Australian Exclusive Economic Zone Research Articles

Delineating spatial use combined with threat assessment to aid critical recovery of northeast Australia’s endangered hawksbill turtle, one of western Pacific's last strongholds

The current rate of decline in the globally significant western Pacific hawksbill turtle nesting population on Milman Island on the northern Great Barrier Reef (neQLD) suggests that it could be functionally extinct within a decade. Yet a poor understanding of the relative importance and spatial distribution of threats to this population has been a major impediment to recovery actions. For the first time, we assess all threats to the neQLD stock using a combination of a post-hatchling dispersal model, new satellite tracking of post-nesting migrations and a comprehensive review of existing data. We overlay migration routes and foraging areas from the satellite tracking data with spatially referenced threat layers to analyse threat exposure. We found all tracked hawksbills remained in Australian waters, with migration to foraging areas in Queensland including western Cape York to western Torres Strait (n = 8), and eastern Cape York to eastern Torres Strait (n = 5). These results underscore the critical importance of foraging habitats in Queensland (particularly western Queensland) to the Millman Island nesting population. In contrast, the Lagrangian post-hatchling dispersal model predicted a concentration of turtles in the Torres Strait to Gulf of Papua region, with most final positions in Australian waters (63%), followed by Papua New Guinea (31%), Solomon Islands (3%), Indonesia (2%), Vanuatu (0.49%), New Caledonia (1%). Even though 37% of post-hatchling turtles were predicted to recruit to foraging areas outside of the Australian Exclusive Economic Zone (EEZ), none of the 25 turtles tracked left the Australian EEZ (13 in this study and 12 previously). This suggests that survival to breeding is low for turtles outside of the Australian EEZ, but other explanations are discussed. No single pervasive threat was identified in the threat risk assessment however, fisheries (bycatch/ghost gear) interactions, direct harvesting and climate change were considered to have the potential to impede recovery or result in further decline in the population. Fisheries and harvesting should be the priorities for immediate management actions. The lack of spatial protection in foraging habitats in western Queensland was identified as a major policy gap requiring immediate attention if this population’s trajectory is to be reversed and remain one of western Pacific’s strongholds.

First records of Hamacantha species from seamounts off eastern Australia (Porifera, Demospongiae, Merliida), with description of four new species.

Four new species of encrusting Hamacantha (Vomerula) are described from bathyal depths of seamounts off Queensland and Tasmania in southeast Australia (H. (V.) novacula sp. nov., H. (V.) melliflura sp. nov., H. (V.) ridleyi sp. nov., H. (V.) levii sp. nov.). A previously described species known only from New Caledonia (H. (V.) acerata Lévi, 1993) has also been redescribed. A tabular comparison of all known species of H. (Vomerula) is provided, bringing the number of known species in the subgenus to 26. This is also the first record of the genus Hamacantha from the Australian Exclusive Economic Zone.

Marine Acoustic Zones of Australia

Underwater sound is modelled and mapped for purposes ranging from localised environmental impact assessments of individual offshore developments to large-scale marine spatial planning. As the area to be modelled increases, so does the computational effort. The effort is more easily handled if broken down into smaller regions that could be modelled separately and their results merged. The goal of our study was to split the Australian maritime Exclusive Economic Zone (EEZ) into a set of smaller acoustic zones, whereby each zone is characterised by a set of environmental parameters that vary more across than within zones. The environmental parameters chosen reflect the hydroacoustic (e.g., water column sound speed profile), geoacoustic (e.g., sound speeds and absorption coefficients for compressional and shear waves), and bathymetric (i.e., seafloor depth and slope) parameters that directly affect the way in which sound propagates. We present a multivariate Gaussian mixture model, modified to handle input vectors (sound speed profiles) of variable length, and fitted by an expectation-maximization algorithm, that clustered the environmental parameters into 20 maritime acoustic zones corresponding to 28 geographically separated locations. Mean zone parameters and shape files are available for download. The zones may be used to map, for example, underwater sound from commercial shipping within the entire Australian EEZ.

A new carnivorous sponge (Porifera) from the Coral Sea

A new species of carnivorous sponge, Lycopodina coralseaensis sp. nov., family Cladorhizidae, is described from the Louisiade Plateau, Coral Sea, off the east coast of Australia at bathyal depths of ~2000 m, collected during the RV Investigator 2019 voyage. The new species differs from other Lycopodina with stipitate morphology by lacking forceps microscleres, similar to L. nikitawimandi Ekins et al., 2020a but differing in having only a very small single size class of palmate anisochelae, and most importantly by having a third category of mycalostyle echinating the stem and basal holdfast. This new species is the sixth Lycopodina recently described as new from the Australian Exclusive Economic Zone (L. nikitawimandi, L. helios, L. cassida, L. brochidodroma and L. hystrix), bringing the total number of carnivorous sponges known so far from Australia to 26.

Future Distribution of Suitable Habitat for Pelagic Sharks in Australia Under Climate Change Models

Global oceans are absorbing over 90% of the heat trapped in our atmosphere due to accumulated anthropogenic greenhouse gases, resulting in increasing ocean temperatures. Such changes may influence marine ectotherms, such as sharks, as their body temperature concurrently increases towards their upper thermal limits. Sharks are high trophic level predators that play a key role in the regulation of ecosystem structure and health. Because many sharks are already threatened, it is especially important to understand the impact of climate change on these species. We used shark occurrence records collected by commercial fisheries within the Australian continental Exclusive Economic Zone (EEZ) to predict changes in future (2050 to 2099) relative to current (1956 to 2005) habitat suitability for pelagic sharks based on an ensemble of climate models and emission scenarios. Our predictive models indicate that future sea temperatures are likely to shift the location of suitable shark habitat within the Australian EEZ. On average, suitable habitat is predicted to decrease within the EEZ for requiem and increase for mackerel sharks, however, the direction and severity of change was highly influenced by the choice of climate model. Our results indicate the need to consider climate change scenarios as part of future shark management and suggest that more broad-scale studies are needed for these pelagic species.

Shark conservation hindered by lack of habitat protection

Many of the world’s shark populations are in decline, indicating the need for improved conservation and management. Well managed and appropriately located marine parks and marine protected areas (MPAs) have potential to enhance shark conservation by restricting fisheries and protecting suitable habitat for threatened shark populations. Here, we used shark occurrence records collected by commercial fisheries to determine suitable habitat for pelagic sharks within the Australian continental Exclusive Economic Zone (EEZ), and to quantify the amount of suitable habitat contained within existing MPAs. We developed generalised linear models using proportional occurrences of pelagic sharks for three families: Alopiidae (thresher), Carcharhinidae (requiem), and Lamnidae (mackerel) sharks. We also considered aggregated species from the Lamnidae and Carcharhinidae families (‘combined sharks’ in the models). Using a set of environmental predictors known to affect shark occurrence, including chlorophyll-a concentration, salinity, sea surface temperature, and turbidity, as well as geomorphological, geophysical, and sedimentary parameters, we found that models including sea surface temperature and turbidity were ranked highest in their ability to predict shark distributions. We used these results to predict geographic regions where habitat was most suitable for pelagic sharks within the Australian EEZ, and our results revealed that suitable habitat was limited in no-take zones within MPAs. For all shark groupings, suitable habitats were found mostly at locations exposed to fishing pressure, potentially increasing the vulnerability of the pelagic shark species considered. Our predictive models provide a foundation for future spatial planning and shark management, suggesting that strong fisheries management in addition to MPAs is necessary for pelagic shark conservation.

Long-term trends and a risk analysis of cetacean entanglements and bycatch in fisheries gear in Australian waters

Assessments of fisheries interactions with non-target species are crucial for quantifying anthropogenic threatening processes and informing management action. We perform the first multi-jurisdictional analysis of spatial and temporal trends, data gaps and risk assessment of cetacean interactions with fisheries gear for the entire Australian Exclusive Economic Zone. Bycatch and entanglement records dating from 1887 to 2016 were collected from across Australia (n = 1987). Since 2000 there has been a substantial increase in reported bycatch and entanglements and this is likely the result of improved monitoring or recording by some jurisdictions and fisheries as well as changing fishing effort, combined with continuing recovery of baleen whale populations after cessation of commercial whaling. A minimum of 27 cetacean species were recorded entangled, with over 30% of records involving interactions with threatened, vulnerable or endangered species. Three times the number of dolphins and toothed whales were recorded entangled compared to baleen whales. Inshore dolphins were assessed as most vulnerable to population decline as a result of entanglements, though humpback whales, common bottlenose dolphins, and short-beaked common dolphins were the most frequently caught. Only one-quarter of animals were reported to have survived entanglement, either through intervention or self-release from fishing gear. Spatial mapping of the records highlighted entanglement hotspots along the east and west coast of the continent, regions where high human population density, high fishing effort, and high density of migrating humpback whales all occur, augmented by high captures of dolphins in shark control gear along the east coast. Areas of few entanglements were more remote, highlighting substantial bias in entanglement reporting. Our gap analysis identified discrepancies in data quality and recording consistency both within and between jurisdictions. Disparities in the types of fisheries data provided for the analysis by different state agencies limited our ability to compile bycatch data in a representative and systematic way. This research highlights the need for improved standardised data recording and reporting by all agencies, and compulsory sharing of detailed fisheries interaction and effort data, as this would increase the value of entanglement and bycatch data as a conservation and management tool.

Review of the batfish genus Halicmetus Alcock, 1891 from Australian waters, with descriptions of two new species (Lophiiformes: Ogcocephalidae).

A taxonomic review of species of the Indo-Pacific batfish genus Halicmetus occurring in the Australian Exclusive Economic Zone is provided. Treatments of six species in the region, including diagnoses of the widespread Halicmetus niger Ho, Endo Sakamaki, 2008, H. reticulatus Smith Radcliffe, 1912 and H. ruber Alcock 1891, a reclassification of the poorly known H. marmoratus Weber, 1913, and descriptions of two new species, H. westraliensis n. sp. (an Australian endemic) and H. drypus n. sp. (from the northern sector of the Australian Exclusive Economic Zone off Norfolk Island). The Australian species can be distinguished from each other and regional congeners by a combination of morphometrics, meristics and colouration. A key is provided for all known species of the genus.

Traditional Fishermen in Rote Island: An Alternative Livelihood to Illegal Fishing Activities in the Indonesian-Australian Transboundary Waters

At the moment there are about 210 Indonesian fishermen, many from Rote Island, the majority from the village of Papela, still detained in Australia Detention Centres for carrying on illegal fishing activities in the Australian Exclusive Economic Zone. These fishing activities are not driven by economic factors only, but also by their historical background. By understanding the economic, historical and socio-cultural background of the fishermen, a comprehensive solution for illegal fishing might be established. This research aims to ascertain an alternative economic activity for the fishermen that can give increased job opportunities for the fishermen to attain a sustainable livelihood as part of sustainable economic development. This research has used qualitative and quantitative analysis techniques including stakeholder interviews, descriptive researcher observations, a household survey and Policy Analysis Matrix (PAM). The results of the research show that; (i) since the beginning of the 17th century, the traditional fishermen of Papela have made regular offshore fishing trips to waters that are now within the Australian Exclusive Economic Zone; (ii) based on socio-cultural assessment and economic calculations, a salt pond business is an efficient business with comparative advantages for the Papela fishermen as an alternative source of income; and (iii) even though, a salt pond business has economic potential and has already been conducted by a small number of people in Papela, the government’s will to support the salt farmer seems weak.

Trawl exposure and protection of seabed fauna at large spatial scales

AbstractAimTrawling is the most widespread direct human disturbance on the seabed. Knowledge of the extent and consequences of this disturbance is limited because large‐scale distributions of seabed fauna are not well known. We map faunal distributions in the Australian Exclusive Economic Zone (EEZ) and quantify the proportion of their abundance that occurs in areas 1) that are directly trawled and 2) where legislation permanently prohibits trawling—defined as percentage exposure or protection, respectively. Our approach includes developing a method that integrates data from disparate seabed surveys to spatially expand predicted benthos distributions.LocationAustralia.MethodsWe collate data from 18 seabed surveys to map the distribution of seabed invertebrates (benthos) in nine regions. Our approach combines data from multiple surveys, groups taxa within taxonomic classes and uses Random Forests to predict spatial abundance distributions of benthos groups from environmental variables. Exposure and protection of benthos groups were quantified by mapping their predicted abundance distributions against the footprint of trawling and legislated boundaries of marine reserves and fishery closures.ResultsTrawling is currently prohibited from more area of Australia's EEZ (58%) than is trawled (<5%). Across 134 benthos groups, 96% had greater protection of abundance than exposure. The mean trawl exposure of benthos‐group abundance was 7%, compared to mean protection of 38%, whereas the mean abundance neither trawled nor protected was 55%. Fishery closures covered 19% less study area than marine reserves, but overlapped with a higher proportion (5% more) of benthos‐group abundance.Main ConclusionsThis study provides the most extensive quantitative assessment of the current exposure of Australia's benthos to trawling. Further, it highlights the contribution of fishery closures to marine conservation. These results help identify regions and taxa that are at greatest potential risk from trawling and support managers to achieve balance between conservation and sustainable industries in marine ecosystems.

Trends in derelict fishing nets and fishing activity in northern Australia: Implications for trans-boundary fisheries management in the shared Arafura and Timor Seas

Fishing is the major human activity within the ‘semi-enclosed’ Arafura and Timor Seas (ATS). Since the early 2000’s, Australia’s sparsely populated, remote northern shores have reported very high levels of foreign, fishing-related marine debris. Limited information is available about the temporal and spatial variation of this fishing debris or its origin. We examine trends in derelict fishing nets (and marine debris) at multiple sites in the Northern Territory and Gulf of Carpentaria and, explore its potential origin and relationship with fishing activity in the region. Further, we investigate temporal trends in domestic and foreign fishing activity (legal and illegal) in the ATS and also foreign fishing vessel sightings in the northern waters of the Australian Exclusive Economic Zone (AEEZ). Our results confirm that foreign fishing debris (nets, rope and gear) is the major source of marine debris (63%) on Australia’s northern shores. Over the period 2003–2008, a total of 2305 derelict fishing nets were washed ashore; of these, 89% were identified of foreign origin (i.e. manufacture), compared to 11% attributed to Australian fishing vessels or fisheries. Industrial foreign and Indonesian-flagged fisheries – particularly, illegal, unreported and unregulated (IUU) trawling activity – and small-scale Indonesian IUU fisheries (primarily targeting shark) in the Arafura Sea are likely the major sources of these nets. Derelict nets comprised mostly trawl nets (71%) and gillnets/drift nets (12%); with 95% of all identified net sourced from the nations of Taiwan, Indonesia, Thailand and Korea. Our data also supports consistent under-reporting by these foreign trawl operators in the Indonesian Exclusive Economic Zone (IEEZ) of the ATS.The arrival and increase in derelict nets in northern Australia post-2000 coincided with sharp increases in both industrial foreign fishing (illegal, legal) and Indonesian small-scale fisheries within the IEEZ waters of the ATS. Including, over the period 2000–2007, a 2-fold increase in ‘non-motorised’ vessels, and a 5-fold increase in the number of motorised vessels, particularly in vessels less than 5GT. Further, this major increase in fishing activity in the IEEZ corresponded to a 3-fold increase in foreign fishing vessels (FFVs) (legal, illegal) sightings in northern Australian waters. Within the AEEZ, derelict net loads and sightings of illegal FFVs, both peaked and reached a maximum in 2005 (188kgkm−1yr; 6956 vessels) and then sharply reduced (>80%) following major border control, surveillance and security operations in the northern Australia in 2005–2006. However, post-2007, illegal FFV sightings inside the AEEZ have increased again. Significantly, derelict nets and small-scale IUU fishing activity in the AEEZ is linked to a broader pattern of poverty, overfishing and displacement of small scale fishers in coastal fisheries in the Arafura Sea (and South East Asia), due primarily to the expansion of industrial (illegal, legal) trawl fisheries. Strengthening of regional fisheries management (particularly under the RPOA-IUU) is urgently required to tackle IUU fishing, the key source of fishing debris in the ATS. While fisheries capacity reduction is a critical priority, it needs to be supported by a regional multi-sectoral response framed within the context of food security and rural economic development.

Distribution and abundance of skates (Bathyraja spp.) on the Kerguelen Plateau through the lens of the toothfish fisheries

Three species of skate, Bathyraja eatonii, B. irrasa and B. murrayi, are commonly taken as incidental by-catch in Patagonian toothfish (Dissostichus eleginoides) longline and trawl fisheries, and the mackerel icefish (Champsocephalus gunnari) trawl fishery on the Kerguelen Plateau (KP) in the southern Indian Ocean. Data from fishery observations for 1997–2014 shows that the three skates were widely distributed across the Kerguelen Plateau, showing different spatial distributions, linked mainly with depth. Off Heard Island and McDonald Islands (HIMI), in the southern part of the KP, B. eatonii and B. irrasa were most abundant to the north and northwest of Heard Island, out to the edge of the Australian Exclusive Economic Zone (EEZ), and were caught down to depths of 1790m and 2059m respectively. The smallest species, B. murrayi, occurred mainly in the shallower waters down to 550m, and was most abundant to the north and northeast, close to Heard Island. Around Kerguelen Islands, in the northern part of the KP, skates were most abundant between the 500m and 1000m contours circling and extending from the islands.Catch rates were modelled using zero-inflated GAMs and GLMs. The catch rates of skates from the trawl fisheries in the Australian EEZ surrounding Heard Island and McDonald Islands have shown little evidence of depletion on the main trawl fishing grounds, although there is evidence of a decrease in the average total length of B. eatonii. The marine reserves and the conservation measures employed by the Commission for the Conservation of Antarctic Marine Living Resources in the HIMI fisheries, appear to provide effective protection for the skates, at least in the shallower waters where the trawl fisheries operate. B. irrasa taken in the deeper waters where longline fishing occurs have shown a slight decline in catch rate over the years of the HIMI fishery. Although all skates are returned to the water from this fishery, survival rates are unknown and careful monitoring should continue to assess the status of these stocks. There appears to be little change in the abundance of the skate species at Kerguelen in the time period.This study provides the first review of skate by-catch across both the HIMI and Kerguelen fisheries. Ongoing monitoring of species specific by-catch levels and further research to determine the important life history parameters of these species are required, particularly for B. irrasa which is taken in both trawl and longline fisheries.

First records of the grey nurse shark Carcharias taurus (Lamniformes: Odontaspididae) from oceanic coral reefs in the Timor Sea

The threatened grey nurse shark (Carcharias taurus) is reported for the first time from oceanic coral reefs in the Timor Sea. Generally known from temperate and subtropical coastal reef habitats, this species was encountered by Indonesian traditional fishers on oceanic coral reefs in an area of the Australian Exclusive Economic Zone known as the 1974 MoU Box, some 200 km from the Australian mainland. The presence ofC. tauruson these remote tropical reefs bears important management implications, including the species’ protected status in Australian waters and the challenges of regulating catches in areas permitted for traditional Indonesian fishing.

Two new genera in the family Podospongiidae (Demospongiae: Poecilosclerida) with eight new Western Pacific species

New material collected from the Western Pacific has necessitated a revision of family Podospongiidae and the establishment of two new genera, Neopodospongia gen. nov. and Diplopodospongia gen. nov. Neopodospongia gen. nov. was established for a group of sponges characterised by a leathery ectosome, strongyloxeas, aciculospinorhabds, and sigmoidal protospinorhabds. Diplopodospongia gen. nov., was established for a group of thinly encrusting deep-water sponges that have anisoxeas and dumbbell-shaped spinorhabds. Eight new species of Podospongiidae are described here: two species of Podospongia du Bocage, 1869; P. virga sp. nov., from northern New Zealand and P. colini sp. nov., from Indonesia, three species of Neopodospongia from New Zealand; N. pagei gen. nov. sp. nov., N. bergquistae gen. nov. sp. nov., and N. exilis gen. nov. sp. nov., and three species of Diplopodospongia; D. rara gen. nov. sp. nov. and D. teliformis gen. nov. sp. nov. from New Zealand, and D. macquariensis gen. nov. sp. nov. from the Australian Exclusive Economic Zone surrounding Macquarie Island in the Southern Ocean. In addition, the Irish encrusting sponge P. normani (Stephens 1915) has been reassigned to Neopodospongia gen. nov. An updated identification key to Podospongiidae genera is included.

Benthic environments of the Lord Howe Rise submarine plateau: Introduction to the special volume

The Australian exclusive economic zone (EEZ) contains1.6 million km 2 of submarine plateaus, equal to about 13.8% of the world's known inventory of these features. This disproportionate occurrence of plateaus presents Australia with an increased global responsibility to understand and protect the benthic habitats and associated ecosystems. This special volume presents the results of two major marine surveys carried out on the Lord Howe Rise plateau during 2003 and 2007, during which benthic biological and geological samples, underwater photographs, video and multibean sonar bathymetry data were collected. The benthic habitats present on Lord Howe Rise are dominated by slowly-accumulating, low-energy, soft-sediment habitats, but also include hard/rocky substrates covering a small area of volcanic peaks (around 31 km 2) and parts of other larger seamounts (e.g., the Lord Howe Island seamount) which support rich and abundant epifaunal assemblages dominated by suspension feeding invertebrates. These rocky habitats appear to qualify as ecologically and biologically significant areas under the United Nations Convention on Biological Diversity (CBD) scientific selection criteria 1 (uniqueness or rarity), 4 (vulnerability, fragility, sensitivity or slow recovery) and 7 (naturalness). The collection of papers included in this special volume represents a major advance in knowledge about benthic habitats of the Lord Howe Rise, but also about the ecology of submarine plateaus in general.

Marine Biodiversity in the Australian Region

The entire Australian marine jurisdictional area, including offshore and sub-Antarctic islands, is considered in this paper. Most records, however, come from the Exclusive Economic Zone (EEZ) around the continent of Australia itself. The counts of species have been obtained from four primary databases (the Australian Faunal Directory, Codes for Australian Aquatic Biota, Online Zoological Collections of Australian Museums, and the Australian node of the Ocean Biogeographic Information System), but even these are an underestimate of described species. In addition, some partially completed databases for particular taxonomic groups, and specialized databases (for introduced and threatened species) have been used. Experts also provided estimates of the number of known species not yet in the major databases. For only some groups could we obtain an (expert opinion) estimate of undiscovered species. The databases provide patchy information about endemism, levels of threat, and introductions. We conclude that there are about 33,000 marine species (mainly animals) in the major databases, of which 130 are introduced, 58 listed as threatened and an unknown percentage endemic. An estimated 17,000 more named species are either known from the Australian EEZ but not in the present databases, or potentially occur there. It is crudely estimated that there may be as many as 250,000 species (known and yet to be discovered) in the Australian EEZ. For 17 higher taxa, there is sufficient detail for subdivision by Large Marine Domains, for comparison with other National and Regional Implementation Committees of the Census of Marine Life. Taxonomic expertise in Australia is unevenly distributed across taxa, and declining. Comments are given briefly on biodiversity management measures in Australia, including but not limited to marine protected areas.

At-sea distribution of satellite-tracked Grey-faced Petrels, Pterodroma macroptera gouldi, captured on the Ruamaahua (Aldermen) Islands, New Zealand

We used satellite telemetry to determine the at-sea distribution of 32 adult (non-breeders and failed breeders) Grey-faced Petrels, Pterodroma macroptera gouldi, during July-October in 2006 and 2007. Adults captured at breeding colonies on the Ruamaahua (Aldermen) Islands ranged across the southwestern Pacific Ocean and Tasman Sea between 20-49°S and 142°E and 1300W Petrels were located almost exclusively over offshore waters> 1000 m depth. The extent of their distributions was similar across years, but petrels ranged farther south and west in 2006. Individuals displayed a high degree of spatial overlap (48-620/0 among individuals) and area use revealed three general hotspots within their overall range: waters near the Ruamaahua Islands; the central Tasman Sea; and the area surrounding the Chatham Rise. In July-August 2006, most petrels congregated over the Tasman Sea, but for the same period in 2007 were predominantly associated with Chatham Rise. The home ranges of petrels tended to overlap disproportionately more than expected with the Australian Exclusive Economic Zone and less than expected with High Seas, relative to the area available in each zone, in July-August 2006. Accordingly, multiple nations are responsible for determining potential impacts resulting from fisheries bycatch and potential resource competition with Grey-faced Petrels.

Climate change impact on NW Shelf seabed evolution and its implication for offshore pipeline design

In this paper, the impact of climate change on seabed sediment transport in the north-western region of the Australian Exclusive Economic Zone (EEZ) has been investigated by a state-of-the-art numerical sediment transport model, Sedsim. It links the environmental forces and seabed response into a dynamic sedimentation system. Although numerical implementation of some forcing and responses is approximate, it is a significant step forward in understanding the nature of potential long-term seabed changes as well as in evaluating the likely impact of climate change on the northwest Australian continental shelf. It was found that: the modelled high-energy climate change scenario produced 17% and 38% increases on total volumes of seabed transport in the northern and southern part of the Australian northwest region respectively; the Indonesian ThroughFlow (ITF), the Leeuwin Current (LC) and high energy waves (associated with tropical cyclones) play the most important roles in large-scale long-term evolution of the NW seafloor; offshore pipeline design could usefully incorporate the changed risk profiles due to long-term non-stationarity of climate-derived forcing processes.

Application of biophysical information to support Australia's representative marine protected area program

In order to protect the biological diversity of marine life in Australia's exclusive economic zone (EEZ), the Commonwealth Government has passed the Environment Protection and Biodiversity Conservation (EPBC) Act. The Act is being implemented through the preparation of regional marine plans (that commenced in 2001) and by designing networks of representative marine protected areas (MPAs) in both Commonwealth and State waters. In the absence of direct information about the distribution of seabed biodiversity, appropriate surrogates must be used instead. A major constraint is the short time-frame available to managers to make decisions; only information that is readily accessible and available can be used under these circumstances. Existing seabed bathymetry data were used to produce a geomorphic features map of the Australian EEZ. This map was used in conjunction with existing fish diversity information and other data to derive a benthic bioregionalisation (2005) that subdivides Australia's EEZ into 41 bioregions including 24 biologically unique provinces. Biophysical variables measured at broad spatial scales apart from bathymetry (and derived variables such as seabed slope) include ocean primary production, seabed sediment properties, temperature and sediment mobilisation due to waves and tides. To better characterise habitats on the Australian continental margin, Geoscience Australia has created “seascape” maps that integrate multiple layers of spatial data that are useful for the prediction of the distribution of biodiversity. An example is presented from the southwest margin of Australia; here, we used ER-Mapper's unsupervised ISO class algorithm to simultaneously classify six variables, with equal weighting, to yield a range of statistically different classes. The broad spatial coverage provided by the analysis of biophysical data provides information complementary to the knowledge of sites important to threatened or endangered species, to iconic sites of high conservation value and to the available (mostly very limited) direct measurements of biodiversity (hot spots). Seascape and geomorphic habitat maps have assisted managers in Australia with broad-scale marine planning and in the design of representative MPA networks.

Prompt Release Procedures and the Challenge for Fisheries Law Enforcement: The Judgment of the International Tribunal for the Law of the Sea in The ‘Volga’ Case (Russian Federation V Australia)

On 23 December 2002, the International Tribunal for the Law of the Sea ('ITLOS') ordered the prompt release of the Russian 1ongline fishing vessel Volga, at the time detained by Australian authorities in Fremantle, upon the posting of a bond or other security of A$l 920 000. The Volga was arrested for allegedly fishing without authorisation by a boarding party from the Royal Australian Navy frigate HMAS Canberra in the Australian Exclusive Economic Zone ('EEZ') surrounding Heard and McDonald Islands in the Southern Ocean on 7 Februarv 2002. At issue in the ITLOS proceedings was not whether the activities of the Vo1ga failed to comply with Australian fisheries law, but rather whether the financial security and other requirements, which Australia set as the conditions for release of the vessel, breached Australia's obligation under the UN Convention on the Law of the Sea ('LOSC') to allow the prompt release of detained vessels upon the posting of a 'reasonable bond or other security'. Although the question of what amounts to a 'reasonable' bond has been considered by ITLOS on previous occasions, in each case the dispute centred on the reasonableness of the methods used by the detaining state to set the required financial security; such as how the detained vessel, catch and gear were valued and how the maximum possible fines available under domestic law were determined. The important aspect of the proceedings in The 'Volga' Case was that it was the first time the Tribunal had been asked to consider whether additional non-financial conditions could be set for the release of a detained vessel. It was also the first time Australia had appeared before ITLOS as a respondent. The decision rendered by ITLOS is instructive not only for Australia's future conduct in handling foreign fishing vessels detained for alleged illegal fishing in Australian waters, but also for other coastal countries which face continual pressure from various forms of illegal foreign fishing.