Coral bleaching is the detrimental expulsion of algal symbionts from their cnidarian hosts, and predominantly occurs when corals are exposed to thermal stress. The incidence and severity of bleaching is often spatially heterogeneous within reef-scales (<1 km), and is therefore not predictable using conventional remote sensing products. Here, we systematically assess the relationship between in situ measurements of 20 environmental variables, along with seven remotely sensed SST thermal stress metrics, and 81 observed bleaching events at coral reef locations spanning five major reef regions globally. We find that high-frequency temperature variability (i.e., daily temperature range) was the most influential factor in predicting bleaching prevalence and had a mitigating effect, such that a 1 °C increase in daily temperature range would reduce the odds of more severe bleaching by a factor of 33. Our findings suggest that reefs with greater high-frequency temperature variability may represent particularly important opportunities to conserve coral ecosystems against the major threat posed by warming ocean temperatures.
A changing climate, in particular a warming ocean, is likely to impact marine industries in a variety of ways. For example, aquaculture businesses may not be able to maintain production in their current location into the future, or area-restricted fisheries may need to follow the fish as they change distribution. Preparation for these potential climate impacts can be improved with information about the future. Such information can support a risk-based management strategy for industries exposed to both short-term environmental variability and long-term change. In southern Australia, adverse climate impacts on valuable seafood industries have occurred, and they are now seeking advice about future environmental conditions. We introduce a decision tree to explain the potential use of long-term climate projections and seasonal forecasts by these industries. Climate projections provide insight into the likely time in the future when current locations will no longer be suitable for growing or catching particular species. Until this time, seasonal forecasting is beneficial in helping industries plan ahead to reduce impacts in poor years and maximize opportunities in good years. Use of seasonal forecasting can extend the period of time in which industries can cope in a location as environmental suitability declines due to climate change. While a range of short-term forecasting approaches exist, including persistence and climatological forecasts, only dynamic model forecasts provide a viable option for managing environmental risk for marine industries in regions where climate change is reducing environmental suitability and creating novel conditions.
Most research studies related to biodiversity offsetting have focused on governance systems already in place in the terrestrial realm – these studies tend to rely on an approach of organizational economics, in particular in relation to mitigation banking schemes. In this study, emerging marine offsetting governance systems has been analyzed using the Actor–Network Theory (ANT) with the aim of highlighting the key elements that enable the emergence of marine offsetting tools. The ANT framework has been applied to four case studies in California using data collected in a field study that consisted of interviewing 30 stakeholders working closely with the issue of marine offsetting. Employing ANT allowed to ascertain the role of commonly studied elements such as impacted ecosystems, sizing methodologies and ecological engineering techniques. Further, it highlighted the key role of other critical factors, such as ‘skilled intermediaries’, who succeed in overcoming uncertainties generated by the use of new tools and contribute to leading other stakeholders towards the goal: the offset instrument. These mediators call upon effective translation processes to put forward new arguments: a change in spatial and temporal scales and adaptive solutions. The findings point to a line of approach that encourages reconfiguring environmental governance systems that could benefit from feedbacks from Integrated Coastal Zone Management (ICZM) and Marine Spatial Planning (MSP) processes, in order to facilitate the development of marine offset schemes.
Marine eutrophication in the North-East Atlantic (NEA) strongly relies on nutrient enrichment at the river outlets, which is linked to human activities and land use in the watersheds. The question is whether human society can reduce its nutrient emissions by changing land use without compromising food security. A new version of Riverstrahler model (pyNuts-Riverstrahler) was designed to estimate the point and diffuse nutrient emissions (N, P, Si) to the rivers depending on land use in the watersheds across a large domain (Western Europe agro-food systems, waste water treatment). The loads from the river model have been used as inputs to three marine ecological models (PCOMS, ECO-MARS3D, MIRO&CO) covering together a large part of the NEA from the Iberian shelf to the Southern North Sea. The modelling of the land-ocean continuum allowed quantifying the impact of changes in land use on marine eutrophication. Pristine conditions were tested to scale the current eutrophication with respect to a “natural background” (sensu WFD), i.e. forested watersheds without any anthropogenic impact. Three scenarios representing potential management options were also tested to propose future perspectives in mitigating eutrophication. This study shows that a significant decrease in nitrogen fluxes from land to sea is possible by adapting human activities in the watersheds, preventing part of the eutrophication symptoms in the NEA rivers and adjacent coastal zones. It is also shown that any significant achievement in that direction would very likely require paradigmatic changes at social, economic and agricultural levels. This requires reshaping the connections between crop production and livestock farming, and between agriculture and local human food consumption. It also involves cultural changes such as less waste production and a shift towards lower-impact and healthier diets where half of the animal products consumption is replaced by vegetal proteins consumption, known as a demitarian diet (http://www.nine-esf.org/node/281/index.html).
Understanding the full extent of past ecological changes in human-influenced marine systems is needed to inform present management policies, but is often hampered by the scarcity of information about exploitation practices and population status over the entire history of fishing. The history of commercial fishing in South East Australia is relatively recent and thus easier to document. Our aim is to reconstruct such history and to use this information to understand general patterns and consequences of fishing exploitation. Intense exploitation of marine resources arrived in South East Australia with European colonization in the early 1800s, and unregulated sealing, whaling and oyster dredging resulted in the first documented significant impact on local marine populations. Exploitation extended to demersal resources in 1915 when the trawl fishery developed. Between the early 1800s and the 1980s, some of the exploited stocks collapsed, but fishing moved further offshore and in deeper waters as technology improved and new resources became available or were discovered. This phase of fisheries expansion masked the unsustainable nature of some fishing industries, such as trawling and whaling, and postponed the need for management regulations. From the 1990s onward, an increasing awareness of the depleted nature of some fisheries led to the establishment of management strategies aiming at a more sustainable exploitation of target stocks and, from the mid-2000s onwards, management strategies were revised and improved to better address the effect of fishing on multiple components of marine ecosystems. This led to the recovery of some depleted populations and to increased habitat protection. The relatively short history of fishing exploitation and the small scale of the fishing industry in South East Australia played a significant role in limiting the magnitude of fishing impacts on local populations and helped to achieve recoveries when fisheries restrictions were imposed. However, the experience in South East Australia also shows that ecological improvements for some depleted populations can be slow, suggesting that the time to recovery may be longer than expected despite relatively low historical and present levels of exploitation, favorable social conditions and a large investment in resource management and scientific research.
Bycatch interactions with deep-sea elasmobranchs are increasingly common and can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and post-release mortality (PRM) than their shallower counterparts. Unfortunately, robust PRM rates have not yet been estimated for longline-caught deep-sea sharks, and as such are not currently incorporated into total fishery mortality estimates or bycatch assessments, limiting the effectiveness of current conservation or management initiatives. We empirically estimated PRM for 2 focal taxa of deep-sea shark, the Cuban dogfish Squalus cubensis and the gulper shark Centrophorus sp., using post-release enclosures deployed at-depth. We calculated 24 h PRM rates of 49.7 ± 8.5% (mean ± SE) for S. cubensis and 83 ± 16% for Centrophorus sp. and identified blood lactate, total length, glucose, and vitality scores as predictors of PRM in S. cubensis. We also observed all 24 h PRM within 11 h post-capture and demonstrated the effects of recovery depth and at-vessel blood chemistry metrics on post-release behavior. Our results suggest that PRM rates of deep-sea sharks are high and highlight the need for filling in this gap in fishery mortality estimates for other common discards in the future.
Food insecurity remains a common problem for Southeast Asian communities that specialise in fishing. Food insecurity is closely linked to other social conditions, and the linkages between these social conditions and their underlying drivers are less well explored in fishing contexts than they are in agricultural contexts. In this paper I draw on fieldwork from a community that specialises in fishing in the Western Philippines to examine the linkages between and drivers of food and water insecurity. Food insecurity is common, and characterised by a lack of funds to buy food, particularly during periods of bad weather. Water insecurity is also characterised by the need to pay for the delivery of drinking water from one of several remote sources. Because of the central role of markets in communities that specialise in fishing, I argue that both food and water insecurity are driven by income poverty. Understanding the relations between food and water insecurity and the wider drivers of poverty in specialised fishing community contexts should generate improved understandings of how food and water insecurity persist, and how these conditions may be better addressed.
For the first time, this research addresses the assessment of the quality of knowledge embedded in beach quality indexes from a socioecological perspective. We took the most widespread beach quality indexes and identified, selected and assessed the most important existing assumptions. We scored the robustness of these assumptions, using an inclusive methodology (stakeholder meeting, four focus groups and an online questionnaire). The NUSAP criteria for assessing the value-ladenness of scientific studies (Influence of resource limitations, (Im)Plausibility, Choice space, Agreement among peers, Analysts’ subjectivity and Influence on global results) were contrasted and discussed. A final list of the 10 weakest assumptions was presented and discussed. Most of these assumptions are fairly robust, but attention should mainly focus on their influence on global outcomes and (im)plausibility, as the weakest scored criteria. The choice space scores revealed the possibility of including new alternatives to the assumptions, when necessary. Assumptions loaded with framing concepts are weaker than those linked to more concrete objectives. We detected dissociation between the discourse and the operational development of the indexes, in which the narratives prioritizing user satisfaction are predominant and scientific data analysis is often decontextualized. We therefore suggest that science should be opened up throughout the building process of indexes: from the identification of problems to the reporting of results and related uncertainties. The NUSAP method proved to be useful for identifying weak points in beach quality indexes.
This article illustrates how the creation of a Marine Protected Area (MPA) in Malta is failing to adequately include stakeholders in the configuration of conservation targets and measures, leaving local fishers increasingly disempowered. Through a series of interviews and long-term participatory observation, it has been found that the leaders who represent local fishers are failing to communicate the MPA process to their community. Instead, they are using their position in the MPA negotiations to subjugate and silence the fishing community in general and trammel netters in particular. Moreover, in their support for the MPA, these community leaders reproduce the state's conservation discourse to pressure authorities to ban trammel net fishing, with whom they tend to be in competition. It is concluded that the state's narrow focus on ecology, the tight deadlines set out in the EU Habitats Directive, and the misrepresentation of the fishers, has characterised the process of creating this MPA. If artisanal livelihoods are not protected by conservation policies, fishers may regard conservation as a threat to their way of life, and resist policy measures. This compromises conversation efforts and can make the enforcement of the MPAs more expensive. This paper recommends a revision of the community consultation policies of the MPA to allow broader and more representative participation from the local community by encouraging engagement throughout the process as part of a consensual approach to effective marine conservation.
Understanding global fisheries patterns contributes significantly to their management. By combining harmonized unmapped data sources with maps from satellite tracking data, regional tuna management organisations, the ranges of fished taxa, the access of fleets and the logistics of associated fishing gears the expansion and intensification of marine fisheries for nearly a century and half (1869–2015) is illustrated. Estimates of industrial, non-industrial reported, illegal/unreported (IUU) and discards reveal changes in country dominance, catch composition and fishing gear use. Catch of industrial and non-industrial marine fishing by year, fishing country, taxa and gear by 30-min spatial cell broken to reported, IUU and discards is available. Results show a historical increase in bottom trawl with corresponding reduction in the landings from seines. Though diverse, global landings are now dominated by demersal and small pelagic species.