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Sea turtles worldwide face a range of threats including sea level rise and warming associated with climate change, predation by invasive species, plastic and light pollution, coastal development, and human interference. Conservation managers have a long history of aiding sea turtle populations, from protecting nests to head-starting hatchlings. Due to these challenges faced by turtles, there is a constant focus on assessing the likely success of proposed conservation interventions to help inform decision-making processes. We develop an age-based, spatially implicit population model for the north-west shelf stock of Australia’s endemic flatback turtle Natator depressus that estimates the long-term outcomes of a range of onshore and offshore conservation interventions. Analysis of the model shows that young adults contribute most to population growth (i.e. have highest expected future reproductive success); however, this is often the most difficult life stage to manipulate in the field. Observable outcomes of interventions are often delayed for many years, especially for on shore activities (e.g. protecting eggs and hatchlings), due to late age to maturity. The potential impact of warming-induced female bias on population dynamics was also investigated. Although such bias increases population growth rates in the short term, negative effects of the bias (e.g. reduced female mating success) and negative environmental effects (e.g. reduced survival rates, habitat loss) can lead to sustained declines. Population models can rapidly assess climate change and conservation impacts on turtle dynamics and can guide monitoring efforts for real-world application.

Marine conservation programs face significant challenges engaging different audiences to participate in conservation actions. While it is understood that images can play a crucial role in shaping people's behaviours, in the context of marine conservation, research has focused on the effect of words. We know little about the effect of images on influencing people's intentions. Thus, there is scant guidance for marine conservation programs wanting to use images to improve communication and engagement strategies. This study addresses this gap by assessing how images are used in social media in Australian turtle conservation programs. Specifically, using visual framing analysis and online surveys, we assessed whether images of conservation actions or conservation threats increase participants emotions, self-efficacy, and intentions to engage in pro-conservation behaviours, using flatback turtles as a case study. We find that 1) images of animals are commonly used on social media, with certain types of images (e.g. landscapes, conservation actions) generating higher user engagement; 2) images on Twitter and Instagram generated higher user engagement than on Facebook; 3) images of conservation actions increased feelings of hope and self-efficacy, while images of conservation threats increased feelings of fear and reduced self-efficacy; and 4) feelings of self-efficacy increased participants' intentions to support low-effort conservation actions. Results suggest that the types of images posted on social media can influence viewers' emotions and intentions to engage in pro-conservation behaviours. Our findings provide guidance for conservation programs and managers to develop improved communication and engagement strategies through visual media.

Sea turtles are facing significant threats, including anthropogenic warming, predation from feral animals, and sea level rise. While a range of intervention options are available, resource constraints and increasing time pressures means managers face the difficult task of prioritising options. To achieve successful conservation outcomes, managers are increasingly seeking to understand the social acceptability, as well as biological plausibility and economic feasibility, of these intervention options. Previous studies have used expert opinion as predictors of social acceptability, given their technical knowledge and experience implementing the interventions; however, the assumption that the social acceptability of interventions is the same for both the general public and experts is largely untested. We tested this assumption using surveys to assess the social acceptability of 24 interventions proposed for a population of flatback turtles Natator de - pressus in northwest Australia. Survey responses were collected from community members (residents) and experts (resource managers and researchers). Experts were asked to provide their own opinion of acceptability and how they perceived community members would rate intervention options. In general, residents ranked interventions that directly intervene with human behaviour or the environment as more acceptable than those that directly target turtles, while experts tended to favour direct turtle interventions. Experts incorrectly predicted that the community would not be influenced by the target of the intervention. Our findings highlight the importance of understanding social acceptability of interventions before implementation to inform management decisions and engagement and communication strategies, particularly when interventions might be controversial or restrict human behaviour directly.

The conservation of marine ecosystems and species is inherently complex, plagued by social, political, economic and ecological uncertainty. Navigating these challenges to sustain marine systems requires the understanding, consideration and uptake of multiple knowledge systems within decision-making processes. Participatory research approaches, such as knowledge co-production, are advocated given their potential to generate knowledge with those who are most affected by the issue at hand and, based on that knowledge, develop and implement meaningful conservation practices collaboratively. In doing so participatory research is positioned to make marine research more democratic and impactful, and as such, has been a field of growing research enquiry. The aim of this study, therefore, is to synthesise (via a systematic scoping review) the existing literature to generate guidance that can help researchers and practitioners plan and apply participatory research approaches in a complex marine context. Results from systematically identifying and analyzing 337 articles show that the implementation of participatory research approaches are most common in the global north. Participatory research approaches most frequently included representatives from government, industry and civil society (e.g. community groups), while indigenous groups and communities were rarely included. A diversity of participatory research approaches have been used in relation to marine conservation in different settings and at various stages of the participatory process, each with their own challenges and benefits, that can lead to either positive outcomes for actors (e.g. social learning) or negative outcomes (e.g. disempowerment). We draw on our findings to provide guidance for improving the implementation of participatory research approaches in marine conservation such as taking the time to understand context before commencing participatory research approaches, and ensuring transparency with all actors

Australia’s endemic flatback turtle Natator depressus is the focus of a long-term conservation program aimed at securing the persistence of healthy populations in the northwest of Australia into the future. Primary threats to flatback turtles include (1) sea level rise, (2) predation from introduced species, (3) temperature increases, (4) onshore and nearshore light, (5) marine debris, and (6) modification to beaches. Population declines resulting from these threats have been reported or are anticipated, and a range of intervention options are possible that may limit their negative impact. Following methods previously developed and applied to iconic marine species and habitats, we generated a range of intervention options, and asked experts to prioritise those actions using an intervention prioritisation tool (IPT) and the public to prioritise based on social acceptability assessment (SAS). The IPT allows different conservation interventions to be assessed based on their economic cost, implementation feasibility, social acceptability, and perceived effectiveness in maintaining or increasing future turtle populations while simultaneously accounting for expert confidence in their assessment. Results generated by the IPT and SAS can be explored further to resolve uncertainty, a process that can help managers and experts alike in their decisionmaking process associated with flatback conservation. While this paper is focused on interventions relating to flatback turtles, we propose that our IPT can be applied in different settings to enable consideration of interventions for a range of threatened species and habitats to guide research and conservation investment decisions by managers.

Marine heatwaves (MHWs) cause disruption to marine ecosystems, deleteriously impacting macroflora and fauna. However, effects on microorganisms are relatively unknown despite ocean temperature being a major determinant of assemblage structure. Using data from thousands of Southern Hemisphere samples, we reveal that during an "unprecedented" 2015/16 Tasman Sea MHW, temperatures approached or surpassed the upper thermal boundary of many endemic taxa. Temperate microbial assemblages underwent a profound transition to niche states aligned with sites over 1000 km equatorward, adapting to higher temperatures and lower nutrient conditions bought on by the MHW. MHW conditions also modulate seasonal patterns of microbial diversity and support novel assemblage compositions. The most significant affects of MHWs on microbial assemblages occurred during warmer months, when temperatures exceeded the upper climatological bounds. Trends in microbial response across several MHWs in different locations suggest these are emergent properties of temperate ocean warming, which may facilitate monitoring, prediction and adaptation efforts.

Human-induced climate change is a threat to marine species and ecosystems worldwide, including sea turtles. As climate changes are projected to intensify, directed management and intervention is required to safeguard the future of vulnerable species and ecosystems. Prioritisation tools that explore the cost−benefit−risk can help in the choice of interventions. However, an often-overlooked element underpinning the success of directed interventions is the extent to which they are perceived as acceptable by local communities (i.e. social acceptability). We assess the social acceptability for a range of adaptation interventions for flatback turtles Natator depressus (FBTs) in north-western Australia. A survey of residents in Port Hedland and Broome showed that FBTs are important to the identity of both towns and local FBT decline or extinction would have negative local social and economic impacts. In both locations, survey respondents expressed strong support for intervening to protect FBTs and there was broad agreement between respondents from both locations on the most and least acceptable interventions. For example, in both locations the most acceptable intervention was to restrict 4-wheel-drive beach access for locals and visitors and the least acceptable was to intervene genetically in the FBT populations. In the case of FBT conservation in Port Hedland and Broome, (1) interventions that limit human behaviour, as opposed to interfering with the species themselves, are likely to be most socially acceptable, and therefore (2) are also most likely to be implemented successfully and avoid conflicts within the community.

Knowledge of factors affecting a species' breeding biology is crucial to understanding how environmental variability impacts population trajectories and enables predictions on how species may respond to global change. The Australian fur seal ( Arctocephalus pusillus doriferus , AUFS) represents the largest marine predator biomass in southeastern Australia, an oceanic region experiencing rapid warming that will impact the abundance and distribution of prey. The present study (1997–2020) investigated breeding phenology and pup production in AUFS on Kanowna Island, northern Bass Strait. The pupping period varied by 11 days and the median pupping date by 8 days and were negatively correlated to 1- and 2-year lagged winter zonal winds, respectively, within Bass Strait. While there was no temporal trend over the study period, annual pup production (1386–2574 pups) was negatively correlated to 1-year lagged summer zonal winds in the Bonney Upwelling region and positively correlated to the current-year Southern Oscillation Index (SOI). In addition, a fecundity index (ratio of new-born pups to adult females at the median pupping date) was positively correlated with current-year Southern Annular Mode (SAM) conditions. Periods of positive SOI and positive SAM conditions are forecast to increase in coming decades, suggesting advantageous conditions for the Kanowna Island AUFS population.

The highly dynamic nature of the marine environment can have a substantial influence on the foraging behaviour and spatial distribution of marine predators, particularly in pelagic marine systems. However, knowledge of the susceptibility of benthic marine predators to environmental variability is limited. This study investigated the influence of local-scale environmental conditions and large-scale climate indices on the spatial distribution and habitat use in the benthic foraging Australian fur seal ( Arctocephalus pusillus doriferus ; AUFS). Female AUFS provisioning pups were instrumented with GPS or ARGOS platform terminal transmitter tags during the austral winters of 2001–2019 at Kanowna Island, south-eastern Australia. Individuals were most susceptible to changes in the Southern Oscillation Index that measures the strength of the El Niño Southern Oscillation, with larger foraging ranges, greater distances travelled and more dispersed movement associated with 1-yr lagged La Niña-like conditions. Additionally, the total distance travelled was negatively correlated with the current year sea surface temperature and 1-yr lagged Indian Ocean Dipole, and positively correlated with 1-yr lagged chlorophyll- a concentration. These results suggest that environmental variation may influence the spatial distribution and availability of prey, even within benthic marine systems.

Prolonged high-temperature extreme events in the ocean, marine heatwaves, can have severe and long-lasting impacts on marine ecosystems, fisheries and associated services. This study applies a marine heatwave framework to analyse a global sea surface temperature product and identify the most extreme events, based on their intensity, duration and spatial extent. Many of these events have yet to be described in terms of their physical attributes, generation mechanisms, or ecological impacts. Our synthesis identifies commonalities between marine heatwave characteristics and seasonality, links to the El Niño-Southern Oscillation, triggering processes and impacts on ocean productivity. The most intense events preferentially occur in summer, when climatological oceanic mixed layers are shallow and winds are weak, but at a time preceding climatological maximum sea surface temperatures. Most subtropical extreme marine heatwaves were triggered by persistent atmospheric high-pressure systems and anomalously weak wind speeds, associated with increased insolation, and reduced ocean heat losses. Furthermore, the most extreme events tended to coincide with reduced chlorophyll-a concentration at low and mid-latitudes. Understanding the importance of the oceanic background state, local and remote drivers and the ocean productivity response from past events are critical steps toward improving predictions of future marine heatwaves and their impacts.

Climate change poses significant emerging risks to biodiversity, ecosystem function and associated socioecological systems. Adaptation responses must be initiated in parallel with mitigation efforts, but resources are limited. As climate risks are not distributed equally across taxa, ecosystems and processes, strategic prioritization of research that addresses stakeholder-relevant knowledge gaps will accelerate effective uptake into adaptation policy and management action. After a decade of climate change adaptation research within the Australian National Climate Change Adaptation Research Facility, we synthesize the National Adaptation Research Plans for marine, terrestrial and freshwater ecosystems. We identify the key, globally relevant priorities for ongoing research relevant to informing adaptation policy and environmental management aimed at maximizing the resilience of natural ecosystems to climate change. Informed by both global literature and an extensive stakeholder consultation across all ecosystems, sectors and regions in Australia, involving thousands of participants, we suggest 18 priority research topics based on their significance, urgency, technical and economic feasibility, existing knowledge gaps and potential for cobenefits across multiple sectors. These research priorities provide a unified guide for policymakers, funding organizations and researchers to strategically direct resources, maximize stakeholder uptake of resulting knowledge and minimize the impacts of climate change on natural ecosystems. Given the pace of climate change, it is imperative that we inform and accelerate adaptation progress in all regions around the world.

Marine heatwaves (MHWs) can cause devastating impacts to marine life. Despite the serious consequences of MHWs, our understanding of their drivers is largely based on isolated case studies rather than any systematic unifying assessment. Here we provide the first global assessment under a consistent framework by combining a confidence assessment of the historical refereed literature from 1950 to February 2016, together with the analysis of MHWs determined from daily satellite sea surface temperatures from 1982–2016, to identify the important local processes, large-scale climate modes and teleconnections that are associated with MHWs regionally. Clear patterns emerge, including coherent relationships between enhanced or suppressed MHW occurrences with the dominant climate modes across most regions of the globe – an important exception being western boundary current regions where reports of MHW events are few and ocean-climate relationships are complex. These results provide a global baseline for future MHW process and prediction studies.

Marine heatwaves (MHWs) are extreme climatic events in oceanic systems that can have devastating impacts on ecosystems, causing abrupt ecological changes and socioeconomic consequences. Several prominent MHWs have attracted scientific and public interest, and recent assessments have documented global and regional increases in their frequency. However, for proactive marine management, it is critical to understand how patterns might change in the future. Here, we estimate future changes in MHWs to the end of the 21st century, as simulated by the CMIP5 global climate model projections. Significant increases in MHW intensity and count of annual MHW days are projected to accelerate, with many parts of the ocean reaching a near-permanent MHW state by the late 21st century. The two greenhouse gas (GHG) emission scenarios considered (Representative Concentration Pathway 4.5 and 8.5) strongly affect the projected intensity of MHW events, the proportion of the globe exposed to permanent MHW states, and the occurrence of the most extreme MHW events. Comparison with simulations of a natural world, without anthropogenic forcing, indicate that these trends have emerged from the expected range of natural variability within the first half of the 21st century. This discrepancy implies a degree of “anthropogenic emergence,” with a departure from the natural MHW conditions that have previously shaped marine ecosystems for centuries or even millennia. Based on these projections we expect impacts on marine ecosystems to be widespread, significant and persistent through the 21st century.

Considerable attention has been directed at understanding the consequences and impacts of long-term anthropogenic climate change. Discrete, climatically extreme events such as cyclones, floods, and heatwaves can also significantly affect regional environments and species, including humans. Climate change is expected to intensify these events and thus exacerbate their effects. Climatic extremes also occur in the ocean, and recent decades have seen many high-impact marine heatwaves (MHWs)—anomalously warm water events that may last many months and extend over thousands of square kilometers. A range of biological, economic, and political impacts have been associated with the more intense MHWs, and measuring the severity of these phenomena is becoming more important. Progress in understanding and public awareness will be facilitated by consistent description of these events. Here, we propose a detailed categorization scheme for MHWs that builds on a recently published classification, combining elements from schemes that describe atmospheric heatwaves and hurricanes. Category I, II, III, and IV MHWs are defined based on the degree to which temperatures exceed the local climatology and illustrated for 10 MHWs. While there is a long-term increase in the occurrence frequency of all MHW categories, the largest trend is a 24% increase in the area of the ocean where strong (Category II) MHWs occur. Use of this scheme can help explain why biological impacts associated with different MHWs can vary widely and provides a consistent way to compare events. We also propose a simple naming convention based on geography and year that would further enhance scientific and public awareness of these marine events.

Heatwaves are important climatic extremes in atmospheric and oceanic systems that can have devastating and long-term impacts on ecosystems, with subsequent socioeconomic consequences. Recent prominent marine heatwaves have attracted considerable scientific and public interest. Despite this, a comprehensive assessment of how these ocean temperature extremes have been changing globally is missing. Using a range of ocean temperature data including global records of daily satellite observations, daily in situ measurements and gridded monthly in situ-based data sets, we identify significant increases in marine heatwaves over the past century. We find that from 1925 to 2016, global average marine heatwave frequency and duration increased by 34% and 17%, respectively, resulting in a 54% increase in annual marine heatwave days globally. Importantly, these trends can largely be explained by increases in mean ocean temperatures, suggesting that we can expect further increases in marine heatwave days under continued global warming.

© 2017 Cambridge Philosophical Society Climate change is driving a pervasive global redistribution of the planet's species. Species redistribution poses new questions for the study of ecosystems, conservation science and human societies that require a coordinated and integrated approach. Here we review recent progress, key gaps and strategic directions in this nascent research area, emphasising emerging themes in species redistribution biology, the importance of understanding underlying drivers and the need to anticipate novel outcomes of changes in species ranges. We highlight that species redistribution has manifest implications across multiple temporal and spatial scales and from genes to ecosystems. Understanding range shifts from ecological, physiological, genetic and biogeographical perspectives is essential for informing changing paradigms in conservation science and for designing conservation strategies that incorporate changing population connectivity and advance adaptation to climate change. Species redistributions present challenges for human well-being, environmental management and sustainable development. By synthesising recent approaches, theories and tools, our review establishes an interdisciplinary foundation for the development of future research on species redistribution. Specifically, we demonstrate how ecological, conservation and social research on species redistribution can best be achieved by working across disciplinary boundaries to develop and implement solutions to climate change challenges. Future studies should therefore integrate existing and complementary scientific frameworks while incorporating social science and human-centred approaches. Finally, we emphasise that the best science will not be useful unless more scientists engage with managers, policy makers and the public to develop responsible and socially acceptable options for the global challenges arising from species redistributions.

Long‐term datasets needed to detect the impacts of global change on southern biodiversity are still scarce and often incomplete, challenging adaptation planning and conservation management. Biological data are probably most limited in arid countries and from the oceans, where natural environmental variability (‘noise’) means that long time series are required to detect the ‘signal’ of directional change. Significant national and international investment and collaboration are needed for most southern nations to reliably track biodiversity trends and improve conservation adaptation to rapid climate change. Emerging early warning systems for biodiversity, incorporating regional environmental change drivers, citizen science and regional partnerships, can all help to compensate for existing information gaps and contribute to adaptation planning.

Marine heatwaves (MHWs) have been observed around the world and are expected to increase in intensity and frequency under anthropogenic climate change. A variety of impacts have been associated with these anomalous events, including shifts in species ranges, local extinctions and economic impacts on seafood industries through declines in important fishery species and impacts on aquaculture. Extreme temperatures are increasingly seen as important influences on biological systems, yet a consistent definition of MHWs does not exist. A clear definition will facilitate retrospective comparisons between MHWs, enabling the synthesis and a mechanistic understanding of the role of MHWs in marine ecosystems. Building on research into atmospheric heatwaves, we propose both a general and specific definition for MHWs, based on a hierarchy of metrics that allow for different data sets to be used in identifying MHWs. We generally define a MHW as a prolonged discrete anomalously warm water event that can be described by its duration, intensity, rate of evolution, and spatial extent. Specifically, we consider an anomalously warm event to be a MHW if it lasts for five or more days, with temperatures warmer than the 90th percentile based on a 30-year historical baseline period. This structure provides flexibility with regard to the description of MHWs and transparency in communicating MHWs to a general audience. The use of these metrics is illustrated for three 21st century MHWs; the northern Mediterranean event in 2003, the Western Australia 'Ningaloo Niño' in 2011, and the northwest Atlantic event in 2012. We recommend a specific quantitative definition for MHWs to facilitate global comparisons and to advance our understanding of these phenomena.

Evidence is accumulating that many marine ectotherms are undergoing rapid changes in their life‐history characteristics. These changes have been variously attributed to fisheries‐induced evolution, inhibited adult growth rate due to oxygen limitation at higher temperatures, and plastic responses to density dependence or changes in ocean productivity. Here, we review the diverse underlying mechanisms by which plastic and evolutionary responses to climate change and fisheries are likely to produce similar life‐history trends in harvested marine ectotherms, leading to faster life‐histories with earlier maturation and smaller adult size‐at‐age. While mechanistically understanding these growth and maturation changes may be difficult, it is becoming clear that changing life‐histories will lead to modified population dynamics, productivity and natural mortality of the affected species. We discuss how the observed and expected life‐history changes could affect the assumptions and uncertainty within single and multispecies models currently used in marine ecosystem management, highlighting that models which allow for dynamic life‐history traits often report significantly different estimates of stock biomass. Given that both climate‐ and harvest‐induced life‐history changes are likely to intensify and possibly amplify each other, there is an urgent need to adequately assess the implications of faster life‐histories for marine ecosystem management. This is especially true for data‐poor stocks, where growth and maturation are not regularly assessed. Targeted monitoring can be used to inform responsive management, but for improved sustainability outcomes, a precautionary approach to management that is robust to life‐history trends is advised.

© 2016 The Authors. Climate change is a major threat to food security in Pacific Island countries, with declines in food production and increasing variability in food supplies already evident across the region. Such impacts have already led to observed consequences for human health, safety and economic prosperity. Enhancing the adaptive capacity of Pacific Island communities is one way to reduce vulnerability and is underpinned by the extent to which people can access, understand and use new knowledge to inform their decision-making processes. However, effective engagement of Pacific Island communities in climate adaption remains variable and is an ongoing and significant challenge. Here, we use a qualitative research approach to identify the impediments to engaging Pacific Island communities in the adaptations needed to safeguard food security. The main barriers include cultural differences between western science and cultural knowledge, a lack of trust among local communities and external scientists, inappropriate governance structures, and a lack of political and technical support. We identify the importance of adaptation science, local social networks, key actors (i.e., influential and trusted individuals), and relevant forms of knowledge exchange as being critical to overcoming these barriers. We also identify the importance of co-ordination with existing on-ground activities to effectively leverage, as opposed to duplicating, capacity.

Aim The redistribution of species with climate change is well documented. Even so, the relative contribution of species detectability to the variation in measured range shift rates among species is poorly understood. How can true range shifts be discerned from sampling artefacts? Location Australia. Methods We simulate range shifts for species which differ in their abundance for comparison to patterns derived from empirical range shift data from two regional‐scale (100s km) empirical studies. We demonstrate the use of spatial occupancy data in a distance‐to‐edge (DTE) model to assess changes in geographical range edges of fish species within a temperate reef fish community. Results Simulations identified how sampling design can produce relatively larger error in range shift estimates in less abundant species, patterns that correspond with those observed in real data. Application of the DTE model allowed us to estimate the location of the true range edge with high accuracy in common species. In addition, upper confidence bounds for range edge estimates identified species with range edges that have likely shifted in location. Conclusions Simulation and modelling approaches used to quantify the level of confidence that can be placed in observed range shifts are particularly valuable for studies of marine species, where observations are typically few and patchy. Given the observed variability in range shift estimates, the inclusion of confidence bounds on estimates of geographical range edges will advance our capacity to disentangle true distributional change from artefacts of sampling design.

The poleward flowing East Australian Current (EAC) is characterised by its separation from the coast, 100-200 nautical miles north of Sydney, to form the eastward flowing Tasman Front and a southward flowing eddy field. The separation zone greatly influences coastal ecosystems for the relatively narrow continental shelf (only 15-50. km wide), particularly between 32-34°S. In this region the continental shelf has a marked shift in the seasonal temperature-salinity relationship and elevated surface nitrate concentrations. This current parallels the portion of the coast where Australia's population is concentrated and has a long history of scientific research. However, understanding of physical and biological processes driven by the EAC, particularly in linking circulation to ecosystems, is limited. In this special issue of 16 papers on the EAC, we examine the effects of climatic wind-stress forced ocean dynamics on EAC transport variability and coastal sea level, from ENSO to multi-decadal time scales; eddy formation and structure; fine scale connectivity and larval retention. Comparisons with the poleward-flowing Leeuwin Current on Australia's west coast show differences in ecosystem productivity that can be attributed to the underlying physics in each region. On average there is double the chlorophyll a concentration on the east coast than the west. In comparison to the Leeuwin, the EAC may have less local retention of larvae and act as a partial barrier to onshore transport, which may also be related to the local spawning and early life history of small pelagic fish on each coast. Inter-annual variations in the EAC transport produce a detectable sea-level signal in Sydney Harbour, which could provide a useful fisheries index as does the Fremantle sea level and Leeuwin Current relationship. The EAC's eddy structure and formation by the EAC are examined. A particular cold-core eddy is shown to have a "tilt" towards the coast, and that during a rotation the flow of pa

Large pelagic predators move quickly in and out of local ecosystems that may be separated by long distances: their trophic effects are determined by their behaviour while present. To investigate movement and local residence times of one such predator we implanted 29 acoustic tags into juvenile southern bluefin tuna (Thunnus maccoyii) (SBT) in the Great Australian Bight. We used acoustic detectors at a reef known to attract tuna and detected fifteen SBT on 941 occasions over 62 days. SBT were tagged at the reef, 40 km, and 120 km distant. A total of 100% of local and 60% of SBT tagged 40 km away were subsequently recorded at the reef. Presence and absence was related to an upwelling event. Water temperature decreased just after SBT departure from the monitoring region. The immediate area was aerially surveyed 22 times for SBT schools during the experiment. We combined aerial survey observations with computer simulation, calibrated against field studies of SBT movement, to test the hypothesis that tuna could be well simulated by a correlated random walk throughout the area of known occurrence. The most plausible explanation for the observed behaviour was short-term (hours) fidelity to schools combined with medium-term (weeks) fidelity to bathymetric features. The present study illustrates how dynamic models aid interpretation of experiments designed to understand trophic effects of large pelagic predators.

Global oceans are experiencing not only increased levels of human exploitation, but also major changes to their physics, chemistry and biology. These alarming changes have prompted calls for new and improved conservation and management tools if the future sustainability of oceanic ecosystems is to be assured. Spatial management, although widely used in coastal and nearshore environments, is one strategy yet to be adequately considered for open ocean systems. Resistance to both investigation and implementation of this management approach stems predominantly from the perception that given the highly dynamic nature of the ocean, adequate protection of both its biological and physical componentswould require regulation of vast regions.To examine this assertion, a series of reserve networkswere modelled using the reserve design tool Marxan for an oceanic region off eastern Australia. Consideration was given to a set of biological, physical and social features. Three distinct management approaches were evaluated; fisheries priority, conservation priority, and equal fisheries-conservation priority. Reserve solution area requirements ranged from 7 to 26% of the focus area, falling within the lower end of the range of areas suggested in the published reports. This analysis suggests that percentage area requirements for oceanic protected areas should not be an impediment to further consideration

Interannual and decadal variability in ocean survival of salmon are well known, but the mechanisms through which environmental variability exerts its effects are poorly understood. Data on hatchery-reared coho salmon (Oncorhynchus kisutch) from individual releases (1973–1998) along the species’ entire North American range were analyzed to provide information on survival and size. Three geographic regions (north of Vancouver Island, Puget Sound and Strait of Georgia, and the outer coast south of the tip of Vancouver Island) showed coherent trends in survival and size of returning fish. Within each region, multivariate nonlinear models were used to relate coho survival and final size to spatially and temporally tailored environmental variables at time periods of release, jack return, and adult return. The most important environmental variable, as indicated by the highest amount of variance explained, was a calculated proxy for mixed-layer depth, followed by sea level. In all regions, survival and adult size were most influenced by environmental conditions at the release time. A shallow mixed layer was associated with increased survival and decreased size in all regions. Improved understanding of the relationship between environmental conditions and size and survival of coho salmon provides insight into production patterns in the coastal ocean.

Ecosystem models are becoming increasingly important as pressure from fisheries intensifies and ecosystem-based fisheries management becomes more widely used. Trophic webs often form the basis of ecosystem models and ecosystem-specific dietary information is crucial for optimal model performance. This is particularly the case if model predictions are used in management decisions. The Tasmanian live fish fishery for banded morwong was used as a case study to investigate the importance of trophic information, model simplification and aggregation error on ecosystem model results. Dietary analysis of 6 commonly captured reef fish was undertaken. Significant trophic overlap was found between blue throat wrasse Notolabrus tetricus and purple wrasse N. fucicola, and banded morwong Cheilodactylus spectabilis and bastard trumpeter Latridopsis forsteri. Marblefish Aplodactylus arctidens and long-snouted boarfish Pentaceropsis recurvirostris had significantly different diets from other species studied. Using this information, a detailed qualitative model was produced and then simplified through the aggregation of variables. Variables were aggregated using 3 methods: Euclidean distance, Bray-Curtis similarity, and regular equivalence for inclusion in 3 simplified models. Variable aggregation is undertaken in many studies and may create aggregation error. Each aggregation method produced a different proportion of incorrect model predictions as a result of aggregation error. The model simplified using regular equivalence produced the least aggregation error and a web structure aligned with the dietary analysis. More widespread use of these methods in fisheries management should be considered.

Australia is truly a maritime nation; over 90% of the population of 20 million live within 120 km of the coast and Australia has sovereign rights over approximately 8.1 million km2 of ocean. Australia’s oceans generate significant economic wealth; about $52 billion per year or 8% of gross domestic product through activities such as fisheries (Figure 1–1), tourism and recreation, shipping and offshore gas and petroleum extraction. Fisheries and aquaculture are important industries in Australia, both economically (gross value over $2.5 billon, Figure 1-2) and socially. Marine life and ecosystems also provide invaluable services including coastal defence, nutrient recycling and greenhouse gas regulation valued globally at $27 trillion per annum (Constanza et al. 1997).

Global oceans are experiencing not only increased levels of human exploitation, but also major changes to their physics, chemistry and biology. These alarming changes have prompted calls for new and improved conservation and management tools if the future sustainability of oceanic ecosystems is to be assured. Spatial management, although widely used in coastal and nearshore environments, is one strategy yet to be adequately considered for open ocean systems. Resistance to both investigation and implementation of this management approach stems predominantly from the perception that given the highly dynamic nature of the ocean, adequate protection of both its biological and physical componentswould require regulation of vast regions.To examine this assertion, a series of reserve networkswere modelled using the reserve design tool Marxan for an oceanic region off eastern Australia. Consideration was given to a set of biological, physical and social features. Three distinct management approaches were evaluated; fisheries priority, conservation priority, and equal fisheries-conservation priority. Reserve solution area requirements ranged from 7 to 26% of the focus area, falling within the lower end of the range of areas suggested in the published reports. This analysis suggests that percentage area requirements for oceanic protected areas should not be an impediment to further consideration

Large pelagic predators move quickly in and out of local ecosystems that may be separated by long distances: their trophic effects are determined by their behaviour while present. To investigate movement and local residence times of one such predator we implanted 29 acoustic tags into juvenile southern bluefin tuna (Thunnus maccoyii) (SBT) in the Great Australian Bight. We used acoustic detectors at a reef known to attract tuna and detected fifteen SBT on 941 occasions over 62 days. SBT were tagged at the reef, 40 km, and 120 km distant. A total of 100% of local and 60% of SBT tagged 40 km away were subsequently recorded at the reef. Presence and absence was related to an upwelling event. Water temperature decreased just after SBT departure from the monitoring region. The immediate area was aerially surveyed 22 times for SBT schools during the experiment. We combined aerial survey observations with computer simulation, calibrated against field studies of SBT movement, to test the hypothesis that tuna could be well simulated by a correlated random walk throughout the area of known occurrence. The most plausible explanation for the observed behaviour was short-term (hours) fidelity to schools combined with medium-term (weeks) fidelity to bathymetric features. The present study illustrates how dynamic models aid interpretation of experiments designed to understand trophic effects of large pelagic predators.

Ecosystem models are becoming increasingly important as pressure from fisheries intensifies and ecosystem-based fisheries management becomes more widely used. Trophic webs often form the basis of ecosystem models and ecosystem-specific dietary information is crucial for optimal model performance. This is particularly the case if model predictions are used in management decisions. The Tasmanian live fish fishery for banded morwong was used as a case study to investigate the importance of trophic information, model simplification and aggregation error on ecosystem model results. Dietary analysis of 6 commonly captured reef fish was undertaken. Significant trophic overlap was found between blue throat wrasse Notolabrus tetricus and purple wrasse N. fucicola, and banded morwong Cheilodactylus spectabilis and bastard trumpeter Latridopsis forsteri. Marblefish Aplodactylus arctidens and long-snouted boarfish Pentaceropsis recurvirostris had significantly different diets from other species studied. Using this information, a detailed qualitative model was produced and then simplified through the aggregation of variables. Variables were aggregated using 3 methods: Euclidean distance, Bray-Curtis similarity, and regular equivalence for inclusion in 3 simplified models. Variable aggregation is undertaken in many studies and may create aggregation error. Each aggregation method produced a different proportion of incorrect model predictions as a result of aggregation error. The model simplified using regular equivalence produced the least aggregation error and a web structure aligned with the dietary analysis. More widespread use of these methods in fisheries management should be considered.