Coastal wetlands are among the most productive ecosystems in the world. They generate critical services for humans including shoreline protection, carbon storage, pollution mitigation, and fisheries production. Restoration of coastal wetlands has historically been viewed as a secondary conservation strategy, but recently—given the continued loss of wetlands worldwide—many non-governmental and governmental organizations have elevated habitat restoration to be a primary method for wetland conservation. The long-held paradigm in coastal wetland restoration has been to restore target habitats by reducing physical stressors and avoiding competition among outplants, such as mangrove saplings or Spartina plugs. Recent ecological research, however, reveals that positive species interactions, such as facilitation, are critical to wetland recovery after disturbance. Here, we review the scientific evidence for the importance of positive species interactions in the recovery of salt-marsh and mangrove ecosystems and assess the extent to which they have been integrated into restoration studies. We found that only a small proportion of studies of marsh and mangrove restoration examined the effects of positive species interactions, despite the important role they play in the regrowth of coastal wetlands. We outline how positive species interactions can be systematically incorporated into future restoration work and discuss how this incorporation can help the reestablishment of coastal wetland biota through: (1) trophic facilitation, (2) stress reduction, and (3) associational defenses. The absence of positive interactions in restoration designs may partially explain the significant disparities between the functioning of natural and restored coastal plant ecosystems.
We present a general size- and age-structured demographic model of the continental phase of catadromous eels’ life cycle, allowing for the incorporation of (i) fluctuations of juvenile recruitment, (ii) density-dependent settlement and sex determination, (iii) plastic body growth and sexual dimorphism, and (iv) vital rates driven by body size rather than age. The model can be used to assess (i) standing stock, (ii) fishing yield, and (iii) spawner production under different recruitment and management scenarios. We demonstrate the model by applying it to a European eel stock (Camargue lagoons, southern France) that was continuously monitored for 17 years (1993–2009). Results indicate that the upper limit to settlement in the Camargue water system is ∼419 eels ha−1 per year. A balanced sex ratio occurs for a settlement of ∼94 eels ha−1, shifting towards males at higher densities. Catchability is higher in adult silver eels than in sub-adult yellow eels, possibly due to behavioural differences. Estimated standing stock ranged between 7 and 19 kg ha−1. Fishing yield was 5–7 kg ha−1 per year, while spawner escapement ranged between 0 and 13 kg ha−1per year (<30% of what would occur in the absence of fishing and obstacles to migration).
Pollution of the environment with plastic debris is a significant and rapidly expanding threat to biodiversity due to its abundance, durability, and persistence. Current knowledge of the negative effects of debris on wildlife is largely based on consequences that are readily observed, such as entanglement or starvation. Many interactions with debris, however, result in less visible and poorly documented sublethal effects, and as a consequence, the true impact of plastic is underestimated. We investigated the sublethal effects of ingested plastic in Flesh-footed Shearwaters (Ardenna carneipes) using blood chemistry parameters as a measure of bird health. The presence of plastic had a significant negative effect on bird morphometrics and blood calcium levels and a positive relationship with the concentration of uric acid, cholesterol, and amylase. That we found blood chemistry parameters being related to plastic pollution is one of the few examples to date of the sublethal effects of marine debris and highlights that superficially healthy individuals may still experience the negative consequences of ingesting plastic debris. Moving beyond crude measures, such as reduced body mass, to physiological parameters will provide much needed insight into the nuanced and less visible effects of plastic.
The adaptive capacity of individuals, from their cells to their overall performance, allows species to adjust to environmental change. We assess a hierarchy of responses (from cells to organismal growth and behaviour) to understand the flexibility of adaptive responses to future ocean conditions (warming and acidification) in two species of fish with short lifespans by conducting a long-term mesocosm/aquarium experiment. Fishes were exposed to elevated CO2 and temperature in a factorial design for a five-month period. We found a feedback mechanism between cellular defence and behavioural responses. In circumstances where their antioxidant defence mechanism was activated (i.e. warming or acidification), increased feeding rates prevented oxidative damage (i.e. during warming). However, when feeding rates failed to increase to provide additional energy needed for antioxidant defence, oxidative damage could not be prevented (warming + acidification). In contrast, when the activation of antioxidant defence was not required, energy intake from increased feeding was redirected to increased fish growth (acidification, warming + acidification), whilst no gain in growth rate was observed where feeding remained unchanged (acidification or warming). This adaptive strategy seems to rely on the inherent behavioural response of fishes to their environment and such adjustability shows the kind of responses that organisms may express to prevail in future ocean climate. Indeed, assessing the link between responses from cellular to organismal levels, using a diversity of fitness indicators and behaviour, provides a fundamental understanding of how organisms as a whole may adjust to prevail in a future world.
Marine extraction accounts for one third of the world’s hydrocarbon production. Several analyses suggest that seismic surveys employed in oil exploration harm marine life; however, their long-term impacts have not been extensively studied. We examine debates between fishers, the oil industry, and governmental authorities over the effects of oil explorations in Tabasco, Mexico. The study employs ideas from historical ontology in tracing the contested production of truth-claims about exploration in the context of scientific uncertainty. It shows how actors, through their different engagements with the sea, and with different degrees of power, frame claims about the relations between exploration and fish. We argue that fishers, through their efforts to “think like fish” produce situated knowledges about the effects of oil exploration. They explain a disappearance of fish by their understanding that seismic surveys disturb fish migration, impair the hearing of fish and cause fish death. Oil company and governmental representatives frame the impacts of oil exploration as insignificant by separating environmental and social dimensions, by isolating individual exploration events, and by arguing that possible effects are transitional. Due to scientific indeterminacy, oil exploration is malleable in the hands of powerful political representations that understate its possible impacts on marine socio-environments.
This study re-examines the marine spatial planning (MSP) process for Germany's North Sea exclusive economic zone (EEZ), one of the earliest European examples of MSP. It does so in order to answer whether in this case MSP was an example of post-political planning (Swyngedouw, 2010; Tafon, 2018; Tafon et al., 2018). Building on earlier research (Jay et al., 2012; Kannen, 2014), the analysis adopts a political ecology perspective, and uses a stakeholder analysis and interviews to identify main actors in the MSP process and their interests in and perceptions of the North Sea, its management and the MSP process. The results confirm earlier research that MSP was used strategically to facilitate offshore wind energy development at the expense of other uses. MSP resolved some matters of spatial competition but not all, and solved few underlying conflicts, since these involve deep-seated tensions among diverse actor perceptions of the North Sea and its management. The research finds the German North Sea EEZ remains a politicized environment, in which MSP is a post-political approach to planning. The research highlights inter-agency tensions and politics as further signs that MSP as post-political planning has not eliminated politics in sea management.
National authorities in many countries advise their populations to eat more seafood, for health and sometimes for environmental purposes, but give little guidance as to what type of seafood should be consumed. The large diversity in species and production methods results in variability both in the nutritional content and in the environmental performance of seafoods. More targeted dietary advice for sustainable seafood consumption requires a better understanding of the relative nutritional benefits against environmental costs of various types of seafood. This study analyzes the combined climate and nutritional performance of seafood commonly consumed in Sweden, originating all over the world. Nutrient density scores, assessed by seven alternative methods, are combined with species- technology- and origin-specific greenhouse gas emission data for 37 types of seafood. An integrated score indicates which seafood products provide the greatest nutritional value at the lowest climate costs and hence should be promoted from this perspective. Results show that seafoods consumed in Sweden differ widely in nutritional value as well as climate impact and that the two measures are not correlated across all species. Dietary changes towards increased consumption of more seafood choices where a correlation exists (e.g. pelagic species like sprat, herring and mackerel) would benefit both health and climate. Seafoods with a higher climate impact in relation to their nutritional value (e.g. shrimp, Pangasius and plaice) should, on the other hand, not be promoted in dietary advice. The effect of individual nutrients and implications of different nutrient density scores is evaluated. This research is a first step towards modelling the joint nutritional and climate benefits of seafood as a concrete baseline for policy-making, e.g. in dietary advice. It should be followed up by modelling other species, including environmental toxins in seafood in the nutrition score, and expanding to cover other environmental aspects.
Microplastics pollution is a global paradigm that raises concern in relation to environmental and human health. This study investigated toxic effects of microplastics and mercury in the European seabass (Dicentrarchus labrax), a marine fish widely used as food for humans. A short-term (96 h) laboratory bioassay was done by exposing juvenile fish to microplastics (0.26 and 0.69 mg/L), mercury (0.010 and 0.016 mg/L) and binary mixtures of the two substances using the same concentrations, through test media. Microplastics alone and mercury alone caused neurotoxicity through acetylcholinesterase (AChE) inhibition, increased lipid oxidation (LPO) in brain and muscle, and changed the activities of the energy-related enzymes lactate dehydrogenase (LDH) and isocitrate dehydrogenase (IDH). All the mixtures caused significant inhibition of brain AChE activity (64–76%), and significant increase of LPO levels in brain (2.9–3.4 fold) and muscle (2.2–2.9 fold) but not in a concentration-dependent manner; mixtures containing low and high concentrations of microplastics caused different effects on IDH and LDH activity. Mercury was found to accumulate in the brain and muscle, with bioaccumulation factors of 4–7 and 25–40, respectively. Moreover, in the analysis of mercury concentrations in both tissues, a significant interaction between mercury and microplastics was found. The decay of mercury in the water increased with microplastics concentration, and was higher in the presence of fish than in their absence. Overall, these results indicate that: microplastics influence the bioaccumulation of mercury by D. labrax juveniles; microplastics, mercury and their mixtures (ppb range concentrations) cause neurotoxicity, oxidative stress and damage, and changes in the activities of energy-related enzymes in juveniles of this species; mixtures with the lowest and highest concentrations of their components induced different effects on some biomarkers. These findings and other published in the literature raise concern regarding high level predators and humans consuming fish being exposed to microplastics and heavy metals, and highlight the need of more research on the topic.
In December 2017, the United Nations General Assembly decided to convene an intergovernmental conference to elaborate an international legally binding instrument on marine biodiversity in areas beyond national jurisdiction. This legally binding instrument would address four elements, namely marine protected areas, marine genetic resources, environmental impact assessments and capacity building and technology transfer. One of the indicators for the success of the legally binding instrument will be an institutional mechanism that is both effective and that can co-exist with existing mechanisms. There is already a proposal for an institutional mechanism under the implementing agreement. However, the proposed institutional mechanism was developed largely with marine protected areas in mind. The purpose of this article is to determine whether this proposed mechanism could work also for the marine genetic resources element of the proposed treaty. This is necessitated by the fact that the marine genetic resources element of the proposed treaty is far more complex and raises issues that are more intractable.
Expected temperature rise and seawater pH decrease may affect marine organism fitness. By a transplant experiment involving air-temperature manipulation along a natural CO2 gradient, we investigated the effects of high pCO2 (~1100 μatm) and elevated temperature (up to +2 °C than ambient conditions) on the reproductive success, recruitment, growth, shell chemical composition and oxygen consumption of the early life stages of the intertidal reef-building vermetid Dendropoma cristatum. Reproductive success was predominantly affected by temperature increase, with encapsulated embryos exhibiting higher survival in control than elevated temperature conditions, which were in turn unaffected by altered seawater pH levels. Decreasing pH (alone or in combination with temperature) significantly affected the shell growth and shell chemical composition of both embryos and recruits. Elevated temperatures along with lower pH led to decreases of ~30% oxygen consumption and ~60% recruitment. Our results suggest that the early life stages of the reef-builder D. cristatum are highly sensitive to expected environmental change, with major consequences on the intertidal vermetid reefs they build and indirectly on the high biodiversity levels they support.
- Marine Protected Areas (MPAs) are being implemented worldwide, yet there are few cases where managers make specific predictions of the response of previously harvested populations to MPA implementation.
- Such predictions are needed to evaluate whether MPAs are working as expected, and if not, why. This evaluation is necessary to perform adaptive management, identifying whether and when adjustments to management might be necessary to achieve MPA goals.
- Using monitoring data and population models, we quantified expected responses of targeted species to MPA implementation and compared them to monitoring data.
- The model required two factors to explain observed responses in MPAs: (a) pre‐MPA harvest rates, which can vary at local spatial scales, and (b) recruitment variability before and after MPA establishment. Low recruitment years before MPA establishment in our study system drove deviations from expected equilibrium population size distributions and introduced an additional time lag to response detectability.
- Synthesis and applications. We combined monitoring data and population models to show how (a) harvest rates prior to Marine Protected Area (MPA) implementation, (b) variability in recruitment, and (c) initial population size structure determine whether a response to MPA establishment is detectable. Pre‐MPA harvest rates across MPAs plays a large role in MPA response detectability, demonstrating the importance of measuring this poorly known parameter. While an intuitive expectation is for response detectability to depend on recruitment variability and stochasticity in population trajectories after MPA establishment, we address the overlooked role of recruitment variability before MPA establishment, which alters the size structure at the time of MPA establishment. These factors provide MPA practitioners with reasons whether or not MPAs may lead to responses of targeted species. Our overall approach provides a framework for a critical step of adaptive management.
Fishery improvement projects (FIPs) are multi-stakeholder platforms for engaging retailers, importers, processors, and others in seafood supply chains directly in the policy-making and management of fisheries. FIPs vary in design and aim, making their evaluation complex. Studies to date have highlighted successes but also raised concerns about the performance of FIPs in improving fisheries. Drawing on a comprehensive dataset of attributes on all public FIPs, combined with sustainabilityperformance data on the management of the target fisheries, their fishing levels, and stock status, this paper evaluates the performance of FIPs worldwide on improving fisheries, using exploratory data analysis methods and regression-based statistical approaches. The results showed that FIPs improved critical problems in target fisheries in the range between 60% and 82%, depending on the sustainability criteria considered. Performance did not vary between artisanal and industrial FIPs or according to the economic development status of the country. The probability of achieving improvements in management and overfishing domains is higher for fisheries with FIPs compared to those without. Variability in performance was related to the specific characteristics and history of each FIP, based on which further steps in research were suggested.
The topic of Micro(nanoplastics) in the marine environment is attracting attention because of their potential impact in sea organisms and humans. There are several sources of Micro (nanoplastics) such as micro and nanoparticle production or fragmentation off bigger plastics. Nanoplastics can have a bigger capacity to concentrate toxic compounds either associated with its production or sorbed from the environment has not been extensively evaluated. Indications suggest that nanoplastics carry more toxics than microplatics (more than million times than seawater). These nanoplastics can also carry microorganisms. There is no harmonization of methodologies for sampling and analysis of micro(nanoplastics) and there are limits in the accuracy of sizes of these particles that can be detected. Calculation of their possible concentrations in the environment is biased by the analytical instrumentation. This paper summarizes the knowledge gaps in the analysis and repercussions of micro(nanoplastics) in the environment and organisms.
The populations most susceptible to environmental degradation are often the populations that rely most on the natural world for sustenance. Within the many isolated islands that are part of rural Indonesia, many communities are dependent on natural resources for their livelihoods, but paradoxically members of these communities often engage in practices that destroy their natural resources. The current research uses survey methodology to investigate determinants of sustainable behavioral intentions of participants (N = 104) living in coastal communities in Sulawesi, Indonesia—specifically through the lens of an adapted theory of planned behavior model. Results showed that participants with stronger intentions to use nets and lines to fish had more negative attitudes to destructive fishing, a greater sense that their behavior and that of their community affects marine life, and greater belief that other villages are responsible for degrading reefs. Participants with stronger intentions to prevent their waste from going into the ocean had more negative attitudes to throwing waste in the ocean, greater perceptions of control over the behavior, and more positive perceptions of change in the health of the reefs. Although some of the findings align with theory and past research, some were unexpected, highlighting the importance of conducting research to identify motivators of sustainable practices in developing world, low resource communities.
The building blocks of a virus derived from de novo biosynthesis during infection and/or catabolism of preexisting host cell biomass, and the relative contribution of these 2 sources has important consequences for understanding viral biogeochemistry. We determined the uptake of extracellular nitrogen (N) and its biosynthetic incorporation into both virus and host proteins using an isotope-labeling proteomics approach in a model marine cyanobacterium Synechococcus WH8102 infected by a lytic cyanophage S-SM1. By supplying dissolved N as 15N postinfection, we found that proteins in progeny phage particles were composed of up to 41% extracellularly derived N, while proteins of the infected host cell showed almost no isotope incorporation, demonstrating that de novo amino acid synthesis continues during infection and contributes specifically and substantially to phage replication. The source of N for phage protein synthesis shifted over the course of infection from mostly host derived in the early stages to more medium derived later on. We show that the photosystem II reaction center proteins D1 and D2, which are auxiliary metabolic genes (AMGs) in the S-SM1 genome, are made de novo during infection in an apparently light-dependent manner. We also identified a small set of host proteins that continue to be produced during infection; the majority are homologs of AMGs in S-SM1 or other viruses, suggesting selective continuation of host protein production during infection. The continued acquisition of nutrients by the infected cell and their utilization for phage replication are significant for both evolution and biogeochemical impact of viruses.
In 2018, about one billion people of the Earth’s 7.6 billion lived in marine coastal zones. The people, their property, and the infrastructure that supports them, and a city or national per capita GDP are at risk at multiple levels. These include coastal erosion, high and spring tides that cause lowland flooding, weather-related events (storm surges, flooding, wind, crop loss, unprotected anchorage, stabilization of navigation channels, and rarely, killer tsunamis). These coastal zones now, and more so in the future, are likely to be at high risk because of global warming-driven sea level rise. Human activity inshore can increase the level of risk from the above cited sources, such as flooding by abetting subsidence because of overuse of coastal aquifers for a water supply. Dikes, breakwaters, sea walls, and related structures are designed to thwart for some time (50 years?) damaging, destructive forces that assault coastal regions worldwide. They are costly to build and maintain but in short and long terms present economic benefits that preserve much, much more in capital investment.
- Understanding marine mammal distributions is essential for conservation, as it can help identify critical habitat where management action can be taken. The semi‐enclosed Gulf of Corinth, Greece, has been identified as an Important Marine Mammal Area by the International Union for Conservation of Nature (IUCN) Marine Mammal Protected Areas Task Force, based on the regular occurrence of odontocete populations. A 7‐year (2011–17) dataset of boat‐based surveys was used to model and predict the distribution of striped dolphins, Stenella coeruleoalba, common dolphins, Delphinus delphis, and common bottlenose dolphins, Tursiops truncatus, in the entire Gulf (2400 km2).
- Multiple geographic, bathymetric, oceanographic, and anthropogenic variables were incorporated in a combined generalized additive model and generalized estimation equation (GAM‐GEE) framework to describe dolphin occurrence and produce distribution maps.
- Modelling indicated that striped and common dolphins prefer deep waters (>300 m) in the central and southern part of the Gulf, whereas bottlenose dolphins prefer shallow waters (<300 m) and areas close to fish farms along the northern–central shore.
- Model‐based maps of the predicted distribution identified a preferred habitat encompassing most of the Gulf, also revealing: (i) hot spots of dolphin distribution covering about 40% of the Gulf's surface; (ii) an almost complete overlap of striped and common dolphin distribution, consistent with the hypothesis that common dolphins modified their habitat preferences to live in mixed species groups with striped dolphins; (iii) a clear partitioning of striped/common and bottlenose dolphin habitat; and (iv) the important role played by fish farms for bottlenose dolphins, consistent with studies conducted elsewhere in Greece.
- Evidence provided by this study calls for area‐specific and species‐specific management measures to mitigate anthropogenic impacts.
Development of global ocean observing capacity for the biological EOVs is on the cusp of a step-change. Current capacity to automate data collection and processing and to integrate the resulting data streams with complementary data, openly available as FAIR data, is certain to dramatically increase the amount and quality of information and knowledge available to scientists and decision makers into the future. There is little doubt that scientists will continue to expand their understanding of what lives in the ocean, where it lives and how it is changing. However, whether this expanding information stream will inform policy and management or be incorporated into indicators for national reporting is more uncertain. Coordinated data collection including open sharing of data will help produce the consistent evidence-based messages that are valued by managers. The GOOS Biology and Ecosystems Panel is working with other global initiatives to assist this coordination by defining and implementing Essential Ocean Variables. The biological EOVs have been defined, are being updated following community feedback, and their implementation is underway. In 2019, the coverage and precision of a global ocean observing system capable of addressing key questions for the next decade will be quantified, and its potential to support the goals of the UN Decade of Ocean Science for Sustainable Development identified. Developing a global ocean observing system for biology and ecosystems requires parallel efforts in improving evidence-based monitoring of progress against international agreements and the open data, reporting and governance structures that would facilitate the uptake of improved information by decision makers.
Marine pollution due to littering from anthropogenic activities is a serious global environmental problem—the main reason accumulation of debris in the environment, including in the ocean. There is a significant hazard coming from plastic debris. Besides entanglement and ingestion, marine plastics debris has more complex problems and can release additional and by-product chemical substances. If we keep producing and not doing anything, a recent study said by 2050 there would be three times more plastic than fish in the ocean. We only have a limited understanding of marine plastic debris distribution, implication, fate, and behavior. Science is the key to getting the right alternative for processing debris. To prevent marine pollution successfully requires education and outreach programs, strong laws and policies, and law enforcement for government and private institutions. This chapter explores marine plastic debris.
Environmental niche modelling is an acclaimed method for estimating species’ present or future distributions. However, in marine environments the assembly of representative data from reliable and unbiased occurrences is challenging. Here, we aimed to model the environmental niche and distribution of marine, parasitic nematodes from the Pseudoterranova decipiens complex using the software Maxent. The distribution of these potentially zoonotic species is of interest, because they infect the muscle tissue of host species targeted by fisheries. To achieve the best possible model, we used two different approaches. The land distance (LD) model was based on abiotic data, whereas the definitive host distance (DHD) model included species-specific biotic data. To assess whether DHD is a suitable descriptor for Pseudoterranova spp., the niches of the parasites and their respective definitive hosts were analysed using ecospat. The performance of LD and DHD was compared based on the variables’ contribution to the model. The DHD-model clearly outperformed the LD-model. While the LD-model gave an estimate of the parasites’ niches, it only showed the potential distribution. The DHD-model produced an estimate of the species’ realised distribution and indicated that biotic variables can help to improve the modelling of data-poor, marine species.