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Cu samples were irradiated with 10 MeV Au3+ ions at 200 °C to damage levels of 5, 10, and 15 displacements per atom (dpa) as an analogue to study long term self-irradiation effects of alpha-decay in Pu. Samples were then subject to accelerated aging at 350 °C for 1 h in air resulting in mixed oxide layer growth (Cu2O and CuO). Raman spectroscopy revealed that the CuO phase fraction was gradually decreased as the damage level increased. These findings indicate that accumulated damage from self-irradiation causes quantifiable modifications in metal oxidation that could serve as a novel forensic signature.

Biogenic structures that persist post‐mortem are ubiquitous, but rarely considered as key ecological features. Post‐mortem structures in many ecological systems exert community‐level effects and thus the dynamics of their degradation (i.e. taphonomy) become important in affecting community functions and ecosystem services, and these often‐overlooked effects may rival the influence of recruitment and typical post‐recruitment processes. Moreover, in some highly researched habitat types, post‐mortem structures may be mistaken for living organisms, thus introducing significant error into our understanding of population processes. We examined widespread patterns and processes in marine assemblages with calcareous tubeworms and brackish‐water assemblages with bryozoans, in order to test the importance of taphonomy for populations and communities. In tubeworm assemblages, taphonomic variability caused differential accumulation of post‐mortem structures, exerting community‐level influence, and importantly it negated effects from recruitment on the community functions. For tubeworms and bryozoans, proportions of post‐mortem structures varied between sheltered and exposed habitats with overall distributional variability being caused by the share of post‐mortem structures, not living animals. Population‐level inferences in such systems would be extremely problematic without careful differentiation of dead/living structures. Dynamics emerging from the interaction of taphonomic processes and recruitment ecology are relevant for many other important biogenic habitats, especially coral reefs with death assemblages of bleached corals; a failure to consider variability in processes acting on the death assemblages, alongside the living, may severely distort understanding of patterns and processes in populations and communities.

This study describes diet and feeding habits of two common bycatch elasmobranchs in East Australia: The Eastern Fiddler Ray Trygonorrhina fasciata (Muller & Henle, 1841) and the Sydney Skate Dentiraja australis (Macleay, 1884). Using stomach content analysis, we describe diet composition, food preferences and trophic levels of these batoids. Crustaceans were major components in the diet of both species which included teleosts and cephalopods. There was no indication of sex-related distinction in the diet of either species. The estimated trophic level (TL) of the T. fasciata was TL = 3.36 and the D. australis was TL = 3.43.

AIM: Climate change is redistributing species globally, resulting in altered community structures and ecosystem functioning. The current paradigm is that species should track temperature isoclines along latitudinal and depth gradients to remain within their thermal niches. However, the many exceptions to this rule point to complex ecological and environmental processes often overlooked in statistical models predicting species redistributions. We tested the contributions of natural versus anthropogenic climate change to the long‐term spatio‐temporal dynamics of assemblages of range‐shifting tropical fishes at the leading edge of redistribution fronts. LOCATION: East coast of Australia. TAXON: Tropical coral‐reef fishes. METHODS: We analysed 16 years (2003–2018) of tropical species occurrences at two temperate locations using traditional diversity metrics (richness, accumulation curves and β‐diversity). We also quantified the role of primary environmental covariates and estimated species associations using joint species distribution models. RESULTS: We reveal that tropical species richness has increased in this temperate ecosystem over time. Furthermore, we show that the richness of tropical vagrant species increased with the sea‐surface temperature experienced by both local vagrants and their putative source populations at the southern Great Barrier Reef, which accounted for 23.1% and 22.1% of the explained variance, respectively. We also detected a signal from El Nino‐Southern Oscillation, as species turnover and richness peaked during the strong La Nina event of 2010–2011. MAIN CONCLUSIONS: While the increases in ocean temperature and strength of the surface ocean current due to anthropogenic climate change are gradually favouring the poleward redistribution of tropical species, natural climatic oscillations can have a strong additive effect by rapidly modifying the pool of incoming species and potentially disrupting local communities.

Effective conservation planning requires biotic data across an entire region. In data-poor ecosystems conservation planning is informed by using environmental surrogates (e.g. temperature) predominantly in two ways: to develop habitat classification schemes (1) or develop species distribution models (2). We test the utility of both approaches for conservation planning of marine ecosystems, and rank environmental surrogates, such as depth and distance from shore, according to their power to predict the distribution and abundance of biotic species. Specifically, we compared a habitat classification scheme; based on coarse levels of habitat types derived from depth and distance from shore; against species distribution models, which predict fish abundance and prevalence as a function of environmental surrogates (depth, distance from shore, latitude, reef area, zoning, and several metrics of habitat structural complexity). We consistently set conservation target levels to 21% of each conservation feature, following global standards and a sensitivity analyses. Thus when running scenarios to protect fish species we aimed to protect at least 21% of each species, and when running scenarios of habitat classes, we aimed to protect at least 21% of each habitat class. We found that when aiming to protect 21% of the chosen conservation targets, distribution models protected 21% of the predicted abundance/occurrence of all modelled species and functional groups, but did not protect most habitats. Contrastingly, using a habitat classification scheme protected 21% of all habitat types and 34% of all species and functional groups, but required protecting three times more area. Thus, using only distribution models as targets in data-poor ecosystems could be a risky conservation planning strategy. Ultimately the best conservation outcomes were achieved by incorporating local knowledge to synthesize the conservation outcomes of both scenarios.

Rubble islands are dynamic sedimentary features present on reef platforms that evolve under a variety of morphodynamic processes and controlling mechanisms. They provide valuable inhabitable land for small island nations, critical habitat for numerous species, and are threatened by climate change. Aiming to investigate the controlling mechanisms dictating the evolution of One Tree Island (OTI), a rubble island in the Southern Great Barrier Reef, we combined different remotely-sensed data across varying timescales with wave data extracted from satellite altimetry and cyclone activity. Our findings show that (1) OTI had expanded by 7% between 1978 and 2019, (2) significant gross planform decadal adjustments were governed by the amount, intensity, proximity, and relative position of cyclones as well as El Niño Southern Oscillation (ENSO) phases, and (3) the mechanisms of island growth involve rubble spits delivering and redistributing rubble to the island through alongshore sediment transport and wave overtopping. Frequent short-term monitoring of the island and further research coupling variations in the different factors driving island change (i.e., sediment availability, reef-wave interactions, and extreme events) are needed to shed light on the future trajectory of OTI and other rubble islands under a climate change scenario.

Interactions among selection, gene flow, and drift affect the trajectory of adaptive evolution. In natural populations, the direction and magnitude of these processes can be variable across different spatial, temporal, or ontogenetic scales. Consequently, variability in evolutionary processes affects the predictability or stochasticity of microevolutionary outcomes. We studied an intertidal fish, Bathygobius cocosensis (Bleeker, 1854), to understand how space, time, and life stage structure genetic and phenotypic variation in a species with potentially extensive dispersal and a complex life cycle (larval dispersal preceding benthic recruitment). We sampled juvenile and adult life stages, at three sites, over three years. Genome-wide SNPs uncovered a pattern of chaotic genetic patchiness, that is, weak-but-significant patchy spatial genetic structure that was variable through time and between life stages. Outlier locus analyses suggested that targets of spatially divergent selection were mostly temporally variable, though a significant number of spatial outlier loci were shared between life stages. Head shape, a putatively ecologically responsive (adaptive) phenotype in B. cocosensis also exhibited high temporal variability within sites. However, consistent spatial relationships between sites indicated that environmental similarities among sites may generate predictable phenotype distributions across space. Our study highlights the complex microevolutionary dynamics of marine systems, where consideration of multiple ecological dimensions can reveal both predictable and stochastic patterns in the distributions of genetic and phenotypic variation. Such considerations probably apply to species that possess short, complex life cycles, have large dispersal potential and fecundities, and that inhabit heterogeneous environments.

Climate change is altering the latitudinal distributions of species, with their capacity to keep pace with a shifting climate depending on the stochastic expression of population growth rates, and the influence of compensatory density feedback on age‐specific survival rates. We use population‐abundance time series at the leading edge of an expanding species’ range to quantify the contribution of stochastic environmental drivers and density feedbacks to the dynamics of life stage‐specific population growth. 2. Using a tropical, range‐shifting Indo‐Pacific damselfish (Abudefduf vaigiensis) as a model organism, we applied variants of the phenomenological Gompertz‐logistic model to a 14‐year dataset to quantify the relative importance of density feedback and stochastic environmental drivers on the separate and aggregated population growth rates of settler and juvenile life stages. 3. The top‐ranked models indicated that density feedback negatively affected the growth of tropical settlers and juveniles. Rates of settlement were negatively linked to temperatures experienced by parents at potential source populations in the tropics, but their subsequent survival and that of juveniles increased with the temperatures experienced at the temperate sink. Including these stochastic effects doubled the deviance explained by the models, corroborating an important role of temperature. By incorporating sea‐surface temperature projections for the remainder of this century into these models, we anticipate improved conditions for the population growth of juvenile coral‐reef fishes, but not for settlers in temperate ecosystems. 4. Previous research has highlighted the association between temperature and the redistribution of species. Our analyses reveal the contrasting roles of different life stages in the dynamics of range‐shifting species responding to climate change, as they transition from vagrancy to residency in their novel ranges.

Increasingly, urbanised coastlines are being armoured by shoreline protection structures, such as seawalls. Seawalls typically lack the complex microhabitats and protective spaces of natural shorelines and consequently organisms that settle on them may be particularly susceptible to predation. We tested whether the addition of complex microhabitats to seawalls enhances the survivorship of oysters, key habitat-forming species on intertidal shores, by reducing the intensity of predation. At two sites in Sydney Harbour, we compared the magnitude and sources of mortality of juvenile oysters among (1) flat tiles, without crevices or ridges; (2) complex tiles, with 2.5 cm high ridges, separated by crevices; and (3) complex tiles, with 5 cm high ridges, separated by crevices. We also compared predatory fish visitation and feeding among sites and treatments using GoPro® cameras. The abundance and feeding of predatory fish was much greater at one of the study sites than the other, but at neither site differed among treatments. At the site with greater predatory fish abundances, survivorship of juvenile oysters was 50% greater on the 5 cm complex tiles than flat tiles, and on complex tiles approximately 300% greater in crevices than on ridges. Of the dead oysters, almost all were cracked, indicative of fish predation. In contrast, at the site with fewer predatory fish, there were no detectable differences in oyster survivorship between treatments. These results suggest that the addition of complex habitat to seawalls could be an effective strategy in reducing fish predation pressure on juvenile oysters at sites with abundant predatory fish. A greater understanding of the site-specific pressures is required to enhance the abundances of desirable species and functions on seawalls.

Adequately sampling benthic cover in marine ecosystems is a challenge with most methods encompassing only a small portion of the area for which cover is estimated. Recent advances in photogrammetric techniques are providing opportunity to map expansive areas of reef. This study aimed to evaluate the adequate level of sampling for traditional quadrat-based designs at ecologically relevant scales. We used large-area (~250 m2), high-resolution (0.911 ± 0.143 mm/pixel) mosaics to assess the precision and reproducibility of quadrat-based benthic sampling and identify the most efficient strategy (size and number of quadrats). There was a strong relationship between the percent cover of benthic classes and the level of sampling effort required to adequately sample them. As expected, larger quadrats were found to be more efficient when sampling effort was expressed in number of quadrats. This study aims to identify the optimal level of sampling (least effort that would result in a given target precision) to characterize coral reef benthic communities (whatever they are) within each site. As such, the sites selected were intentionally very different and together represented the broad scale of heterogeneity found in shallow coral reef communities. Abundance data can be used in combination with the relationships presented here to determine the optimal sampling protocols for management approaches to coral reef monitoring.

Complex life cycles may evolve to dissociate distinct developmental phases in an organism's lifetime. However, genetic or environmental factors may restrict trait independence across life stages, constraining ontogenetic trajectories. Quantifying covariance across life stages and their temporal variability is fundamental in understanding life-history phenotypes and potential distributions and consequences for selection. We studied developmental constraints in an intertidal fish (Bathygobius cocosensis: Gobiidae) with a discrete pelagic larval phase and benthic juvenile phase. We tested whether traits occurring earlier in life affected those expressed later, and whether larval traits were decoupled from postsettlement juvenile traits. Sampling distinct cohorts from three annual breeding seasons afforded tests of temporally variability in trait covariance. From otoliths (fish ear stones), we measured hatch size, larval duration, pelagic growth (larval traits) and early postsettlement growth (juvenile trait) in 124 juvenile B. cocoensis. We used path analyses to model trait relationships with respect to their chronological expression, comparing models among seasons. We also modelled the effect of season and hatch date on each individual trait to quantify their inherent variability. Our path analyses demonstrated a decoupling of larval traits on juvenile growth. Within the larval phase, longer larval durations resulted in greater pelagic growth, and larger size-at-settlement. There was also evidence that larger hatch size might reduce larval durations, but this effect was only marginally significant. Although pelagic and postsettlement growth were decoupled, pelagic growth had postsettlement consequences: individuals with high pelagic growth were among the largest fish at settlement, and remained among the largest early postsettlement. We observed no evidence that trait relationships varied among breeding seasons, but larval duration differed among breeding seasons, and was shorter for larvae hatching later within each season. Overall, we demonstrate mixed support for the expectation that traits in different life stages are independent. While postsettlement growth was decoupled from larval traits, pelagic development had consequences for the size of newly settled juveniles. Temporal consistency in trait covariances implies that genetic and/or environmental factors influencing them were stable over our three-year study. Our work highlights the importance of individual developmental experiences and temporal variability in understanding population distributions of life-history traits.

Marine Protected Areas (MPAs) are a key management tool for the conservation of biodiversity and restoration of marine communities. While large, well-designed and enforced MPAs have been found to be effective, results from small MPAs vary. The Hawkesbury Shelf, a coastal bioregion in New South Wales, Australia, has ten small, near-shore MPAs known as Aquatic Reserves with a variety of protection levels from full no-take to partial protection. This study assessed the effectiveness of these MPAs and analysed how MPA age, size, protection level, wave exposure, habitat complexity, and large canopy-forming algal cover affected fish, invertebrate and benthic communities. We found aspect, protection level, complexity and algal canopy to be important predictors of communities in these MPAs. Most MPAs, however, were not effective in meeting their goals. Only full no-take protection (three out of ten MPAs) had a significant impact on fish assemblages. One no-take MPA—Cabbage Tree Bay—which is naturally sheltered from wave action and benefits from an active local community providing informal enforcement, accounted for most of the increased richness of large fish and increased biomass of targeted fish species. Our findings suggest that small MPAs can enhance biodiversity and biomass on a local scale but only if they have full no-take protection, are in sheltered locations with complex habitat, and have positive community involvement to engender support and stewardship. These results provide a baseline for robust assessment of the effectiveness of small MPAs and inform future management decisions and small MPA design in other locations.

Habitat structural complexity influences biotic diversity and abundance, but its influence on marine ecosystems has not been widely addressed. Recent advances in computer vision and robotics allow quantification of structural complexity at higher-resolutions than previously achieved. This provides an important opportunity to determine the ecological role of habitat structural complexity in marine ecosystems. We used high-resolution three-dimensional (3D) maps to test multiple structural complexity metrics, depth and benthic biota as surrogates of fish assemblages across hundreds of meters on subtropical reefs. Non-parametric multivariate statistics were used to determine the relationship between these surrogates and the entire fish assemblage. Fish were divided into functional groups, which were used to further investigate the relationship between surrogates and fish abundance using generalized linear models. Fish community composition and abundance were strongly related to habitat complexity metrics, benthic biota and depth. Surface rugosity and its variance had a significant positive influence on the abundance of piscivores and sediment infauna predators, and a negative effect on the abundance of predators, herbivores, planktivores and cleaners. Final models for fish functional groups explained up to 68% of the variance. The best metrics to explain the variance in fish abundance were benthic biota (25 7.5% of variance explained, mean  SE) and complexity metrics (16 6.6%, mean  SE). Our results show that high-resolution 3D maps and derived metrics can predict a large percentage of variance in fish abundance and potentially serve as useful surrogates of fish abundance across all functional groups in spatially dynamic reefs.

The United States of America, as most other countries, emphasizes commercial fisheries when reporting statistics to the Food and Agriculture Organization of the United Nations (FAO), and excludes data from other sectors, such as recreational fisheries. Our study is a first attempt to account comprehensively for all sources of total U.S. marine catches from the Exclusive Economic Zone waters along the West Coast of the continental USA from 1950 to 2017 in one dataset, i.e., excluding the states of Alaska and Hawaii. Total reconstructed catches for 1950–2017 were 1.2 times higher than the data reported by the USA to the FAO. Commercial landings dominated catches, with 65% from large-scale, industrial fisheries and 31% from small-scale, commercial fisheries. Recreational fisheries accounted for 4% of the total catch, after accounting for post-release mortality. Total catches were highest in 1950 at around 750,000 t and declined to 570,000 t by 2017. Internationally unreported discards increased from 24,000 t in 1950 to 86,000 t in 1989, but declined after the introduction of bycatch reduction devices to around 10,000 t year−1 by the mid-2010s. Total catches by taxonomic category suggest a decline in the diversity in catches. Levels of reporting for total catches is excellent for recent decades, with around 95% of total catches accounted for by the mid-2010s, but around 40% of catches were missing from data reported to the FAO between the late 1960s and early 1990s. This discrepancy was largely driven by industrial catches of North Pacific hake (Merluccius productus) that were not in the officially reported data. Our results suggest that recreational fisheries and discards can make up a considerable component of total catches over time. We suggest that the USA include their recreational catch estimates in their annual data submission to the FAO, retroactively to 1950.

Natasha Hardy, Tina Berry, Brendan P. Kelaher, Simon D. Goldsworthy, Michael Bunce, Melinda A. Coleman, Bronwyn M. Gillanders, Sean D. Connell, Michelle Blewitt, Will Figueira

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. The effect of temperature on predator–prey dynamics has the potential to be an important factor regulating ecological interactions and is becoming increasingly common due to climate-change-driven range shifts and species introductions. Here, we use mesocosm experiments to evaluate the thermal sensitivity of burst swimming (a proxy for prey escape ability) and mortality rates of cohorts of introduced tropical and resident temperate marine fishes in the presence of a local temperate predator. Increasing temperature (17–21–25 °C) resulted in a reduction in predation rates (by Hypoplectrodes maccullochi, family Serranidae) on the tropical prey species (Abudefduf vaigiensis, family Pomacentridae) which were more warm adapted, whereas predation rates on the temperate prey species (Atypichthys strigatus, family Kyphosidae) remained unchanged over the 17–21 °C range (25 °C not tested). These changes were linearly related to predator–prey burst swimming ratios, which decreased with increasing temperature for the tropical prey but remained largely unchanged for the temperate prey. By demonstrating the temperature sensitivity of predator–prey interactions, our work highlights the importance of linking physiology with ecology to understand the consequences of climate-driven range shifts and species introductions.

Scleractinian corals often exhibit high levels of morphological plasticity, which is potentially important in enabling individual species to occupy benthic spaces across a wide range of environmental gradients. This study tested for differences in the three-dimensional (3D) geometry of three branching corals, Acropora nasuta, Pocillopora spp. and Stylophora pistillata among inner-, mid- and outer-shelf reefs in the central Great Barrier Reef, Australia. Important attributes of coral morphology (e.g., surface area to volume ratio) were expected to vary linearly across the shelf in accordance with marked gradients in environmental conditions, but instead, we detected non-linear trends in the colony structure of A. nasuta and Pocillopora spp. The surface area to volume ratio of both A. nasuta and Pocillopora spp. was highest at mid-shelf locations, (reflecting higher colony complexity) and was significantly lower at both inner-shelf and outer-shelf reefs. The branching structure of these corals was also far more tightly packed at inner-shelf and outer-shelf reefs, compared to mid-shelf reefs. Apparent declines in complexity and inter-branch spacing at inner and outer-shelf reefs (compared to conspecifics from mid-shelf reefs) may reflect changes driven by gradients of sedimentation and hydrodynamics. The generality and explanations of observed patterns warrant further investigation, which is very feasible using the 3D-photogrammetry techniques used in this study.

Successful marine management relies on understanding patterns of human use. However, obtaining data can be difficult and expensive given the widespread and variable nature of activities conducted. Remote camera systems are increasingly used to overcome cost limitations of conventional labour‐intensive methods. Still, most systems face trade‐offs between the spatial extent and resolution over which data are obtained, limiting their application. We trialed a novel methodology, CSIRO Ruggedized Autonomous Gigapixel System (CRAGS), for time series of high‐resolution photo‐mosaic (HRPM) imagery to estimate fine‐scale metrics of human activity at an artificial reef located 1.3 km from shore. We compared estimates obtained using the novel system to those produced with a web camera that concurrently monitored the site. We evaluated the effect of day type (weekday/weekend) and time of day on each of the systems and compared to estimates obtained from binocular observations. In general, both systems delivered similar estimates for the number of boats observed and to those obtained by binocular counts; these results were also unaffected by the type of day (weekend vs. weekday). CRAGS was able to determine additional information about the user type and party size that was not possible with the lower resolution webcam system. However, there was an effect of time of day as CRAGS suffered from poor image quality in early morning conditions as a result of fixed camera settings. Our field study provides proof of concept of use of this new cost‐effective monitoring tool for the remote collection of high‐resolution large‐extent data on patterns of human use at high temporal frequency.

Habitat structural complexity is a key factor shaping marine communities. However, accurate methods for quantifying structural complexity underwater are currently lacking. Loss of structural complexity is linked to ecosystem declines in biodiversity and resilience. We developed new methods using underwater stereo-imagery spanning 4 years (2010-2013) to reconstruct 3D models of coral reef areas and quantified both structural complexity at two spatial resolutions (2.5 and 25 cm) and benthic community composition to characterize changes after an unprecedented thermal anomaly on the west coast of Australia in 2011. Structural complexity increased at both resolutions in quadrats (4 m(2)) that bleached, but not those that did not bleach. Changes in complexity were driven by species-specific responses to warming, highlighting the importance of identifying small-scale dynamics to disentangle ecological responses to disturbance. We demonstrate an effective, repeatable method for quantifying the relationship among community composition, structural complexity and ocean warming, improving predictions of the response of marine ecosystems to environmental change.

In this work Hf–C–N coatings were deposited on silicon substrates by reactive R.F. magnetron co-sputtering from two hafnium and carbon targets in a reactive nitrogen atmosphere at various negative bias voltages from 0 to 150 V. The effect of the bias voltage on the chemical composition, crystalline structure and mechanical properties was studied by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD) and nanoindentation. The results show that the obtained films have a Hf /( C + N ) ratio of around 1 and present an evolution with the bias voltage from a quasi-amorphous structure, with a low hardness (6 GPa) to crystalline Hf 2 CN films with a high hardness (23 GPa) and electrical resistivity values in the order of 10 4 Ω·cm − 1 . This study shows the potential for hard and electrically conductive Hf–C–N films in industrial applications.

Habitat structural complexity is a key determinant of the distribution of marine biota. It mediates several abiotic and biotic processes and provides resources including shelter from prey and water current and a surface for attachment and growth. Recent studies based on remote sensing have examined the influence of various measures of complexity on a range of marine biota, though until now there has been no attempt to review and synthesise the findings. This review and meta-analysis of 51 studies developed a standardised rank-based scoring metric (Rs1-10) that enabled meaningful comparisons of the influence of various measures of complexity and other predictors across these disparate studies. While measures of terrain variability and morphology were important, often in site- and species-specific circumstances, other predictors, including derivatives of hydroacoustic backscatter, abiotic and biotic habitat descriptors, and relative geographic location often outperformed measures of complexity. Of note, Rs1-10 identified surface rugosity, one of the most well-known, utilised and conceptualised measures of complexity, to be of the poorest performing predictors. Explanations for the generally poor performance of measures of complexity included the ability of other predictors to act as broad surrogates of other structuring environmental gradients, the ecological relevance of measures, and whether they capture complexity too broad or specific for the target organism, in addition to the potentially confounding role of spatial extent and resolution. Having been identified, such considerations provide opportunities for improved design and implementation of the next generation of remote sensing studies with improved potential for the conservation of biodiversity and management of marine resources. In particular, those based on photogrammetry, which can capture high resolution 3D models of the seafloor over extents far greater than that achievable using in-situ diver methods.

Temperature fluctuations have caused considerable biological and ecological impacts on marine organisms and their communities. For example, increased temperatures in sub-tropical environments have led to the influx of tropical “vagrant” marine species into cooler temperate waters in a phenomenon called ‘tropicalisation’. Here we combine metabolic performance metrics, feeding manipulations and nutritional geometry models to examine the influence of temperature on macronutrient selection (energy amounts of protein, lipid and carbohydrates) in the Indo-Pacific damselfish Abudefduf vaigiensis and explore the role of temperature and macronutrient intake on individual performance (active and routine metabolic rate, and burst swim speed). Indo-pacific damselfish fed non-randomly from presented food blocks, showing selection for their macronutrient intake. In our high-temperature treatment we observed a significant increase in the intake of protein and lipid, but not carbohydrate. The fish in our low-temperature treatment had a significantly higher active metabolic rate and burst swim speed compared to our high-temperature treatment. Our findings provide evidence that the vagrant Indo-Pacific Damselfish in Sydney are able to select specific macronutrients in their diets ameliorating the effects on performance when thermally stressed. This work also suggests some underlying level of acclimation to or selection for colder water temperatures in these relatively recently recruited fish. Further studies should benefit from the approach proposed here, to better understand the ecological and evolutionary drivers that influence the survival of tropical species in marginal thermal habitats.

Anthropogenic structures are increasingly common in natural environments and present novel habitats for resident organisms. Marine breakwalls are similar to natural reefs in that they also provide habitat for diverse assemblages of mobile animals. However, it is unclear if fish assemblages on these artificial structures differ from those on neighbouring natural reefs in ecologically important ways. In this study, we compared fish assemblages at breakwalls and natural reefs in three different regions along 530 km of the East Australian coast. We found that fish assemblages associated with breakwalls were more diverse than those associated with natural reefs in two of the three regions studied. The functional niches being filled were similar at both habitats, with the exception of a higher abundance of piscivores at some breakwalls. However, β diversity tended low on the homogenous breakwalls compared to more heterogeneous natural reefs and was significantly lower at one region. The habitat heterogeneity model suggests that structural alterations to the layout of infrastructure could contribute to improving their ecological effects, potentially increasing β diversity.

© 2018 Booth, Beretta, Brown and Figueira. An 18-year database of coral reef fish expatriation poleward in South East Australia was used to estimate persistence of coal reef fish recruits on temperate reefs. Surveys have identified over 150 coral reef fish species recruiting to temperate reefs at latitudes of 34°S (Sydney) and 60 species to 37°S (Merimbula) with 20 and 5 species respectively overwintering in at least 1 year over the study duration. We developed indices of vulnerability of key species to drops in water temperatures, by relating drops in abundances of species to temperature drops. Twenty species were ranked according to their temperature vulnerability. Overall, the families Chaetodontidae (butterflyfishes), Acanthuridae (surgeonfishes), Labridae (wrasses) and Pomacetnridae (damselfishes) had similar cold-water tolerance. However, there was considerable variability within families, for instance in the Pomacentridae, species from the genus Abudefduf appeared to have better cold-temperature tolerance than the other species. Predicted minimum overwintering temperature varied from 15.6°C to 19.8°C, with some species showing lower Tzero at Merimbula, the more poleward location. There was general concordance between a species' tolerance to cold-water and its tendency to occur as an overwinter but also notable exceptions. So while this work demonstrates the potential utility of tolerance to seasonal temperature drops as a means to predict range expansion capacity of vagrant species, the exceptional cases serve to highlight alternative factors. Specifically, tolerance to seasonal cooling of water is not the only important factor when predicting the range expansion capacity of a species. Factors affecting the general abundance of the vagrants, such as habitat suitability and competitor/predator environments will also be critical where overwinter survival becomes a lottery.

Growth and contraction of ecosystem engineers, such as trees, influence ecosystem structure and function. On coral reefs, methods to measure small changes in the structure of microhabitats, driven by growth of coral colonies and contraction of skeletons, are extremely limited. We used 3D reconstructions to quantify changes in the external structure of coral colonies of tabular Acropora spp., the dominant habitat-forming corals in shallow exposed reefs across the Pacific. The volume and surface area of live colonies increased by 21% and 22%, respectively, in 12 months, corresponding to a mean annual linear extension of 5.62 cm yr−1 (±1.81 SE). The volume and surface area of dead skeletons decreased by 52% and 47%, respectively, corresponding to a mean decline in linear extension of −29.56 cm yr−1 (±7.08 SE), which accounted for both erosion and fragmentation of dead colonies. This is the first study to use 3D photogrammetry to assess fine-scale structural changes of entire individual colonies in situ, quantifying coral growth and contraction. The high-resolution of the technique allows for detection of changes on reef structure faster than other non-intrusive approaches. These results improve our capacity to measure the drivers underpinning ecosystem biodiversity, status and trajectory.

Habitat structural complexity is one of the most important factors in determining the makeup of biological communities. Recent advances in structure‐from‐motion and photogrammetry have resulted in a proliferation of 3D digital representations of habitats from which structural complexity can be measured. Little attention has been paid to quantifying the measurement errors associated with these techniques, including the variability of results under different surveying and environmental conditions. Such errors have the potential to confound studies that compare habitat complexity over space and time. This study evaluated the accuracy, precision, and bias in measurements of marine habitat structural complexity derived from structure‐from‐motion and photogrammetric measurements using repeated surveys of artificial reefs (with known structure) as well as natural coral reefs. We quantified measurement errors as a function of survey image coverage, actual surface rugosity, and the morphological community composition of the habitat‐forming organisms (reef corals). Our results indicated that measurements could be biased by up to 7.5% of the total observed ranges of structural complexity based on the environmental conditions present during any particular survey. Positive relationships were found between measurement errors and actual complexity, and the strength of these relationships was increased when coral morphology and abundance were also used as predictors. The numerous advantages of structure‐from‐motion and photogrammetry techniques for quantifying and investigating marine habitats will mean that they are likely to replace traditional measurement techniques (e.g., chain‐and‐tape). To this end, our results have important implications for data collection and the interpretation of measurements when examining changes in habitat complexity using structure‐from‐motion and photogrammetry.

The Neolithic temples of Malta are among the oldest examples of prehistoric architecture, yet the construction of their roofs remains a mystery. The absence of any roofs or roofing material at the temple sites has resulted in conjecture regarding the original appearance of these megalithic structures. The most valuable indications of prehistoric Maltese roof architecture are found in the Neolithic burial complex, the Hypogeum of Hal Saflieni. Two chambers in the Hypogeum are modelled closely after the above-ground temples, with indications of a roof structural system on the ceilings. This paper uses LiDAR and photogrammetry-derived 3D models to provide a partial temple roof reconstruction that has its design entirely based on contemporaneous archaeology. Photogrammetric reconstruction of the Mnajdra and Tarxien temple complexes allowed for detailed architectural analyses including key structural features and any indications of previous roof construction that would be evident in situ. A LiDAR model of the carved chambers of the Hypogeum of Hal Saflieni was superimposed onto corresponding positions in the temple models. Merging the LiDAR imagery onto the photogrammetry temple models confirmed structural consistency between the two megalithic complexes; supporting the theory that the carved facades were a deliberate reflection of the original architecture of the Maltese temples. This evidence points to an entirely new temple roof reconstruction, founded upon the archaeology of Neolithic Malta.

During 2015-2016, record temperatures triggered a pan-tropical episode of coral bleaching, the third global-scale event since mass bleaching was first documented in the 1980s. Here we examine how and why the severity of recurrent major bleaching events has varied at multiple scales, using aerial and underwater surveys of Australian reefs combined with satellite-derived sea surface temperatures. The distinctive geographic footprints of recurrent bleaching on the Great Barrier Reef in 1998, 2002 and 2016 were determined by the spatial pattern of sea temperatures in each year. Water quality and fishing pressure had minimal effect on the unprecedented bleaching in 2016, suggesting that local protection of reefs affords little or no resistance to extreme heat. Similarly, past exposure to bleaching in 1998 and 2002 did not lessen the severity of bleaching in 2016. Consequently, immediate global action to curb future warming is essential to secure a future for coral reefs.

While the consequences of bioinvasions are becoming clearer, our understanding of the environmental and ecological factors driving them is limited due to the complexity of the invasion process. Invasion success can be considered to be influenced by characteristics of the receiving assemblage (habitat, food, community interactions) and disturbances. Studies on the effects of the receiving assemblage have typically focused on a single or small subset of species, rather than on complex, multitrophic assemblages. We used an experimental assemblage consisting of more than 30 taxa from multiple trophic levels to evaluate the importance of the presence of this community and disturbance on colonisation by a generalist invader. To achieve this, we compared colonisation between a disturbed and undisturbed community. In addition, we evaluated the effects of the presence of organic matter of a different source (simulating a disturbance event affecting different habitats) on colonisation. A model generalist invader, the isopod Cirolana harfordi, was introduced to patches of oyster beds with (1) undisturbed (live) assemblages, (2) disturbed assemblages, (3) organic matter (using organic matter of a different source), or (4) no assemblage or organic matter. Our results indicated that the presence of an assemblage (disturbed or not) fostered colonisation; however, colonisation was less successful when the assemblage was undisturbed. Results also indicate that for a disturbance event to affect the colonisation of C. harfordi, it has to directly affect the invaded assemblage. These results add to the understanding of the factors driving invasions, which is important to design management strategies.

The combination of ocean warming and acidification brings an uncertain future to kelp forests that occupy the warmest parts of their range. These forests are not only subject to the direct negative effects of ocean climate change, but also to a combination of unknown indirect effects associated with changing ecological landscapes. Here, we used mesocosm experiments to test the direct effects of ocean warming and acidification on kelp biomass and photosynthetic health, as well as climate-driven disparities in indirect effects involving key consumers (urchins and rock lobsters) and competitors (algal turf). Elevated water temperature directly reduced kelp biomass, while their turf-forming competitors expanded in response to ocean acidification and declining kelp canopy. Elevated temperatures also increased growth of urchins and, concurrently, the rate at which they thinned kelp canopy. Rock lobsters, which are renowned for keeping urchin populations in check, indirectly intensified negative pressures on kelp by reducing their consumption of urchins in response to elevated temperature. Overall, these results suggest that kelp forests situated towards the low-latitude margins of their distribution will need to adapt to ocean warming in order to persist in the future. What is less certain is how such adaptation in kelps can occur in the face of intensifying consumptive (via ocean warming) and competitive (via ocean acidification) pressures that affect key ecological interactions associated with their persistence. If such indirect effects counter adaptation to changing climate, they may erode the stability of kelp forests and increase the probability of regime shifts from complex habitat-forming species to more simple habitats dominated by algal turfs.

Marine protected areas (MPAs) are designed to reduce threats to biodiversity and ecosystem functioning from anthropogenic activities. Assessment of MPAs effectiveness requires synchronous sampling of protected and non-protected areas at multiple spatial and temporal scales. We used an autonomous underwater vehicle to map benthic communities in replicate ‘no-take’ and ‘general-use’ (fishing allowed) zones within three MPAs along 7o of latitude. We recorded 92 taxa and 38 morpho-groups across three large MPAs. We found that important habitat-forming biota (e.g. massive sponges) were more prevalent and abundant in no-take zones, while short ephemeral algae were more abundant in general-use zones, suggesting potential short-term effects of zoning (5–10 years). Yet, short-term effects of zoning were not detected at the community level (community structure or composition), while community structure varied significantly among MPAs. We conclude that by allowing rapid, simultaneous assessments at multiple spatial scales, autonomous underwater vehicles are useful to document changes in marine communities and identify adequate scales to manage them. This study advanced knowledge of marine benthic communities and their conservation in three ways. First, we quantified benthic biodiversity and abundance, generating the first baseline of these benthic communities against which the effectiveness of three large MPAs can be assessed. Second, we identified the taxonomic resolution necessary to assess both short and long-term effects of MPAs, concluding that coarse taxonomic resolution is sufficient given that analyses of community structure at different taxonomic levels were generally consistent. Yet, observed differences were taxa-specific and may have not been evident using our broader taxonomic classifications, a classification of mid to high taxonomic resolution may be necessary to determine zoning effects on key taxa. Third, we provide an example of statistical analyses and sampling design that once temporal sampling is incorporated will be useful to detect changes of marine benthic communities across multiple spatial and temporal scales. Published version

Adriana Vergés et al., Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to 'barrens' when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs. © 2014 The Author(s) Published by the Royal Society. All rights reserved., We thank the Evolution and Ecology Research Centre (UNSW) for funding the workshop on the tropicalization of temperate marine ecosystems that resulted in this review. This study resulted from a workshop convened by A.V., P.D.S. and A.G.P. entitled ‘Shifting species interactions and the tropicalization of temperate marine ecosystems’, held at the Sydney Institute of Marine Science (Australia) in November 2011

We evaluated the commercial and recreational fishery landings over the past 22 years, first at the national level, then for populations of concern (those that are overfished or experiencing overfishing), and finally by region. Recreational landings in 2002 account for 4% of total marine fish landed in the United States. With large industrial fisheries excluded (e.g., menhaden and pollock), the recreational component rises to 10%. Among populations of concern, recreational landings in 2002 account for 23% of the total nationwide, rising to 38% in the South Atlantic and 64% in the Gulf of Mexico. Moreover, it affects many of the most-valued overfished species—including red drum, bocaccio, and red snapper—all of which are taken primarily in the recreational fishery.

© 2019 John Wiley & Sons Ltd Environmental anomalies that trigger adverse physiological responses and mortality are occurring with increasing frequency due to climate change. At species' range peripheries, environmental anomalies are particularly concerning because species often exist at their environmental tolerance limits and may not be able to migrate to escape unfavourable conditions. Here, we investigated the bleaching response and mortality of 14 coral genera across high-latitude eastern Australia during a global heat stress event in 2016. We evaluated whether the severity of assemblage-scale and genus-level bleaching responses was associated with cumulative heat stress and/or local environmental history, including long-term mean temperatures during the hottest month of each year (SSTLTMAX), and annual fluctuations in water temperature (SSTVAR) and solar irradiance (PARZVAR). The most severely-bleached genera included species that were either endemic to the region (Pocillopora aliciae) or rare in the tropics (e.g. Porites heronensis). Pocillopora spp., in particular, showed high rates of immediate mortality. Bleaching severity of Pocillopora was high where SSTLTMAX was low or PARZVAR was high, whereas bleaching severity of Porites was directly associated with cumulative heat stress. While many tropical Acropora species are extremely vulnerable to bleaching, the Acropora species common at high latitudes, such as A. glauca and A. solitaryensis, showed little incidence of bleaching and immediate mortality. Two other regionally-abundant genera, Goniastrea and Turbinaria, were also largely unaffected by the thermal anomaly. The severity of assemblage-scale bleaching responses was poorly explained by the environmental parameters we examined. Instead, the severity of assemblage-scale bleaching was associated with local differences in species abundance and taxon-specific bleaching responses. The marked taxonomic disparity in bleaching severity, coupled with high mortality of high-latitude endemics, point to climate-driven simplification of assemblage structures and progressive homogenisation of reef functions at these high-latitude locations.