Mangrove ecosystems are threatened by climate change. We investigated the effects of expected future (year 2100) drought intensities and rising sea levels on the spatial extent and biomass production of mangroves located along the southern Iranian semi-desert coastal areas of the Persian Gulf (PG) and the Gulf of Oman (GO) under the projections of the RCP 8.5 climate change scenario. To do so, we first needed to establish a robust link of past drought intensities to spatial extents and biomass amounts of mangroves in the study region that would enable the prediction of biomass for the climatic conditions projected by the RCP 8.5 scenario for the year 2100. Large differences in drought intensities in the past pointed to a coordinated wet (1986–1998) and a dry (1998–2017) period throughout the study area and resulted in strong correlations of drought intensity to spatial extents and above- and below-ground biomass amounts. Whereas landward mangrove margins expanded modestly during the wet and contracted severely during the dry periods, leading to variable net areal gains and losses over time, seaward mangrove margins retreated during both periods, presumably due to rising sea levels. By the end of the 21st century, predicted values of biomass per hectare in the remaining mangroves exceeded current values by 47–64% (above-ground) and 41–48% (below-ground) due to a reduced drought intensity predicted for the region. Assuming no landward expansion, predicted mangrove areas declined between 4.9 and 7.2% for every 10 cm rise in sea levels, resulting in a net loss of total mangrove biomass between 18 and 56% throughout the study region at a sea level rise of 100 cm. Variability among sites at all times was partly due to differences in drought intensities, coastal topographies, and differential rates of sedimentation and subsidence/uplift, with greater adverse effects on the coastal areas of the GO than the PG. We conclude that adverse effects of rising sea levels on the extent of mangroves were only partly offset by the increased biomass in the remaining mangroves following reduced drought severities predicted for the end of the 21st century. It is still unclear to what degree mangroves can take advantage of lesser drought intensities predicted for the end of the 21st century and expand their landward margins.
Climate change and its accompanying sea-level rise is set to create risks to the United States’ stockpile of spent nuclear fuel, which results largely from nuclear power. Coastal spent fuel management facilities are vulnerable to unanticipated environmental events, as evidenced by the 2011 tsunami-related flooding at the Fukushima plant in Japan. We examine how policy-makers can manage climate risks posed to the coastal storage of radioactive materials, and identify the coastal spent fuel storage sites that will be most vulnerable to sea-level rise. A geospatial analysis of coastal sites shows that with six feet of sea-level rise, seven spent fuel sites will be juxtaposed by seawater. Of those, three will be near or completely surrounded by water, and should be considered a priority for mitigation: Humboldt Bay (California), Turkey Point (Florida), and Crystal River (Florida). To ensure policy-makers manage such climate risks, a risk management approach is proposed. Further, we recommend that policy-makers 1) transfer overdue spent fuel from cooling pools to dry casks, particularly where located in high risk sites; 2) develop a long-term and comprehensive storage plan that is less vulnerable to climate change; and 3) encourage international nuclear treaties and standards to take climate change into account.
As an emerging contaminant in the environment, microplastics have attracted worldwide attention. Although research methods on microplastics in the environment have been reported extensively, the data on microplastics obtained cannot be comparable due to different methods. In this work, we critically reviewed the analytical methods of microplastics, including sample collection, separation, identification and quantification. Manta trawl and tweezers or cassette corers are used to collect water samples and sediments, respectively. For biota sample, internal organs need to be dissected and separated to obtain microplastics. Density differences are often used to separate microplastics from the sample matrix. Visual classification is one of the most common methods for identifying microplastics, and it can be better detected by combining it with other instruments. However, they are not suitable for detection nanoplastics, which may lead to underestimation of risk. The abundance of microplastics varies with the detection method. Thus, the analytical methods for microplastics need to be standardized as soon as possible. Meanwhile, new methods for analyzing nanoplastics are urgently needed.
Global warming is driving changes in the distribution patterns of many species, leading to a general tropicalization and meridionalization of biota. In this context, populations of some marine species are in regression while others are expanding their populations. Such is the case of benthic cnidarians belonging to the order Zoantharia and suborder Brachycnemina, whose populations are able to cause phase-shifts in coral reef ecosystems. Marine assemblages in the subtropical Canary Islands region consist of a combination of both temperate and tropical species, mainly due to the east-to-west seawater temperature gradient that naturally exists throughout the archipelago. This can reach a 2 °C difference (≈23-25 °C east to west in summer months). These biogeographical features make the archipelago a unique location to research into biota reorganisation processes. The aim of this study was to establish a baseline of the distribution and abundance data of zoantharian Brachycnemina populations in the Canary Islands. To elucidate whether these species are potential bioindicators of ocean warming processes, patterns of species distribution and their relationships with the temperature gradient across the archipelago were also evaluated. Results demonstrated that intertidal and subtidal populations of Palythoa aff. clavata and P. caribaeorum, respectively, followed distribution patterns related to the temperature ranges recorded in situ by data loggers. Extensive populations were found in the western islands where seawater temperatures are warmer than the eastern islands. Since biota reorganisation usually produces loss of ecosystem functions, it is essential to establish baseline datasets of climate change indicators and also effective monitoring programmes. These will allow early detection of phase-shifts before they lead to significant changes in ecosystem dynamics.
Ornamental fish have been legally harvested since the 1930's but in the 60's, cyanide fishing was first documented. Target fish exposed to the chemical are temporarily paralysed making them easier to catch, but with high post-capture mortality and significant ecological impacts, its use is banned in most exporting countries. To differentiate illegally caught fish from those sustainably collected, efforts to develop a post-collection detection test began nearly 30 years ago. However, even the most promising approach has been questioned by other researchers as unrepeatable under different experimental conditions. In this paper we summarise the evidence-base for establishing a cyanide detection test for live fish by evaluating current approaches. We describe the key knowledge gaps which continue to limit our progress in implementing a screening programme and highlight some alternative solutions which may provide greater short to medium term opportunities to prevent the illegal practise before fish enter the supply chain.
Coral reef refugia are habitats which possess physical, biological and ecological characteristics that make them likely to be relatively resilient to future climate change. Identification of refugia locations will be important to ensure suitable marine conservation planning is undertaken to protect sites where coral ecosystems will be better preserved now and in the future. This paper presents (1) a review of current knowledge of the oceanographic conditions and coral community in the Revillagigedo Archipelago Large Scale Marine Protected Area, (2) the first assessment of the potential for the Revillagigedo Archipelago to act as a climate refugia site for corals and coral reefs in the eastern tropical Pacific, and (3) consequent management and learning opportunities, to inform reef conservation both locally and globally. Through utilising published literature, remote and in situ environmental data, and field observations it was found that the Revillagigedo area exhibits a combination of distinctive characteristics in the coral community and in oceanographic processes which support conditions of refugia. The potential for refugia is further enhanced due to the absence of significant secondary anthropogenic stressors. This leads to a recommendation to establish the Revillagigedo as a globally significant ‘sentinel site’ where, through long-term monitoring of oceanographic conditions and of the coral and associated ecosystems, the effects of climate change can be quantified, and the effectiveness of specific refugia attributes established. This information may then be used to underpin the recognition of potential coral refugia elsewhere, and to guide MPA designation and management decisions to enhance their effectiveness.
As oceans continue to warm under climate change, understanding the differential growth responses of corals is increasingly important. Scleractinian corals exhibit a broad range of life-history strategies, yet few studies have explored interspecific variation in long-term growth rates under a changing climate. Here we studied growth records of two coral species with different growth forms, namely branching Isopora palifera and massive Porites spp. at an offshore reef (Myrmidon Reef) of the central Great Barrier Reef (GBR), Australia. Skeletal growth chronologies were constructed using a combination of X-radiographs, gamma densitometry, and trace element (Sr/Ca) analysis. General additive mixed-effect models (GAMMs) revealed that skeletal density of I. palifera declined linearly and significantly at a rate of 1.2% yr−1 between 2002 and 2012. Calcification was stable between 2002 and 2009, yet declined significantly at a rate of 12% yr−1 between 2009 and 2012 following anomalously high sea surface temperatures (SST). Skeletal density of massive Porites exhibited a significant non-linear response over the 11-year study period (2002−2012) in that density was temporarily reduced during the 2009–2010 anomalously hot years, while linear extension and calcification showed no significant trends. Linear extension, density and calcification rates of I. palifera increased to maximum growth of 26.7–26.9 °C, beyond which they declined. In contrast, calcification and linear extension of Porites exhibited no response to SST, but exhibited a significant linear decline in skeletal density with increasing SST. Our results reveal significant differences in coral growth patterns among coral growth forms, and highlight both the resistant nature of massive Porites and sensitivity of branching I. palifera. Future research should target a broad range of coral taxa within similar environments to provide a community-level response of ocean warming on coral reef communities.
Sustainability in the provision of ecosystem services requires understanding of the vulnerability of social-ecological systems (SES) to tipping points (TPs). Assessing SES vulnerability to abrupt ecosystem state changes remains challenging, however, because frameworks do not operationally link ecological, socio-economic and cultural elements of the SES. We conducted a targeted literature review on empirical assessments of SES and TPs in the marine realm and their use in ecosystem-based management. Our results revealed a plurality of terminologies, definitions and concepts that hampers practical operationalisation of these concepts. Furthermore, we found a striking lack of socio-cultural aspects in SES vulnerability assessments, possibly because of a lack of involvement of stakeholders and interest groups. We propose guiding principles for assessing vulnerability to TPs that build on participative approaches and prioritise the connectivity between SES components by accounting for component linkages, cascading effects and feedback processes.
Found in the coastal waters of all continents, gillnets are the largest component of small-scale fisheries for many countries. Numerous studies show that these fisheries often have high bycatch rates of threatened marine species such as sea turtles, small cetaceans and seabirds, resulting in possible population declines of these non-target groups. However, few solutions to reduce gillnet bycatch have been developed. Recent bycatch reduction technologies (BRTs) use sensory cues to alert non-target species to the presence of fishing gear. In this study we deployed light emitting diodes (LEDs) - a visual cue - on the floatlines of paired gillnets (control vs illuminated net) during 864 fishing sets on small-scale vessels departing from three Peruvian ports between 2015 and 2018. Bycatch probability per set for sea turtles, cetaceans and seabirds as well as catch per unit effort (CPUE) of target species were analysed for illuminated and control nets using a generalised linear mixed-effects model (GLMM). For illuminated nets, bycatch probability per set was reduced by up to 74.4 % for sea turtles and 70.8 % for small cetaceans in comparison to non-illuminated, control nets. For seabirds, nominal BPUEs decreased by 84.0 % in the presence of LEDs. Target species CPUE was not negatively affected by the presence of LEDs. This study highlights the efficacy of net illumination as a multi-taxa BRT for small-scale gillnet fisheries in Peru. These results are promising given the global ubiquity of small-scale net fisheries, the relatively low cost of LEDs and the current lack of alternate solutions to bycatch.
The Mediterranean Sea is a biodiversity hotspot where intense fishing pressure is associated with high bycatch rates of protected species (sea turtles and cetaceans) and top predators (sharks). Since the conservation of these species has become a priority, fishery scientists are faced with the challenge of reducing incidental catch, which entails high rates of mortality. Among the species threatened by fishing activities, the loggerhead turtle (Caretta caretta) is a charismatic species considered as “vulnerable” at the global scale. In the Mediterranean Sea trawl nets are the gears with the highest probability of catching protected species incidentally. A new flexible Turtle Excluder Device (TED) was tested for the first time on commercial bottom trawlers to assess its effectiveness in reducing bycatch in the Mediterranean Sea. Analysis of the total catches of the hauls made with and without the TED showed that the difference in terms of weight was not significant. The catch of the main commercial species showed similar rates without a significant loss of size (i.e. total length) with the exception of the largest anglerfish (Lophius spp.). The bycatch of control nets included mostly rays and sharks, but never turtles, although the authors learned from the crews of other vessels operating in the same areas at the time of the trials that they had caught some loggerhead turtles. Our study demonstrates that TED scan be adopted without significantly affecting commercial catch. This informs fishers and managers for a practical and effective means that may reduce the bycatch of threatened species in coastal Mediterranean demersal multispecies fisheries. The measures involving gear modifications require significant investment but they are technically feasible and are capable of improving the conservation prospects of these endangered species. Besides ensuring normal earnings, the TED induced a significant reduction of debris and litter in the codend, thus reducing catch sorting time and improving catch quality.
There is recent evidence of widespread declines of shovelnose ray populations (Order Rhinopristiformes) in heavily fished regions. These declines, which are likely driven by high demand for their fins in Asian markets, raises concern about their risk of over-exploitation and extinction. Using life-history theory and incorporating uncertainty into a modified Euler-Lotka model, the maximum intrinsic rates of population increase (rmax) were estimated for nine species from four families of Rhinopristiformes, using four different natural mortality estimators. Estimates of mean rmax, across the different natural mortality methods, varied from 0.03 to 0.59 year-1 among the nine species, but generally increased with increasing maximum size. Comparing these estimates to rmax values for other species of chondrichthyans, the species Rhynchobatus australiae, Glaucostegus typus, and Glaucostegus cemiculus were relatively productive, while most species from Rhinobatidae and Trygonorrhinidae had relatively low rmax values. If the demand for their high-value products can be addressed then population recovery for some species is likely possible, but will vary depending on the species.
Many tropical and subtropical species are sensitive to sudden temperature changes, especially drops in temperature. During winters 2009–2010 and 2010–2011, unusually cold temperatures occurred in many parts of Florida, USA, resulting in increased mortality of Florida manatees, sea turtles, fish, corals, and other species. The Florida manatee, in particular, is highly susceptible to cold stress and death when water temperatures drop below 20°C. We sought to characterize the magnitude and timing of reports of cold-related manatee carcasses in relation to fluctuations in water and air temperatures in central-east and central-west Florida during the six winters from 2008 to 2014. We used a generalized linear model to predict counts of manatee carcasses with a cold-related cause of death reported over 7-day bins in relation to various short-term (two weeks or less) and cumulative (incrementally summed from the start of the winter) heating-degree-day effects (HDD; < 20°C) and a categorical winter variable. Using water temperature data, the top-ranked model in both regions included a short-term temperature effect (14-day HDD sum) that preceded increases in reports of cold-related manatee carcasses by 7 days. Cumulative exposure to cold weather over the winter amplified effects on mortality in the central-east region. Quantifying the relationship between cold events and manatee mortality helps us prepare for rescue and salvage operations when extremely cold weather is forecast. This is especially important because anticipated loss or degradation of warm-water refuges due to human activities and sea level rise could potentially impact the manatee population in the future. These methods could also be applied to other species susceptible to cold-related mortality.
- Despite a relatively long history of scientific interest fuelled by exploratory research cruises, the UK deep sea has only recently emerged as the subject of targeted and proactive conservation. Enabling legislation over the past 10 years has resulted in the designation of marine protected areas and the implementation of fisheries management areas as spatial conservation tools. This paper reflects on progress and lessons learned, recommending actions for the future.
- Increased investment has been made to improve the evidence base for deep‐sea conservation, including collaborative research surveys and use of emerging technologies. New open data portals and developments in marine habitat classification systems have been two notable steps to furthering understanding of deep‐sea biodiversity and ecosystem functioning in support of conservation action.
- There are still extensive gaps in fundamental knowledge of deep‐sea ecosystems and of cause and effect. Costs of new technologies and a limited ability to share data in a timely and efficient manner across sectors are barriers to furthering understanding. In addition, whilst the concepts of natural capital and ecosystem services are considered a useful tool to support the achievement of conservation goals, practical application is challenging.
- Continued collaborative research efforts and engagement with industry to share knowledge and resources could offer cost‐effective solutions to some of these barriers. Further elaboration of the concepts of natural capital and ecosystem services will aid understanding of the costs and benefits associated with human–environment interactions and support informed decision‐making in conserving the deep sea.
- Whilst multiple challenges arise for deep‐sea conservation, it is critical to continue ongoing conservation efforts, including exploration and collaboration, and to adopt new conservation strategies that are implemented in a systematic and holistic way and to ensure that these are adaptive to growing economic interest in this marine area.
In Paris in 2015, the global community agreed to limit global warming to well below 2 ∘∘C, aiming at even 1.5 ∘∘C. It is still uncertain whether these targets are sufficient to preserve marine ecosystems and prevent a severe alteration of marine biogeochemical cycles. Here, we show that stringent mitigation strategies consistent with the 1.5 ∘∘C scenario could, indeed, provoke a critical difference for the ocean’s carbon cycle and calcium carbonate saturation states. Favorable conditions for calcifying organisms like tropical corals and polar pteropods, both of major importance for large ecosystems, can only be maintained if CO22 emissions fall rapidly between 2025 and 2050, potentially requiring an early deployment of CO22 removal techniques in addition to drastic emissions reduction. Furthermore, this outcome can only be achieved if the terrestrial biosphere remains a carbon sink during the entire 21st century.
No-take marine protected areas (MPAs) are an important tool for conserving marine biodiversity and managing fisheries. However, with increasing environmental change driven by local and global stressors, it is critical to understand whether MPAs can continue to provide social, economic and conservation benefits in the long-term. Here, we compare coral reef benthic and fish assemblages across 17 paired MPA-fished control sites on three heavily populated, high elevation “mainland” islands, and four lowly populated, low elevation “offshore” islands that differed in their exposure to recent typhoons. Despite lower cover of macroalgae in MPAs compared to fished areas, especially on mainland islands, there were no consistent differences in benthic assemblages or total hard coral cover between paired MPA and fished reefs. Typhoons had severe negative effects on live hard coral cover, regardless of island type or MPA protection, and typhoon impacted reefs supported different fish assemblages and lower total biomass of fish, compared to non-impacted reefs. Although fish assemblage structure and total biomass differed between mainland and offshore islands, MPAs consistently supported a higher total biomass of fish than fished areas, with the magnitude of the MPA effect lower on typhoon impacted reefs. Our findings suggest that despite inherent differences in environmental conditions between mainland and offshore island coral reefs, MPAs can provide benefits to fish biomass, even when reefs are affected by typhoons. The development of management strategies that incorporate sound coastal land-use practices, while positioning MPAs in areas less prone to typhoon impact, will provide MPAs the best chance of success if climatic extremes increase.
This study investigates the bottlenose dolphin (Tursiops truncatus, Montagu 1821) habitat use in the Portofino marine protected area (NW Italy) and adjacent waters, a core area for the dolphins and a highly touristic area in the Mediterranean Sea. A permanent automated real-time passive acoustic monitoring system, able to detect and track dolphins continuously, was tested in the area within the activities of the Life+ Nature project ARION. The habits of bottlenose dolphins was investigated considering the resident rate inside the area, which quantifies the amount of time dolphins spent in these waters, by means of random forest regression. The dependency of dolphin resident rate was analyzed in relation to four explanatory variables: sea surface temperature, season, time of day, and proximity to the coast. Dolphins spent more time in the area during spring and when sea surface temperature ranged between 15–16°C. Summer resulted the season with lower dolphin residency with significant difference between working day and weekend, in the last the lowest residency was recorded. Main findings provide important information to properly manage the area in order to protect bottlenose dolphins.
Marine spatial planning aims to create a framework for the oceans and seas that minimise conflicts between economic activities within the marine environment while maintaining good environmental status. Although reports by international – and national – organisations suggest there are economic benefits to marine spatial planning this analysis has, to date, been aspatial. Employing an explorative Q methodology approach with ten participants, this paper seeks to address this spatial and distributive gap by exploring stakeholders (marine renewable energy, fishing industry, aquaculture and marine tourism) perceptions of the economic impacts of marine spatial planning across varying (local to national) geographical scales in the U.K. The paper develops a typology of three different perspectives on the economic impacts of marine spatial planning: the optimistic ‘place-makers’; the sceptical ‘place-holders’; and the utilitarian ‘place-less’. Findings highlight that participants loading onto a specific ‘type’ cannot simply be explained by stakeholder categorisation. This research contributes to the coastal management literature by identifying differing perceptions on the ‘spatial economic impact’ of marine spatial planning by economic actors utilising marine and coastal areas in the U.K.
The success of Marine Spatial Planning (MSP) depends on the effective participation of small-scale fishers (SSFs), and the extent to which marine governance in general can address the problems they face. As Poland's MSP in areas that are key to small-scale fisheries are yet to begin, this paper explores tensions in the country's looming coastal MSP processes through clarifying both the risks faced by SSFs and their perspectives on MSP. Using semi-structured interviews with SSFs and analytical literature reviews on small-scale fisheries, it is found that Poland's MSP is cast against a contentious history of marine resource management that shapes negative perceptions of and attitudes towards both the European Union-mediated MSP and marine scientists. Notably, SSFs believe that (1) authorities often undervalue and underutilize their experiential knowledge, (2) MSP is intended primarily to facilitate the siting of offshore wind farms and, (3) scientific knowledge is either not effectively communicated or is at the service of investors. A discussion follows that proposes measures through which planners can ensure procedural fairness. The paper concludes by offering TURF-Reserves as a novel and integrated co-management system within MSP which has potentials for empowering SSFs and revitalizing Poland's small-scale fisheries, while ensuring effective marine protection.
Natural protected areas are often required to concurrently support conservation and tourism development. Estimating the ecosystem's carrying capacity and setting up visitor access limitations is a common approach in maximising resource use to avoid environmental degradation. Our research used a case study strategy and a political ecology approach to analyse the conflict surrounding a carrying capacity-based management plan implemented in a Mediterranean marine protected area under severe pressure from scuba diving. A mixed documental and discourse analysis method based on fieldwork, grey literature and 16 semi-structured interviews with representatives of seven groups of stakeholders was used. Results indicate that although the carrying capacity approach was instrumentally supported by all groups, conventional scientific ecological knowledge played only a specious role in decision-making. Factors related to path dependency, neoliberal governance frameworks, uneven distribution of power among stakeholders and regulatory weaknesses were found to be the most influential in facilitating increased visitor pressure in the reserve. We conclude that, in order to be effective and mitigate social conflict, natural resource management strategies based on the carrying capacity concept must be complemented with a precursory assessment of the biopolitical context to align the goals of planning with the possibilities of the socially constructed environment.
Multi-purpose marine protected areas (MPAs) are prevalent world-wide as institutional mechanisms deployed in the marine environment to manage multiple uses, conserve resources and protect ecosystems. Yet some people may experience disadvantage following the implementation of new MPAs. One understudied aspect of MPAs is the distribution of advantages and disadvantages and how best to address the “justice” concerns that they raise. This article identifies a framework of principles, methods and tools to address these concerns. It devises a “MPA justice model” and demonstrates its applicability to a Taiwanese case study. In 2014, Taiwan proclaimed its first multiple-purpose MPA, the South Penghu Marine National Park and the case study shows ways that the MPA’s socio-economic sustainability could have been better accomplished. The article focuses on future MPA establishment that incorporates distributional fairness and procedural legitimacy into MPA site designation and zoning design - but might also be adapted to use retrospectively in MPA review processes.