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The mission of Australia's Integrated Marine Observing System (IMOS), established under the Federal Government's national collaborative research infrastructure program, is to deliver ocean observations to the marine and climate science community. However, the observations have many uses, ranging from real-time operational forecasting to understanding of processes and policy decision making. Observations need to be provided in a format that fits the purpose of the intended application. Turning observations into usable data, time series, gridded products and analyses broadens the use of such observations. Value adding by developing products that are relevant to end-user needs and easily accessible to non-scientists is also required as a strategic response to new and emerging socioeconomic, legal and policy priorities. This paper describes some of the pathways on which IMOS observations are being delivered and used in Australia, demonstrating the value that ocean observations have for society. This paper is an overview of how marine observations collected by the Integrated Marine Observing System are delivered and used by the Australian community. Users of marine observations include marine scientists, industry, government and the community in general. The paper demonstrates the value of ocean observations and the need to make the data available and accessible in order for their potential to be reached. [ABSTRACT FROM AUTHOR]

Context: Researchers studying animals need to ensure that sampling procedures and the methods they use are as harmless and non-disruptive as possible, particularly when their focal species are threatened or protected. White sharks (Carcharodon carcharias) are Vulnerable under the IUCN Red List, protected globally, and are frequently studied by marine ecologists. Aims: To assess white shark responses to research activities (i.e. tagging and biopsy procedures, and electric deterrent trials) conducted at the Neptune Islands Group Marine Park (South Australia, Australia). Methods: Trends in shark residency following research activities were assessed by comparing shark abundance (number of sharks detected by acoustic receivers and sighted by cage-diving operators) before, during, and after scientific expeditions, and to natural fluctuations in the absence of research activities using 8 years (2013–2021) of acoustic tracking and daily sighting reports from a wildlife tourism industry. Key results: Number of white sharks and residency decreased after sampling. However, changes observed following research activities were similar to natural fluctuations, suggesting that these changes reflected natural variations rather than being due to sharks responding negatively to the research activities. Conclusions: Our study showed that external tagging, biopsies, or deterrent trials do not affect short- and long-term residency or abundance of white sharks, probably owing to the research activities being minimally intrusive and to sharks having efficient immune systems and remarkable ability to heal from injuries. Implications: Re-evaluating study methods forms part of the researcher's responsibilities to ensure best practice and to abide by national and international codes for the care and use of animals for scientific purposes. Researchers studying animals, particularly threatened or protected species, must ensure their activities are as harmless and non-disruptive as possible. We evaluated changes in white shark residency following three types of research activities and found evidence that none of them might have negatively affected these animals. Similar assessments should be performed when working with other species to ensure best practice and abide by codes for the care and use of animals. Photograph by Andrew Fox. [ABSTRACT FROM AUTHOR]

Context: Understanding migratory species' habitat selection is complicated by variation in movement strategies. Stable-isotope analysis provides a powerful tool to investigate such variation. Aims: We used acoustic telemetry and stable-isotope analysis to better understand the movement strategies of Port Jackson sharks. Methods: We compared the δ13C and δ15N values of fin tissue from acoustically tracked individuals that undertook three distinct movement strategies. Hierarchical cluster analysis was then used to cluster movement strategies of a larger sample of sharks on the basis of δ13C and δ15N values. Key results: Tracked individuals that remained in Jervis Bay were enriched in 13C, compared with those that migrated south after the breeding season. Individuals were assigned to six clusters and δ13C and δ15N values indicated that migrating males and females may utilise different geographical areas or niches during the non-breeding season. Conclusions: By using stable isotope analysis and acoustic telemetry, we identified distinct groups of Port Jackson sharks with similar broad-scale movement strategies. Implications: These variable movement strategies may lead to different reproductive fitness advantages on an individual and population level, having implications for the broader ecosystem, given the important role mesopredators play in southern reef marine ecosystems. We used a combination of stable-isotope analysis and acoustic telemetry to validate whether variation in stable-isotope values correlated with acoustically tracked migration patterns and to examine size-based and sex-specific variation in non-breeding season movements at the population level. We found evidence of differential migration patterns and sexual segregation among six clusters of Port Jackson sharks, suggesting that individuals may modulate their migratory behaviour for different reproductive-fitness benefits. [ABSTRACT FROM AUTHOR]

Context: It is common for recreational anglers to discard waste produced from filleting catches back into the water, which results in a highly spatio-temporally predictable food subsidy for wildlife to scavenge. However, the behavioural responses of these scavengers has received little attention. Aims: We aimed to assess the visitation of a common mesopredatory scavenger in relation to temporal patterns in waste discarding at a boat ramp in south-eastern Australia. Methods: Using passive acoustic telemetry, the movements of 13 adult female smooth stingrays (Bathytoshia brevicaudata) were tracked, and patterns in their acoustic detections and duration of time spent in different sections within the study area were compared. Key results: Use of the study area was strongly focused around the boat ramp, and peaked during periods of increased provisioning activity (i.e. afternoons and weekends). Environmental variables had limited influence on visitation, suggesting that the use of the area was not likely to be linked to natural behaviours. Conclusions: The observed patterns indicated that the movements of smooth stingrays were linked to waste-discard practices by recreational anglers. Implications: This study has implications for the management of discard practices for recreational fishing. The discarding of recreational fish-cleaning waste back into waterways is a common practice, and these resources are scavenged by several species. We show that the movements of a common consumer, the smooth stingray, are strongly linked to when and where this activity occurs. Foraging of provisioned resources has various impacts for wildlife. Therefore, improved management of discard practices for recreational fishing is recommended. [ABSTRACT FROM AUTHOR]

Context: Coastal and estuarine finfish species are responding to human-induced climate change by altering their distributions. In tropical regions, the species mostly affected by warming have limited acclimation capacity or live close to their upper thermal limits. Consequently, coastal fish assemblages may dramatically contract in range, experience declining population abundance or local extinction. Aim: Here we use two different predictive modelling techniques that cope with non-linear empirical relationships between responses and environmental predictors to investigate distribution change. Methods: The habitat-suitability models we use are the maximum entropy model (MaxEnt) and the generalised additive model (GAM). We built the models for the period 2004–2019 with environmental data relevant to coastal systems. We incorporated climate change at current conditions, near future (2015–2054) and distant future (2055–2100) from CMIP6 climate models. Key results: We identified bathymetry and sea-surface temperature to be key variables explaining the current and future distribution of coastal finfish and elasmobranchs of the Great Barrier Reef coast in central Queensland. Conclusions: We showed how the distributions of valuable fisheries species will change under future warming conditions. Implications: The objective is to inform fisheries management supporting the restructure of existing fisheries or the development of new resources for the dual purposes of conservation and food security. Coastal and estuarine finfish species are responding to human-induced climate change by altering their distribution. In tropical regions, the species mostly affected by warming have limited acclimation capacity or live close to their upper thermal limits. Consequently, coastal fish assemblages may dramatically contract in range, experience declining population abundance or local extinction. We use habitat-suitability models to predict the distribution of species in the current (2004–2019) and future (2015–2100) time periods. The predictions inform conservation and fisheries management. [ABSTRACT FROM AUTHOR]

We reviewed 9350 Australian species-level records and confirmed 64 species of the marine planktonic dinoflagellate genera Dinophysis Ehrenb. (17 species), Phalacroma F.Stein (12), Metaphalacroma L.S.Tai (1), Pseudophalacroma Jörg. (1), Ornithocercus F.Stein (7), Histioneis F.Stein (11 spp.), Parahistioneis Kof. & Skogsb. (4), Histiophysis (Kof. & Mich.) Kof. & Skogsb. (1), Citharistes F.Stein (2) and Amphisolenia F.Stein (8), from the period 1938–2019. The widespread D. acuminata Clap. & J.Lachm., D. acuta Ehrenb., D. caudata Kent, D. fortii Pavill., and D. tripos Gourret have attracted attention as causative organisms of diarrhetic shellfish poisoning in temperate Australian waters. We discriminate between Dinophysis and Phalacroma. We newly report from Australian waters O. assimilis Jörg., Metaphalacroma skogsbergii L.S.Tai, Parahistioneis pieltainii Osorio-Taffal, Amphisolenia extensa Kof., A. inflata G.Murr. & Whitt. and A. rectangulata Kof. We rediscovered Histiophysis rugosa (Kof. & Mich.) Kof. & Skogsb. here illustrated with two cells from the Coral Sea. The ornate tropical genera Ornithocercu s and Histioneis are excellent warm-water indicators, reflecting the southward reach of the East Australian and Leeuwin currents, whereas D. truncata Cleve is a cold-water Subantarctic species. A comprehensive review of 60 years of distribution data and taxonomic samples of marine dinophysoid dinoflagellates in Australian waters resolved 64 Ornithocercus taxa, which are illustrated by light and electron microscopy. Selected bloom-forming Dinophysis species are the cause of diarrhetic shellfish poisoning, while tropical genera such as Ornithocercus and Histioneis deserve careful attention in monitoring for southward range expansions. We rediscovered rare tropical species such as Histiophysis rugosa (Kof. & Mich.) Kof. & Skogsb., previously described on the basis of a single specimen only. [ABSTRACT FROM AUTHOR]

There are increasing concerns over the possible effects of aquaculture pens on the local abundance and residency of sharks, and its associated risk for shark bites at nearby beaches and surf breaks. We used acoustic tracking and a before–during–after–control–impact design to assess the residency and local abundance of 117 bronze whalers and 843 white sharks around a 45-m-diameter aquaculture pen installed in South Australia for tourism purposes. Only 14 bronze whalers (12.0% of individuals tagged) and nine white sharks (1.1% of individuals tagged) were detected throughout the 5-year monitoring period and there was no evidence of the pen affecting these sharks, in either the number of sharks detected or number of detections (proxy for length of time detected). The low amount of interactions with the pen was likely to be due to a combination of low fish biomass, pen installed in a shallow location, local shark species being migratory species, and good husbandry practices. Adequate planning and management, and good husbandry practices, such as removal of dead fish from pens and avoiding over-feeding to ensure the feed is entirely consumed, are key to reducing shark interactions with cage fish and associated infrastructure. Sharks are often observed interacting with caged fish and aquaculture industries. We tracked ∼900 bronze whalers and white sharks to determine whether local shark populations are affected by an aquaculture pen installed for tourism purposes. We found no evidence that sharks were attracted by the pen or stayed in the region for extended periods because of the pen. Good husbandry practices, shallow location, and shark species being migratory likely contributed to the low number of interactions with the pen. [ABSTRACT FROM AUTHOR]

Context: The spanner crab (Ranina ranina) stock of eastern Australia is distributed across two state jurisdictions and, as a non-migratory species with a pelagic larval phase, connectivity within this stock is likely to occur by larval dispersal, driven by ocean currents. Aims: To understand connectivity and patterns of larval supply in the eastern Australian spanner crab stock. Methods: Lagrangian particle tracking methods were used to simulate larval transport around the key spanner crab fishing regions in eastern Australia. Key results: Spawning off central Queensland (Qld) supplies a large proportion of recruits, supporting both the Qld and New South Wales (NSW) fisheries. Lagged larval settlement showed significant correlations to catch-per-unit-effort and the proportion of total harvest taken within the NSW fishery, providing evidence to suggest that the NSW fishery may be reliant on spawning activity in Queensland. Conclusions: The Qld and NSW fisheries are highly connected and the broad-scale patterns identified by the current modelling approach could provide an indicator of potentially good or bad recruitment years, particularly as finer resolution, and refined reproductive biology knowledge on spanner crabs becomes available. Implications: The Qld and NSW fisheries are highly connected with a source–sink structure and it is recommended that a co-management strategy be adopted. This paper models the dispersal of larval spanner crabs to demonstrate that the eastern Australian spanner crab (Ranina ranina) population is dependent on larval supply from the northern region (Queensland). Fluctuations in catch metrics within the southern region (New South Wales) are correlated with a predicted recruitment index. Understanding larval connectivity is vital for cross-jurisdictional fisheries, particularly for species with pelagic larval phases. [ABSTRACT FROM AUTHOR]

Understanding connectivity is crucial for the effective conservation and management of biota. However, measuring connectivity directly is challenging and it is often inferred based on assumptions surrounding dispersal potential, such as environmental history and species life history traits. Genetic tools are often underutilised, yet can infer connectivity reliably. Here, we characterise and compare the genetic connectivity and genetic diversity of three diadromous Australian fish species: common galaxias (Galaxias maculatus), tupong (Pseudaphritis urvillii) and Australian grayling (Prototroctes maraena). For each species, we investigate the extent of genetic connectivity across a study region in south-eastern Australia (~700 km). We further determine the potential roles of contemporary ocean currents in shaping the patterns of genetic connectivity observed. Individuals across multiple rivers were sampled and >3000 single nucleotide polymorphisms were genotyped for each species. We found differences in genetic connectivity for the three species: common galaxias were highly connected, and Australian grayling and tupong exhibited patterns of isolation by distance. The degree of genetic connectivity for tupong and Australian grayling appeared unrelated to oceanic currents. This study indicates that the degree of connectivity for different diadromous species can vary greatly despite broadly similar life history strategies, highlighting the potential value of genetic tools for informing species-specific management plans. The population connectivity of freshwater fish that use marine environments for growth is often highly complex and varies greatly between species. Yet, despite this, these species often remain critically understudied, hampering current conservation efforts. This study characterises the genetic connectivity of three such species found across the Victorian coast: common galaxias (Galaxias maculatus), tupong (Pseudaphritis urvillii), and Australian grayling (Prototroctes maraena). We show that each species exhibits unique patterns of genetic connectivity, helping inform best practice management for maintaining connectivity between populations within each species. [ABSTRACT FROM AUTHOR]

Limited information exists about the temporal residency patterns of marine predators, especially at the individual level. Temporal partitioning of resources can reduce intra-specific competition, but this has seldom been examined in predators in marine ecosystems. Here, we used 8 years of acoustic telemetry data from 27 receivers deployed in a large coastal embayment to examine the temporal residency of 51 Port Jackson sharks (Heterodontus portusjacksoni), during their breeding season. We found that the residency lengths of male and female Port Jackson sharks on breeding reefs differed throughout the breeding season, with males showing longer residency at the start of the season and females showing longer residency at the end of the season. Port Jackson sharks also showed a 24-h or diel periodicity in their detection patterns. Although the majority of individuals were nocturnal, a small proportion of sharks was detected more frequently during the day, possibly to reduce competition for resources. Surprisingly, there was no difference in the sex ratio nor the size of diurnal and nocturnal individuals. This study provides long-term insight into the temporal residency patterns of mesopredatory sharks at a breeding site and, more broadly, our results highlight the importance of studying temporal variation at the individual level in movement ecology studies. We used acoustic telemetry data of 51 Port Jackson sharks over 8 years to examine temporal variation in their use of breeding aggregation sites. Males and females showed variation in residency length over the breeding season. Individuals typically showed 24-h periodicity in site use, but exhibited variation in the time of day that they were present. These data suggest that individual variation in residency may mediate competition among individuals. [ABSTRACT FROM AUTHOR]

Cetaceans are iconic predators that serve as important indicators of marine ecosystem health. The Bremer Sub-Basin, south-western Australia, supports a diverse cetacean community including the largest documented aggregation of killer whales (Orcinus orca) in Australian waters. Knowledge of cetacean distributions is critical for managing the area's thriving ecotourism industry, yet is largely sporadic. Here we combined aerial with opportunistic ship-borne surveys during 2015–2017 to describe the occurrence of multiple cetacean species on a regional scale. We used generalised estimating equations to model variation in killer whale relative density as a function of both static and dynamic covariates, including seabed depth, slope, and chlorophyll a concentration, while accounting for autocorrelation. Encountered cetacean groups included: killer (n = 177), sperm (n = 69), long-finned pilot (n = 29), false killer (n = 2), and strap-toothed beaked (n = 1) whales, as well as bottlenose (n = 12) and common (n = 5) dolphins. Killer whale numbers peaked in areas of low temperatures and high primary productivity, likely due to seasonal upwelling of nutrient-rich waters supporting high prey biomass. The best predictive model highlighted potential killer whale 'hotspots' in the Henry, Hood, Pallinup and Bremer Canyons. This study demonstrates the value of abundance data from platforms of opportunity for marine planning and wildlife management in the open ocean. Every summer, a remote area 50 km off Bremer Bay, Western Australia, attracts many dozens of killer whales in what are currently the largest recorded numbers of the predator in Australian waters. New data collected aboard vessels show that this hotspot may be one of many found across an extensive network of underwater canyons where food is likely plentiful. Mapping whale aggregations is a key step in supporting and managing the region's thriving wildlife tourism industry. Photograph by Rebecca Wellard, Curtin University and Project ORCA. [ABSTRACT FROM AUTHOR]

Knowledge about the coastal zooplankton of the south-eastern Indian Ocean is limited, with few studies having compared assemblages across the latitudinal range of the western seaboard of Australia. The dominant oceanographic feature in this region is the Leeuwin Current, which transports warm, lower-salinity, tropical waters southward along the shelf-edge. This study examined data collected by Australia's Integrated Marine Observing System at three coastal National Reference Stations located at 22°S 114°E, 32°S 115°E and 34°S 122°E. Spatial and temporal patterns in zooplankton abundance, composition and diversity were investigated, and differences in assemblage structure, particularly with respect to copepods, were related to oceanographic conditions. Clear dissimilarities among copepod assemblages were observed, becoming weaker in winter owing to enhanced connectivity of species driven by alongshore and cross-shelf transport in the Leeuwin Current. Both physical and biogeochemical factors were significant in structuring copepod assemblages, with seawater density, incorporating temperature and salinity, exerting the greatest influence. The results suggest that both broad-scale latitudinal gradients and mesoscale events contribute to variation in zooplankton assemblages in these waters. This study provides the first detailed comparison of zooplankton assemblages among the north-west, south-west and southern coastal waters of Western Australia, and enhances understanding of the processes influencing zooplankton distribution and structure. We used data collected by Australia's Integrated Marine Observing System to investigate variation in zooplankton distribution and structure at three coastal National Reference Stations located on the western seaboard of Australia. The results suggest that the oceanography of the region, largely driven by the Leeuwin Current which flows poleward along the Western Australian coast, is an important influence in structuring zooplankton populations in these waters. [ABSTRACT FROM AUTHOR]

Coral bleaching is the dysfunction of the coral–algal endosymbiosis and is characterised as a loss of Symbiodiniaceae cells from host tissues or the loss of photosynthetic pigments. This breakdown of symbiosis occurs as a result of elevated temperature beyond the organism's thermal threshold. The thermal tipping points within the symbiosis have not yet been well resolved, and the mechanisms underlying the various cellular processes of the corals bleaching response remain unknown. This study characterised the cellular responses of the symbiont Cladocopium sp. (syn. clade C3) within the host coral Acropora aspera during exposure to thermal stress. Exposure to temperatures between 2 and 3°C below the bleaching threshold, equating to 2-degree heating weeks (DHWs), results in changes to the symbiont cell morphology and cell division rates. Once corals were exposed to 4 DHWs, over 90% of the symbiont cells showed signs of degradation. Although sub-bleaching thermal stress is not sufficient to trigger bleaching alerts at an ecological scale, this stressor substantially affects the coral symbiosis. It is therefore vital that we begin to quantify how sub-bleaching thermal stress affects the fitness of Symbiodiniacea populations, their coral hosts and subsequently reefs worldwide. Algal symbionts play a critical role in the energy budget of the coral. In this study, we demonstrate that the algal symbionts are significantly affected at temperatures below when visual coral bleaching signs are observed. It is clear that our current understanding of bleaching has overlooked what is happening to the symbiosis before bleaching is visually evident on coral reefs. [ABSTRACT FROM AUTHOR]

We reviewed 15 572 Australian species-level records of the marine planktonic dinoflagellate Tripos Bory (formerly Ceratium Schrank, a genus now restricted to freshwater species). The genus is represented by over 50 species and numerous varieties and forms in Australian tropical, subtropical and temperate marine waters and the Southern Ocean. There exists considerable plasticity in the morphology of many species, which has confounded species delimitations and created uncertainty around their spatial distributions. We newly illustrate by light and electron microscopy the rarely reported Tripos hundhausenii (Schröd.) Hallegr. & Huisman comb. nov. first described from the Arabian Sea, but increasingly being observed in Sydney coastal waters. A large number of Tripos species are widely distributed in temperate, subtropical and tropical waters and their distributions have remained remarkably stable in Australian waters over the past 60–80 years. By contrast, we identified a narrow group of warm-water species, including T. belone (Cleve) F.Gómez, T. cephalotus (Lemmerm.) F.Gómez, T. dens (Ostenf. & E.J.Schmidt) F.Gómez, T. digitatus (F.Schütt) F.Gómez, T. gravidus (Gourret) F.Gómez, T. incisus (G.Karst.) F.Gómez, T. paradoxides (Cleve) F.Gómez and T. praelongus (Lemmerm.) F.Gómez, that are commonly encountered off Sydney, rarely found down to Eden and Batemans Bay or Bass Strait, but occasionally occur as far south as King Island and Maria Island, Tasmania. These rare tropical Tripos species are carried southward by the East Australian and Leeuwin Currents and deserve careful attention in monitoring for future range expansions, changes in seasonality or upwelling or incursion of deep tropical waters. [ABSTRACT FROM AUTHOR]

A national observing network has been operating over the past 4 years to inform the scientific and economic challenges of ocean acidification (OA) facing New Zealand. The New Zealand Ocean Acidification Observing Network (NZOA-ON) consists of 12 sites across varied coastal ecosystems. These ecosystems range from oligotrophic ocean-dominated systems to eutrophic river-dominated systems, with sites that are pristine or affected by agriculture and urbanisation. Fortnightly measurements of total alkalinity and dissolved inorganic carbon provide the baseline of carbonate chemistry in these varied ecosystems and will facilitate detection of future changes, as well as providing a present-day baseline. The National Institute of Water and Atmospheric Research and the University of Otago have developed a 'grass-roots' sampling program, providing training and equipment that enable sampling partners to collect field samples for analyses at a central laboratory. NZOA-ON leverages existing infrastructure and partnerships to maximise data captured for understanding the drivers of chemical changes associated with OA and ecological responses. NZOA-ON coordinates with and contributes to global initiatives to understand and mitigate the broader impacts of OA. A description of NZOA-ON is presented with preliminary analyses and comparison of data from different sites after the first 4 years of the network. The New Zealand Ocean Acidification Observing Network (NZOA-ON) has been developed to inform the scientific and economic challenges that New Zealand is facing in response to more acidic ocean waters. Remote field sites are distributed across New Zealand coastal waters to better understand how ocean chemistry is changing in response to increasing atmospheric carbon dioxide and how ecosystems will be affected. [ABSTRACT FROM AUTHOR]

In this study we investigated the distribution of dissolved and particulate zinc (dZn and pZn respectively) and its isotopes in the Subantarctic Zone as part of a Geotraces Process voyage. dZn and pZn depth profiles contrasted each other, with dZn showing depletion within the euphotic zone while pZn profiles showed enrichment. Fitting a power law equation to the pZn profiles produced an attenuation factor of 0.82, which contrasted values for particulate phosphorus, cadmium and copper. The results indicate that zinc has a longer regeneration length scale than phosphorus and cadmium, but shorter than copper. The differential regeneration of pZn relative to that of particulate phosphorus likely explains why dZn appears to have a deeper regeneration profile than that of phosphate. The dZn isotope (δ66Zndissolved) profiles collected across the Subantarctic Zone showed differing profile structures. For one station collected within an isolated cold-core eddy (CCE), δ66Zndissolved showed surface enrichment relative to deep waters. The corresponding pZn isotope profiles within the CCE did not show enrichment; rather, they were subtly depleted in surface waters and then converged to similar values at depth. Zinc isotope fractionation can be explained through a combination of fractionation processes associated with uptake by phytoplankton, zinc complexation by natural organic ligands and zinc regeneration from particulate matter. This study investigated the distribution of dissolved and particulate zinc and its isotopes in the Subantarctic Zone. Zinc had a longer regeneration length scale than phosphorus and cadmium, but a shorter one than copper. In addition, the isotope composition of dissolved and particulate zinc was affected by chemical (complexation), biological (uptake and regeneration), physical (mixing and particle sinking) and seasonal variations acting in concert. [ABSTRACT FROM AUTHOR]

Movements of 89 acoustically tagged subadult and adult white sharks (Carcharodon carcharias) were monitored off the south and west coasts of Western Australia (WA) between December 2008 and May 2016 by a network of up to 343 passive acoustic receivers. In all, 290 inter-regional movements, totalling 185 092 km were recorded for 73 of these sharks. Estimated rates of movement in excess of 3 kmh-1 (mean 1.7 km h-1; maximum 5.6 km h-1) were common, even over distances of thousands of kilometres. Detections indicated that white sharks may be present off most of the south and lower west coasts of WA throughout the year, although they are more likely to be encountered during spring and early summer and are least likely to be present during late summer and autumn. There was limited evidence of predictable return behaviour, seasonal movement patterns or coordination of the direction and timing of individual shark's movements. Nevertheless, the data suggest that further analyses of movements in relation to ecological factors may be useful predictors of shark activity at local scales. It is hoped that these data may be useful for informing public safety initiatives aimed at mitigating the risks associated with human encounters with white sharks off the WA coast. [ABSTRACT FROM AUTHOR]

The benefits of marine protected areas are difficult to estimate for mobile species, but their effectiveness can be increased if essential habitats, such as nursery areas, are protected. In the present study we examined movements of juvenile blacktip reef (Carcharhinus melanopterus) and sicklefin lemon (Negaprion acutidens) sharks in a coastal nursery in northern Australia. Telemetry-derived data were modelled using Brownian bridges and overlaid with maps of habitats and no-take zones. Juvenile N. acutidens were typically residents (≥30 days) of the nursery with small areas of core space use (,1.9 km²), whereas juvenile C. melanopterus were non-residents (<30 days) and used larger areas (<5.6 km²). Both species exhibited positive selection for sandflats and mangroves, and avoidance of deeper lagoonal and slope habitats. Monthly patterns were examined only for resident N. acutidens, and residency decreased with increasing shark length and varied seasonally for males but not females. Space use showed weak declines with increasing tidal range, and slight increases with mean air pressure, rainfall and shark length. Protecting sandflat and vegetated habitats may increase the efficacy of no-take zones for juvenile N. acutidens, because they exhibit residency and affinity to these features. Conversely, such protection will be of limited benefit for juvenile C. melanopterus, because they exhibit low residency and broader movements. [ABSTRACT FROM AUTHOR]

A goal of designed artificial reefs (ARs) is to enhance fish abundance, species diversity and fishing opportunities by providing food and refuge for fish. Quantifying the contribution of ARs to coastal ecosystems and fisheries productivity requires an understanding of fish presence at the structure and connectivity with surrounding habitats. In the present study, the movements and presence of 10 eastern fiddler rays (Trygonorrhina fasciata), 17 Port Jackson sharks (Heterodontus portusjacksoni) and 18 bluespotted flathead (Platycephalus caeruleopunctatus) were monitored using acoustic telemetry around a designed AR in 38-m depth near Sydney, Australia. Fiddler rays exhibited an average short-term presence of 43% at the AR, and 26% over the &#~20-month monitoring period, which was significantly higher than the other two species. Fish tagged at the AR showed high affinity to the site at which they were tagged compared with fish tagged on natural reef. All three species moved frequently between the AR and the other reefs in the area, indicating that the AR may increase the connectivity between adjacent habitats and aid the dispersion of benthic species. The moderate presence at the AR suggests that these species may contribute to some biomass production at this AR by incorporating this reef in their natural range. [ABSTRACT FROM AUTHOR]

Investigating niche overlap in exploited fish species can reveal behavioural information necessary to improve conservation and fisheries management at a species level. The present study examined spatial and dietary overlap between two co-occurring reef fish, namely Plectropomus leopardus and P. maculatus, at an inshore reef in the Great Barrier Reef Marine Park using acoustic telemetry and stable isotopes. Movements of tagged fish within an acoustic array of 19 receivers deployed along a narrow reef portion of Orpheus Island were monitored for up to 3 years. Although space use was similar between species, spatial overlap was rare and P. maculatus (n = 30) was consistently deeper than P. leopardus (n = 32). Dietary overlap between species was high based on overlapping δ15N and δ13C isotopic niches in muscle tissue (n = 20). The complementary stable isotope and acoustic telemetry data revealed these species had similar isotopic niches but distinct space use patterns, which may be a product of competition for resources. These findings show species-specific behaviours within a genus commonly managed or reported as a single entity, and provide new information on partitioning of resources by Plectropomus spp. in inshore reef environments. [ABSTRACT FROM AUTHOR]

Spatial management of fish populations can potentially be optimised by incorporating responses to environmental variables, such as diel, tidal, lunar and seasonal factors, but individual variability in habitat use and behaviour may complicate such efforts. Acoustic tagging and tracking of 84 Lethrinus nebulosus in the Ningaloo Marine Park indicated that sizes of individual habitat utilisation kernels were similar across diel and tidal cycles, but varied greatly among individuals. Clearly differentiated diel and tidal habitat use patterns were evident in significant proportions of individuals, particularly in relation to tidal phase. For the majority of residents, home-range sizes were reasonably stable over periods of 2-4 years, but in some cases core areas did shift over time. At seasonal time scales, peaks of seasonal activity and home range area were recorded during spawning season (October-December). Long-distance return migrations to spawning locations were observed that were among the longest observed for any reef fish (over 130 km). Suspected spawning-related movements were recorded almost exclusively in fish >500-mm fork length, and were semilunar, following quarter moons in October-December. Significant individual-level variability in movement and habitat use patterns, evident across multiple temporal scales, has important implications for the management of L. nebulosus populations. [ABSTRACT FROM AUTHOR]

Knowledge of the broad-scale movement patterns of sharks is essential to developing effective management strategies. Currently there is a large bias in studies focusing on species that are either large apex predators or found in tropical to subtropical regions. There is limited knowledge of the movements and migrations of benthic and temperate shark species. The present study used passive acoustic telemetry to investigate the movement patterns of a benthic shark species, the Port Jackson shark (Heterodontus portusjacksoni). Individuals were tagged with acoustic transmitters between 2012 and 2014 and their movements were monitored within Jervis Bay and along the east Australian coastline for up to 4 years. Male and female Port Jackson sharks demonstrated high levels of philopatry to both Jervis Bay and their tagging location across multiple years. Although males and females did not differ in their arrival times, females departed from Jervis Bay later than males. Approximately half the tagged individuals migrated in a southward direction, with individuals being detected at Narooma, Bass Strait and Cape Barron Island. This study provides conclusive evidence of bisexual philopatry in a benthic temperate shark species, confirming previous hypotheses, and presents the most detailed migration route for Port Jackson sharks to date. [ABSTRACT FROM AUTHOR]

Broad-scale acoustic telemetry networks are being established worldwide. The 10-year anniversary of the Integrated Marine Observing System's Animal Tracking Facility provided the opportunity to assess the efficiency of one of the first national-scale acoustic telemetry networks. Acoustic networks are comprised of acoustic receiver arrays that detect high-frequency transmitters attached to animals that pass within detection range. Herein we assessed the efficiency of eight curtains to detect passing animals by calculating the standardised mean number of detections and transmitters detected at each station. The aim was to determine how many receivers could be decommissioned fromeach curtain while maintaining its integrity (i.e. detection of all species passing the array). Pivotal locations were defined as the furthest station at which all species would still be detected and where at least 75%of the detections and transmitterswould still be detected. By applying these criteria, we were able to improve the cost-effectiveness of our network significantly, reducing the number of stations from 132 to 85 (64% of the original network), yet still retaining 84% of total detections, 86% of transmitters and 100% of detected species. The present study provides a useful framework for refining acoustic telemetry networks. [ABSTRACT FROM AUTHOR]

Acoustic telemetry is used to investigate a diverse suite of questions regarding the biology and ecology of a range of aquatic species, and is an important tool for fisheries and conversation management. Herein we present a brief review of the Australian acoustic telemetry literature in the context of key areas of progress, drawing from several recent studies and identifying areas for future progress. Acoustic telemetry has been increasingly used in Australia over the past decade. This has included substantial investment in a national acoustic array and the associated development of a national acoustic telemetry database that enables tag deployment and detection data to be shared among researchers (the Integrated Marine Observing System Animal Tracking Facility). Acoustic telemetry has contributed to important areas of management, including public safety, design and management of marine protected areas, the use of closures in fisheries management, informing environmental flow regimes and the impacts of fisheries enhancements, and is most powerful when used as a complementary tool. However, individual variability in movement often confounds our ability to draw general conclusions when attempting to characterise broad-scale patterns, and more work is required to address this issue. This overview provides insight into the important role that acoustic telemetry plays in the research and management of Australian aquatic ecosystems. Application of the technology transcends aquatic environments and bureaucracies, and the patterns revealed are relevant to many of the contemporary challenges facing decision makers with oversight of aquatic populations or ecosystems. [ABSTRACT FROM AUTHOR]

The preserved stomach contents from the manta ray, collected in 1935, that provided the basis for the 2009 taxonomic resurrection of the species Manta alfredi, were examined. The majority of the material comprised calanoid copepods (61.7%) and trypanorhynch cestodes (34.6%), with minor contributions by arrow worms, a barnacle larva and a nematode. Comparison of the size-frequency distributions of stomach contents with that of zooplankton from the Great Barrier Reef region suggest that this manta ray preferentially ingested large copepods, or that the filter mechanism used to extract prey from the water was selective for prey items over 0.8 mm in length. This is the first description of the diet of M. alfredi from stomach contents, and is consistent with previous inferences about what this species consumes. [ABSTRACT FROM AUTHOR]

Deep-water sharks have low biological productivity and are vulnerable to exploitation with species-specific regional life history required to enable effective management. The present study describes the life history of two squalids collected from Australia: (1) the piked spurdog (Squalus megalops) from the tropical Great Barrier Reef; and (2) the Philippine spurdog (S. montalbani) from New South Wales. Maximum observed ages for males and females were 18 and 25 years for S. megalops and 28 and 27 years for S. montalbani. Multiple growth models were all well supported and indicated very slow growth rates for both species. The tropical S. megalops population was smaller and older at maturity than previously reported temperate populations. Males were mature at 352-mm stretched total length (LST) and 12.6 years, whereas females were mature at 422 mm LST and 19.1 years. Squalus montalbani males were mature at 700 mm LST and 21.8 years, whereas females were mature at 800 mm LST and 26 years. Fecundity was lower for S. megalops than S. montalbani with two to three compared with nine to 16 embryos. Both species have a conservative life history, although in the event of overfishing the longer-lived, later-maturing and deeper-dwelling S. montalbani is likely to take longer to recover than S. megalops. [ABSTRACT FROM AUTHOR]

Despite being critically endangered, the at-sea behaviour of hawksbill turtles (Eretmochelys imbricata) remains insufficiently understood to support a global conservation strategy. Habitat location and spatial use are poorly documented, which is particularly true for the globally important Australian hawksbill population. We equipped 10 adult female hawksbill turtles nesting on Groote Eylandt, northern Australia, with Fastloc GPS and Argos satellite transmitters. Wequantified fine-scale habitat use and area-restricted search behaviour, and located potential feeding and developmental habitats by simulating hatchling turtle dispersal patterns by using a particle-tracking hydrological model. During the breeding season, females mostly remained near their nesting site. Post-breeding, all turtles migrated to foraging sites on the Australian continental shelf, primarily in the Gulf of Carpentaria in coastal seagrass pastures, but also offshore near coralreef platforms. The distribution of adult foraging grounds was similar to simulated dispersal patterns of hatchling turtles from distant rookeries, thus highlighting the ecological significance of the Gulf of Carpentaria for hawksbill turtles. Although this hawksbill turtle population is likely to be endemic to Australian waters, national and international conservation initiatives are required to mitigate sources of anthropogenic mortality (e.g. illegal tortoise-shell trade, incidental captures in fishing gear, marine debris, seabed mining exploitation). [ABSTRACT FROM AUTHOR]

During the austral spring of 2009 several significant dust storms occurred in south-east Australia including the so-called 'Red Dawn' event in late September. Estimates of 2.5 Mt total suspended particulate sediment lost off the Australian coast in the 3000 km long dust plume make it the largest off-continent loss of soil ever reported. Much of this material was transported over the coastline of New South Wales and into the adjacent Tasman Sea. Long-term model simulations of dust deposition over the south-west Tasman Sea suggest the amount deposited during the spring of 2009 was approximately three times the long-term monthly average. Previous satellite-based analyses of the biological response of Tasman Sea waters to dust-derived nutrients are equivocal or have observed no response. Satellite-derived surface chlorophyll concentrations in the southern Tasman during the spring of 2009 are well above the climatological mean, with positive anomalies as high as 0.5 mgm-3. Dust transport simulations indicate strong deposition to the ocean surface, which during both the 'Red Dawn' event and mid-October 2009 dust storm events was enhanced by heavy precipitation. Cloud processing of the dust aerosol may have enhanced iron bioavailability for phytoplankton uptake. [ABSTRACT FROM AUTHOR]

Changes in the offshore oceanographic processes are suspected to be the cause of a recent dramatic decline in the settlement of post-larvae of the Western Australian spiny lobster (Panulirus cygnus), which has greatly reduced the productivity from the world's second-largest spiny lobster fishery. The present study assessed whether there are differences in the nutritional condition of the larvae of P. cygnus sampled from two pairs of cyclonic eddies (CEs) and anticyclonic eddies (AEs). Morphometric and biochemical analyses were undertaken on the mid-late-stage larvae (VI, VII, VIII) sampled offshore from two pairs of adjacent counter-rotating mesoscale eddies in the Leeuwin Current off Western Australia. The results showed that larvae captured from CEs had greater average total dry mass (P < 0.001) than those from AEs. Stage VIII larvae from CEs contained more protein (P < 0.008) (38.5% ± 5.4 s.e.) and lipid (P < 0.005) (67.2% ± 12.1) than did those from AEs. The possible causes for these differences are uncertain but may be related to differences in water temperatures in CEs v. AEs influencing the ability of phyllosomas to accumulate nutritional reserves. A recent dramatic decline in the settlement of post-larvae of the Western Australian spiny lobster may be due to changes in the offshore oceanographic processes. This research reported that late-stage phyllosomas of spiny lobster in cyclonic eddies of the Leeuwin Current are in a substantially better nutritional condition than are those in anticyclonic eddies. These differences may be related to differences in water temperatures and would influence their settlement. [ABSTRACT FROM AUTHOR]

Artificial reefs are a popular fisheries management tool, but the effect of these reefs on the abundance of fish in the surrounding pelagic environment is uncertain. Pelagic baited remote underwater video (PBRUV) was used to observe the fish assemblage surrounding an offshore artificial reef (OAR), near Sydney, Australia. PBRUVs were deployed at three distances (30, 100, 500 m) from the OAR, and compared with a drop camera deployed directly over the OAR. There was a significantly greater abundance of fish on the OAR, but no significant difference in abundance at the 30-, 100- or 500-m distances. Two highly mobile non-resident species (Seriola lalandi, Pseudocaranx dentex) were significantly more abundant on the OAR, but this association was not detected 30 m away. The lack of a significant difference in total fish abundance, or in assemblage composition, between the 30-, 100- and 500-m distances suggests that any association with the OAR is on a localised scale (<30 m). One exception was the ocean leatherjacket (Nelusetta ayraudi), which had an association detected 100 m from the OAR. This predominantly small-scale effect may be influenced by the proximity of this OAR to numerous natural reefs. Underwater video was used to observe the fish assemblage surrounding an offshore artificial reef, in Sydney, Australia. We found up to 10 times more fish on the reef itself than at 30, 100 and 500 m from the reef. This suggests that artificial reefs are very effective at increasing fish abundance, but generally act on a localised scale (<30 m). [ABSTRACT FROM AUTHOR]

No-take marine protected areas (MPAs) represent an effective biodiversity conservation tool for a range of species including resident reef fishes that are intrinsically vulnerable to overfishing and other localised impacts. The western blue groper (Achoerodus gouldii) is the largest permanent-resident reef teleost in southern Australian waters and has the second-oldest recorded age of any labrid at 70 years. Acoustic telemetry was used to investigate whether adult A. gouldii can be effectively protected within adequately sized no-take MPAs. Ten passive acoustic receivers tracked the movements of 15 A. gouldii individuals (69-112-cm total length; 7-31-kg weight) at a site off north-western Kangaroo Island, South Australia. Most of the fish displayed high site fidelity (91-100% residence time for 10 of the 11 fish with useful data) for a narrow strip of fringing coastal reef (~1-km length by ~40-m width) throughout a 12-month period. Mean home-range along-shore length and area were estimated at 1076 ± 83 m (s.e.), and 45 188 ± 3497 m², respectively (n = 11 fish with useful data). Comparison with other resident temperate-reef teleosts indicated no relationship between fish length and home-range area, and that A. gouldii has a relatively small home range. The high site fidelity and small home range of adult A. gouldii individuals makes localised populations amenable to a high level of protection within no-take MPAs. The western blue groper (Achoerodus gouldii) is a large, long-lived fish that is intrinsically vulnerable to overfishing and other localised impacts. A 12-month acoustic tracking study aimed at determining the movements of adult A. gouldii confirmed that individuals are highly amenable to protection within adequately sized and appropriately located no-take marine protected areas. For one of the largest temperate-reef fishes so far tracked using acoustic technology, A. gouldii has a relatively small home range. [ABSTRACT FROM AUTHOR]

Wind stress forcing is a critical driver of oceanographic processes. In the absence of over-ocean wind measurements, re-analysis products and over-land measurements are often used. The present paper compares a unique wind-data series from an ocean mooring with two re-analysis products and data from six over-land sites in Sydney, Australia, to determine whether these data can infer over-ocean wind conditions. Four oceanographic moorings are located here; however, over-ocean meteorological observations are no longer available. Correlations between over-ocean and over-land sites wind stress were <0.8, whereas for re-analysis products, correlations ranged from 0.28 to 0.72. Re-analysis products were unable to resolve variability at the over-ocean site with periods shorter than 2 days, indicating that they are not appropriate wind proxies for the coastal ocean. Somewhat counter-intuitively, our results showed that proximity of over-land sites to the over-ocean site does not necessarily imply the highest correlation or the lowest error and careful site selection is required. An upwelling study showed that wind observations from selected over-land sites can accurately represent isotherm uplift in the coastal ocean. Threshold wind stress values that uplift isotherms at these over-land sites are provided, along with a recommendation for the use of the over-land site that best represents over-ocean wind conditions in this region. Offshore wind stress data is necessary for many different applications; however, in the coastal ocean around Australia, it is seldom available. A proxy wind stress data source in the Sydney region was found by comparing offshore wind data (that is no longer collected) with data from over-land meteorological stations and re-analysis products. The results show that careful site selection is required and the implications for oceanographic modelling in the coastal area are discussed. [ABSTRACT FROM AUTHOR]