Biofouling – The Next Big Thing?

Barring some additional work on type-approval the issue of ballast water treatment is now settled following the MEPC 71 decision to allow a delay of at least two years. However, biofouling and the question of preventing invasive species has now moved on to the second chapter as new vectors are considered for regulation.

At MEPC 71 it was announced that a new technical co-operation project had been agreed that would effectively be a continuation of the GloBallast project which officially ended in June this year. A statement issued in mid-August after the meeting said the IMO has secured further funding from the Global Environment Facility (GEF) to prepare a full-scale document for a new global project aimed at assisting with implementation of the IMO Guidelines for controlling and managing ships’ biofouling.

The GloFouling Partnerships project is a collaboration between the Global Environment Facility (GEF), the United Nations Development Programme (UNDP) and the IMO just as the GloBallast partnership was. The GloFouling Partnerships project concept was approved by the GEF Council in May 2017, with a total funding of $6.9m earmarked for implementation.

The project is now going through a detailed preparation phase to be resubmitted to the GEF for endorsement before implementation can commence. The full name of the new project will be Building Partnerships to Assist Developing Countries to Minimize the Impacts from Aquatic Biofouling (GloFouling Partnerships). It will focus on the implementation of the IMO Guidelines for the control and management of ships’ biofouling, which provide guidance on how biofouling should be controlled and managed to reduce the transfer of invasive aquatic species.

When did discussions on biofouling start?

This development should not come as a big surprise since it was telegraphed some years back and discussed at various meetings even before the 2004 Ballast water Treatment Convention was adopted. In fact, biofouling has been identified as a means for transferring species for decades and before ballast water treatment was even considered as needing regulation.

It could even be argued that by initially concentrating on ballast water treatment, the IMO had in fact chosen the wrong target. Almost every scientific treatise on invasive species suggests that hull fouling accounts for the majority of species transfers. Some putting it as the cause of 60% of all identified invasive species whereas ballast water scores between 15% and 20% with other vectors such as aquaculture , both accidental and deliberate introductions on a par with ballast and the balance being through other means. Often overlooked in the studies are factors such as floating debris and by attachment to other animals.


Frequently the exact means by which an invasive species arrived will never be discovered. The zebra mussel, often held up as an example of the economic damage invasive species can inflict, apparently is said to have arrived in the Great Lakes in the ballast tank of an unknown ship.

That is a possibility, but the same species also found its way from the Black Sea to the UK in 1824, Rotterdam in 1826, Hamburg in 1830 and Copenhagen in 1840, well before water was being used as ballast and therefore by some other means.

What is the IMOs view on biofouling?

Many would say that the IMO has a confused attitude towards what constitutes pollution and environmental protection. Having banned coatings containing TBT – acknowledged as the most effective anti-fouling yet developed – because of their adverse effect on marine fauna, then deciding that the issue of invasive species was of equal importance and that ballast water must be treated to kill potential hitchhikers. The focus has again moved back to the outer hulls and how to stop the transfer of species carried as biofouling.

In attempting to first control transfer of species via ballast water, the IMO and most of those involved in early discussions probably considered that chemical dosing would be sufficient. It was only later when thoughts turned to what effect any residual chemicals may have on species at the point of discharge that the issue of ballast water treatment suddenly became so complicated.

While attention was mainly on ballast water, a number of states, notably Australia, New Zealand and states in the US such as California, were also considering and formulating rules for dealing with other methods. An 2001 report on Aquatic Nuisance Species (ANS) by the US EPA stated “While most studies agree that ballast water discharges are the primary source of ANS introductions from vessels, ships can also transport living organisms on the hull, in sea chests, in seawater piping systems, on the rudder, entangled in the anchor or in the anchor chain, in chain lockers or caught up in fishing nets”. An Australian report from around the same time actually singled out biofouling as the prime cause.

At the IMO, the issue was mentioned along with ballast water but it was only after the first ballast treatment systems were gaining type approval that the MEPC took any concrete action on biofouling. This was to be in the form of guidelines adopted at MEPC 62 in July 2011. The Guidelines can be found as Resolution MEPC.207(62).

In the introduction to the guidelines, the IMO meekly acknowledges its contradictory stance saying, “While the International Convention on the Control of Harmful Anti-Fouling Systems on Ships, 2001 (AFS Convention) addresses anti-fouling systems on ships, its focus is on the prevention of adverse impacts from the use of anti-fouling systems and the biocides they may contain, rather than preventing the transfer of invasive aquatic species”.

The IMO guidelines were actually based on an Australian version devised some years previously and introduced to the IMO at MEPC 56 as an information paper. Australia and New Zealand had jointly formulated even earlier rules that were in force until quite recently. These could be found in the Australian and New Zealand Environment and Conservation Council (ANZECC) Code of Practice for Antifouling and In-water Hull Cleaning and Maintenance, 1997.

When the IMO introduced its guidelines, most in shipping felt that in most of it there was nothing new. After all generations of shipowners had appreciated that a fouled hull led to all manner of problems. Aside from the loss of performance of the vessel in terms of speed and fuel consumption, there were penalties associated with performance claims if the vessel was under time charter and the extra weight of fouling meant a loss of earning capacity.

For those reasons alone, maintaining the hull in the best condition possible was basic husbandry practice.

Within the IMO guidelines were administrative tasks that although currently voluntary will likely now become mandatory as the IMO attempts to turn the recommendations into regulation. In some cases, ships may already be under an obligation to undertake these tasks as flag states may have incorporated all or some of it into national requirements.

The tasks involved are the drawing up of a ship specific biofouling management plan and record book. The format and content of the plan is laid out in the guidelines which also contain provisions for education and training for officers and crew in controlling and managing biofouling, sections on in-water inspections and cleaning, consideration of so-called niche areas such as sea chests, thrusters and the like where fouling is heaviest during the design stage for new vessels.

The issue of sea chest and similar fouling is as well-known as that of hull fouling and there are several systems on the market to prevent it. As examples, Cathelco has an impressed current cathodic system and Evoqua’s chemical Chloropac Marine Growth Prevention System has been around for decades – it is also used in the company’s ballast treatment system and even comes in a dual-purpose variant that deals with both issues.

The inclusion of in-water inspection and cleaning was something new for many owners. Except for ships with non-biocidal coatings, any cleaning or re-application of coatings was prohibited in many ports. It was also an additional unwelcome expenses as the presence of biofouling could be surmised by the mere fact that ships speed and performance was deteriorating.


For the most part, the guidelines and the actions expected of owners are in relation to the ship’s anti-fouling coatings. Recognising this, most coatings manufacturers were more than happy to do some of the preparatory work and produced templates for owners to complete with specific ship details.

It should be remembered that this recommendation came at a time when, as a result of the AFS Convention, coatings manufacturers were introducing new products at a very fast rate. Replacing the older products with new ones was not always the easiest of tasks as there were several innovative and untried technologies involved in the new products and their performance needed to be experienced before any meaningful plans could be devised.

It was also a period when ships were transitioning from high service speeds to slow steaming and when extended drydocking periods were also being introduced.

Biofouling – The coatings

Today, choosing an anti-fouling paint depends much more on the ship’s operational profile than it once did. While there were always premium, mid-range and budget options for TBT coatings, the array of products on offer today across all makers can be quite confusing.

Selecting an appropriate product requires fore knowledge of what the ship will be doing through the life of the coating. Easy enough for a vessel on a scheduled service but less so for say a bulker that may have periods of inactivity and trade to vastly different geographical and environmental conditions. The drydocking schedule is another factor that needs to be considered. Having selected what the owner thinks is the best choice, the usual practice is to forget about it once applied unless it seems not to be performing as promised.

What is perhaps most disconcerting about any possible future regulation with regard to biofouling management is the potential for expensive and disruptive enforcement. With the best will in the world, no owner can expect to be able to monitor the condition of the hull and any species attaching to it on a continuous basis.

Fouling can and usually does, commence within hours of a ship entering the water after delivery or drydocking. Although the first colonists are likely to be slime producing bacteria which are relatively harmless as species but which do attract higher species to settle. Even if harmless, the slime does have an effect on performance. One scientific paper claims that a biofilm 1 mm thick can increase the ship hull friction by 80%, which translates into a 15% loss in speed. Some bacteria are acid-producing and can cause corrosion.

Assuming the ship operates within the parameters of the chosen coating, larger species are less likely to be as successful as the bacteria. But if they do, ship fuel consumption can increase dramatically – as much as 20% or more in the worst cases. That is bad enough in cash terms but it will also increase emissions proportionately and that can also be a problem with MRV and possible market based measures on the way.

No coating is immune to mechanical damage and almost every ship will experience some from time to time. Contact with floating debris, navigation in ice, tug work and groundings are the usual causes. It is hard to know what any regulation will allow in the way of anything less than a perfect coating. Even a very small damage site could allow the attachment of a highly adaptive invasive species but whether it does or not no one would know.

Furthermore, the extent of any fouling on a ship’s hull is not necessarily an indication of the damage it could do to a coastal environment. A ship which operates solely in an area of same risk and which is quite heavily fouled may be harbouring a small colony of more invasive species picked up from contact with another vessel or floating debris.

The ballast water management convention contains no details of penalties for contravention as this is left to flag and port states. Since there is as yet no convention for biofouling management there are no requirements on flag or port states to introduce any. That is not to say that they cannot nor do they have to accept the IMO guidelines.

As an example, the California State Lands Commission (SLC) has recently reminded interested parties that the California Biofouling State regulations become effective on 1 October 2017. There is a new form to do this and a requirement to manage biofouling very much in line with the IMO guidelines including having a plan and a record book. The records that have to be kept include average speeds and times spent in port. The reporting requirements come into effect immediately but some other aspects of the rules only apply from 1 January 2018.

New Zealand also has similar rules coming into effect in May 2018 but earlier this year it set a precedent by refusing entry to a ship because it was considered a danger to biosecurity due to heavy biofouling. The bulk carrier DL Marigold was ordered to leave the port of Tauranga in March this year only a few weeks before the vessel was scheduled to undergo a routine drydocking. It was also prevented from entering Fijian waters before being finally being cleaned by divers in international waters.

Heavy fouling for relatively slow-moving vessels in the days immediately before a drydocking and after two to three years operating in tropical waters is not unusual. Ship operators must be hoping that the case of DL Marigold is a one-off and not a sign of things.