The sensitivity of Antarctic sea-ice to increasing glacial freshwater release into the Southern Ocean is studied in a series of 31-year ocean/sea-ice/iceberg model simulations. Glaciological estimates of ice-shelf melting and iceberg calving are used to better constrain the spatial distribution and magnitude of freshwater forcing around Antarctica. Two scenarios of glacial freshwater forcing have been designed to account for a decadal perturbation in glacial freshwater release to the Southern Ocean. For the first time, this perturbation explicitly takes into consideration the spatial distribution of changes in the volume of Antarctic ice shelves, which is found to be a key component of changes in freshwater release. In addition, glacial freshwater-induced changes in sea ice are compared to typical changes induced by the decadal evolution of atmospheric states. Our results show that, in general, the increase in glacial freshwater release increases Antarctic sea ice extent. But the response is opposite in some regions like the coastal Amundsen Sea, implying that distinct physical mechanisms are involved in the response. We also show that changes in freshwater forcing may induce large changes in sea-ice thickness, explaining about one half of the total change due to the combination of atmospheric and freshwater changes. The regional contrasts in our results suggest a need for improving the representation of freshwater sources and their evolution in climate models.
At the United Nations Ocean Conference in June 2017, Member States reaffirmed their obligation to conserve and responsibly use the oceans, seas and marine resources for sustainable development. Promoting the use of effective and appropriate area- based management tools, such as marine protected areas, was among the renewed pledges. Marine protected areas o er one of the best options for maintaining healthy oceans. In the last decade, countries around the world have progressively taken actions to designate new, or to enlarge existing, marine protected areas to safeguard natural resources and ecological functions. To date, around 14.4 per cent of the world’s coastal and marine areas under national jurisdictions are declared protected. This signals the commitment of the global community to safeguard these precious ecosystems. For marine protected areas to be truly effective, however, they also require strong governance that involves relevant users and stakeholders, influences their behaviour, and ultimately reduces the impacts that result from extractive practices. Effective sharing of costs and benefits of marine protected areas is an essential step to ensure genuine sustainable development.
A growing number of studies have documented increasing dominance of warm-water fish species (“tropicalisation”) in response to ocean warming. Such reorganization of communities is starting to occur in a multitude of local ecosystems, implying that tropicalisation of marine communities could become a global phenomenon. Using 32 years of trawl surveys in the Bay of Somme (English Channel, France), we aimed to investigate the existence of a tropicalisation in the fish community at the local scale of the estuary during the mid-1990s, a period where an exceptional temperature rise occurred in Northeast Atlantic. A long-term response occurred (with a major transition over 6 years) that was characterized by a marked diminution in the abundance of cold-water species in parallel to a temperature rise generated by the ocean-scale phenomenon, the Atlantic Multidecadal Oscillation, which switched from a cool to a warm phase during the late 1990s. Despite finding no significant increase in the dominance of warm-water species, the long-term diminution of cold-water species suggests that the restructuring of the fish community was mainly influenced by global-scale environmental conditions rather than local ones and that indirect effects may also occurred through biological interactions.
Highly dynamic ocean environments can experience dramatic changes over relatively short timeframes, affecting the spatial distribution of resources and therefore the presence or absence of highly mobile species. We use simulation studies to investigate how different temporal resolutions might affect the results of species distribution models for highly mobile species (e.g. cetaceans) in marine environments.
Azores archipelago, Portugal.
We developed three virtual species with different habitat preferences influenced by (1) only static (topographic), (2) only dynamic (oceanographic), and (3) both dynamic and static variables. Assuming that species would reposition themselves daily according to these preferences (as has been observed for large marine foragers such as cetaceans), we used two different approaches (generalized linear model and generalized boosted model) to test the effect of using daily, weekly and monthly environmental datasets to model distributions.
The results showed that the selection of different temporal scales has a very important effect on model predictions. When dynamic variables are important components of habitat preference, models based on daily or weekly timeframes performed best at reconstructing the known niche.
It is important that we consider temporal resolution when applying species distribution models. Several factors (e.g. species ecology and oceanographic characteristics of the ecosystem) should be taken into consideration when selecting an adequate temporal scale for niche modelling. For fine scale applications (e.g. dynamic ocean management), highly dynamic ecosystems, and highly mobile species, our results suggest exploring temporal resolution of 7–8 days rather than coarser temporal scales. For some applications annual, seasonal or even monthly averages may produce inferior or inaccurate models.
The oceans absorb ~25% of the annual anthropogenic CO2 emissions. This causes a shift in the marine carbonate chemistry termed ocean acidification (OA). OA is expected to influence metabolic processes in phytoplankton species but it is unclear how the combination of individual physiological changes alters the structure of entire phytoplankton communities. To investigate this, we deployed ten pelagic mesocosms (volume ~50 m3) for 113 days at the west coast of Sweden and simulated OA (pCO2 = 760 μatm) in five of them while the other five served as controls (380 μatm). We found: (1) Bulk chlorophyll a concentration and 10 out of 16 investigated phytoplankton groups were significantly and mostly positively affected by elevated CO2 concentrations. However, CO2 effects on abundance or biomass were generally subtle and present only during certain succession stages. (2) Some of the CO2-affected phytoplankton groups seemed to respond directly to altered carbonate chemistry (e.g. diatoms) while others (e.g. Synechococcus) were more likely to be indirectly affected through CO2 sensitive competitors or grazers. (3) Picoeukaryotic phytoplankton (0.2–2 μm) showed the clearest and relatively strong positive CO2 responses during several succession stages. We attribute this not only to a CO2 fertilization of their photosynthetic apparatus but also to an increased nutrient competitiveness under acidified (i.e. low pH) conditions. The stimulating influence of high CO2/low pH on picoeukaryote abundance observed in this experiment is strikingly consistent with results from previous studies, suggesting that picoeukaryotes are among the winners in a future ocean.
Heterotrophic feeding in newly-settled coral planulae can potentially improve survivorship and accelerate early development in some species; however, an optimal diet to facilitate this does not currently exist. This study evaluated the efficacy of three heterotrophic feeding regimes (enriched rotifers, unfiltered seawater, and a novel, particulate diet), against a wholly-phototrophic treatment on Acropora hyacinthus, A. loripes, A. millepora, and A. tenuis recruits, over 93 days post-settlement. The unfiltered seawater treatment recorded maximum survival for all species (A. hyacinthus 95.9±8.0%, A. loripes: 74.3±11.5%, A. millepora: 67±12.7%, A. tenuis: 53.2±11.3%), although not significant. Growth (% surface area gain) was also greatest in the unfiltered seawater, and this was significant for A. millepora (870±307%) and A. tenuis(693±91.8%) (p<0.05). Although total lipid concentration was relatively stable across treatments, the lipid class composition exhibited species-specific responses to each treatment. Lower saturated and higher polyunsaturated fatty acids appeared beneficial to recruit performance, particularly in the unfiltered seawater, which generally contained the highest levels of 20:5n-3 (EPA), 22:6n-3 (DHA), and 20:4n-6 (ARA). The present study demonstrates the capacity of a nutritionally adequate and readily accepted heterotrophic feeding regime to increase coral recruit survival, growth, and health, which can greatly reduce the time required in cost- and labour-intensive culture.
What (and how) we grow, harvest or extract from the ocean has significant implications for long term sustainability of this immense ecosystem. Our current industrial approach to seafood harvesting is clearly not sustainable and cities can and must take the lead in developing new approaches. Urbanites must begin to shift their consumer and political power behind more sustainable ideas and practices. Some of these new approaches are explored here, including support for smaller scale, locally based fishing (and new mechanisms such as Community Supported Fisheries [CSFs]), and a shift towards more sustainable and humane forms of shellfish aquaculture and ocean vegetable farming.
International instruments of fisheries governance have set the core principles for the management of highly migratory fishes. We evaluated the progress of tuna Regional Fisheries Management Organizations (tRFMOs) in implementing the ecological component of ecosystem-based fisheries management (EBFM). We first developed a best case tRFMO for EBFM implementation. Second, we developed criteria to evaluate progress in applying EBFM against this best case tRFMO. We assessed progress of the following four ecological components: target species, bycatch species, ecosystem properties and trophic relationships, and habitats. We found that many of the elements necessary for an operational EBFM are already present, yet they have been implemented in an ad hoc way, without a long-term vision and a formalized plan. Overall, tRFMOs have made considerable progress monitoring the impacts of fisheries on target species, moderate progress for bycatch species, and little progress for ecosystem properties and trophic relationships and habitats. The tRFMOs appear to be halfway towards implementing the ecological component of EBFM, yet it is clear that the “low-hanging fruit” has been plucked and the more difficult, but surmountable, issues remain, notably the sustainable management of bycatch. All tRFMOs share the same challenge of developing a formal mechanism to better integrate ecosystem science and advice into management decisions. We hope to further discussion across the tRFMOs to inform the development of operational EBFM plans.
The marine world is, to many, remote and exotic. For city residents to fully embrace the wonder and beauty of the ocean world, and to actively work on its behalf, it will require emotional connection and caring. There are many different ways to do this and several of the more compelling and creative are described here: using social media to foster a sense of fascination and concern for the great white shark; taking children into the water and challenging them to find, look, touch and learn about the nature there; sending real-time video images from underwater divers to the surface; developing new long term institutions, such as a New York Harbor School and the Billion Oyster Project, to educate and engage residents of all ages. There are now compelling models that other cities can follow to foster this deep sense of emotional connection and caring for the marine realm.
The interconnectedness of ecosystems and the integration of policy and society are relevant aspects of integrated management grounded in knowledge exchange practices. Such processes may also promote social learning, the joint and collaborative knowledge to tackle environmental problems. Thus, understanding knowledge exchange is an additional strategy to promote and understand social learning. This article analyzed a knowledge exchange process related to the elaboration of a proposal for the spatial delimitation of a marine protected area in Brazil, a developing country. By combining process observation and geographical information system tools, proposed areas and criteria for delimitation elaborated by different groups of stakeholders (non-scientists and scientists), separately and in an integrated discussion, were compared and used to test the hypotheses that integration under a knowledge exchange process can bring substantive changes in the outcomes of a management process, and that knowledge exchange processes can promote social learning. Results showed that the integration of different knowledge led to results that none of the groups reached in separate discussions, such as the identification of new areas, delimitation of an area of influence and new criteria for delimitation. Changes in knowledge, the framing and reframing of the processes, understating system complexity and social context were observed, which indicates that knowledge exchange promoted social learning. Additionally, the criteria used to support the delimitation proposals in the studied area can be applied to other marine protected areas in other contexts, and the methods used to guide the discussion can be adapted to other issues.
An Adaptive assessment and management toolkit has been developed for data-limited fisheries.
The toolkit is a comprehensive package for assessing and managing small-scale fisheries.
A simple but powerful open-source toolkit dashboard can be used online or offline.
The toolkit can accommodate varying degrees of data availability and multiple indicators.
The toolkit was piloted for nine species in Karimunjawa National Park, Indonesia.
Sharks are charismatic predators that play a key role in most marine food webs. Their demonstrated vulnerability to exploitation has recently turned them into fagship species in ocean conservation. Yet, the assessment and monitoring of the distribution and abundance of such mobile species in marine environments remain challenging, often invasive and resource-intensive. Here we pilot a novel, rapid and non-invasive environmental DNA (eDNA) metabarcoding approach specifcally targeted to infer shark presence, diversity and eDNA read abundance in tropical habitats. We identifed at least 21 shark species, from both Caribbean and Pacifc Coral Sea water samples, whose geographical patterns of diversity and read abundance coincide with geographical diferences in levels of anthropogenic pressure and conservation efort. We demonstrate that eDNA metabarcoding can be efectively employed to study shark diversity. Further developments in this feld have the potential to drastically enhance our ability to assess and monitor elusive oceanic predators, and lead to improved conservation strategies.
Small-scale fisheries play an important role in contributing to food security, nutrition, livelihoods and local and national economies. However, there is often limited data and information available on their contributions, and hence small scale fisheries tend to be overlooked and marginalized in policy processes, leading to low levels of support for the sector. This proceedings provides a summary of the presentations, discussions, conclusions and recommendations of the “Workshop on Improving our Knowledge on Small-Scale Fisheries: Data Needs and Methodologies,” held at the Food and Agriculture Organization of the United Nations headquarters in Rome, Italy, in June 2017. Through the workshop, it was determined that a comprehensive new study to illuminate the hidden contributions of small-scale fisheries to the three dimensions of sustainable development, as well as identification of key threats to these contributions was needed.
As human impacts on marine ecosystems escalate, there is increasing interest in quantifying sub-lethal physiological and pathological responses of marine mammals. Glucocorticoid hormones are commonly used to assess stress responses to anthropogenic factors in wildlife. While obtaining blood samples to measure circulating hormones is not currently feasible for free-swimming large whales, immunoassay of fecal glucocorticoid metabolites (fGCs) has been validated for North Atlantic right whales Eubalaena glacialis (NARW). Using a general linear model, we compared fGC concentrations in right whales chronically entangled in fishing gear (n = 6) or live-stranded (n = 1), with right whales quickly killed by vessels (n = 5) and healthy right whales (n = 113) to characterize fGC responses to acute vs. chronic stressors. fGCs in entangled whales (mean ± SE: 1856.4 ± 1644.9 ng g-1) and the stranded whale (5740.7 ng g-1) were significantly higher than in whales killed by vessels (46.2 ± 19.2 ng g-1) and healthy whales (51.7 ± 8.7 ng g-1). Paired feces and serum collected from the live-stranded right whale provided comparison of fGCs in 2 matrices in a chronically stressed whale. Serum cortisol and corticosterone in this whale (50.0 and 29.0 ng ml-1, respectively) were much higher than values reported in other cetaceans, in concordance with extremely elevated fGCs. Meaningful patterns in fGC concentration related to acute vs. chronic impacts persisted despite potential for bacterial degradation of hormone metabolites in dead whales. These results provide biological validation for using fGCs as a biomarker of chronic stress in NARWs.
Low Elevation Coastal Zones (LECZ) are located at less than 10 m above sea level. Because of human encroachment, combined with sea level rise and increased storminess, LECZ are at an increasing risk of flooding and erosion. In consequence, there is a growing need for shoreline protection. Traditionally, hard infrastructure was used, with positive local results, but negative regional impacts when flows were not maintained. Therefore, ecosystem-based coastal protection has been considered as an alternative. We explored the scientific literature to look for evidence that proves the effectiveness of natural ecosystems for protection against flooding and erosion, when these events are a problem to society. We found that although the protective role of vegetation has been mentioned for over 50 years, most of the studies date from the last decade and have been performed in the USA and the Netherlands. Mangroves, saltmarshes and coastal dunes are the ecosystems most frequently studied. The evidence we found includes anecdotal observations, experimental tests, mathematical analyses, models and projections, economic valuations and field observations. Although mostly effective, there are limitations of an ecosystem-based approach and probably, different strategies can be combined so that protection is improved while additional ecosystem services are maintained. We conclude that, besides improving coastal protection strategies, it is fundamental to reduce human pressure by mobilizing populations inland (or at least promoting new developments further inland), and minimizing the negative impact of human activities. We need to be better prepared to deal with the climate change challenges that will affect LECZ in the not very distant future.
This study presents an economic valuation survey to estimate the social demand of a convenience sample for undertaking forest management measures aimed at reducing the negative impact of forest fires on terrestrial and marine ecosystems. The paper spans the traditional focus in forest economics by considering also the negative effects caused by forest fires in coastal areas, highlighting this way how the externalities go beyond the terrestrial area and can also affect marine ecosystems. Results from a willingness to pay in space modelling approach show that people are sensitive to the biodiversity losses produced by forest fires and are willing to pay (work on a voluntary basis) to undertake activities that reduce their impact. The main negative externalities are concerned to the terrestrial wildlife (animals and vegetation), following by the erosion and marine biodiversity losses and the pests and diseases prevention.
As the levels of radioactivity in seafood have fallen back into the safe range, Fukushima fisheries are considering reopening. However, even if seafood from the Fukushima area were sufficiently safe to distribute to seafood markets, its value may be undermined because of the damage done to its reputation by the Fukushima disaster. We quantified consumers’ preferences for seafood from Fukushima and adjacent prefectures to examine the extent of the reputational damage to Fukushima seafood. We conducted a choice experiment to measure consumers’ willingness to pay for seafood from the Fukushima area. We also measured the impact of displaying ecolabels [Marine Stewardship Council (MSC) and Marine Eco-label Japan (MEL)] on Fukushima products. The results indicated that Fukushima products are considerably discounted compared with products displayed as domestic; even products from adjacent prefectures are substantially discounted. By contrast, consumers positively evaluated locally labeled products. We also found that demersal fish are discounted more than pelagic fish that inhabit the ocean surface off the shore of Fukushima.
The degradation of coral reefs is widely reported, yet there is a poor understanding of the adaptability of reef fishes to cope with benthic change. We tested the effects of coral reef degradation on the feeding plasticity of four reef fish species. We used isotopic niche sizes and mean δ15N and δ13C values of each species in two coral reefs that differed in benthic condition. The species chosen have contrasting feeding strategies; Chaetodon lunulatus (corallivore), Chrysiptera rollandi (zooplanktivore), Halichoeres melanurus (invertivore) and Zebrasoma velifer (herbivore). We predicted that the corallivore would have a lower mean δ15N value and a smaller isotopic niche size in the degraded reef, that the herbivore and the invertivore might have a larger isotopic niche size and/or a different mean δ13C value, whereas the zooplanktivore might be indifferent since the species is not linked to coral degradation. Some results matched our predictions; C. lunulatus had a smaller niche size on the degraded reef, but no difference in mean δ15N and δ13C values, and H. melanurus displayed an increase in niche size and a lower mean δ15N value on the degraded reef. Some other results were contrary to our predictions; whereas Z. velifer and C. rollandi had smaller mean δ13C values but no difference in niche size. Our findings suggest there may be feeding plasticity to maintain a similar diet despite contrasting habitat characteristics, with different amplitude depending on species. Such findings suggest that certain species guilds would probably adapt to changes linked to habitat degradation.
For Pacific Island communities, social change has always been a part of their socio-political lives, while environmental changes were always transient and reversible, so that they understood and engaged with their ocean as a provider for food, culture and life. However, recent unprecedented and irreversible changes brought on by global climate change challenge this norm and alter their lagoons and adjacent oceans into unfamiliar territories. Climate change already is affecting, and has been projected to continue to disproportionately impact, Pacific Island Countries and Territories (PICTs) through rising temperatures, sea-level rise, saltwater intrusion of freshwater resources, coastal erosion, an increase in extreme weather events, altered rainfall patterns, coral reef bleaching, and ocean acidification. While knowledge is building about potential impacts on ecosystems and some target stocks, there is little information available for communities, governments and regional institutions on how to respond to these changes and adapt. What are the consequences for marine conservation, fisheries management and coastal planning at local, national and regional scales? What strategies and policies can best support and enable responses to these challenges across different scales? What opportunities exist to finance necessary climate change adaptation and mitigation measures? To consider these urgent issues, this paper synthesises innovative research methods, and studies many of the looming scientific, policy and governance challenges from a diversity of perspectives and disciplines.
Spatial planning has to deal with trade-offs between various stakeholders’ wishes and needs as part of planning and management of landscapes, natural resources and/or biodiversity. To make ecosystem services (ES) trade-off research more relevant for spatial planning, we propose an analytical framework, which puts stakeholders, their land-use/management choices, their impact on ES and responses at the centre. Based on 24 cases from around the world, we used this framing to analyse the appearance and diversity of real-world ES trade-offs. They cover a wide range of trade-offs related to ecosystem use, including: land-use change, management regimes, technical versus nature-based solutions, natural resource use, and management of species. The ES trade-offs studied featured a complexity that was far greater than what is often described in the ES literature. Influential users and context setters are at the core of the trade-off decision-making, but most of the impact is felt by non-influential users. Provisioning and cultural ES were the most targeted in the studied trade-offs, but regulating ES were the most impacted. Stakeholders’ characteristics, such as influence, impact faced, and concerns can partially explain their position and response in relation to trade-offs. Based on the research findings, we formulate recommendations for spatial planning.