Designated Exchange Areas Project – Providing informed

Designated Exchange Area Project Final Report i

Designated Exchange Areas Project –Providing informed decisions on the discharge of Ballast Water in Australia (Phase 2)

Emma Knight, Simon Barry, Rupert Summerson, Scott Cameron and Rebecca Darbyshire

Designated Exchange Area Project Final Report ii

© Commonwealth of Australia 2007

This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth. Requests and inquiries concerning reproduction and rights should be addressed to the Commonwealth Copyright Administration, Attorney General’s Department, Robert Garran Offices, National Circuit, Barton ACT 2600 or posted at http://www.ag.gov.au/cca.

The Australian Government acting through the Bureau of Rural Sciences has exercised due care and skill in the preparation and compilation of the information and data set out in this publication. Notwithstanding, the Bureau of Rural Sciences, its employees and advisers disclaim all liability, including liability for negligence, for any loss, damage, injury, expense or cost incurred by any person as a result of accessing, using or relying upon any of the information or data set out in this publication to the maximum extent permitted by law.

Postal address: Bureau of Rural Sciences GPO Box 858 Canberra, ACT 2601

Designated Exchange Area Project Final Report iii

Executive Summary Invasive Marine Pests and Ballast Water

Invasive marine pests pose a threat to Australian marine environments and to industries dependent on these environments. Exchanging ballast water is one mechanism for the introduction and translocation of marine pests. The Australian Government requires the management of internationally sourced ballast water. However, there are no arrangements in place for the management of domestically sourced ballast water except for Victoria.

The Convention

The International Convention for the Control and Management of Ships’ Ballast Water and Sediments (the Convention) provides for a globally consistent approach to the management of marine pests in ballast water and sediment.

Ballast Water Management Arrangements

The Australian Government, States and the Northern Territory agreed to apply the Convention in the development of nationally consistent Ballast Water Management Arrangements as part of the National System for the Prevention and Management of Marine Pest Incursions. Risk management of domestically sourced ballast water by the implementation of exchange areas is an interim measure while onboard treatment systems are being introduced. These systems are being phased in over the next 10 years and will be mandatory on all ships by 2016.

Designated Exchange Areas Project

In general, ships entering Australian ports from international locations can exchange ballast water at a distance greater than 200 nautical miles from the coastline and in waters deeper than 200 metres, adhering to international regulations. However, ships travelling between Australian ports will generally be unable to comply with the regulations without deviating from or delaying their original voyage. Under the Convention, Australia can designate ballast water exchange areas for ships that would have to deviate from their usual route or delay their intended arrival to comply with the regulations.

The aim of this project was to identify locations that could be designated as areas for ships on domestic routes to undertake ballast water exchange. This was achieved by evaluating the overall risk of pest establishment and cost to the shipping industry of different management strategies. Three options for designated boundaries were investigated; 3, 12 and 24 nautical miles from the coast.

Questionnaire Based Risk Assessment

A questionnaire was developed from information gathered in previous work (Phase 1 of this project) and was completed by experts in marine pests and invasion biology. Experts were asked to estimate the risk of pests establishing from ballast water discharge at a number of locations around Australia, relative to the risk of establishment from discharge in a nearby port environment. The experts scored risk based on latitude, longitude, distance from the coast, depth and larval survivability. These results were used to model the risk around

Designated Exchange Area Project Final Report iv

Australia.

Analysis of Environmental Risk

The results indicate that the risk of establishment depends on:

• depth • distance from the coast • water movement and • latitude

Risk decreases with depth and distance from the coast. The risk extends further to the north of Australia, however the volume of ships carrying domestically sourced ballast water is significantly lower in these areas.

Balancing Environmental Risk and Cost to Industry

The areas of concern are those where the risk of establishment is high and where ships carrying domestically sourced ballast water are operating. The further the boundary from the coast, the greater the environmental protection, however this is coupled with a greater cost to the shipping industry due to ships being required to deviate from their route.

A boundary of 3 nautical miles provides an average risk reduction of 60% and will have a minor impact on the shipping industry. A boundary of 12 nautical miles provides greater environmental protection with an average risk reduction of 75%, and will have a relatively moderate impact on the shipping industry. A boundary of 24 nautical miles reduces the average risk by a further 10%, but comes at a significant cost to industry.

Torres Strait and Great Barrier Reef to be Considered Separately

Due to the high risk recorded through the Torres Strait and Great Barrier Reef and the environmental sensitivity of these areas, it is recommended that these areas be examined separately when designating ballast water exchange areas.

Designated Exchange Area Project Final Report v

1 Contents Executive Summary .........................................................................................................................iii

1 Contents .....................................................................................................................................v

2 INTRODUCTION.........................................................................................................................7 2.1 Background .........................................................................................................................7 2.2 The Problem........................................................................................................................8 2.3 Previous Work .....................................................................................................................8 2.4 Objectives of DEAP Project (Phase 2) ................................................................................9 2.5 Structure of this Report......................................................................................................10

3 METHODS.................................................................................................................................11 3.1 Introduction........................................................................................................................11 3.2 Expert Questionnaire.........................................................................................................11 3.2.1 Development of the Questionnaire............................................................................12

Scenario locations ....................................................................................................................12 Selection of Experts .................................................................................................................12 Evaluation of Risk.....................................................................................................................12 Larval Baselines .......................................................................................................................13 Scenarios .................................................................................................................................14 Answer Sheet ...........................................................................................................................16

3.2.2 Analysis of the Questionnaire Results.......................................................................17 Mapping the Risk......................................................................................................................18

3.3 Economic and Practical Impacts .......................................................................................19 3.3.1 Shipping data.............................................................................................................19

Identifying ballast water carrying ships on domestic routes.....................................................20 Generalised route.....................................................................................................................20 Overlays of risk and shipping data ...........................................................................................21

4 RESULTS AND DISCUSSION .................................................................................................21 4.1 Risk Analysis - Expert Questionnaire ................................................................................21 4.2 Shipping Data ....................................................................................................................27 4.3 Risk versus Cost................................................................................................................30

Ballast water exchange area boundaries.................................................................................30 Summary of the estimated risk of establishment at 3, 12 and 24 nautical miles .....................30 Maps of the estimated risk at 3, 12 and 24 nautical miles .......................................................32 Acceptance of a certain level of risk.........................................................................................36

Designated Exchange Area Project Final Report vi

4.4 Examples...........................................................................................................................40 4.4.1 Brisbane – Sydney ....................................................................................................40 4.4.2 Sydney – Melbourne..................................................................................................44 4.4.3 Western Australia ......................................................................................................47 4.4.4 Northern Territory ......................................................................................................49 4.4.5 Further examples.......................................................................................................52

5 CONCLUSION ..........................................................................................................................53

References .......................................................................................................................................55

Appendix A: Questionnaire ............................................................................................................56 Email sent to experts asking them to participate in the study..................................................56 The email sent to participants containing the questionnaire....................................................57 The cover letter ........................................................................................................................57 Information document...............................................................................................................58 Scenarios .................................................................................................................................64 Answer Sheet ...........................................................................................................................70 Shipping Map ...........................................................................................................................73

Appendix B: Participants................................................................................................................74

Appendix C: Additional Maps ........................................................................................................75

Appendix D: Great Barrier Reef & Torres Strait Examples .........................................................80

Designated Exchange Area Project Final Report 7

2 INTRODUCTION

2.1 Background This report is the result of the Designated Exchange Areas project conducted by the Bureau of Rural Sciences (BRS) for the Invasive Marine Species Programme (IMSP), Corporate Policy Division, Australian Government Department of Agriculture Fisheries & Forestry. The project aims to inform decisions on the development of designated ballast water exchange areas for the National System for the Prevention and Management of Marine Pest Incursions (National System) Ballast Water Management Arrangements.

Invasive marine species pose a significant threat to Australia’s marine industries and environment. Marine pests may be introduced into Australian waters and translocated around the country by a range of human and natural means. One of the potential vectors for introduction and translocation is through ballast water, carried by commercial ships to ensure stability, trim and structural integrity.

Since July 2001, the Australian Government has had in place requirements for the management of internationally sourced ballast water that apply to all ships arriving from overseas. The Australian Quarantine and Inspection Service (AQIS) is the lead agency for the management of ballast water sourced from overseas. Part of AQIS’ charter is to ensure that foreign ballast water has been managed in accordance with the requirements before permitting its discharge inside Australia’s territorial sea. Any ballast water that has been exchanged at sea by an approved method is deemed to be acceptable for discharge in Australian ports and waters. However, AQIS ballast water management does not regulate ballast water sourced from inside Australia’s territorial sea. The Victorian Government has had requirements for the management of domestically sourced ballast water in place since July 2004.

The Australian Government was instrumental in developing the International Convention for the Control and Management of Ships’ Ballast Water and Sediments (the Convention), to ensure a globally consistent approach to the management of marine pests in ballast water and sediment. The text of the Convention was agreed at the International Maritime Organization (IMO) Diplomatic Convention in February 2004. Australia signed the Convention on 27 May 2005, subject to ratification. Australia is considering ratification of the Convention (bringing the Convention into force within Australia) as part of the process of developing National Ballast Water Management Arrangements.

A High Level Officials Group (HLG) of Australian Government, States and Northern Territory officials agreed to the development of the National System to manage domestic ballast water as part of a single consistent national ballast water management system. The new ballast water arrangements will provide for a single set of requirements and a single coordinating contact centre. The requirements will be implemented under Australian Government legislation for international ballast water and state/territory legislation for domestic ballast water.

The National Introduced Martine Pest Coordination Group (NIMPCG) is responsible for the development of the National System. Through the National System, the Australian, Northern Territory and state governments are developing nationally consistent ballast water management arrangements. These requirements will be consistent with the Convention and allow Australia to manage the risk from marine pest introductions from both internationally and domestically sourced ballast water.


The Convention provides for the management of ballast water through two main mechanisms – exchange and treatment. The designation of ballast water exchange areas is an interim solution for approximately 10 years. Introduction of ballast water treatment systems are to be phased from 2009 and will be mandatory for all ships by 2016. These systems will provide a high level of risk mitigation and annul the need for ships to undertake ballast water exchange at sea. This project investigates the designation of ballast water exchange areas to reduce the risk of translocating harmful aquatic organisms around Australia’s marine environment until onboard treatments become available.

2.2 The Problem Australia intends to ratify the Convention through the development of the National System’s Ballast Water Management Arrangements (BWMA). Therefore, the BWMA must be consistent with the Convention and, as such ships must comply with the Convention’s Regulation B-4.1. Regulation B-4.1 specifies that a ship conducting ballast water exchange shall:

.1 whenever possible, conduct ballast water exchange at least 200 nautical miles from the nearest land and in water at least 200 metres in depth

.2 where a ship is unable to meet point 1. above, conduct ballast water exchange as far from nearest land as possible, and in all cases at least 50 nautical miles from the nearest land and in water at least 200 metres in depth.

Regulation B-4.2 of the Convention has provision for Australia to designate ballast water exchange areas for ships that would have to deviate from their usual route or delay their intended arrival to meet Regulation B-4.1. Regulation B-4.2 states that:

‘in sea areas where the distance from the nearest land or depth does not meet the parameters described in paragraph 1.1. or 1.2, the port State may designate areas, in consultation with adjacent or other States, as appropriate, where a ship may conduct Ballast Water exchange, taking into account the Guidelines described in paragraph 1.1.’

Due to Australia’s geographical layout and location, ships entering Australian ports from foreign ports will generally be able to comply with Regulation B-4.1. However, ships travelling between Australian ports will generally be unable to comply with Regulation B-4.1 without deviating from or delaying their original voyage. This presents a significant cost for industry to comply with the exchange requirements and may lead to increased safety concerns. Hence it is important that Australia designate sufficient ballast water exchange areas for these ships.

2.3 Previous Work Previous work in this area has concentrated on two key areas. Hobday et al. (2002) modelled particle dispersal and produced baselines of risk which calculated the percent of particles that reached “suitable” habitat, defined by depth. While this work allowed the bounding of the risks associated with ballast water exchange, the conversion between a particular baseline and the actual risk was not defined due to the complexity of the underlying processes. Barry et al. (unpublished) considered the diluting effects of exchange and port discharge. They argued that exchanging in open coastal waters offers a significant reduction in the risk of marine pests establishing compared to discharge without treatment in port, due to the effects of dilution and dispersal. This project uses expert understandings of these issues to calibrate these results.

The Designated Exchange Areas project (DEAP) contains two phases. Phase 1 of this project involved the identification and collation of information to be considered in designating a ballast


water exchange area(s). The information was complied into a Geographic Information System (GIS). The data included distance contours, Marine Protected Areas, Fisheries areas and existing shipping routes. The data were used in Phase 2 to assess the risks of marine pest incursions via ballast water discharged, as well as to assist in determining areas which may be suitable for ballast water exchange. The information obtained from Phase 1 is presented below in Figure 1.

Figure 1. Data collected from Phase 1 of the project, including depth, shipping, shipping traffic, marine protected areas and levels of commercial fisheries catch.

2.4 Objectives of DEAP Project (Phase 2) The objective of this project (DEAP Project Phase 2) is to inform decisions on locations that Australia could designate as areas for ships to undertake ballast water exchange as per the requirements of the Convention. The risk posed by ships conducting ballast water exchange within a designated area was assessed. This was achieved by minimising any threat or harm to the environment, human health, property or resources. In determining the designated ballast water exchange areas for Australia, minimising additional costs imposed on the shipping industry to comply with the Convention was also considered.

The designation of ballast water exchange areas must be consistent with the Convention and consider a combination of biological risks, economic costs and practical issues to reach a final conclusion.

• Biological Risks

― Different species are likely to pose different risks from port to port depending on factors such as temperature, water depth, currents and physiology. Determining the risk of all invasive marine species currently inhabiting Australian ports would be time consuming and would result in different exchange zones being proposed


for each species. Experts on marine pest incursions were consulted throughout this project to determine biological risks.

• Economic Costs

― Requiring ships to undertake ballast water exchange in areas off their original routes will increase the costs associated with transportation of goods via sea. The potential delays and extra costs to be imposed on the industry to obtain the required environmental protection is an important factor when considering exchange areas.

• Practical Areas

― Areas deemed practical to be designated for ballast water discharge zones can be identified from the information gathered in Phase 1 of this project.

2.5 Structure of this Report There are two main sections to this report, namely the ‘methods’ and ‘results and discussion’. The ‘methods’ section describes the processes used to develop the expert questionnaire and carry out the risk analysis. It describes how practical issues as well as economic impacts on the shipping industry were considered. The ‘results and discussion’ section presents the relationship between risk and the variables used in the model and uses this relationship to map risk around Australia. The influences of shipping routes and traffic density on risk are discussed. The associated cost to industry of imposing designated exchange areas is also outlined in this section.

Four appendices are also attached. These contain the questionnaire provided to the experts, a list of the experts who participated, additional maps describing risk and maps investigating the risk to the Great Barrier Reef and Torres Strait.


3 METHODS

3.1 Introduction This report considers the biological, economic and practical impacts of designating exchange areas. The information collated in Phase 1 was used to develop a questionnaire to quantify and assess the biological risk of ballast water exchange in coastal environments. The questionnaire was completed by a panel of experts in marine pests and invasion biology. To evaluate the economic and practical impacts of designated exchange areas, shipping routes and densities were investigated.

3.2 Expert Questionnaire The use of a questionnaire to conduct risk assessment has been employed by previous studies. For example, Cunningham et al (2003) used a survey of experts to estimate the feasibility and costs of eradication for a range of weeds. This was achieved by asking experts to examine 15 hypothetical weed profiles based on specific plant attributes. Experts then estimated the probability of eradication across 8 broad price ranges. The results obtained from this questionnaire highlighted which characteristics of a species posed the greatest risk of infestation, according to the experts. As a result, 10 species of weed were identified as high risk and were marked for eradication (Cunningham et al 2003). The use of questionnaires in this study was found to be transparent, scientifically objective and efficient. The success of this case was ensured by the use of widely accepted principles and methods that have previously been subject to peer review in the scientific community (Cunningham et al 2003).

Modelling the biological risk explicitly is an alternate method to an expert questionnaire. Upon considering the development of such a model, several issues became apparent. Firstly, previous approaches, such as that of Hobday et al (2002), have highlighted certain physical processes which are relevant to the biological risk. They were, however unable to provide estimates of the risk due to the complexity and uncertainty in the knowledge of the processes involved. The second, more practical constraint to this approach is the time required to produce such a complex model. Policy makers have committed to urgent action on this issue and a decision on designated ballast water exchange areas is to be made over the coming months.

In order to conduct an assessment of the biological risk of ballast water exchange, a set of hypothetical scenarios were developed and experts were asked to assess the risk at certain locations. This methodology was favoured for several reasons. Firstly, it efficiently and holistically utilises the information collated in Phase 1 of this project. Secondly, this method could be completed in a timely manner. Thirdly, the questionnaire was developed to focus explicitly on the risk of exchange, which is of interest to management.

The methodology employed in this report, specifically the incorporation of an expert based questionnaire, posed several potential difficulties. The most notable being the swift compliance of the experts in completing the survey. An added complexity was ensuring that enough data was collected from different areas around Australia. It was important to include enough locations and variables to ensure that sufficient data was obtained to draw conclusions. However, it was also important to not include too many variables, as this would have required a large number of scenarios to cover all comparisons. This may have affected the response rate as it would be time consuming for the experts.


3.2.1 Development of the Questionnaire

Scenario locations Twelve locations around the Australian coastline were chosen as scenarios (see Figure 2). The locations were selected to cover a range of environments, depths, distances from land and areas with high levels of domestic shipping activity.

Figure 2: Scenario locations and domestic shipping activity.

Selection of Experts Experts with scientific experience in marine pest and invasion biology were invited to complete the questionnaire. As the results of this project are to be presented to NIMPCG to provide a framework for designating areas for ballast water exchange, NIMPCG members from each state were asked to nominate experts from their jurisdiction.

Evaluation of Risk Currently, ships are allowed to discharge domestic ballast water (ballast water that originates from an Australian port or within the territorial sea of Australia) into Australian ports and waters (except in Victoria). The risk evaluated in this report was measured relative to the current practice. Experts were asked to estimate the risk of discharging ballast water at each location relative to the risk of discharging in a nearby port environment.

For every scenario, each expert was asked to assess the risk of discharging ballast water at a number of sites. The experts were asked to consider the set of species that would establish if the ballast water was discharged in a nearby port environment and then estimate the percentage of these species that would establish if the ballast water was discharged at each site. For example, a


score of 10 indicates that the expert thinks that 10% of the species that would have established if discharged in port would establish if discharged at the particular site in question. In this context, establishment refers to an organism being able to find suitable habitat and survive.

The experts were additionally asked to assume that the ballast water originated from a similar latitude to the discharge location (which provides a conservative assessment). A further assumption for the amount of ballast water discharged at a location was also implied, asking the experts to mentally average the amount of water that would be discharged in normal ballast water exchange activities. The experts were also asked to average over possible port environments. They were asked to further assume that the suite of species involved is the suit of species that they think are being translocated between Australian ports in ballast water, now and in the future.

While it is logical that the experts would want to consider variables such as the species involved, source of water, discharge amount, wave energy, habitat type and other variables, it was beyond the scope of this project, the available data, the timeline for the decision process and the nature of the decision for these options to be included. The designated exchange areas will not be defined differentially based on organisms or ship characteristics, instead it is intended that a single zone will be defined. It will be a zone that potentially needs to protect against introductions in the future as well as for translocations of species currently present. Thus, the experts were asked to mentally average over the unspecified components, based on their understanding of the complex processes involved.

Larval Baselines The larval baselines were developed in a study conducted by CSIRO Marine Research aimed at providing a scientific framework for selecting ballast water uptake and discharge zones around the Australian continent (Hobday et al, 2002). In this study, combinations of biological species information, ocean current estimates and modelled larval trajectories were examined to produce a series of estimated risk contours around the Australian coastline. These baselines were built based on large and small scale water movement and therefore they were included in this study as a proxy for currents and tides.

Hobday et al (2002) modelled larval trajectories using geostrophic and wind-driven current estimates. The larval trajectories were then used to calculate the probability that larvae from any off shore cell would arrive at the coast within a larval duration time. The estimates of the discharge baselines based on modelled trajectories are dependent on both the larval duration and depth limits. The baselines were developed using biological species information (estimated maximum depth, duration and planktonic period) for the 12 target species currently used in the Ballast Water Decision Support System. Although a limited set of pest species were used to develop these baselines, the combination of maximum depth and larval duration used resulted in 15 unique life history combinations, and these should be applicable to additional pest species as management considers necessary.

The baselines are displayed in the form of (a)wk (b)m (c)%, where (a)wk refers to larval duration in weeks, (b)m refers to maximum settlement depth in metres and (c)% is the percentage of larvae discharged at that line that will reach the maximum settlement depth within the larval duration time. In the questionnaire used in this study, three larval baselines were chosen to cover the range of discharge sites within the 50 nautical mile, 200 metre depth zone. All three have a settlement depth of 50 metres, and a survival percentage of 50%, and differ in the larval duration, covering 1, 2 and 4 weeks. A 4th baseline is also included in some of the scenarios, which covers the “worst case” of 12 week larval duration and settlement depth of 200m for a 50% survival percentage. Figure 3 shows the location of the selected larval baselines.


Figure 3: Selected larval baselines from Hobday et al. (2002)

The 1wk 50m 50% larval baseline can be interpreted as: for a species that has a larval duration of 1 week and can establish at a depth of 50m, 50% of the larvae discharged at this line will cross the 50m isobath within a week. For points within this baseline, more than 50% of the larvae will cross the 50m isobath within a week and for points outside the baseline, less than 50% of the larvae will cross the 50m isobath within a week.

Hobday et al (2002) built a very detailed model accounting for the settlement depth and larval duration for a range of species as well as for the complexities of tides and currents. However, this model does not take dilution effects into account (Barry et al. unpublished), nor does it represent other factors such as habitat suitability, temperature and predation. This emphasizes the difficulty in building a detailed model for the risk, highlighting the reasons why an expert based risk assessment was used in the current project. The larval baselines from Hobday et al (2002) were included so that the experts could consider them together with the other factors which they feel are important in assessing biological risk.

Scenarios The scenarios were presented to the experts in the form of 12 maps. Figure 4 shows the map for the scenario located off the coast near Robe, Figure 5 the map for the scenario located off the coast near Darwin and Figure 6 the map for the scenario located off the coast near Brisbane. Maps for all scenarios can be found in the questionnaire attached in Appendix A.


Figure 4: Scenario 8 - Robe

Figure 5: Scenario 6 – Darwin


Figure 6: Scenario 7 - Brisbane

Each map shows the following:

• Coast

• 12 and 50 nautical mile distances from the Australian coastline as defined by the Territorial Sea Baseline (http://www.ga.gov.au/nmd/mapping/marbound/bndrs.jsp#tsb)

• 50 and 200 metre isobath. These define the area in which ballast water exchange areas can be designated.

• Bathymetry of the offshore region. This comprised a digital elevation model (DEM) overlain (with a transparency 50%) over a hillshaded DEM which gave both a perspective view of the seabed and a sense of the water depth.

• Selected larval baselines from Hobday et al (2003) (explained below).

• The scenario discharge points, each of which was annotated with the water depth at that point and its unique number.

It is important to note that the discharge sites within each scenario were not actual sites proposed for ballast water exchange, rather they were hypothetical for the purpose of informing the assessment of biological risk.

Answer Sheet The answer sheet provided in the questionnaire contained the longitude, latitude, distance to coast and depth for each discharge site within each location. An excerpt of this table is presented in Table 1. The complete answer sheet can be found in the questionnaire attached in Appendix A. Experts were asked to enter their estimate of the relative risk of discharge of ballast water for each site within each location. The experts were advised that their responses could be made public however the identity of the respondents would remain confidential.


Table 1: Answer sheet used by experts to record their estimate of the risk for each discharge site for each scenario.

Scenario Location Exchange Site Coordinates Depth

(m)

Distance offshore

(nm) Risk of Ballast Water Discharge (%)

144.348 E 1 -39.168 S

72 32.52

145.471 E 2 -39.216 S

74 32.63

146.749 E 3 -39.221 S

67 9.26

147.944 E

1 Bass Straight

4 -39.034 S

62 36.27

116.751 E 1 -20.295 S

42 6.02

116.584 E 2 -20.010 S

58 25.44

116.368 E 3 -19.732 S

65 45.13

116.107 E

2 Dampier

4 -19.513 S

120 61.33

3.2.2 Analysis of the Questionnaire Results The results of the questionnaire were entered into a database and loaded into the statistical package R (R Development Core Team, 2006) for analysis. The data provided to the experts for consideration in estimating the risk at each discharge site was:

• Latitude

• Longitude

• Distance from coast

• Depth

• Larval survivability

The aim of the analysis was to model the risk as estimated by the experts as a function of the above variables. For each discharge site, the distance to coast, depth, longitude, latitude and the risk as estimated by the expert were known. A measure of the larval baseline needed to be included in the analysis. This was obtained by giving the coast a score of 0, the first baseline a score of 10, the 2nd baseline a score of 20, the 3rd baseline a score of 30 and the 4th baseline a score of 40. The TOPOGRID routine in ArcGIS was used to interpolate between the baselines. It was necessary to modify the baselines before using TOPOGRID as some lines crossed each other in the vicinity of East Timor and east of Papua New Guinea.

Figure 7 contains the map for the scenario located off the coast near Robe. The numbers in the white boxes show the values assigned to the coast and the larval baselines. The numbers in the pink boxes show the values of the derived larval baseline measure obtained by interpolating between baselines.


Figure 7 Values of the larval baseline measure at the exchange sites in the Robe scenario.

Mapping the Risk The risk model was determined using the estimated risk provided by the experts for each discharge point within each scenario. The risk was then modelled using as a generalised additive mixed model in R (R Development Core Team, 2006) using the gamm function in the mgcv package (Wood, 2006). The risk was treated as pseudo binomial (using the quasibinomial family in the gamm function). The variables that were considered in the generalised additive mixed model for the risk were:

• Depth

• Distance from coast

• Derived larval baseline measure

• Latitude

• Longitude

These variables were fitted as smooth terms using smoothing splines. Expert was fitted as a random effect in the model to account for differences in the estimates of risk between experts.

The initial model fitted to the risk data was gamm(risk~s(depth)+s(distance)+s(larval.baseline)+s(latitude) +s(longitude), family=quasibinomial, random=list(expert=~1))


This fits a model of the form

longitude)()latitude(eline)larval.bas()distance()depth(1

log)(ogit 54321 fffffp

ppl +++++=⎟⎟⎠

⎞⎜⎜⎝

⎛−

= α

where p is the risk and f represents a smooth function.

Risk around the Australian coast was estimated using this model. A GIS grid was created for each variable in the model and was loaded into R. The risk for each grid point was estimated using the risk model based on the value of the latitude, depth, distance to coast and derived larval baseline measure at that grid point. The estimates of the risk of establishment for each grid point were then imported into ArcInfo GRID for integration with the GIS datasets for analysis and mapping.

3.3 Economic and Practical Impacts Requiring ships to complete ballast water exchange in a designated area may require ships to delay and/or deviate from their shipping route. This could represent a significant cost to the shipping industry.

A number of studies have previously been conducted to estimate the cost impact on Australian shipping of ballast water exchange management strategies for domestic voyages. Blias and Delforce (2003) assessed the costs (direct government costs and direct commercial shipping costs) of implementing a Decision Support System risk-based Ballast Water Management regime and Mandatory Ballast Water exchange for all ships. O’Keeffe (2005) built on the work of Blias and Delforce (2003) to consider the marginal cost of managing coastal shipping for a variety of target species. Bax et al. (2006) analysed the impact of ballast water management on southeast Australian shipping. The Centre for International Economics have prepared a draft Regulation Impact Statement looking at the costs of various designated ballast water exchange areas based on the earlier work conducted by ABARE, BRS and CSIRO.

Initially this project was to extend this work and produce a grid of the additional cost of exchange for deviations from usual shipping routes. However, a number of complexities need to be considered to extend this work to a spatial level such as, type and size of ship, the ship route and speed, the amount of ballast water and the method of discharge. To produce a universal cost surface would require a large number of assumptions. Given the diversity of the shipping industry, these assumptions would be difficult to create and justify. Due to the time constraints of the decision process, the development a cost surface was beyond the scope of this project. To overcome this issue, shipping data was analysed to determine the routes typically travelled by ballast water carrying ships. This information was considered with the biological risk to investigate the practical and economic issues related to designating areas for ballast water exchange.

3.3.1 Shipping data There are a number of sources of data on shipping movements in Australia. Lloyds Register of Shipping Movements is compiled from data provided by the ports management authorities. However, it is not easy to derive spatial data from this register. Customs and Quarantine compile records of international ships arrivals but do not maintain records of domestic shipping. Australian Maritime Safety Authority (AMSA) operates the Australian Ship Reporting System (AUSREP) whereby all ships, including domestic shipping, report their position every 24 hours while they are within the AUSREP area (an area much bigger than the Australian Exclusive Economic Zone).

The purpose of the AUSREP system is to track ships to assist with the management of shipping accidents including for search and rescue missions. All ships operating into and between


Australian ports are required to report their positions at designated reporting points. The AUSREP data provides daily position reports as well as ship information such as ship type, size, speed and heading for at least 97% of ships over 50 metres in length operating within Australian waters. Each voyage is assigned a unique identifier and the position reports along each route indicate the origin and destination of the voyage.

AUSREP data includes descriptions of the ship and voyage. The ship description includes ship type, ship length and tonnage. Voyage description include origin, destination, the type of report (start of voyage, position reports en route, end of voyage report), date and time of the report, speed at the time of the report and heading.

The daily position reports in the AUSREP data allow spatial expression of shipping traffic around Australia, however the exact route between the reporting positions is not known. Drawing straight lines between position reports result in a number of voyages being represented as travelling overland. Another issue using 24 hourly position reports is that some ships tend to report at certain locations on their voyage (such as near waypoints), hence the position reports under-represent the volume of shipping traffic on sections of the voyage where ships do not report.

Identifying ballast water carrying ships on domestic routes The aim of this research was to identify ballast water exchange areas for shipping that cannot meet the ballast water exchange requirements of the Convention. Ships were identified as domestic if they engaged in domestic voyages and exchanged ballast water from one Australian port to another.

There are two broad categories of ships that carry ballast water; bulkers and tankers and container and general cargo ships. Identification of ship type is important as different ships carry and manage ballast water differently. Bulkers and tankers typically transport goods one-way on their cargo leg and then take on ballast water for their return trip. This ballast water then needs to be discharged to accommodate cargo for the next cargo leg. The second type of ship includes container ships, general cargo ships, car carriers and cruise ships. These ships typically do repetitive routes, loading and unloading cargo along the way. These ships usually carry both cargo and ballast water on most legs, taking on and discharging relatively small amounts of ballast water at a succession of ports. Ships with ballast water holding capacity smaller than 50 metres were excluded from this analysis.

Many ships arrive in Australia from international waters and then move between domestic ports either on a single or continuous voyage permit. Identifying domestic voyages involves the identification of voyages whose origin and destination are Australian ports. Hence, position reports for ships whose origin or destination were entry or exit into the AUSREP region were excluded.

The presence of missing data in the origin and destination fields for a position report complicated this approach. For position reports where this data was not provided, the missing information was determined by tracing the voyage back to its origin using the unique voyage identifier.

Generalised route To summarise the information from the AUSREP data about the routes typically travelled by ballast water carrying ships, an in-shore route around Australia was created. Origin position reports were grouped into 19 major port groupings. For example, Sydney, Botany Bay, Newcastle and Port Kembla were grouped. A generalised route linking the ports was determined, as well as the frequency of ships travelling on each leg of the route.


Overlays of risk and shipping data To consider the implications of various limits for the designation of areas for ballast water exchange, a series of maps with shipping data superimposed on risk were developed. In consultation with the IMSP, it was decided to define designated areas by distance from coast. Designated areas defined by distances of 3, 12 and 24 nautical miles from the Australian territorial sea baseline were considered. A designated area of beyond 12 nautical miles implies that ships would be required to exchange ballast water at least 12 nautical miles from the coast.

4 RESULTS AND DISCUSSION

4.1 Risk Analysis - Expert Questionnaire The questionnaire was sent to 25 experts. Of these, a total of 13 completed the questionnaire within the required timeframe. All nominated NIMPCG members returned a completed answer sheet. A list of the respondents is provided in Appendix B.

One of the responses was not included in the analysis as the answers were not completed in a manner that reflected the methodology outlined in the instructions. Figure 8 displays the results of the 12 questionnaires that were used to develop the risk model. The estimated risk is plotted for each expert for each discharge location within each scenario. There are separate panels for each scenario. The estimated risk is shown on the vertical axis and the discharge site number is on the horizontal axis. Each line represents the response of a different expert.

As expected, there is variation in the risk estimated between the different experts. There is however, a general trend in the responses. Note the risk decreases for all scenarios as the discharge site number increases for all sites other than Torres Strait and Darwin. All of discharge locations at the other sites are numbered in order from the closest to furthest from the coast. The risk drops off as distance from coast increases, which is accompanied by an increase in depth. The discharge sites for the Torres Strait and Darwin scenarios are numbered differently, with sites 2 and 3 closest to the coast and hence the shallowest, having higher risk.


Figure 8 The results of the Expert Questionnaire used to develop the risk model.

Figure 9 contains plots of the various components of the model. These plots show the effect of each of the explanatory variables on risk. The solid line represents the smooth function between risk and each explanatory variable, while the dashed lines represent two standard errors above and below the estimate of the smooth function.


Figure 9: Effect of each explanatory variable in the initial model on the estimated risk.

A decreasing linear relationship is observed between the estimated risk and depth, as depth increases the estimated risk decreases. Similarly, the relationship between the estimated risk and the derived larval baseline measure is a decreasing linear trend. There is a positive linear relationship between the estimated risk and latitude. The estimated risk decreases with increasing distance from coast. This relationship is non linear, flattening out at a distance of approximately 60 nautical miles. Longitude does not appear to influence the estimated risk. Distance from coast is the only term in the model that has a non-linear relationship with the estimated risk.

The significance of each term in the model was assessed using Wald tests (Wood, 2006). The output obtained from the function anova.gam is presented in Table 2. Longitude was not a significant term in the model and was removed.


Table 2 The results of Wald tests of the significance of each term in the full model.

Approximate significance of smooth terms: edf Est.rank F p-value s(depth) 1.000 1.000 9.249 0.00247 s(distance) 2.728 6.000 15.062 <0.0001 s(larval.baseline) 1.000 1.000 104.538 <0.0001 s(latitude) 1.000 1.000 17.471 <0.0001 s(longitude) 1.000 1.000 1.827 0.17706

The final model fitted to the risk data was: gamm(risk~s(depth)+s(distance)+s(larval.baseline)+s(latitude), family=quasibinomial, random=list(expert=~1))

Figure 10 contains plots of the components of the final model. Table 3 contains the results of the Wald tests for significance of each term in the mode. All terms in the final model were significant.

Figure 10 Effect of each explanatory variable in the final model on the estimated risk.


Table 3 The results of Wald tests of the significance of each term in the final model.

Approximate significance of smooth terms: edf Est.rank F p-value s(depth) 1.000 1.000 11.567 0.000720 s(distance) 2.477 5.000 16.038 <0.00001 s(larval.baseline) 1.000 1.000 124.517 <0.00001 s(latitude) 1.724 4.000 5.807 0.000139

The final model was used to estimate the risk for each grid point based on the value of the latitude, depth, distance to coast and derived larval baseline measure at that grid point. The estimated risk for each grid point was then exported into ASCII arrays and imported into ArcInfo GRID for integration with the GIS datasets for analysis and mapping. The map of the estimated risk is provided in Figure 11.

Figure 11 Map of the estimated risk on a continuous scale.

The map in Figure 11 displays the risk on a continuous scale. For ease of interpretation, the risk was grouped into discrete intervals. Intervals of 10% were used from 0% to 50%, that is 0-10%, 11-20% and so forth. Data above 50% were put into a single group, labelled 50+. Figure 12 displays the risk in terms of these discrete intervals.


Figure 12 Map of the estimated risk using discrete intervals.

The risk was modelled as a function of the depth, distance from coast, derived larval baseline measure and the latitude. While the risk decreases as the distance from coast increases, the rate at which it decreases is not constant around the Australian coastline. The risk extends further in the north than in the south due to the combined effect of latitude, the derived larval baseline measure and the depth. Note that the water is generally shallower in the north as seen in Figure 13.

The risk at a location is an estimate of the risk of discharging ballast water at that location relative to the risk of discharging in a nearby port environment. The list of species that could establish in a port environment to the north of Australia will be different to the list of species that could establish in a port environment to the south of Australia. The higher risk in the north indicates that, of the species that could establish if discharged in a nearby port environment in this area, a high percentage of these would establish if discharged off the coast. It does not necessarily indicate that a greater number of species are likely to establish in the north. It does however indicate that relative to the species that would establish if discharged in a nearby port environment, a higher percentage of these species would establish in the north than in the south. This is reflected by the significance of latitude in the model.

There is a sharp decline in the risk off the southeast coast. This is largely driven by the derived larval baseline measure and depth. Depth increases rapidly off the southeast coast (as seen in Figure 13) and the larval baselines are very close to each other on the southeast coast (as seen in Figure 3).

Risk does not increase towards the coasts of countries that lie to the north of Australia (Papua New Guinea, Indonesia and East Timor) shown in Figure 12. This is a consequence of the risk being modelled relative to the Australian coastline only.


Figure 13 Water depth in metres

4.2 Shipping Data Figure 14 displays the daily position reports of all ships from the 2005 AUSREP data. Ships which used and exchanged ballast water with an Australian origin and destination were selected. Figure 15 displays the position reports for the selected voyages from the AUSREP 2005 data. To superimpose shipping data on the risk, an in-shore route around Australia was determined. This generalised route and the frequencies of ships travelling on each leg of the route are displayed in Figure 16. Figure 44 in Appendix C displays the same map with the names of the ports used to develop the generalised route.

The position reports in Figure 15 suggest that the southeast coast of Australia has the highest volume of ships carrying domestic ballast water. This is also reflected by the frequencies in Figure 16 where the busiest section is the first half of the leg between Sydney and Melbourne (approximately 2170 voyages in 2005). The ship position reports (represented by dots) cannot be used to infer shipping density as many ships will travel along the same route and report their position from the same reporting points along the route. The position reports for the Sydney to Melbourne and Bass Strait leg are very close to each other as they are required to use a designated traffic separation scheme. Conversely, there are no ship routeing measures in the Brisbane to Sydney leg and the position reports are more spread out.

The volume of ships carrying domestic ballast water is greatest off the southeast coast of Australia between Brisbane and Melbourne (in excess of 2500 trips in 2005). In 2005, a reasonable amount of ships carrying domestic ballast water did so off the Queensland coast, petering out in the north. Similarly there was a reasonable number of ships carrying domestic ballast water between Melbourne and Geraldton, decreasing to the west. There is a much smaller volume of ships carrying domestic ballast water off the northwest coast of Australia, with only 30 domestic ballast


water carrying ships travelling between Geraldton and Darwin and 33 between Darwin and Wiepa in 2005.

Figure 14 2005 AUSREP daily position reports.


Figure 15 2005 AUSREP daily position reports for domestic ballast water carrying voyages only.

Figure 16 Generalised route and frequencies of domestic ballast water carrying voyages over each section of the route, overlayed on the position reports for domestic ballast water carrying ships from the 2005 AUSREP data.


4.3 Risk versus Cost

Ballast water exchange area boundaries To consider the implications of designated areas for ballast water exchange, a series of maps of the risk with the shipping data superimposed were developed. The designated areas considered were areas outside of 3, 12 and 24 nautical miles from the Australian territorial sea baseline. These boundaries were chosen for administrative reasons as they define Australia’s maritime zones as prescribed under the United Nations Law of the Sea Convention 1982. Following the Offshore Constitutional Settlement, the Commonwealth and the States/Northern Territory have agreed that the first 3 nautical miles adjacent to the territorial sea baseline is the outer limit of the Coastal Waters. In general, the adjacent State or Territory has primary responsibility for water within these waters. The Commonwealth has jurisdiction over the territorial waters (12 nautical miles from the Territorial Sea Baseline), the Contiguous Zone (24 nautical miles from the Territorial Sea Baseline) and out to the limits of the Exclusive Economic Zone and, in some cases, to the continental shelf.

Summary of the estimated risk of establishment at 3, 12 and 24 nautical miles Figure 17 shows the 3, 12 and 24 nautical mile distance contours. The estimated risk of establishment is dependent on location and as a result, it varies along the 3, 12 and 24 nautical miles lines. Figure 18 contains a graphical summary of the estimated risk at 1 kilometre spacings along the 3, 12 and 24 nautical mile lines, and Table 4 contains a numerical summary.

Figure 17 Map of the estimated risk displaying the 3, 12 and 24 nautical mile lines from the territorial sea baseline.


Table 4: Summary of the estimated risk along the 3, 12 and 24 nautical mile distance contours.

Figure 18 Box plots of the estimated risk along the 3, 12 and 24 nautical mile lines.

The above box plots indicate that the range spanned by the estimated risk decreases with distance from the coast, along with the median estimated risk. At a distance of 3 nautical miles from the territorial sea baseline, the estimated risk ranges from 2% to 53%. Whereas along the 12 and 24 nautical mile lines, the risk ranges from 1% to 43% and 0% to 41% respectively. The range is very similar for the 12 and 24 nautical mile lines. 75% of the estimated risk values along the 24 nautical mile line are less than 25%, whereas along the 12 nautical mile line, less than half of the estimated risk is less than 25%.

It is important to note that these summaries do not take into account the location and therefore do not represent variation of coastal characteristics or quantity of shipping. As discussed in the next section, the risk is particularly high through the Great Barrier Reef and Torres Strait and this area needs to be considered separately when designating ballast water exchange areas. The estimates of the risk presented in the above summaries are inflated by the high risks through these regions.

Distance Minimum 1st Quartile

Median Mean 3rd Quartile

Maximum

3 nm 1.95 31.51 39.98 37.77 45.47 53.10

12nm 0.67 15.65 27.77 24.64 34.75 42.66

24nm 0.30 2.09 9.17 12.68 22.77 41.19


Maps of the estimated risk at 3, 12 and 24 nautical miles The designated boundary areas of 3, 12 and 24 nautical miles were superimposed on the risk map as shown in Figures 19, 20 and 21 respectively. In these maps, the area on the inside of the boundary is shown in white. For example, in Figure 20, a boundary of 3 nautical miles was designated, ships would not be able to discharge ballast water within 3 nautical miles from the territorial sea baseline. The designated ballast water exchange area becomes focussed on all of the area outside 3 nautical miles.

There is a dark orange band outside of the 3 nautical mile line in some areas along the northern coastline in Figure 19. The estimated risk in these areas is between 40 and 50%. This equates to a 50 to 60% reduction in risk from the current practices. Off the southwest coast, the highest risk outside of 3 nautical miles is between 30 and 40% as indicated by the light orange band. This is equivalent to a risk reduction between 60 and 70%. Off the southeast coast, the highest risk outside of 3 nautical miles is between 20 and 30%, equating to a 70 to 80% reduction in risk from the current practice.

Along some parts of the northern coastline, the estimated risk outside of 12 nautical miles is between 30 and 40%, as indicated by the light orange areas in Figure 20. This equates to an estimated reduction in risk of 60 to 70% from current practices. Along the southern coast of Australia, the highest risk outside of 12 nautical miles is between 20 and 30%. The risk along the majority of the southern coast is less than 20%, providing an 80% reduction of risk.

Figure 21 illustrates that outside of 24 nautical miles, there is a very small area through the Torres Strait where the risk is between 30 and 40%. Along the rest of the north coast, the highest risk outside of 24 nautical miles is between 20 and 30%. The highest risk outside of 24 nautical miles along the south coast is between 10 and 20% with the majority of the risk along the south coast being less than 10%.

Figure 19 Estimated risk outside of 3 nautical miles from the territorial sea baseline.





The risk noticeably decreases with distance from the coast. The further the boundary of the designated exchange is from the coast, the greater the impact on the shipping industry. To explore the risk in relation to current shipping routes, the shipping reports of domestic ballast water carrying ships from the 2005 AUSREP data were overlayed on the map of the risk, shown in Figure 22. This map highlights that although the risk is higher along the northern coast, there is a relatively low density of ships carrying domestic ballast water in this area. However, it is difficult to ascertain the risk in the areas of high shipping density due to the risk being masked out by the dots representing the position reports. This was resolved by summarising the shipping information by the use of the generalised route and frequencies as discussed in 4.2. Figure 22 displays the generalised route and frequencies of domestic ballast water carrying voyages on each leg of the route for the 2005 AUSREP data, overlayed on the map of the estimated risk. Figure 45 in Appendix C displays the same map with the names of the ports used to develop the generalised route.

The areas of concern are those where risk of establishment is high and where ships carrying domestic ballast water are operating. The risk is reasonably low, less than 10% in most places off the southeast coast of Australia, where the volume of ships carrying domestic ballast water is greatest (1-3,000 voyages per year). The risk increases to between 20 and 30% through Bass Strait and along the South Australian coast. However, the majority of ships travel off the coast rather than in the higher risk areas along the coast. The risk is higher along the west coast of Australia but the volume of ships is lower (approximately 640 voyages per year). Again, the majority of the ships travel off the coast in this region, rather than in the higher risks areas along the coast. The southwest corner of Western Australia and the coast near Darwin are areas of concern as ships travel very close to the coast. There is a moderate amount of domestic ballast water carrying shipping off the southwest corner. The volume of shipping traffic is particularly low near Darwin relative to the rest of Australia (approximately 30 voyages in 2005).

The area of greatest concern is through Torres Strait and the Great Barrier Reef. There is a moderate amount of domestic ballast water carrying shipping travelling through this area and the estimated risk of establishment is as high as 50%, only offering a 50% reduction in risk from current practices. Australia argued for the Great Barrier Reef and Torres Strait to be classed as ‘nearest land’ in the Convention, preventing any ballast water from entering this marine environment. In order to be consistent with the Convention, it is important that a ballast water exchange area is not designated within the Great Barrier Reef and Torres Strait. Accordingly, it is recommended that these areas be considered separately when determining designated areas for ballast water exchange.


Figure 22 2005 AUSREP daily position reports for domestic ballast water carrying ships overlayed over the estimated risk.

Figure 23 The estimated risk and generalised route and frequencies of domestic ballast water carrying voyages over each section of the route from the 2005 AUSREP data.


Acceptance of a certain level of risk To further explore the areas of concern, another two series of overlays were developed based on an acceptance of a certain level of risk. The first series assumes a 10% acceptance of risk of the chance of establishment in a port environment. Figures 24, 25 and 26 display the areas where the risk is greater than 10% outside 3, 12 and 24 nautical miles respectively, with the generalised route and frequencies overlayed to determine the areas of concern. Appendix C contains the same series of maps with the domestic ballast water carrying voyages position reports from the 2005 AUSREP data overlayed.

Figure 24 indicates that if a boundary of 3 nautical miles was designated, there are areas off the northern coast were the estimated risk of establishment is as high as 50%. However, there are very few domestic ballast water carrying ships operating in these areas. In 2005 there were only 33 domestic ballast water carrying voyages that travelled the section of water between Weipa and Darwin, and only 30 voyages between Darwin and Dampier. The exception to this is the Great Barrier Reef and Torres Strait, where there were as many as 728 voyages along the section of coast between Gladstone and Mackay. This area however, is to be considered separately. Along the coast of Western Australia, where the traffic density is high, there are areas where the risk is a high as 40%. In the very high ship operational region off the south eastern coast there are areas where the risk is as high as 30%.

Figure 25 indicates that if a boundary of 12 nautical miles was designated, the highest risk off the northern coast would be reduced to less than 40%, to less than 30% off the western coast and to less than 20% off the south eastern coast. Figure 26 shows that if a boundary of 24 nautical miles was designated, the highest risk off the northern coast would be reduced to less than 30%, except through the Torres Strait. At the 12 nautical mile boundary, there are limited areas around the rest of the coast where the risk reaches 20%.

It is important to take the amount of domestic ballast water carrying ships operating in an area into account when considering the risk. Figure 24 suggests that if a boundary of 3 nautical miles was designated and a 10% level of risk was accepted, one of the areas of concern is off the coast between Adelaide and Melbourne. In 2005 there were over 900 domestic ballast water carrying voyages along this section and the risk in the area of the generalised route is between 10% and 30%. However, recall from Section 4.2 that the generalised route is an inshore route. Figure 16 illustrates that through this section, a lot of the domestic ballast water carrying voyages travel further out from the coast than the generalised route, in an area where the risk is less than 10%, suggesting that this area is not of great concern (this can also be seen in Figure 46 in Appendix C).

If the designated area boundary was set at 12 nautical miles, ships would have to exchange ballast water outside of the 12 nautical mile line. Figure 25 indicates that in the area off the coast between Adelaide and Melbourne, the risk outside of 12 nautical miles in the area that ships are operating is less than 20%. This equates to an 80% reduction in the risk from the current practice. Figure 26 suggests that if a boundary of 24 nautical miles is designated and a level of risk of 10% is accepted, there are very few areas of concern along this route. Additionally, in these areas the risk is only as high as 20%, which means an 80% reduction in risk from the current practice.

Another area of concern is the coast off Western Australia, especially the south western corner where ships tend to travel close to the coast. If a boundary of 3 nautical miles was designated and a 10% level of risk was accepted, Figure 24 suggests that the risk is as high as 40% in some areas. Note the generalised route is an inshore route and the majority of ships travel further from the coast than this route suggests (see also Figure 46 in Appendix C). If a boundary of 12 nautical miles was designated, Figure 25 indicates that this risk reduces to a maximum of 30%. If a boundary of 24 nautical miles was designated, Figure 26 suggests that this risk is reduced to less than 20%.


Figure 24 Map showing areas outside of 3 nm with estimated risk greater than 10%, with the generalised route and frequencies.




The second series of maps assumes a 20% acceptance of risk of chance of establishment in a port environment. This equates to an acceptance of an 80% reduction in risk from the current practice. Figures 27, 28 and 29 display the areas outside 3, 12 and 24 nautical miles respectively where the risk is greater than 20%, with the generalised route and frequencies overlayed. Appendix C contains the same series of maps with the domestic ballast water carrying voyages position reports from the 2005 AUSREP data overlayed.

Figure 27 indicates that if a boundary of 3 nautical miles was designated, and a 20% level of risk was accepted, then the areas of greatest concern other than the Great Barrier Reef and Torres Strait are the northern and western coastline. The estimated risk of establishment is as high as 40% in some areas along the western coastline and as high as 50% in some areas along the northern coastline. However, the amount of ships carrying domestic ballast water is relatively low in these areas, particularly along the northern coast. Figure 28 illustrates that the risk is reduced to less than 30% along the western coastline and to less than 40% along the northern coastline, if a boundary of 12 nautical miles is designated. When this boundary is increased to 24 nautical miles, there are very few areas of concern, as indicated in Figure 29.






4.4 Examples To closely assess the impact of requiring ships to travel outside of 3, 12 and 24 nautical miles to exchange ballast waster, several examples were considered. The examples focus on areas of high volumes of domestic ballast water carrying ships and/or high risk regions. The first two examples focus on areas that have a high density of ships carrying domestic ballast water. The first example looks at a section between Brisbane and Sydney where 1543 domestic ballast water carrying voyages were recorded in 2005. The second looks at a section between Sydney and Melbourne where there were 2170 voyages. The third focuses on an area off the northwest corner of Australia, where the shipping traffic is less with 640 voyages, yet the risk of establishment is greater. The final example considers an area near Darwin where the shipping density is much lower with only 33 voyages, with higher risk.

In each example, the location of the domestic ballast water carrying ships position reports was considered in relation to the 3, 12 and 24 nautical mile boundaries to determine the distance the ships would have to deviate. The estimated risk at the 3, 12 and 24 nautical mile line was then determined. This information was used to investigate the relationship between the reduction in risk achieved and the impact on shipping by placing the designated area boundary further from the coast.

4.4.1 Brisbane – Sydney This example focuses on the area with the highest concentration of ships carrying domestic ballast water – the region between Brisbane and Sydney. Figure 30 shows the area considered in this


example. Figure 31 provides a close up of this area and displays the location of the position reports of ships carrying domestic ballast water in relation to the 3, 12 and 24 nautical mile boundaries. This map indicates that ships roughly follow the 12 nautical mile line, however some ships travel as close as 3 nautical miles and others travel further than 24 nautical miles from the coast. Very few ships would have to deviate to travel outside of 3 nautical miles, a number of ships would have to deviate to travel outside of 12 nautical miles, while a very large proportion of ships would have to deviate to travel outside of 24 nautical miles.

To understand the level of environmental protection that boundaries of 3, 12 and 24 nautical miles provide, the risk was overlayed to produce Figure 32. To further investigate the risk in this area, it was necessary to zoom in on the area, as the density of the position report, if very high, mask out the risk. The black box in Figure 32 shows the area that was focused on and Figure 33 is a map of this area. The estimated risk and 95% confidence interval for the risk at the location represented by the black line are provided for 3, 12 and 24 nautical miles. These numbers are also presented in Table 5.

The estimated risk from the model at 3 nautical miles is 32.87%, with 95% confidence that the true risk lies between 20.35% and 45.39%. If the ballast water exchange boundary is pushed out to 12 nautical miles, the risk drops to 6.47%. This is a significant decrease in the risk, as evidenced by the confidence interval for 3 nautical miles (20.35,45.39) not overlapping with the confidence interval for 12 nautical miles (2.74,10.19). If the boundary is pushed out to 24 nautical miles, the risk drops to 1.22%. Again, this is a significant drop in risk, as shown by the lack of intersection of the confidence intervals.

A designated ballast water exchange area of 3 nautical miles would have a minimal impact on the shipping industry and provides an estimated 67.13% reduction in risk from the current practice. Extending the designated area boundary to 12 nautical miles provides an estimated 95.53% risk reduction and would have a moderate impact on the shipping industry. Stretching this boundary to 24 nautical miles would provide a risk reduction of 98.78%. The extra 5.25% reduction in risk achieved between the 12 out to 24 nautical miles comes with a major impact on the industry, with the majority of ships needing to deviate from their routes. The 95.53% reduction in risk achieved by setting the ballast water exchange area boundary at 12 nautical miles provides a high level of environmental protection without imposing a high cost on the shipping industry.


Figure 30 Area between Brisbane and Sydney to be considered.

Figure 31 Shipping position reports between Brisbane and Sydney relative to the 3,12 and 24 nautical miles lines.


Figure 32 Overlay of the risk along the Brisbane to Sydney route.

Figure 33 Estimated risk with 95% confidence interval for 3, 12 and 24 nautical miles.


Table 5 Estimates of the risk of establishment along with 95% confidence intervals at 3, 12 and 24 nautical miles for the location shown in Figure 33.

95% confidence interval Distance

(nautical miles)

Estimated

Risk Lower limit Upper limit

3 32.87% 20.35% 45.39%

12 6.47% 2.74% 10.19%

24 1.22% 0.31% 2.13%

4.4.2 Sydney – Melbourne This example focuses on a section between Sydney and Melbourne where there were 2170 domestic ballast water carrying voyages in 2005. Figure 34 shows the area considered in this example. Figure 35 provides a close up of this area, and displays the location of the domestic ballast water carrying ships position reports in relation to the 3, 12 and 24 nautical mile boundaries. This map indicates that ships roughly follow the 12 nautical mile line from Sydney down the coast, cutting closer near Cape Howe and then head out beyond 24 nautical miles from the coast towards Wilsons Promitory.

Very few ships would have to deviate to travel outside a designated ballast water exchange area of 3 nautical miles. A number of ships would have to deviate to travel outside of 12 nautical miles, particularly around Cape Howe. The majority of ships would need to deviate to travel outside of 24 nautical miles.

To understand the level of environmental protection that boundaries of 3, 12 and 24 nautical miles provide, the risk was overlayed to produce Figure 36. To take a closer look at the risk in this area, it was necessary to zoom in. The black box in Figure 36 shows the area that was focused on and Figure 37 is a map of this area. The estimated risk and 95% confidence interval for the estimated risk at the location represented by the black line are provided for 3, 12 and 24 nautical miles. These numbers are also presented in Table 6. The estimated risk from the model at 3 nautical miles is 28.02%. If the ballast water exchange area boundary is pushed out to 12 nautical miles, the risk drops to 5.43%. This is a significant decrease in the risk, as evidenced by the lack of intersection of the confidence intervals. If the boundary is extended to 24 nautical miles, the risk drops to 0.89%. Again this is a significant drop in the risk, as evidenced by the non-crossing of the confidence intervals.

A designated ballast water exchange area of 3 nautical miles would have a minimal impact on the shipping industry, and provides an estimated reduction in risk of 71.98%. Extending the designated area boundary to 12 nautical miles provides an estimated 94.57% risk reduction and would have a moderate impact on the shipping industry. Further extension of this boundary to 24 nautical miles provides a risk reduction of 99.11%. The extra 4.54% reduction in risk achieved by pushing the boundary from 12 to 24 nautical miles comes with a major impact on the industry, with the majority of ships deviating significantly from their route. The 94.57% reduction in risk achieved by setting the ballast water exchange area boundary at 12 nautical miles provides a high level of environmental protection without having an overly large an impact on the shipping industry.


Figure 34 Area between Sydney and Melbourne to be considered.

Figure 35 Shipping position reports between Sydney and Melbourne relative to the 3,12 and 24 nautical mile lines.


Figure 36 Overlay of the risk along the Sydney to Melbourne route.





(nautical miles)

Estimated


3 28.02% 16.30% 39.73%

12 5.43% 2.26% 8.61%

24 0.89% 0.16% 1.61%

4.4.3 Western Australia This example focuses on the southwest corner of Western Australia where there were 640 domestic ballast water carrying voyages in 2005. Figure 38 shows the area considered. Figure 39 provides a close up of this area and displays the location of the domestic ballast water carrying ships position reports in relation to the 3, 12 and 24 nautical mile boundaries. This map indicates that ships roughly follow the 12 nautical mile line as they have in the previous examples. Very few ships would have to deviate to travel outside of 3 nautical miles, a number of ships would have to deviate to travel outside of 12 nautical miles, while a very large number of ships would have to deviate to travel outside of 24 nautical miles.

To understand the level of environmental protection that boundaries of 3, 12 and 24 nautical miles provide, the risk was overlayed to produce Figure 40. The estimated risk and 95% confidence interval for the estimated risk at the location represented by the black line are provided for 3, 12 and 24 nautical miles. These numbers are also presented in Table 7. The estimated risk from the model at 3 nautical miles is 35.16%. If the ballast water exchange area boundary is increased to 12 nautical miles, the risk drops to 20.05%. This is a significant decrease in the risk, as evidenced by the non-overlapping confidence intervals. If the boundary is further increased to 24 nautical miles, the risk drops to 4.64%. Again this is a significant drop in the risk, as evidenced by the lack of intersection of the confidence intervals.

A designated ballast water exchange area of 3 nautical miles would have a minimal impact on the shipping industry, providing an estimated 64.84% reduction in risk from the current practice. Pushing the designated area boundary to 12 nautical miles provides an estimated 79.95% risk reduction and would have a moderate impact on the shipping industry. Extending this boundary to 24 nautical miles would provide a risk reduction of 95.36%. By pushing the boundary from 3 to 12 nautical miles, the risk is reduced by 15.11%, and by pushing the boundary to 24 nautical miles, the risk is reduced by a further 15.42%. In the two previous examples, 12 nautical miles provided a risk reduction of at least 90%. In this example, 12 nautical miles only provides an 80% reduction, and it is necessary to go out to 24 nautical miles to achieve a reduction of over 90%. However, an 80% reduction at 12 nautical miles is still a significant reduction and provides a high level of environmental protection without imposing an excessively high a cost on the shipping industry.


Figure 38 Area in southwest Western Australia to be considered.

Figure 39 Shipping position reports around southwest Western Australia relative to the 3,12 and 24 nautical mile lines.





(nautical miles)

Estimated


3 35.16% 22.13% 48.19%

12 20.05% 11.10% 29.00%

24 4.64% 2.00% 7.27%

4.4.4 Northern Territory This example focuses on an area along the northern coast near Darwin where there were 33 domestic ballast water carrying voyages in 2005. Figure 41 shows the area considered in this example. Figure 42 provides a close up of this area and displays the location of the domestic ballast water carrying ships’ position reports in relation to the 3, 12 and 24 nautical mile boundaries. This map shows that ships travel a number of different routes through this section. Ships coming and going to the west either travelling close to the coast to Darwin, or go around Melville Island if they are not coming from or going to Darwin. Ships coming or going to the east travel close to the coast if they are coming from or going to Weipa, or travel beyond 24 nautical


miles if they are coming from or going through the Torres Strait. Most ships travel outside of 3 nautical miles, unless they are entering or exiting Darwin. Ships are unlikely to be conducting ballast water exchange while entering or exiting a port, and will generally wait until they are in open water. Hence, once in open water, very few ships would have to deviate to travel outside of 3 nautical miles, a small number of ships would have to deviate to travel outside of 12 nautical miles, and a slightly greater number of ships would have to deviate to travel outside of 24 nautical miles.

To understand the level of environmental protection that boundaries of 3, 12 and 24 nautical miles provide, the risk was overlayed to produce Figure 40. The estimated risk and 95% confidence interval for the estimated risk at the location represented by the black line are provided for 3, 12 and 24 nautical miles. These numbers are also presented in Table 7. The estimated risk from the model at 3 nautical miles is 46.70%. If the ballast water exchange area is set at 12 nautical miles, the risk drops to 33.58%. Note that this is not a significant decrease in the risk, as evidenced by the overlapping confidence intervals. If the boundary is further increased to 24 nautical miles, the risk drops to 21.15%. This is not a significant drop in the risk from 12 nautical miles, as evidenced by the overlapping confidence intervals, but is a significant decrease from 3 nautical miles.

It is important to note that there were only 33 domestic ballast water carrying voyages through this section in 2005, and off these, approximately half travelled beyond 24 nautical miles on their way to or from the east, in an area where the risk is less than 20%. If the ballast water exchange boundary is set at 3 nautical miles, the ships that do travel close to the coast will be travelling in area where the risk is as high as 50%. If they boundary is pushed out to 12 nautical miles, this risk is reduced to less than 40%. The risk of establishment could be further reduced to less than 30% if the boundary was pushed out to 24 nautical miles. However, this could impact greatly on the shipping industry in other areas around Australia.

Figure 41 Area in the north to be considered.


Figure 42 Shipping position reports in the north relative to the 3, 12 and 24 nautical mile lines.





(nautical miles)

Estimated


3 46.70% 32.05% 61.35%

12 33.58% 20.78% 46.39%

24 21.15% 11.56% 30.74%

4.4.5 Further examples The Invasive Marine Species Programme requested that BRS consider two examples focusing on marine protected areas as these are of concern for the designation of ballast water exchange areas. A series of maps were produced focusing on the Great Barrier Reef and Torres Strait, showing the risk, domestic ballast water carrying ship position and shipping exclusion areas. These maps were produced to inform the process of designating ballast water exchange areas for ships travelling through the Great Barrier Reef and Torres Strait. A second series of maps were produced focusing on the Commonwealth Marine Reserves for Australia’s South-east Marine Region. Both sets are presented in Appendix D.


5 CONCLUSION This report aims to provide information to assist in the designation of ballast water exchange areas to reduce the risk of translocating marine pests around Australia’s marine environment until onboard treatments become available. Biological risk was first assessed followed by the impact on the shipping industry for the environmental protection obtained.

Data collected in Phase 1 of this project were used to construct a questionnaire which was distributed to experts in the field of marine pests and invasive biology. Results from the questionnaire were then used to assess risk around the Australian coastline. The risk was modelled as a function of depth, distance from coast, larval baseline measure (proxy for water movement) and latitude (proxy for temperature). The limits considered for ballast water exchange areas were outside of 3, 12 and 24 nautical miles from the territorial sea baseline.

The estimates of risk reported do not represent absolute risk. The risk at a location is an estimate of the risk of discharging ballast water at that location relative to the risk of discharging in a nearby port environment. Estimates of absolute risk would need to consider additional factors including habitat suitability, temperature tolerances and predation for every species as well as ship ballast water exchange practices.

Analysis of the dependence of risk on the modelled variables found that risk extended further in the north and decreased with larval baseline, depth and distance from the coast. These results highlight the reliance of risk on specific coastal characteristics and location.

The designated areas considered were areas outside of 3, 12 and 24 nautical miles from the Australia territorial sea baseline. It was found that for a 3 nautical mile limit on ballast water exchange, the risk of establishment relative to the risk of establishment from discharge in a port environment was approximately 40-50% in some parts of northern Australia, 30-40% in the southwest, 20-30% in the southeast and approximately 20% in the southern parts.

At 12 nautical miles, the risk in the north was reduced to 30-40%, 20% for parts of the southwest and the south and less than 20% elsewhere. When the boundary was extended to 24 nautical miles, the highest risk in the northern regions was 20-30%, very few areas reached 20% in the southwest and southern parts of Australia and less than 10% was recorded for most other coastal areas. A noticeable exception is the Great Barrier Reef and the Torres Strait, where risk was recorded at levels above 20% in some areas, even at the 24 nautical mile boundary.

The high risk found through the environmentally sensitive areas of the Great Barrier Reef and the Torres Strait is of concern. A moderate amount of ships carrying domestic ballast water travel through this area (approximately 728 trips in 2005). It is recommended that these areas be considered separately when determining designated areas for ballast water exchange.

The areas of concern are those where the risk of establishment is high and where ships carrying domestic ballast water are operating. The risk to Australia associated with marine pest establishment was evaluated in conjunction with impact on the shipping industry. Deviations from typical shipping routes are an important factor to consider when setting designated areas due to the potential cost to the industry. Maps of risk were combined with shipping position reports, allowing for the impact on the shipping industry of each of the boundaries to be assessed in terms of traffic.

To further investigate the impact of designated areas on shipping, four areas were examined separately. For the Brisbane – Sydney and Sydney – Melbourne examples, very few ships would have to deviate from their normal shipping routes to travel outside of 3 nautical miles. A number of ships would have to deviate to travel outside of 12 nautical miles, while a large number of ships would have to deviate to travel outside of 24 nautical miles. The level of risk reduction from current practices at 12 nautical miles was greater than 90% for both routes.


The level of risk reduction for the west coast example at 12 nautical miles was approximately 80%, while an approximate 95% reduction of risk occurred at the 24 nautical mile mark. Although the risk is greater at 12 nautical miles than for the east coast examples, 80% is considered to be a significant reduction.

The estimated risk in the northern Australia example remains relatively high at all 3 boundaries. This region, however, receives very little traffic. Only 33 trips were recorded in 2005. If a 12 nautical mile boundary is set, risk in this region is less than 40%. A 24 nautical mile limit would reduce this risk to less than 20%. A 24 nautical mile boundary may however have a large impact on the shipping industry in other areas of Australia.

A designated ballast water exchange area of 3 nautical miles would have minimal impact on the shipping industry across most coastal areas. Extending the designated area boundary to 12 nautical miles significantly increases the environmental protection obtained and would have a moderate impact on the shipping industry. Further increasing this boundary to 24 nautical miles provides a high level of risk reduction. However, the extra reduction in risk achieved by extending the boundary from 12 to 24 nautical miles comes with a major impact on the industry, with the majority of ships deviating significantly from their route. The reduction in risk achieved by setting the ballast water exchange area boundary at 12 nautical miles provides a high level of environmental protection without having a large impact on the shipping industry.


References Barry S, Dommisse M, Lawrence E, Jenkins G, Hough D, Hatton D and Black K. (unpublished).

Managing ballast on short coastal trips: The environmental risk of coastal exchange. Department of Sustainability and Environment, Melbourne.

Bax N, et. al. (2006). Evaluation of National Control Plan management options for the North Pacific Sea-star Asterias amurensis, CSIRO, Hobart.

Blias A. and Delforce R. (2003). Ballast Water Management: a Comparison of Alternative Approaches, Australian Bureau of Agricultural and Resource Economics, Canberra.

Cunningham DC, Woldendorp G, Burgess MB and Barry SC. (2003). Prioritising sleeper weeds for eradication: Selection of species based on potential impacts on agriculture and feasibility of eradication. Bureau of Rural Sciences, Canberra

Hobday A, Hewitt C, Condie S, Cahill M, Mansbridge J and Ling S (2002). Mapping the Australian Ballast Water Uptake and Discharge Contingency Zones, CSIRO Marine Research, Hobart.

O’Keefe M. (2005). Cost Analysis Tool for the Management of Invasive Marine Pest Species, Bureau of Rural Sciences, Canberra.

R Development Core Team (2006). R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org.

Wood S.N, (2006) Generalized Additive Models: An Introduction with R, Chapman and Hall/CRC, Boca Raton.

Documents

Designated Exchange Areas Project – Providing informed