Introduction of Non-Indigenous Invertebrate Species in the Ballast Water of Ships

MB2080 Briefing Note

The introduction of non-indigenous invertebrate species in the ballast water of ships


The purpose of this briefing note is to outline the potential risks of the introduction of Non-Indigenous Species (NIS) by ballast water and to present recommendations to decrease harmful effects of this event.


Historical records and studies indicate that fouling organisms first crossed oceans on man-made ships, where marine species encrusted onto wooden-hulled vessels were carried from port to port (Bax et al. 2003). As intra and inter-colony trade routes were established and immigration increased (Hewitt et al. 2004), maritime traffic across oceans led to an increased number of NIS in coastal water environments (Reise et al. 1998). In Australia, the history of marine biological invasions most likely began with European contact around the 1800s with exploration and colonisation (Hewitt et al. 2004). While wooden ships were still the main type of vessel used, crews would often scrub the hull and anchor chain at stops along the voyage (Bax et al. 2003). The shift from wooden-hulled to steel-hulled vessels in the modern era leading up to              World War 1 led to the shift from dry ballast to water ballast (Hewitt at al. 2004) as water ballast better controls trim, draft and stability, and helps to maintain safe and efficient transit conditions (Bailey 2015, Niimi 2004). The first signs of water ballast as a potential dispersal mechanism for holo, mero and tycho-plankton were recognised in the late 1890s (Bailey 2015, Hewitt et al. 2004). 

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Becoming an invasive species is not easy, as many criteria must be met for that categorisation. A majority of potential invaders die as they cannot survive the dark and dirty conditions of ballast water tanks over long voyages. Further, invasive species that survive are likely to be confronted with unsuitable environmental conditions at the port of discharge, and even then, suitable species often fail to establish themselves. Most species that succeed in establishment fail to become invasive (Bax et al. 2003); however, the ones that do bring significant risk factors with them.

Newly introduced NIS can threaten biodiversity, marine industries and human health (Bax et al. 2003). Not only do NIS species alter the population of indigenous species by harming them directly, but they also alter the overall ecosystem. They also impact community and ecosystem processes and are therefore a significant force of change in global marine and estuarine communities (Ruiz et al. 2015). After identifying an increase in paralytic shellfish poisoning – whereby humans fall ill as a result of alkaloid toxin contaminated shellfish product consumption – Hallegraeff (1998) outlined a plausible scenario for the successful introduction and establishment of toxic dinoflagellate cysts in Australian waters. He stated that: 1) ballast water was taken in during seasonal planktonic blooms from Korean or Japanese ports, 2) survival of the resting cysts was high due to the voyage in dark ballast tanks, 3) after ballast water discharge, the germination of cysts was successful, accompanied with sustained growth and reproduction in Australian ports, and 4) coastal currents and domestic shipping led to further spreading and culminating under suitable environmental conditions in harmful algal blooms.


At any given moment, with transoceanic cargo shipping being truly global, ten thousand different species are being transported between bio-geographic regions in ballast tanks (Bax et al. 2003). The introduction of NIS into foreign habitats are therefore an inevitable consequence (Bastrop et al. 1998). While there is currently insufficient data to quantify the probability of invasion associated with any particular inoculum density (Bailey 2015, Ruiz et al. 2015), invertebrates appear to have higher breeding and establishment potential – which is increasing at a dramatic rate –because their diet and feeding behaviours suggest greater potential for extensive ecosystem alterations (Bax et al. 2003, Cohen et al. 1995).

The UN recognised that the transfer of invasive species across natural barriers is one of the greatest pressures to the world’s oceans and seas (David et al. 2019). The international convention for the control and management of ship’s ballast water and sediments (i.e. BMW convention) sets the global standards on ballast water management requirements with its aim to reduce the spread of potentially hazardous organisms among ports and other coastal areas (David et al. 2019).




For ballast water treatments to effectively reduce the density and richness of biota, and thus reduce the risk of transferring NIS (Bradie et al. 2010), ballast water management should satisfy each of the following criteria: 1) it must be effective at killing potential invaders, 2) it must be safe for the crew, 3) it must be environmentally friendly and 4) it must be affordable (Tamburri et al. 2002). Gollasch and Leppakoski (2007) proposed a management scenario that can achieve all of these. They suggest that the uptake of ballast water should be minimized or avoided in areas with outbreaks, infestations, sewage outfalls and phytoplanktonic blooms. Furthermore, ballast tanks should be cleaned on a timely basis in mid-ocean or, when the conditions are too rough to do so, under controlled arrangements in port or dry dock. Lastly, unnecessary discharge or uptake of ballast water should be avoided.

CONCLUSIONIt is evident that NIS are a key contributor to environmental change that can result from various human activities, whereby the global movement of ballast water by ships appears to be the largest single vector. Invertebrate species have a proportionately higher chance of invading foreign ports and coasts due to their ability to survive and withstand considerably harsher conditions than other phyla. Centuries of global shipping trade without defined ballast management has now led to thousands of potentially hazardous NIS invasions – the most survivable being invertebrate species – which, if unaddressed, has the potential to cause significant and irreparable harm.


Bailey, SA 2015, ‘An overview of thirty years of research on ballast water as a vector for aquatic invasive species to freshwater and marine environments’, Journal of Aquatic Ecosystem Health and Management, vol. 19, no. 3, pp. 261-268, viewed 19 August 2019, DOI:10.1080/14634988.2015.1027129

Bastrop, R, Jurss, K & Sturmbauer, C 1998, ‘Cryptic species in marine polychaete and their independent introduction from North America to Europe’, Molecular Biology and Evolution, vol. 15, no. 2, pp. 97-103, viewed 19 August 2019, DOI:10.1093/oxfordjournals.molbev.a025919

Bax, N, Williamson, A, Aquero, M, Gonzalez, E & Geeves, W 2013, ‘Marine invasive alien species: a threat to global biodiversity’, Marine Policy, vol. 27, no. 4, pp. 313-323, viewed 19 August 2019, DOI:10.1016/50308-597X(03)00041-1

Bradie, JN, Bailey, SA, van der Velde, G & MacIsaac, HJ 2010, ‘Brine-induced mortality of non-indigenous invertebrates in residual ballast water’, Marine Environmental Research, vol. 70, no. 5, pp. 395-401, viewed 19 August 2019, DOI:10.1016/j,marenvres.2010.08.003

Cohen, AN, Carlton, JT & Fountain MC 1995, ‘Introduction, dispersal and potential impacts of the green crab Carcinus maenas in San Francisco Bay, California’, Marine Biology, vol. 122, no. 2, pp. 225-237, viewed 19 August 2019, DOI:10.1007/BF00348935

David, M, Magaletti, E, Kraus, R & Marini, M 2019, ‘Vulnerability to bioinvasions: current status, risk assessment and management of ballast water through a regional approach – the Adriatic Sea’, Marine Pollution Bulletin, vol. NA, pp. NA, viewed 19 August 2019, DOI:10.1016/j.marpolbul.2019.06.057

Gollasch, S & Leppakoski E 2007, ‘Risk assessment and management scenarios for ballast water mediated species introductions into the Baltic Sea’, Aquatic Invasions, vol. 2, no. 4, pp. 313-340, viewed 19 August 2019, DOI:10.3391/ai.2007.2.4.3

Hallegraeff, GM 1998, ‘Transport of toxic dinoflagellates via ships ballast water: bioeconomic risk assessment and efficacy of possible ballast water management strategies’, Marine Ecology Progress Series, vol. 168, pp. 297-309, viewed 19 August 2019, DOI:10.3354/meps168297

Hewitt, CL, Campbell, ML, Thresher, RE, Martin, RB, Boyd, S, Cohen, BF, Currie, DR, Gomon, MF, Keough, MJ, Lewis, JA, Lockett, MM, Mays, N, McArthur, MA, O’Hara, TD, Pore, GCB, Ross, DJ, Storey, MJ, Watson, JE & Wilson RS 2004, ‘Introduces and cryptogenic species in Port Phillip Bay, Victoria, Australia’, Marine Biology, vol. 144, no. 1, pp. 183-202, viewed 19 August 2019, DOI:10.1007/s00227-003-1173-x

Niimi, AJ 2004, ‘Role of container vessels in the introduction of exotic species’, Marine Pollution Bulletin, vol. 49, no 9-10, pp. 778-782, viewed 19 August 2019, DOI:10.1016/j,marpolbul.2004.06.006

Reise, K, Gollasch, S & Wolff, WJ 1998, ‘Introduced marine species of the North Sea coasts’, Helgolaender Meeresuntersuchungen, vol. 52, pp. 219-234, viewed 19 August 2019, DOI:10.1007/BF02908898

Ruiz, GM, Carlton, JT, Grosholy, ED & Hines, AH 1997, ‘Global invasions of marine and estuarine habitats by non-invasive species: mechanisms, extent, and consequences’, Integrative and Comparative Biology, vol. 37, no. 6, pp. 621-632, viewed 19 August 2019, DOI:10.1093/icb/37.6.621

Tamburri, MN, Wasson K & Matusda M 2002, ‘Ballast water deoxygenation can prevent aquatic introductions while reducing ship corrosion’, Biological Conservation, vol. 103, no. 3, pp. 331-341, viewed 19 August 2019, DOI:10.1016/S0006-3207(01)00144-6


Ship Ballast Water Management

Coursework Ship Ballast Water Management

Table of Contents

Table of Contents………………………………………………………1

1. Introduction………………………………………………………..1

1.1 Reasons of introducing ballast water management on board………………………1

1.2 BWM standard requirements…………………………………………..1

2. IMO approved BWM systems……………………………………………..2

2.1 Ecochlor BWTS……………………………………………………2

2.1.1 Working Principle……………………………………………….2

2.1.2 Process Description………………………………………………2

2.1.3 System specifications……………………………………………..2

2.1.4 System advantages and disadvantages………………………………….2

2.2 Alfa Laval PureBallast………………………………………………..3

2.2.1 Working Principle……………………………………………….3

2.2.2 Process description………………………………………………3

2.2.3 System specification……………………………………………..3

2.2.4 System advantages and disadvantages………………………………….4

3.Suitability on ships…………………………………………………….4




1. Introduction

1.1 Reasons of introducing ballast water management on board

The introduction of steel-hulled vessels, lead to the use of water ballast system where water is pumped in to the vessel to decrease the stresses occurring on the hull, while providing transverse stability and improving propulsion and maneuverability [3]. It also, compensates for weight shifts in different cargo load level operation, thus water ballast ensures the safe and efficient operation of the vessel. However, due to the fact, that marine species, i.e. bacteria, microbes, small invertebrates, eggs, cysts and large various species are getting pumped during the filling process of water ballast [3]. Consequently, creating several problems, such as ecological, health and economic ones.

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1.2 BWM standard requirements

IMO has implemented the following two BWM standards D-1, D-2. D-1 standard requires ship to discharge their ballast water in deep water (200 meters deep) and at distance 200 nautical miles away from land, by doing that it decreases the chances of organisms surviving in the deep-sea water environment. D-2 standard relates to the size of discharged organism, as follows [3]:

Less than
viable organisms per
, which are greater than or equal to
50 mm
in minimum dimensions.

Less than
viable organisms per
, which are in size of
10–50 mm
in minimum dimensions.

Less than
colony-forming unit (cfu) per
100 mL
of toxicogenic vibrio cholerae.

Less than
250 cfu
100 mL
of Escherichia coli.

Less than
100 cfu
per 100 mL of Intestinal Enterococci.

The current status of BWM conventions is showed on figure 1, which shows, when new and existing ships need to comply with D-1 and D-2 conventions and the requirement of having a BWM plan, ballast water record book and the BWTS to be certified by the IMO.

2.1 Ecochlor BWTS

2.1.1 Working Principle

The Ecochlor BWTS is a chemical solution, which consists of a filtration process and a Chlorine Dioxide (
) treatment system to remove smaller organisms.

2.1.2 Process Description

The first step of the BWTS is the filtration system (Figure 2), where the filter mechanism prevents larger objects from entering the inlet chamber. Moving on to the next stage of the filter mechanism is the premilitary process for flushing, where the water goes into a “cake” sediment (Coarse screen) [2]. At this section, variable pressures are applied, depending on the thickness of the sediment, until it reaches the desired pressure (usually 0.5 bar) to initiate the flushing process [2]. The Second stage is the
  supply at the injection point to the water ballast tank, where the smaller particles are removed. The
is supplied from the
generator unit, where a small amount of water is directed through the generator by a booster pump [2]. Moreover, the water follows a flow through a venture, where vacuum is formed at the mixing chamber [2]. At this point, the chemical pumps provide the required amount of Purate and sulfuric acid into the chamber [2]. Thus,
is formed from the chemical reaction, that flows into the venture due to the former vacuum pressure created [2] Finally,
enters the supply water and then it is injected at the ballast water system.

2.1.3 System specifications

There are two main components for this BWTS, the filtration unit, which consists of parts, as showed in the Figure 2 and the treatment module, which consist of components, as shown in figure 3. This type of filters can handle flows from
and are automated cleaned. The overall system can handle variable flows from
  with energy requirements from
7–62.6 kW
as maximum and as typical
4.8–19.8 kW
, as shown in figure 4 and 5.

2.1.4 System advantages and disadvantages

The advantage that offers the filter mechanism is the ability to self-clean, endure heavy loads of sediments and low energy requirements, due to low pressure operation. As far as concerns the treatment module, it can operate with low power consumption, automated and it does not require any changes on the current ballasting operation. Another benefit is that the treatment module can be placed in any convectional space on ship (relative small footprint). Possible disadvantages are that it requires safe storage, and handling on board, since the ClO2 can be explosive, if it is encountered with sparks, sun light and heat. Also, the filtration system needs to be changed in 5 and 10 years interval [6], so it should be matched with a drydocking period to avoid potential downtime of vessel.

2.2 Alfa Laval PureBallast

2.2.1 Working Principle

This type of arrangement utilized Ultra-violet (UV) reactor to achieve biological disinfection and the filtration process to remove the bigger organisms in the ballasting process. Also, it complies with convention of both USCG and IMO.

2.2.2 Process description

During ballasting condition, the incoming sea water goes through a filtration process, where the bigger organisms are getting removed; therefore, improving the quality of the incoming sea water. Afterwards, it goes into an enchanted UV reactor, where the biological disinfection occurs, before entering the ballast tanks [4]. Moreover, the cleaning in-place (CIP) cycle takes place, which is an automated process to clean up the reactor, by recirculating a non-toxic and biodegradable substance solution, and then to fill it up with fresh water, along with the filter. As far as concerns, the deballasting procedures the water goes into the UV reactor stage from the ballast tanks to remove potential organisms, that regrew and afterwards it is discharged into the receiving water at the deballasting site [4].

2.2.3 System specification

This type of arrangement can vary slightly, based on capacity application. The main units in all capacity application is the filter and UV reactor stage. The Pureballast Compact with capacity of
  , which consists of the following two supporting components the CIP and electrical cabinet, as shown in figure 7. The electrical cabinet provides the power for the reactor and can be placed 30m away from it, For Pureballast Complex with accommodated flow of
, the supporting components are CIP, electrical cabinet and LDC1/LDC2 (LDC1 provides power for flows
and when combined with LDC2 for flows of
750 up to 1000m3H
) for flows above
(figure 8). Finally, for larger flows
the Pureballast 3 Std is utilized with supportive equipment of Lamp drive cabinet, CIP and control cabinet and two reactors, where each one can handle flows up to
, as shown in figure 9.  The figures 10,11 and 12 represents the energy consumption of the above-mentioned arrangement at various flows of demand.

2.2.4 System advantages and disadvantages

This type of arrangement can operate at fresh, marine or brackish water [4]. Also, the power demand is significantly less, when the vessel operates within IMO regulations, about 42% in full flow rate [4]. Another advantage of this arrangement is that the system is fully automated. As far as concerns, the installation process it can be flexible, since the components are delivered as loose ones in case of Pureballast 3 Compact Flex and the lamp drive cabinet could be placed up to
meters away for Pureballast 3 Ex (reference). Furthermore, the CIP unit does not require a remote-control dosage, since it is a closed loop system with reusable and non-toxic substance. On the other hand, the substance needs to be replaced every
months and Lamp replacement every
hours of operation [4]. Also, the filter needs to be inspected every year. Finally, possible drawbacks could be the high cost of investment and the high-power consumption requirements in low-clarity water [4].

When considering the choice of BWTS on ships, there are several steps to be considered. First of all, the ballast water treatment system should meet the ballast capacity of the vessel. Moreover, the BWTS should have flexible installations procedures. Another important aspect, is the time required for the system to treat the water, so it might not be applicable depending on the streamline of the vessel. Compliance with both IMO and USCG could be crucial, because it can provide a wider range of offers, when deciding to sell the vessel. Also, the power consumption, maintenance and capital costs are important, as well. Whilst, considering the above in case of Alfa Laval BWTS, the reactor unit has a lifetime of over 20 years [5], which might not be ideal for a newbuilding ship with an expected lifetime of 25 years, since the maintenance costs will be considerably increased [5]. However, it has flexible capacity flow rate, which means it can be applied to all ship-types. Although, in large VLCC and ULCC with capacity of over
, this system is not that competitive, in terms of cost and power consumption. The Ecochlor BWTS can be applied to all ships, except in cases of small passenger ships with flow rates below
. In terms of safety, Pureballast does not imply any immediate danger to the environment, crew and ship structure. However, in the Ecochlor BWTS, the substance is toxic and is refilled by the Ecochlor to avoid any potential accidents, since the system is approved by IMO and USCG it cannot provide any direct threat to the environment. As far as concerns ship structure the substance is a non-corrosive one. Also, the high production of this toxic gas could be a concern, if it leaks. However, there have not been any accidents and is mainly utilized on large bulk carriers (i.e. Panamax, Capesize) and tankers (Suezmax, VLCC). The maintenance cost of BWTS of Alfa Laval are shown in figure 14. Finally, based on Ecochlor president and founder, the maintenance costs for the chemical refill are typically
USD$ per 1 m^3 of water treated [6]. Also, the filtration system needs to be replaced in intervals of 5 and 10 years with costs of
USD$ up to
USD$, depending on size and about
USD$ for miscellaneous maintenance activities [6]. The annual maintenance cost of Pureballast complex flex are shown in figure 14.

1. Imoorg. 2018. Imoorg. [Online]. [25 October 2018]. Available from: infographic_FINAL.pdf

2. Ecochlorcom. 2015. Ecochlor. [Online]. [31 October 2018]. Available from:

3. Imoorg. 2018. Imoorg. [Online]. [31 October 2018]. Available from:

4. Alfalavalcouk. 2018. Alfalavalcouk. [Online]. [31 October 2018]. Available from:

5. Anavees. 2018. Anavees. [Online]. [31 October 2018]. Available from:

6. Ballastwatermanagementcouk. 2018. Ballastwatermanagementcouk. [Online]. [31 October 2018]. Available from:,counting-the-cost-of-ballast-treatment_42146.htm

Figure 1. IMO info graph, relating the implementation of D1-D2 conventions. [1]

Figure 2. General arrangement of Ecochlor Filter system. [2]

Figure 3. Treatment module of Ecochlor BWTS. [2]

Figure 4. Technical data of smallest plant of Ecochlor BWTS [2]

Figure 5. Technical data of largest plant of Ecochlor BWTS [2]

Figure 6. Main components of Alfa Laval PureBallast 3.1. [4]

Figure 7. Alfa Laval PureBallast Compact
Capacity=32 up to 300m3H)
. [4]

Figure 8. Alfa Laval PureBallast Compact Flex
(Capacity=32 up to1000m3H)
. [4]

Figure 9. Alfa Laval PureBallast Std Capacity (32-3000 m3/H). [4]

Figure 10. Technical data of Pureballast Compact Flex. [4]

Figure 11. Technical data of Pureballast Compact. [4]

Figure 12. Technical data of Pureballast Std. [4]

Figure 13. Table from ABS, regarding Ballast water.

Figure 14. Maintenance costs of Alfa Laval Compact Flex (up to
). [5]