Dispersive Model Research Articles

Plankton community structure in response to hydrothermal iron inputs along the Tonga-Kermadec arc

The Western Tropical South Pacific (WTSP) basin has been identified as a hotspot of atmospheric dinitrogen fixation due to the high dissolved iron ([DFe]) concentrations (up to 66 nM) in the photic layer linked with the release of shallow hydrothermal fluids along the Tonga-Kermadec arc. Yet, the effect of such hydrothermal fluids in structuring the plankton community remains poorly studied. During the TONGA cruise (November-December 2019), we collected micro- (20-200 μm) and meso-plankton (>200 μm) samples in the photic layer (0-200 m) along a west to east zonal transect crossing the Tonga volcanic arc, in particular two volcanoes associated with shallow hydrothermal vents (< 500 m) in the Lau Basin, and both sides of the arc represented by Melanesian waters and the South Pacific Gyre. Samples were analyzed by quantitative imaging (FlowCam and ZooScan) and then coupled with acoustic observations, allowing us to study the potential transfer of phytoplankton blooms to higher planktonic trophic levels. We show that micro- and meso-plankton exhibit high abundances and biomasses in the Lau Basin and, to some extent, in Melanesian waters, suggesting that shallow hydrothermal inputs sustain the planktonic food web, creating productive waters in this otherwise oligotrophic region. In terms of planktonic community structure, we identified major changes with high [DFe] inputs, promoting the development of a low diversity planktonic community dominated by diazotrophic cyanobacteria. Furthermore, in order to quantify the effect of the shallow hydrothermal vents on chlorophyll a concentrations, we used Lagrangian dispersal models. We show that chlorophyll a concentrations were significantly higher inside the Lagrangian plume, which came into contact with the two hydrothermal sites, confirming the profound impact of shallow hydrothermal vents on plankton production.

Gulls contribute to olive seed dispersal within and among islands in a Mediterranean coastal area

AbstractAimTo analyse the role of non‐frugivorous birds on seed dispersal, seed dispersal by gulls is expected to be especially instrumental in island ecosystems, as these have a smaller subset of frugivores when compared to the mainland, and because long‐distance dispersal is required for plant colonisation. Here, we investigated the seed dispersal of olives by gulls among 10 islands of the same archipelago to reveal if gulls contribute to long‐distance seed dispersal including different islands, and how gulls' adaptation to domestic olives and individual differences in foraging activities affect their seed dispersal pattern.LocationBalearic Islands in the Western Mediterranean Sea, Spain.TaxonYellow‐legged gulls (Larus michahellis), Domestic and wild Olives (Olea europaea and O. europaea var. sylvestris).MethodsWe developed seed dispersal models of the two ecotypes of olives dispersed by gulls across an archipelago, based on GPS tracking data, gut passage time and seed viability.ResultsMean dispersal distances were 7.67 (±12.48) km in wild and 12.57 (±13.08) km in domestic olives. 7.1% of wild and 8.5% of domestic olives were dispersed among islands. Among these, 8.2% of domestic seeds were transported from large to small islands where gull colonies are located, whereas wild olives were dispersed in more variable directions. Such dispersal pattern of two olive ecotypes was consistent despite the differences in dispersal distances among individuals.Main ConclusionsGulls contributed to long‐distance olive seed dispersal including different islands. The seed dispersal of domestic olives to longer distances with specific directions may facilitate colonisation and expansion of that variant if the conditions of seed deposition sites are suitable. Our findings indicate that gulls are relevant vectors for long‐distance dispersal of large fleshy fruits in island ecosystems where specialist large frugivores are absent.

Two-Dimensional Transport Dispersive Model for Separating Glycolic Acid and NaCl with Ligand Exchange Chromatography

Two-Dimensional Transport Dispersive Model for Separating Glycolic Acid and NaCl with Ligand Exchange Chromatography

Analysis of α + 16O elastic scattering in the semi-microscopical dispersive optical model

We study the elastic scattering cross sections of the α +16O system at 49.5, 69.5, and 80.7 MeV using the optical potentials calculated in the framework of the semi-microscopical dispersive optical model. In this model, the optical potential contains an energy-independent part calculated in the double folding model with a realistic effective nucleon-nucleon interaction, as well as an energy-dependent dynamic polarization potential, the parameters of which are adjusted to the data. The parameters of the real and imaginary parts of the dynamic polarization potential are connected by the dispersion relations.

Modeling spatial patterns of longleaf pine needle dispersal using long-term data

BackgroundPredicting patterns of fire behavior and effects in frequent fire forests relies on an understanding of fine-scale spatial patterns of available fuels. Leaf litter is a significant canopy-derived fine fuel in fire-maintained forests. Litter dispersal is dependent on foliage production, stand structure, and wind direction, but the relative importance of these factors is unknown.ResultsUsing a 10-year litterfall dataset collected within eighteen 4-ha longleaf pine (Pinus palustris Mill.) plots varying in canopy spatial pattern, we compared four spatially explicit models of annual needle litter dispersal: a model based only on basal area, an overstory abundance index (OAI) model, both isotropic and anisotropic litter kernel models, and a null model that assumed no spatial relationship. The best model was the anisotropic model (R2 = 0.656) that incorporated tree size, location, and prevailing wind direction, followed by the isotropic model (R2 = 0.612), basal area model (R2 = 0.488), OAI model (R2 = 0.416), and the null model (R2 = 0.08).ConclusionsAs with previous studies, the predictive capability of the litter models was robust when internally validated with a subset of the original dataset (R2 = 0.196–0.549); however, the models were less robust when challenged with an independent dataset (R2 = 0.122–0.319) from novel forest stands. Our model validation underscores the need for rigorous tests with independent, external datasets to confirm the validity of litter dispersal models. These models can be used in the application of prescribed fire to estimate fuel distribution and loading, as well as aid in the fine tuning of fire behavior models to better understand fire outcomes across a range of forest canopy structures.

Modeling wind-driven seed dispersal using a coupled Lagrangian particle tracking and 1-D [formula omitted]-[formula omitted] turbulence model

We present a one-dimensional k-ɛ model and a Markov chain stochastic Lagrangian particle tracking model to study wind-driven dispersal of forest and grassland seeds. The turbulence model within and above the canopy is implemented for transient winds so that time series of profiles of mean velocity, turbulence kinetic energy, dissipation rate, and the root-mean-square of fluctuating velocity components can be modeled. We validate the model for steady state conditions using observations in a wide range of canopies, and apply the model for predicting time series of seed dispersal of Andropogon gerardii in a tall grass prairie in Missouri, United States. The stochastic seed dispersal model is validated against experimental data from a Quercus-Carya (oak-hickory) forest where seeds were released from different heights for a range of wind speeds. Using the model, we explore the detailed seed movement trajectories, instantaneous velocities, and investigate the relationship between dispersal distance and the seed falling duration and the mean fluctuating velocity during the falling. Moreover, examining the role of individual turbulent velocity components, we elucidate the different roles of horizontal and vertical velocity fluctuations, i.e., the horizontal component mainly contributes to the seed spreading in the wind direction, while the vertical component enhances the long tail of the distribution in the downstream direction, i.e., promoting long-distance-dispersal of seeds by wind.

Analytical and numerical studies on dynamic of complexiton solution for complex nonlinear dispersive model

In this paper, we apply the basic one‐way propagator in order to introduce complex regularized long wave (RLW) equation. The complex RLW can be transformed into a system of nonlinear equations. By adopting a consequence nonlinear system, we can derive an energy conservation law of a complex regularized long wave equation. We then investigate how the Ansatz method may be applied to find a class of solitary wave solutions. Simultaneously, a numerical scheme for solving the model is implemented using a finite difference method based on the energy‐preserving Crank–Nicolson/Adams–Bashforth technique. It is worth mentioning that the obtained system is nonlinear. However, by using the present algorithm, we are able to linearize this system and solve it because of the implicit nature of the system of equations. An a priori estimate of the numerical solutions is derived to obtain a convergence and stability analysis; this yields second‐order accuracy in both time and space. Additionally, some numerical experiments verify computational efficiency. The results indicate that this method is an excellent way to preserve energy conservation, providing second‐order accuracy both in time and space with a maximum norm. In addition, we use the proposed scheme to study the effects of dispersive parameters when proceeding with an initial complex Gaussian condition.

Spatial patterns of within-stock connectivity provide novel insights for fisheries management

While concepts of connectivity are increasingly used in determining locations for marine protected areas, they are much less applied in the management of fish stocks, which are assumed to be well-mixed populations. However, due to seascape structure and often asymmetrical dispersal, the stocks of many species are unlikely to be well mixed and there is potential to enhance management by utilising emerging ecological modelling approaches that incorporate functional connectivity. Here, we apply a new model, MerMADE, that couples biophysical modelling of dispersal with spatial population demography, to predict within-stock patterns of connectivity of sandeels in the North Sea. By deriving origin- and destination-centrality measures, we highlight a set of key origin sites within the area occupied by the stock that contribute immigrants to many other sites and also identify patches that are particularly isolated, unlikely to receive immigrants from elsewhere. We show that the connectivity characteristics of the stock have a strong impact on how rapidly it recovers following a major harvesting event that leads to a patch depletion. Furthermore, the recovery of a local population will depend on the demographic status of the sites from which it can obtain immigrants. Thus, sites that provide strong out-centrality (especially if they themselves have weak in-centrality) and sites that are especially isolated should be harvested less heavily. To reduce the potential for local or regional stock collapse, models incorporating both biophysical dispersal and local demography are needed to support spatially explicit management of commercial marine species.

Optical Solitons for the Dispersive Concatenation Model

The study undertakes a comprehensive exploration of optical solitons within the context of the dispersive concatenation model, utilizing three distinct integration algorithms. These approaches, namely the enhanced Kudryashov' s method, the Riccati equation expansion approach, and the Weierstrass' expansion scheme, offer distinct perspectives and insights into the behavior of optical solitons. By employing the enhanced Kudryashov' s approach, the research uncovers a spectrum of soliton solutions, including straddled, bright, and singular optical solitons. This algorithm not only provides a nuanced understanding of the various soliton types but also highlights the occurrence of singular solitons that exhibit unique characteristics. The Riccati equation expansion approach, on the other hand, yields dark solitons in addition to singular solitons. This particular method expands our comprehension of soliton behavior by encompassing the presence of dark solitons alongside singular ones. This diversification contributes to a more comprehensive grasp of soliton phenomena. Furthermore, the application of the Weierstrass' expansion scheme extends the analysis to encompass bright, singular, and other variations of straddled solitons. This method introduces further complexity and diversity to the optical soliton. Importantly, the study meticulously addresses the parameter constraints that govern the behavior of these solitons. By providing a comprehensive presentation of these constraints, the research enhances the practical applicability of the findings, offering insights into the conditions under which these soliton solutions emerge.

Theoretical Study of Non-Isothermal Gradient Elution Liquid Chromatography.

A two-component model of gradient elution chromatography is investigated to theoretically study the effects of simultaneous variations in temperature and solvent strength on the retention behaviors of elution profiles in thermally insulated liquid chromatographic columns. The gradient elution technique is based on the gradual increase or decrease in eluent strength during the chromatographic operation by varying the composition of the mobile phase. The enthalpy of adsorption is primarily responsible for internal temperature variations inside the column, as heat adsorbs during the adsorption process and releases in the desorption phase. Both types of variations change the propagation speeds of moving pulses inside the column which can lead to better separation of the components and a reduction in the recycling time for the next injection. The equilibrium dispersive model (EDM) coupled with the energy balance equation for temperature and transport equation for the volume fraction of the solvent is utilized to simulate this complex process. The resulting nonlinear model equations are approximated by applying a semi-discrete second-order finite volume scheme. The numerical solutions are used to study the impact of a gradient starting and ending times, volume-fraction of the solvent, solvent strength parameter, the slope of gradient, enthalpy of adsorption, injection temperature, and the ratio of specific heats on the concentration profiles.

Evaluating spotted lanternfly (Hemiptera: Fulgoridae) infestation in the Northern Ohio Valley.

Lycorma delicatula White (spotted lanternfly; SLF) is an invasive pest insect threatening increased agricultural costs as it spreads rapidly westward across the United States. As such, surveying was conducted adjacent to the insect's westernmost quarantine area in 2021-2022 to support multi-state monitoring. Specifically, 2,077 visual and sticky-trap surveys were performed in 13 repeatedly surveyed plots strategically located near high-traffic roadways and rail-lines along the Ohio-West Virginia border. Sites were located in Jefferson (Ohio), Brooke (West Virginia), and Hancock (West Virginia) counties. Only one SLF was detected in 2021 (the third documented Ohio site containing SLF) in close proximity to a railway, consistent with rail-mediated dispersal trends recorded throughout the United States. Thirty-one SLF were captured in 2 Ohio sites in 2022, 30 of which were captured at the same railway site as in 2021. However, 1 of the 31 SLF was found in a plot on a university campus 1.25 km from the nearest railway, along with 10 additional specimens found in a follow-up visual survey of a neighboring woodlot. Failure to detect SLF at nearby survey plots nearer to the closest rail line and commuter parking lots suggests local unaided dispersal in a state with primarily train-mediated dispersal-mirroring trends in affected states with more established SLF populations. Data from this survey are valuable for establishing baselines and early-invasion patterns of SLF dispersal into Ohio, anticipating SLF expansion patterns in Ohio, and eventually contributing to improved SLF dispersal modeling in Ohio, the Midwest, and the United States.

Vegetative fragment production as a means of propagule dispersal for tropical seagrass meadows

Background and aimsLong distance dispersal (LDD) contributes to the replenishment and recovery of tropical seagrass habitats exposed to disturbance, such as cyclones and infrastructure development. However, our current knowledge regarding the physical attributes of seagrass fragments that influence LDD predominantly stems from temperate species and regions. The goal of this paper is to measure seagrass fragment density and viability in two tropical species, assessing various factors influencing their distribution. MethodsWe measured the density and viability of floating seagrass fragments for two tropical seagrass species (Zostera muelleri and Halodule uninervis) in two coastal seagrass meadows in the central Great Barrier Reef World Heritage Area, Australia. We assessed the effect of wind speed, wind direction, seagrass growing/senescent season, seagrass meadow density, meadow location and dugong foraging intensity on fragment density. We also measured seagrass fragment structure and fragment viability; i.e., potential to establish into a new plant. Key resultsWe found that seagrass meadow density, season, wind direction and wind speed influenced total fragment density, while season and wind speed influenced the density of viable fragments. Dugong foraging intensity did not influence fragment density. Our results indicate that wave action from winds combined with high seagrass meadow density increases seagrass fragment creation, and that more fragments are produced during the growing than the senescent season. Seagrass fragments classified as viable for Z. muelleri and H. uninervis had significantly more shoots and leaves than non-viable fragments. We collected 0.63 (±0.08 SE) floating viable fragments 100 m−2 in the growing season, and 0.13 (±0.03 SE) viable fragments 100 m−2 in the senescent season. Over a third (38%) of all fragments collected were viable. ConclusionThere is likely to be a large number of viable seagrass fragments available for long distance dispersal. This study's outputs can inform dispersal and connectivity models that are used to direct seagrass ecosystem management and conservation strategies.

Simulation calculation of electric field distribution in the rat brain irradiated by electromagnetic pulses

Based on the spectrum distribution of electromagnetic pulses (EMPs), we constructed a dispersive electromagnetic model of rats with a fine division of tissues and organs and calculated the internal electric field distribution in the rat brain exposed to EMPs. The results showed that EMP radiation was capable of generating electric field distribution with good uniformity in the rat brain and that the peak field intensity in the rat brain was about 1/250 of that in the spatial domain. The electric field in the cerebral cortex was slightly higher than that in the deep hippocampus, striatum, and thalamus, and it was probably the lowest in the hypothalamus. In the cortex, the electric field was low in the prefrontal cortex, while it was relatively high in the parietal and temporal lobes near the middle and at the back of the brain. The data provide a theoretical quantitative basis for establishment of the dose–effect relationship between the electric field in the rat brain and biological effects of the pulse. In addition, it serves as a reference for simulation calculation of the effect of EMPs in living organisms.

Evolution of plume geometry, dilution and reactive mixing in porous media under highly transient flow fields at the surface water-groundwater interface

Highly transient boundary conditions affect mixing of dissolved solutes in groundwater. An example of these transient boundary conditions occurs at the surface water-groundwater interface, where the water level in rivers can change rapidly due to the operation of hydropower plants, leading to a regime known as hydropeaking. Inspired by this phenomenon, this work studies at laboratory scale the effects of fluctuating surface water bodies on solute transport in aquifers. We performed flow-through experiments at two different flow velocities and under steady and transient flow conditions where a conservative tracer was injected in the system and its concentration measured with optical imaging methods. The experimental results were quantitatively interpreted with numerical simulations implementing a non-linear velocity-dependent dispersive transport model. We estimated plume dilution by computing the dilution index and its evolution as well as two key geometrical metrics of the transient plumes: the perimeter and the area. We further investigated reactive mixing and mixing enhancement considering mixing-controlled bimolecular reactions using different critical mixing ratios. In general, highly transient boundary conditions lead to a larger area, perimeter and plume dilution and the results show greater relative enhancement for the scenarios with low groundwater flow velocity. A linear relationship was observed between the evolution of the area and the dilution index of the plumes for the transient flow scenarios investigated. Considering reactive transport and mixing-limited reactions at the surface water-groundwater interface, we identified different dilution and reaction dominated regimes, characterized, respectively, by increasing and decreasing plume entropies at different mixing ratios of the reactants. Furthermore, reactive mixing was enhanced by transient flows leading to a faster degradation of contaminant plumes compared to corresponding steady flow conditions.

Connectivity-based approach to guide conservation and restoration of seagrass Posidonia oceanica in the NW Mediterranean

Marine population connectivity involves organism movement and interactions in oceanic and coastal settings. It is essential for biodiversity by aiding genetic diversity, species distribution, and recovery from disturbances. It guides resource management strategies like fisheries and conservation planning, ensuring marine ecosystem sustainability. Seagrass meadows play a pivotal role within coastal ecosystems, contributing to essential ecological, physical, and economic functions. Despite the presence of protective policies, a continuous decline of seagrass meadows has been observed in recent years due to the impact of human activities and climate change. In the Balearic Islands of the Mediterranean Sea, these pressures are further intensified by tourism, underlining the pressing requirement to prioritize areas for protection and restoration while considering the connectivity between habitat patches. In this study, the dispersal of Posidonia oceanica, the most widespread seagrass species in the Mediterranean Sea, from semi-enclosed bays and nearshore locations within the Balearic Islands archipelago, is investigated using a high-resolution hydrodynamic model and an individual-based model. The simulations were subjected to analysis through a graph-theoretic approach, revealing significant variations in dispersal probabilities across different years. Notably, Alcudia Bay emerged as a prominent sink, while critical links were identified between Menorca and Mallorca, as well as between Mallorca and Ibiza. This study underscores the value of dispersal modelling and network analysis in conservation planning for foundational species, particularly within a regional, integrated framework of conservation management.

Asymptotic profiles of a nonlocal dispersal SIS epidemic model with Neumann boundary condition

This article studies a nonlocal dispersal susceptible-infected-susceptible (SIS) epidemic model with Neumann boundary condition in spatially heterogeneous environment, where the spatial movement of individuals is described by dσm∫ΩJσ(x−y)[u(y)−u(x)]dy,σ is the scaling of the size of the support of dispersal kernel J, and m represents the cost parameter. We firstly derive the basic reproduction number R0 for this model, and show that 1−R0 has the same sign as the generalised principal eigenvalue of a linear nonlocal operator. We also investigate asymptotic profiles of R0 with respect to σ,m and diffusion rates. Next, the existence and uniqueness of endemic equilibrium state of this model is obtained as R0>1. Finally, we consider the impact of small dispersal spread on the persistence criteria for disease. Particularly, our results illustrate that, even though ∫Ωβ(x)dx>∫Ωγ(x)dx, there exists the possibility of disease control only when m∈[0,2)andσ→0+.

Gulf of Mexico larval dispersal: Combining concurrent sampling, behavioral, and hydrodynamic data to inform end-to-end modeling efforts through a Lagrangian dispersal model

We developed a Lagrangian larval dispersal model to estimate trajectories for eleven fish taxa inhabiting the Gulf of Mexico (GOM). Dispersal models are at family level resolution for Scaridae, Lutjanidae, Scombridae, Labridae, Ophichthidae, and Ophidiidae, at genus level resolution for Hemanthias, and at species level resolution for Trachurus lathami, Decapterus punctatus, Katsuwonus pelamis, and Euthynnus alleteratus. Hydrodynamics are provided by the West Florida Coastal Ocean Model (WFCOM). Larval samples are from the spring and fall SEAMAP ichthyoplankton surveys from 2007 to 2011. The Lagrangian model was run backwards/forwards in time from the sampling event to estimate spawning/settlement locations. Results were used to update larval dispersal dynamics in the GOM Atlantis ‘end-to-end’ ecosystem model for twelve functional groups. We compare dispersal and non-dispersal scenarios in the Gulf of Mexico Atlantis model and find differences in stock abundance and distribution of fish. This highlights that the abundance and distribution of fishery resources are sensitive to changing circulation patterns. This work takes an interdisciplinary approach to understanding larval dynamics and their impacts on ecosystems at the intersection of predictive statistical modeling, hydrodynamic modeling, and ecosystem modeling.

Modeling of breakthrough curves in removal of Cr(VI) and methylene blue using immobilized activated carbon from natural rubber waste

The activated carbon fines, derived from rubber sludge, were effectively immobilized inside calcium alginate beads to remove Cr(VI) ions and methylene blue (MB) in a fixed bed reactor after characterization of beads (FTIR, FESEM-EDS, BET, and thermogravimetric analysis) and batch study. The Langmuir batch uptake capacity was 136.45 and 324.87 mg g−1 for Cr(VI) and MB, respectively, at 30 °C. Contrary to the usual interpretation, it was shown that fitting of PFO model to experimental batch kinetic data may result from diffusive mechanism. Conventional practice of comparison of Bohart-Adams, Thomas, and Yoon-Nelson model being erroneous, these models were replaced by a generic function to explain breakthrough (BTC) curves. The equilibrium dispersive model (axial dispersion coefficient: 0.35 × 10−4 - 2.90 × 10−4 m2 min−1) predicted BTC for intermediate flow rates (5–15 mL min−1) and inlet concentrations (5–15 mg L−1) better than the one based on adsorption kinetics.

Lowest accreting protoplanetary discs consistent with X-ray photoevaporation driving their final dispersal

ABSTRACT Photoevaporation from high-energy stellar radiation has been thought to drive the dispersal of protoplanetary discs. Different theoretical models have been proposed, but their predictions diverge in terms of the rate and modality at which discs lose their mass, with significant implications for the formation and evolution of planets. In this paper, we use disc population synthesis models to interpret recent observations of the lowest accreting protoplanetary discs, comparing predictions from EUV-driven, FUV-driven, and X-ray-driven photoevaporation models. We show that the recent observational data of stars with low accretion rates (low accretors) point to X-ray photoevaporation as the preferred mechanism driving the final stages of protoplanetary disc dispersal. We also show that the distribution of accretion rates predicted by the X-ray photoevaporation model is consistent with observations, while other dispersal models tested here are clearly ruled out.

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

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