled for Hawaii and was not expected in any advance notifications.  The pulling tug had engine trouble and was diverted for repairs.  Investigations on the undersea surface of the dry dock found severe infestations of marine fouling.  Authorities kept the dry dock offshore for two weeks until the tug was repaired and sent on its way.  This unscheduled diversion could have caused disaster within the Hawaiian port if it were not for the actions of an environmentally savvy port agent.

Godwin is part of a committee of maritime industry representatives and marine resource managers.  The committee was created to draft management plans concerning hull fouling.  He said the maritime industry is included, as "the maritime industry will be expected to foot the bill when actions are taken."

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– Vessel hulls: a variable vector of non-indigenous species

Email: b.hayden@nlwa.cri.nz

The National Institute of Water and Atmospheric Research in New Zealand conducted a pilot study to identify tools to manage hull invasion threats.  Hayden reported on the findings from their inspections and comparisons of fouling on the bottom of merchant vessels and ocean going yachts.
 

Hayden makes the point that the places of fouling (on the hull) may be a critical component in determining how to manage for hull invasions.  Her group found the greatest fouling on merchant vessels at props, rudder shafts and bow thrusters.  Commercial vessel hulls were well cleaned due to antifoulants, but other parts of the vessels pose a threat of exotic invaders when fouled.

With the upcoming America's Cup defense in New Zealand, October 2002, authorities are worried about an influx of overseas yachts.  Hayden typically saw a wider variety and quantity of exotic fouling on yachts than those found on commercial vessels.  Pleasure boats were likely to have heaviest fouling on the flat bottom of hulls.

Based on preliminary studies, Hayden feels the merchant vessels pose a LOWER risk of exotic species invasions than recreational vessels.  Pleasure boats enter into New Zealand waters and stay for long periods of time.  This means such yachts pose the greatest risks when it comes to transporting non-indigenous populations.

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Email: Oliver.floerl@jcu.edu.au

Pleasure boat owners may find Floerl's work on hull fouling of recreational vessels of particular interest.  His research examined ways to clean the hull of a pleasure boat to determine what works better than others.

Most interesting was his finding that fouled hulls cleaned manually by scraping and scrubbing are those most susceptible to becoming re-fouled.  The organic remains of barnacles and other organisms are often still present on the hulls in minute quantities even after heavy scrapping.  These remains make it easier for new settlements of fouling organisms.

It appears the only way to stop re-fouling on a boat hull is to completely sterilize the hull or make sure the organisms never get on in the first place.

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Email: minchin@indigo.ie

Having spent years at the University of Fisheries in Ireland, Minchin is one of the pioneers who brought the issue of invasive species in hull fouling to the world's attention.  He outlined some critical links between hull invasions and merchant shipping that need to be addressed if the world wants to formulate management plans.

One of the key factors of hull fouling invaders is the importance of triggering events that induce spawning.  Unlike ballast water invaders, hull foulers reside outside the ship's hulls and are subject to the vagaries of environment.  According to Minchin, water quality changes as a ship moves into a port can set off massive spawning among species residing on the hull.  Rising temperatures in the shallow waters of the port after the species have been relatively dormant in cool ocean waters mean that many organisms will receive a shock that causes them to induce reproduction.  A massive spawning event means a higher potential that exotics can succeed in the new environment.

Other important links between exotic species invasions and merchant shipping include activity levels of the vessels and usage.  Slower vessels with more resting time will have more fouling than the typical merchant fleet.  Vessels such as cruise liners that visit more remote areas could pose a great risk, as do naval vessels that spend long durations at port.  Minchin points out these differences in activity levels mean different potential risks from exotic hull foulers.  Perhaps a different level of managing for non-indigenous species will be required for high risk fouling vessels.

Changing factors in today's ports mean that the risks of exotic species successfully invading a harbor are getting higher.  Minchin notes that water quality is improving throughout the world's ports, increasing the chance of survival for new organisms.  Increasing urbanization has moved vessel traffic to new berthing sites, providing more opportunities for invaders. 

Minchin's observations about usage, activity level and changes in merchant shipping highlight a coming problem.  Coupled with regulatory changes in approved antifouling materials, aquatic invasions from fouling organisms on a ship's hull will very likely rise in the near future.  We are certainly heading towards a new and potentially significant environmental problem, one in which ship owners need to be aware of.

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This page last updated by Miller Associates: Thursday, June 05, 2003