The physical damages to benthic organisms caused by boat anchorages were assessed in the Arraial do Cabo Marine Extractive Reserve (ACMER), Brazil. It is one of the most visited scuba diving sites along the southwestern Atlantic. Through underwater visual observations, we analyzed if benthic organisms were damaged by anchors and/or anchor cabling at two dive sites. A total of 112 anchorages were sampled. Damages to benthic organisms were observed 139 times, mainly affecting epilithic algal matrix, the zoanthid Palythoa caribaeorum, and the fire coral Millepora alcicornis. Damages caused by anchor cables were significantly higher than those caused by anchors at one site. A significant difference between benthic organisms damaged was observed only for P. caribaeorum, caused by the anchor’s cable. We present evidence that, at current visitation levels, anchors are a relevant stressor to benthic organisms at dive sites in ACMER.
The following titles are freely-available, or include a link to a preprint or postprint.
This guide is designed as a consultation tool for environmental journalists in the Mediterranean region. It provides an overview of the main environmental according to experts from various institutions, and the challenges that those threats pose at present and in the future. In addition, it deals with the specificities of the legal and governance framework in the region. The objective is that all this information will provide journalists with as detailed a picture as possible of the environmental situation in the Mediterranean to serve as the basis for future press stories to be explored and developed.
Aiming towards good practice in the planning and approval of offshore wind farms suggestions are provided for the amendment of environmental impact assessment (EIA), an effective marine spatial planning and the establishment of marine compensation measure. The investigation is focused on the situation in Germany as a frontrunner in ecological research on offshore wind energy. After 10 years of research in Germany, it is timely to offer a synopsis of the results especially regarding the successful investigations of mitigation measures. The results are based on published data collected in Germany over the last 10 years, as well as international research. The outcomes of the research were validated by interviewing experts using the Delphi method.
Key findings for good practice in impact assessment, mitigation and compensation:
1. EIAs should focus on decision-relevant subjects of protection (i.e. specific bird species and harbour porpoises).
2. There is a strong necessity for thresholds for the approval process.
3. Exclusion of OWFs in hotspots of sensitive species.
4. Application of state-of-the-art mitigation measures particularly against underwater noise to avoid damages of the hearing of porpoises.
5. The introduction of marine compensation measures is strongly suggested.
We estimated the current level of knowledge concerning several biological characteristics of the Mediterranean marine fishes by carrying out a gap analysis based on information extracted from the literature, aiming to identify research trends and future needs in the field of Mediterranean fish biology that can be used in stock assessments, ecosystem modeling and fisheries management. Based on the datasets that emerged from the literature review, there is no information on any biological characteristic for 43% (n = 310) of the Mediterranean fish species, whereas for an additional 15% (n = 109) of them there is information about just one characteristic. The gap between current and desired knowledge (defined here as having information on most biological characteristics for at least half of the Mediterranean marine fishes) is smaller in length-weight relationships, which have been studied for 43% of the species, followed by spawning (39%), diet (29%), growth (25%), maturity (24%), lifespan (19%) and fecundity (17%). The gap is larger in natural mortality for which information is very scarce (8%). European hake (Merluccius merluccius), red mullet (Mullus barbatus), annular seabream (Diplodus annularis), common pandora (Pagellus erythrinus), European anchovy (Engraulis encrasicolus), European pilchard (Sardina pilchardus) and bogue (Boops boops) were the most studied species, while sharks and rays were among the least studied ones. Only 25 species were fully studied, i.e. there was available information on all their biological characteristics. The knowledge gaps per characteristic varied among the western, central and eastern Mediterranean subregions. The number of available records per species was positively related to total landings, while no relationship emerged with its maximum reported length, trophic level and commercial value. Future research priorities that should be focused on less studied species (e.g. sharks and rays) and mortality/fecundity instead of length-weight relationships, as well as the economy of scientific sampling (using the entire catch to acquire data on as many biological characteristics as possible) are discussed.
Targets and limits for long-term management are used in fisheries advice to operationalize the way management reflects societal priorities on ecological, economic, social and institutional aspects. This study reflects on the available published literature as well as new research presented at the international ICES/Myfish symposium on targets and limits for long term fisheries management. We examine the inclusion of ecological, economic, social and institutional objectives in fisheries management, with the aim of progressing towards including all four objectives when setting management targets or limits, or both, for multispecies fisheries. The topics covered include ecological, economic, social and governance objectives in fisheries management, consistent approaches to management, uncertainty and variability, and fisheries governance. We end by identifying ten ways to more effectively include multiple objectives in setting targets and limits in ecosystem based fisheries management.
The ‘Wild Seafood’ Provisioning Service (WSPS), on which commercial fisheries rely, is probably one of the best studied marine ecosystem services due to its economic relevance and because extensive information sources exist for assessment purposes. Yet, the indicators often proposed are not suitable to describe the capacity of the ecosystem to deliver the WSPS. Therefore this study proposes surplus production (SP), a well-established concept in fisheries science, as the basis to calculate the capacity of marine ecosystems to provide the WSPS. SP is defined as the difference between stock production (through recruitment and body growth) and losses through natural mortality. This is, therefore, the production of the stock that could be harvested sustainably without decreasing the biomass. To assess the sustainability of the exploitation of the WSPS we also developed an indicator for this based on SP and compared it to existing fisheries management indicators. When both SP-based indicators showed a decreasing trend, contrasting with an increasing trend in the existing fisheries management indicators, the calculation of the SP-based indicators was scrutinized revealing that the weighting of the stocks into an aggregated indicator, strongly determines the indicator values, even up to the point that the trend is reversed. The aggregated indicators based on SP-weighted stocks can be considered complementary to existing fisheries management indicators as the former accurately reflect the capacity of the commercial fish to provide the WSPS and the sustainability of the exploitation of this service. In contrast the existing fisheries management indicators primarily reflect the performance of management towards achieving fisheries-specific policy goals.
This is the first study to assess the social costs of marine debris washed ashore and litter left behind by beach visitors along different European coasts. Three identical surveys, including a discrete choice experiment, are implemented at six beaches along different European coastlines: the Mediterranean Sea in Greece, the Black Sea in Bulgaria and the North Sea in the Netherlands. Beach visitors are asked for their experiences with beach litter and their willingness to volunteer in beach clean-up programs and their willingness to pay an entrance fee or increase in local tax to clean up marine litter. Significant differences are found between countries. This has important implications for the size and transferability of the estimated social costs of marine litter across Europe.
Plastic in the global oceans fulfills two of the three conditions for pollution to pose a planetary boundary threat because it is causing planetary-scale exposure that is not readily reversible. Plastic is a planetary boundary threat if it is having a currently unrecognized disruptive effect on a vital Earth system process. Discovering possible unknown effects is likely to be aided by achieving a fuller understanding of the environmental fate of plastic. Weathering of plastic generates microplastic, releases chemical additives, and likely also produces nanoplastic and chemical fragments cleaved from the polymer backbone. However, weathering of plastic in the marine environment is not well understood in terms of time scales for fragmentation and degradation, the evolution of particle morphology and properties, and hazards of the chemical mixture liberated by weathering. Biofilms that form and grow on plastic affect weathering, vertical transport, toxicity, and uptake of plastic by marine organisms and have been underinvestigated. Laboratory studies, field monitoring, and models of the impact of weathering on plastic debris are needed to reduce uncertainty in hazard and risk assessments for known and suspected adverse effects. However, scientists and decision makers must also recognize that plastic in the oceans may have unanticipated effects about which we are currently ignorant. Possible impacts that are currently unknown can be confronted by vigilant monitoring of plastic in the oceans and discovery-oriented research related to the possible effects of weathering plastic.
We provide evidence for temporal displacement of illegal discharges of oil from shipping, a major source of ocean pollution, in response to a monitoring technology that features variation in the probability of conviction by time of day. During the nighttime, evidence collected by Coast Guard aircraft using radar becomes contestable in court because the nature of an identified spot cannot be verified visually by an observer on board of the aircraft. Seasonal variation in time of sunset is used to distinguish evasive behavior from daily routines on board. Using data from surveillance flights above the Dutch part of the North Sea during 1992–2011, we provide evidence for a sudden increase in illegal discharges after sunset across the year. Our results show that even a tiny chance of getting caught and a mild punishment can have a major impact on behavior.
The Gulf of California (GC) is an unique large ecosystem characterized by its rich biodiversity, high biological productivity and endemism of marine life. However, as many other large ecosystems worldwide, it is subject to diverse anthropogenic pressures (overfishing, climate change, losses of biodiversity and habitats, and pollution). We reviewed over 150 studies dealing with contaminants in water, sediments and representative organisms from the GC, and here we discuss the main issues associated to the presence of metals, metalloids, persistent organic pollutants (POPs, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), brominated diphenyl ethers (deca tri-a) (PBDEs), and several other pesticides), plastics, nutrients and algal blooms. The GC ecosystems have been subject to a wide range of pollution sources. Nevertheless, the pollution levels remain relatively low to moderate depending on the location and contaminant type. Contamination hotspots are found i) for metals and metalloids, in sites where mining spills have occurred and ii) for nutrients and pesticides, in wetlands that receive discharges from intensive agricultural and shrimp farming. We also identified sites where harmful algal blooms (HABs) have been observed. However, numerous coastal environments in GC, affected by pollution sources and events have yet been poorly studied. More detailed, extensive and comprehensive studies on the pollution levels and trends, transfer and toxic effects are still needed.
The disruption of the coral–algae symbiosis (coral bleaching) due to rising sea surface temperatures has become an unprecedented global threat to coral reefs. Despite decades of research, our ability to manage mass bleaching events remains hampered by an incomplete mechanistic understanding of the processes involved. In this study, we induced a coral bleaching phenotype in the absence of heat and light stress by adding sugars. The sugar addition resulted in coral symbiotic breakdown accompanied by a fourfold increase of coral-associated microbial nitrogen fixation. Concomitantly, increased N:P ratios by the coral host and algal symbionts suggest excess availability of nitrogen and a disruption of the nitrogen limitation within the coral holobiont. As nitrogen fixation is similarly stimulated in ocean warming scenarios, here we propose a refined coral bleaching model integrating the cascading effects of stimulated microbial nitrogen fixation. This model highlights the putative role of nitrogen-fixing microbes in coral holobiont functioning and breakdown.
Reef sharks may influence the foraging behaviour of mesopredatory teleosts on coral reefs via both risk effects and competitive exclusion. We used a “natural experiment” to test the hypothesis that the loss of sharks on coral reefs can influence the diet and body condition of mesopredatory fishes by comparing two remote, atoll-like reef systems, the Rowley Shoals and the Scott Reefs, in northwestern Australia. The Rowley Shoals are a marine reserve where sharks are abundant, whereas at the Scott Reefs numbers of sharks have been reduced by centuries of targeted fishing. On reefs where sharks were rare, the gut contents of five species of mesopredatory teleosts largely contained fish while on reefs with abundant sharks, the same mesopredatory species consumed a larger proportion of benthic invertebrates. These measures of diet were correlated with changes in body condition, such that the condition of mesopredatory teleosts was significantly poorer on reefs with higher shark abundance. Condition was defined as body weight, height and width for a given length and also estimated via several indices of condition. Due to the nature of natural experiments, alternative explanations cannot be discounted. However, the results were consistent with the hypothesis that loss of sharks may influence the diet and condition of mesopredators and by association, their fecundity and trophic role. Regardless of the mechanism (risk effects, competitive release, or other), our findings suggest that overfishing of sharks has the potential to trigger trophic cascades on coral reefs and that further declines in shark populations globally should be prevented to protect ecosystem health.
Coral reefs serve as natural barriers that protect adjacent shorelines from coastal hazards such as storms, waves, and erosion. Projections indicate global degradation of coral reefs due to anthropogenic impacts and climate change will cause a transition to net erosion by mid-century. Here, we provide a comprehensive assessment of the combined effect of all of the processes affecting seafloor accretion and erosion by measuring changes in seafloor elevation and volume for five coral reef ecosystems in the Atlantic, Pacific, and Caribbean over the last several decades. Regional-scale mean elevation and volume losses were observed at all five study sites and in 77 % of the 60 individual habitats that we examined across all study sites. Mean seafloor elevation losses for whole coral reef ecosystems in our study ranged from −0.09 to −0.8 m, corresponding to net volume losses ranging from 3.4 × 106 to 80.5 × 106 m3 for all study sites. Erosion of both coral-dominated substrate and non-coral substrate suggests that the current rate of carbonate production is no longer sufficient to support net accretion of coral reefs or adjacent habitats. We show that regional-scale loss of seafloor elevation and volume has accelerated the rate of relative sea level rise in these regions. Current water depths have increased to levels not predicted until near the year 2100, placing these ecosystems and nearby communities at elevated and accelerating risk to coastal hazards. Our results set a new baseline for projecting future impacts to coastal communities resulting from degradation of coral reef systems and associated losses of natural and socioeconomic resources.
The subtropical ocean gyres are recognized as great marine accummulation zones of floating plastic debris; however, the possibility of plastic accumulation at polar latitudes has been overlooked because of the lack of nearby pollution sources. In the present study, the Arctic Ocean was extensively sampled for floating plastic debris from the Tara Oceans circumpolar expedition. Although plastic debris was scarce or absent in most of the Arctic waters, it reached high concentrations (hundreds of thousands of pieces per square kilometer) in the northernmost and easternmost areas of the Greenland and Barents seas. The fragmentation and typology of the plastic suggested an abundant presence of aged debris that originated from distant sources. This hypothesis was corroborated by the relatively high ratios of marine surface plastic to local pollution sources. Surface circulation models and field data showed that the poleward branch of the Thermohaline Circulation transfers floating debris from the North Atlantic to the Greenland and Barents seas, which would be a dead end for this plastic conveyor belt. Given the limited surface transport of the plastic that accumulated here and the mechanisms acting for the downward transport, the seafloor beneath this Arctic sector is hypothesized as an important sink of plastic debris.
Natural resource management agencies implement conservation policies with the presumption that they are effective and of benefit to aquatic ecosystems. However, it is often difficult to decide what management action to implement and what will be most effective. Here we call for natural resource management agencies to fully adopt and implement evidence-based management (EBM) for conservation and fisheries management. We support this call by providing a primer on systematic reviews, a core tool in evidence synthesis but one that is rarely used in the context of fisheries management. We highlight the benefits and challenges associated with implementing EBM, with a particular focus on the routine decisions and management actions undertaken by natural resource practitioners. We submit that by adopting EBM, practitioners would have access to the best available evidence on the effectiveness of various management and conservation interventions, while providing defensible and credible evidence to inform decision-making processes and policies.
The abundance and the distribution of trophic resources available for consumers influence the productivity and the diversity of natural communities. Nevertheless, assessment of the actual abundance of food items available for individual trophic groups has been constrained by differences in methods and metrics used by various authors. Here we develop an index of food abundance, the framework of which can be adapted for different ecosystems. The relative available food index (RAFI) is computed by considering standard resource conditions of a habitat and the influence of various generalized anthropogenic and natural factors. RAFI was developed using published literature on food abundance and validated by comparison of predictions versus observed trophic resources across various marine sites. RAFI tables here proposed can be applied to a range of marine ecosystems for predictions of the potential abundance of food available for each trophic group, hence permitting exploration of ecological theories by focusing on the deviation from the observed to the expected.
This article presents data from a citizens jury-inspired deliberative workshop held to tease out stakeholder views of management priorities for a section of the North Sea: the Dogger Bank. As this article reveals, the lessons learned from the Dogger Bank workshop advocate not simply what is required for managing one particular ocean commons, but also highlight some of the public participation research design failings, taking public participation in resource management further by adding to the literature and theoretical discussions on the public sphere. Analysis of the citizens jury-inspired deliberative workshop also highlights the critical issue of power inherent, yet often unacknowledged, in public participation in environmental management. Stakeholder opinions uncovered through workshop discussions also show how commons are viewed today – as an economic resource-- highlighting the trend of the mainstreaming of the commodification of the commons.
This report summarizes the results of a rapid vulnerability assessment (July 2016) and adaptation strategy planning (September 2016) workshops for 10 focal resources in the Territory and National Marine Sanctuary of American Samoa by engaging with stakeholders, including village leaders, community members, resource managers, local government representatives, and business owners that rely on the resources with the goal of increasing climate resilience in the region.
The capability of animals to emit light, called bioluminescence, is considered to be a major factor in ecological interactions. Because it occurs across diverse taxa, measurements of bioluminescence can be powerful to detect and quantify organisms in the ocean. In this study, 17 years of video observations were recorded by remotely operated vehicles during surveys off the California Coast, from the surface down to 3,900 m depth. More than 350,000 observations are classified for their bioluminescence capability based on literature descriptions. The organisms represented 553 phylogenetic concepts (species, genera or families, at the most precise taxonomic level defined from the images), distributed within 13 broader taxonomic categories. The importance of bioluminescent marine taxa is highlighted in the water column, as we showed that 76% of the observed individuals have bioluminescence capability. More than 97% of Cnidarians were bioluminescent, and 9 of the 13 taxonomic categories were found to be bioluminescent dominant. The percentage of bioluminescent animals is remarkably uniform over depth. Moreover, the proportion of bioluminescent and non-bioluminescent animals within taxonomic groups changes with depth for Ctenophora, Scyphozoa, Chaetognatha, and Crustacea. Given these results, bioluminescence has to be considered an important ecological trait from the surface to the deep-sea.
One way that illegal, unreported, and unregulated (IUU) fish catch is laundered into the seafood market is through transshipments at-sea. This practice, which often occurs on the high seas (the areas of ocean beyond national jurisdiction), allows vessels fishing illegally to evade most monitoring and enforcement measures, offload their cargo, and resume fishing without returning to port. At the same time, transshipment at-sea can facilitate trafficking and exploitation of workers who are trapped and abused on fishing vessels. This study gives an overview of high seas transshipment as well as evaluates transshipment at-sea regulations across 17 Regional Fisheries Management Organizations (RFMOs), which are responsible for regulating fisheries on the high seas. Transshipment at-sea regulations have become increasingly strict in most RFMOs since the late 1990s. However, only five RFMOs have mandated a partial ban, and only a single RFMO, the South East Atlantic Fisheries Organization (SEAFO), has mandated a total ban on transshipment at-sea. A total ban on transshipment at-sea across all RFMOs would support the ability of oversight and enforcement agencies to detect and prevent IUU fishing and also likely reduce human trafficking and forced labor on the high seas.