The globally significant green turtle ( Chelonia mydas ) population in the northern Great Barrier Reef is threatened by anthropogenic pressures, including climate change, habitat degradation, and indigenous harvest. Evidence suggesting the population is producing an extreme proportion of females due to increasing temperatures, coupled with temperature-dependent sex determination, is concerning. In response, and to explore management options, we developed two density-independent, stochastic stage-structured metapopulation models: a “Moderate Climate Model” and an “Extreme Climate Model”. The models differ based on climate change projections by incorporating increased female hatchling sex ratios due to global warming and loss of nesting habitat due to sea level rise. The models were based on demographic data from field studies at major rookeries and regional foraging grounds and allowed for variation in operational sex ratios, management actions, and levels of indigenous harvest. Under the Moderate Climate Model, population size increased but could be vulnerable to overharvest of adult females. If overharvest was indicated, the harvest of a proportion of subadults rather than only adult females reduced population declines. Under the Extreme Climate Model, there was a steep population decline even without any harvest, and harvesting subadults accelerated population decline due to the inclusion of subadult males. In the Extreme Climate Model, reversal of population decline depended on male turtles mating with an increased number of females, or management actions to substantially increase the number of male hatchlings produced.
Marine protected areas (MPAs) are key tools in addressing the global decline of sharks and rays, and marine parks and shark sanctuaries of various configurations have been established to conserve shark populations. However, assessments of their efficacy are compromised by inconsistent terminology, lack of standardized approaches to assess how MPAs contribute to shark and ray conservation, and ambiguity about how to integrate movement data in assessment processes. We devised a conceptual framework to standardize key terms (e.g., protection, contribution, potential impact, risk, threat) and used the concept of portfolio risk to identify key attributes of sharks and rays (assets), the threats they face (portfolio risk), and the specific role of MPAs in risk mitigation (insurance). Movement data can be integrated into the process by informing risk exposure and mitigation through MPAs. The framework is operationalized by posing 8 key questions that prompt practitioners to consider the assessment scope, MPA type and purpose, range of existing and potential threats, species biology and ecology, and management and operational contexts. Ultimately, MPA contributions to shark and ray conservation differ according to a complex set of human and natural factors and interactions that should be carefully considered in MPA design, implementation, and evaluation.
Australia's Great Barrier Reef (the GBR) is an iconic natural ecosystem, globally renowned for its majesty and grandeur. The GBR encompasses a vast array of unique and important marine and terrestrial habitats, from deepwater reefs to archetypal barrier reefs, as well as vast seagrass and algal meadows, intertidal mud flats, sand cays, and continental islands. The variety of environments and habitats encompassed within the GBR gives rise to extraordinary biodiversity. The GBR is also unusual compared with most reef systems around the world because the islands and adjacent coastal areas are sparsely populated. Moreover, Australia is a developed economy and does not generally rely heavily on subsistence or artisanal extraction of reef resources. That said, the GBR is being increasingly threatened by anthropogenic activities, such as land clearing and agricultural runoff, coastal development, pollution, and above all, increasing global carbon emissions that are rapidly changing environmental conditions. Sustained and ongoing global climate change has culminated in unprecedented and recurrent mass coral bleaching in recent years, which now represents the foremost threat to the integrity, functioning, and biodiversity of coral reef environments. Significant investment and effort is committed to conserving the GBR, both to maintain the ecological function and human benefits derived from the various natural systems, but the effectiveness and longer-term benefit of established and renewed management actions are conditional on immediate and effective action to reduce global carbon emissions.
Although sea turtles have received substantial focus worldwide, research on the immature life stages is still relatively limited. The latter is of particular importance, given that a large proportion of sea turtle populations comprises immature individuals. We set out to identify knowledge gaps and identify the main barriers hindering research in this field. We analyzed the perceptions of sea turtle experts through an online survey which gathered their opinions on the current state of affairs on immature sea turtle research, including species and regions in need of further study, priority research questions, and barriers that have interfered with the advancement of research. Our gap analysis indicates that studies on immature leatherback Dermochelys coriacea and hawksbill Eretmochelys imbricata turtles are lacking, as are studies on all species based in the Indian, South Pacific, and South Atlantic Oceans. Experts also perceived that studies in population ecology, namely on survivorship and demography, and habitat use/behavior, are needed to advance the state of knowledge on immature sea turtles. Our survey findings indicate the need for more inter-disciplinary research, collaborative efforts (e.g. data-sharing, joint field activities), and improved communication among researchers, funding bodies, stakeholders, and decision-makers.
Context In Queensland, the management of estuarine crocodiles (Crocodylus porosus) by the government is important for ensuring public safety, especially along the populated east coast, where there is a large human population. Aims The present study aimed to determine historical, temporal and spatial patterns of human–crocodile conflict in Queensland. Methods The study used Queensland Government records of estuarine crocodile attacks (1971–2015), sightings by the general public (2003–2015), and removals and relocations for management purposes (1985–2015) to develop General Linear Models describing historical, temporal and spatial patterns. Key results The highest number of attacks, sightings, removals and relocations occurred along the populated east coast between Townsville and the Daintree during wet season months (November–February). There have been 35 crocodile attacks in Queensland since 1971 (total 0.8 per year; fatal 0.3 per year), mostly involving local people or regular visitors (77.1%), specifically adult males (71.4%; mean age 44). There has been an increase in the rate of crocodile attacks over time, with an average of 1.3 per year since 1996, most of which were non-fatal (84%). The number of crocodile sightings has been increasing annually (with a mean of 348 per year since 2011), while the number of crocodiles removed or relocated for management purposes (n = 608) has fluctuating widely each year (range 1–57). Conclusions The level of human–crocodile conflict in Queensland is increasing, and this is likely to be a consequence of increasing human and crocodile populations. While conflict is highest during the wet season, estuarine crocodiles pose a threat to public safety year round. Implications With the increase in conflict, the ongoing management of estuarine crocodiles, through targeted removals in and around areas of higher human habitation and through education, is essential for ensuring public safety into the future.
Defining goals and objectives is a critical component of adaptive management of natural resources because they provide the basis on which management strategies can be designed and evaluated. The aims of this study are: (i) to apply and test a collaborative method to elicit goals and objectives for inshore fisheries and biodiversity in the coastal zone of a regional city in Australia; (ii) to understand the relative importance of management objectives for different community members and stakeholders; and (iii) to understand how diverse perceptions about the importance of management objectives can be used to support multiple-use management in Australia’s iconic Great Barrier Reef. Management goals and objectives were elicited and weighted using the following steps: (i) literature review of management objectives, (ii) development of a hierarchy tree of objectives, and (iii) ranking of management objectives using survey methods. The overarching goals identified by the community group were to: (1) protect and restore inshore environmental assets; (2) improve governance systems; and (3) improve regional (socio-economic) well-being. Interestingly, these goals differ slightly from the usual triple-bottom line objectives (environmental, social and economic) often found in the literature. The objectives were ranked using the Analytical Hierarchical Process, where a total of 141 respondents from industry, government agencies, and community from across Queensland State undertook the survey. The environment goal received the highest scores, followed by governance and lastly well-being. The approach to elicit and rank goals and objectives developed in this study can be used to effectively support coastal resource management by providing opportunities for local communities to participate in the setting of regional objectives.
Sea snakes are an important component of bycatch in commercial and small-scale trawl fisheries in tropical waters and are highly vulnerable to fishing-related mortality. Extensive boat-based surveys were conducted to investigate the assemblage and abundance of sea snakes within a protected shallow coastal bay adjacent to productive trawl fishing grounds. Spine-Bellied Sea Snakes, Hydrophis curtus (previously Lapemis curtus), and Elegant Sea Snakes, Hydrophis elegans, were the most commonly encountered species. Based on the age structure of these two species, the bay was used primarily by juveniles. Temporal trends in age structure and sex ratios showed that H. curtus may use Cleveland Bay as a nursery ground, with gravid females entering the bay in summer months to give birth. In contrast, H. elegans appears to use the bay more consistently through the year, with similar to 30% of individuals being adults. This study also showed that shallow tidal habitats, too shallow for trawl fishing, are regularly used by sea snakes and may provide refugia for vulnerable life stages. The identification and protection of such habitats may further mitigate risks to sea snake populations from trawl fishing.
Resource selection studies often use analytical techniques that provide information at either a population or an individual level. We applied a Bayesian hierarchical model that simultaneously estimates population- and individual-level habitat selection to explore how varying levels of dietary specialisation affect resource requirements of 2 species of sea snakes that occupy the same coastal environment. We used passive acoustic telemetry to monitor the movements of the 2 species—a dietary generalist, Hydrophis (Lapemis) curtus, and a dietary specialist, H. elegans—and investigated how individuals select habitats based on habitat type, depth and proximity to sources of freshwater within a nearshore environment. Composition of diets in both species was also assessed using regurgitated material from captured individuals. Selection of habitats by the 2 species differed, with H. elegans displaying an affinity for mudflat and seagrass habitats <4 km from sources of freshwater and depths <3 m. H. curtus selected for slightly deeper seagrass habitats (1-4 m) further from freshwater sources (2-5 km). Data from regurgitated material showed that the diet of H. curtus comprised at least 4 families of fish and displayed some level of intraspecific predation, whereas H. elegans preyed solely on eels. Both species predominantly selected seagrass areas, indicating that these habitats provide key resources for sea snakes within nearshore environments. The results illustrated the utility of Bayesian hierarchical models when analysing passive acoustic monitoring data to provide population-level habitat selection metrics and incorporate individual-level variability in selection, both of which are necessary to inform targeted management and conservation practices.
Stakeholder engagement is important for successful management of natural resources, both to make effective decisions and to obtain support. However, in the context of coastal management, questions remain unanswered on how to effectively link decisions made at the catchment level with objectives for marine biodiversity and fisheries productivity. Moreover, there is much uncertainty on how to best elicit community input in a rigorous manner that supports management decisions. A decision support process is described that uses the adaptive management loop as its basis to elicit management objectives, priorities and management options using two case studies in the Great Barrier Reef, Australia. The approach described is then generalised for international interest. A hierarchical engagement model of local stakeholders, regional and senior managers is used. The result is a semi-quantitative generic elicitation framework that ultimately provides a prioritised list of management options in the context of clearly articulated management objectives that has widespread application for coastal communities worldwide. The case studies show that demand for local input and regional management is high, but local influences affect the relative success of both engagement processes and uptake by managers. Differences between case study outcomes highlight the importance of discussing objectives prior to suggesting management actions, and avoiding or minimising conflicts at the early stages of the process. Strong contributors to success are a) the provision of local information to the community group, and b) the early inclusion of senior managers and influencers in the group to ensure the intellectual and time investment is not compromised at the final stages of the process.The project has uncovered a conundrum in the significant gap between the way managers perceive their management actions and outcomes, and community's perception of the effectiveness (and wisdom) of these same management actions. Crown Copyright (C) 2016 Published by Elsevier Ltd. All rights reserved.
A wide range of goals and objectives have to be taken into account in natural resources management. Defining these objectives in operational terms, including dimensions such as sustainability, productivity, and equity, is by no means easy, especially if they must capture the diversity of community and stakeholder values. This is especially true in the coastal zone where land activities affect regional marine ecosystems. In this study, the aim was firstly to identify and hierarchically organise the goals and objectives for coastal systems, as defined by local stakeholders. Two case study areas are used within the Great Barrier Reef region being Mackay and Bowen–Burdekin. Secondly, the aim was to identify similarities between the case study results and thus develop a generic set of goals to be used as a starting point in other coastal communities. Results show that overarching high-level goals have nested sub-goals that contain a set of more detailed regional objectives. The similarities in high-level environmental, governance, and socio-economic goals suggest that regionally specific objectives can be developed based on a generic set of goals. The prominence of governance objectives reflects local stakeholder perceptions that current coastal zone management is not achieving the outcomes they feel important and that there is a need for increased community engagement and co-management. More importantly, it raises the question of how to make issues relevant for the local community and entice participation in the local management of public resources to achieve sustainable environmental, social, and economic management outcomes.
Despite being identified in 1938, many aspects of the pathogenesis and epidemiology of fibropapillomatosis (FP) in marine turtles are yet to be fully uncovered. Current knowledge suggests that FP is an emerging infectious disease, with the prevalence varying both spatially and temporally, even between localities in close proximity to each other. A high prevalence of FP in marine turtles has been correlated with residency in areas of reduced water quality, indicating that there is an environmental influence on disease presentation. Chelonid herpesvirus 5 (ChHV5) has been identified as the likely aetiological agent of FP. The current taxonomic position of ChHV5 is in the family Herpesviridae, subfamily Alphaherpesvirinae, genus Scutavirus. Molecular differentiation of strains has revealed that a viral variant is typically present at specific locations, even within sympatric species of marine turtles, indicating that the disease FP originates regionally. There is uncertainty surrounding the exact path of transmission and the conditions that facilitate lesion development, although recent research has identified atypical genes within the genome of ChHV5 that may play a role in pathogenesis. This review discusses emerging areas where researchers might focus and theories behind the emergence of FP globally since the 1980s, which appear to be a multi-factorial interplay between the virus, the host and environmental factors influencing disease expression.
Natural and anthropogenic changes in the marine environment can strongly influence the biology and behaviour of coastal organisms. Understanding how animals that rely on these habitats respond to environmental change is crucial to inform when management actions should be implemented to mitigate or reduce impacts. Here passive acoustic telemetry was used to monitor the movements of spine-bellied sea snakes (Hydrophis curtus) within a coastal ecosystem to define activity patterns in relation to environmental conditions. Presence, movement and three-dimensional home range metrics calculated from monitoring data were tested against environmental (water temperature, atmospheric pressure, wind speed, accumulated rainfall and tidal range) and biological (snout-vent length) factors on daily and monthly temporal scales to identify key environmental drivers of movement and the use of space. A generalised linear mixed model (GLMM) framework using Akaike information criterion (AIC) indicated that tidal reach and atmospheric pressure strongly influenced the daily presence and movements of tagged individuals, respectively. Accumulated rainfall significantly influenced the volume of space used on a monthly timescale. This study presents first estimates of three-dimensional home ranges of sea snakes as well as novel information on how environmental variables influence daily and monthly presence, movements and use of space of coastal sea snakes. These data are important in further understanding the ecology of sea snakes and can inform future management actions for this poorly studied taxon in the light of increased environmental and anthropogenic disturbances.
An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and northern Australia. Three of the seven threatened species occur at Ashmore and Hibernia Reefs in the Timor Sea, while the remaining threatened taxa occur in the Philippines, Niue, and Solomon Islands. The majority of Data Deficient species are found in Southeast Asia. Threats to marine snakes include loss of coral reefs and coastal habitat, incidental bycatch in fisheries, as well as fisheries that target snakes for leather. The presence of two Critically Endangered and one Endangered species in the Timor Sea suggests the area is of particular concern. More rigorous, long-term monitoring of populations is needed to evaluate the success of conservation measures for marine snake species, provide scientifically based guidance for determining harvest quotas, and to assess the populations of many Data Deficient species.
Entanglement in derelict fishing gear and other marine debris is a major threat to the survival of large marine wildlife like cetaceans, seabirds and sea turtles. However, no previous reports of entanglement or entrapment have been recorded in sea snakes (Hydrophiinae). We report here on a sea snake (Hydrophis elegans) found with a ceramic washer encircling its body captured from the north-east coast of Queensland, Australia. The ring had constricted the body and over time caused extensive damage to the underlying tissues. A post-mortem examination showed the snake was severely emaciated as the ring restricted the passage of food to the stomach and intestine. This is the first record of mortality due to marine debris entrapment in sea snakes.
An assessment of marine elapid snakes found 9% of marine elapids are threatened with extinction, and an additional 6% are Near Threatened. A large portion (34%) is Data Deficient. An analysis of distributions revealed the greatest species diversity is found in Southeast Asia and northern Australia. Three of the seven threatened species occur at Ashmore and Hibernia Reefs in the Timor Sea, while the remaining threatened taxa occur in the Philippines, Niue, and Solomon Islands. The majority of Data Deficient species are found in Southeast Asia. Threats to marine snakes include loss of coral reefs and coastal habitat, incidental bycatch in fisheries, as well as fisheries that target snakes for leather. The presence of two Critically Endangered and one Endangered species in the Timor Sea suggests the area is of particular conservation concern. More rigorous, long-term monitoring of populations is needed to evaluate the success of "conservation measures" for marine snake species, provide scientifically based guidance for determining harvest quotas, and to assess the populations of many Data Deficient species.
Estrogens are key mediators of increased uterine contractility at labor. We sought to determine whether membrane-associated estrogen receptors, such as the recently described seven-transmembrane receptor G protein-coupled receptor 30 (GPR30), mediated some of this effect. Using human myometrium obtained at term cesarean section before or after the onset of labor, we demonstrated the presence of GPR30 mRNA and protein using quantitative RT-PCR and Western blotting. GPR30 receptor was localized to the cell membrane and often colocalized with calveolin-1. Using the specific estrogen membrane receptor agonist G-1 and myometrial explants, we showed that membrane receptor activation led to phosphorylation of MAPK and the actin-modifying small heat shock protein 27. Using myometrial strips incubated with G-1 or vehicle we demonstrated that estrogen membrane receptor activation increased the myometrial contractile response to oxytocin. These data suggest that activation of the plasma membrane estrogen receptor GPR30 likely participates in the physiology of the human myometrium during pregnancy and identifies it as a potential target to modify uterine activity.
1. The estuarine crocodile (Crocodylus porosus) is the world's largest living reptile. It predominately inhabits freshwater and estuarine habitats, but widespread geographic distribution throughout oceanic islands of the South-east Pacific suggests that individuals undertake sizeable ocean voyages. 2. Here we show that adult C. porosus adopt behavioural strategies to utilise surface water currents during long-distance travel, enabling them to move quickly and efficiently over considerable distances. 3. We used acoustic telemetry to monitor crocodile movement throughout 63 km of river, and found that when individuals engaged in a long-distance, constant direction journey (>10 km day(-1)), they would only travel when current flow direction was favourable. Depth and temperature measurements from implanted transmitters showed that they remained at the water surface during travel but would dive to the river substratum or climb out on the river bank if current flow direction became unfavourable. 4. Satellite positional fixes from tagged crocodiles engaged in ocean travel were overlaid with residual surface current (RSC) estimates. The data showed a strong correlation existed between the bearing of the RSC and that of the travelling crocodile (r(2) = 0.92, P < 0.0001). 5. The study demonstrates that C. porosus dramatically increase their travel potential by riding surface currents, providing an effective dispersal strategy for this species.
We report on an intersex green turtle, Chelonia mydas, observed at Raine Island, Australia that externally resembled an adult male but internally-based on laparoscopic examination-had both ovarian and testicular structures resembling those of an adult. This individual was the first intersex turtle that has been recorded on a nesting beach during the 39 years of extensive census studies in Queensland. Its observation confirms that the definitive identification of sex with marine turtles remains dependent on observations of their gonads or on observing eggs being laid.