The oceans take up over 1 million tons of anthropogenic CO2 per hour, increasing dissolved pCO2 and decreasing seawater pH in a process called ocean acidification (OA). At the same time greenhouse warming of the surface ocean results in enhanced stratification and shoaling of upper mixed layers, exposing photosynthetic organisms dwelling there to increased visible and UV radiation as well as to a decreased nutrient supply. In addition, ocean warming and anthropogenic eutrophication reduce the concentration of dissolved O2 in seawater, contributing to the spread of hypoxic zones. All of these global changes interact to affect marine primary producers. Such interactions have been documented, but to a much smaller extent compared to the responses to each single driver. The combined effects could be synergistic, neutral, or antagonistic depending on species or the physiological processes involved as well as experimental setups. For most calcifying algae, the combined impacts of acidification, solar UV, and/or elevated temperature clearly reduce their calcification; for diatoms, elevated CO2 and light levels interact to enhance their growth at low levels of sunlight but inhibit it at high levels. For most photosynthetic nitrogen fixers (diazotrophs), acidification associated with elevated CO2may enhance their N2 fixation activity, but interactions with other environmental variables such as trace metal availability may neutralize or even reverse these effects. Macroalgae, on the other hand, either as juveniles or adults, appear to benefit from elevated CO2 with enhanced growth rates and tolerance to lowered pH. There has been little documentation of deoxygenation effects on primary producers, although theoretically elevated CO2and decreased O2 concentrations could selectively enhance carboxylation over oxygenation catalyzed by ribulose-1,5-bisphosphate carboxylase/oxygenase and thereby benefit autotrophs. Overall, most ocean-based global change biology studies have used single and/or double stressors in laboratory tests. This overview examines the combined effects of OA with other features such as warming, solar UV radiation, and deoxygenation, focusing on primary producers.
Increasing numbers of large marine protected areas (LMPAs) are being added to the global conservation estate, raising new challenges for marine social-ecological management and biodiversity conservation. To better understand the importance of spatial heterogeneity and scale in managing LMPAs, we undertook a quantitative, spatially explicit analysis of permit data from the Great Barrier Reef Marine Park. We geo-registered 10,030 permissions from 7478 permits for the period 2007–2017, extracted the information into a 2 × 2 km grid, aggregated the data into six different permission types and explored spatial patterns by permission type and numbers. Permission numbers of different types were all strongly and significantly correlated; access and transport permissions were the most numerous. Commercial harvesting permission numbers were negatively correlated with those for research and education, but not for tourism. Apart from research permissions, the influence of the immediate biophysical environment (coral reefs, proximity to shore) at this scale was low; permission numbers were more influenced by proximity to towns and population density. There was also a broad-scale latitudinal effect, with higher permission numbers in the south, independent of the human geography variables that we measured. Permit numbers have been increasing exponentially over the last decade and show no sign of declining. More generally, our analysis shows how permit data can inform the management activities and needs of LMPAs, while potentially providing a window into long-term shifts in user demands and changing management needs for conservation.
Many U.S. marine fisheries are showing the impacts of climate change. Some species are shifting outside their historical range in response to changing ecosystem conditions, especially warming waters, but also to changing habitats and ocean acidification. This new reality poses challenges to our current management regimes as fish and fishermen move, sometimes into areas dedicated to different historical uses or new ventures. This Perspective will explore how our current fishery management system is being tested by climate change impacts, the efforts underway to adapt science and management to a new normal in the ocean, the constraints of current law, and ideas for future law and regulation that is designed to enable management under climate‐changed conditions.
Sustained ocean observations provide an essential input to ocean scientific research. They also support a wide range of societal and economic benefits related to safety; operational efficiency; and regulation of activities around, on, in, and under seas and the ocean. The ocean economy is large and diverse, accounting for around US$1.5 trillion of global gross value-added economic activity. This is projected to more than double by 2030. Delivering this growth in economic activity is dependent on ocean observations. This review paper summarizes the projected changes in the scale and scope of the ocean economy and the role that observations, measurements, and forecasts play in supporting the safe and effective use of the ocean and ocean resources, at the same time as protecting the environment. It also provides an overview of key future work being planned to develop a better understanding of the present and likely future ocean economy and the role and value of ocean observations in its sustainable realization.
Long-term measurements are imperative to detect, understand, and predict changes in coastal biological communities, but can be both costly and difficult to implement. Here, we compare measurement methods used to document community structure and assess changes in marine systems, and explore potential applications in citizen science. The use of photographs for species identifications and monitoring has become a popular and useful data collection tool, but its use requires evaluation of its effectiveness in comparison to data collected from live examinations. We used settlement panels in San Francisco Bay, a well-studied and vital coastal ecosystem, to compare standardized measures of the invertebrate fouling community through examination of live organisms in the field and via photographs. Overall, our study found that live measurements were more accurate and better represented these marine communities, having higher richness, and diversity measurements than photographic measurements. However, photographic analyses accurately captured the relative abundances of some species and functional groups. We suggest that highly recognizable target taxa or broad scale comparisons of functional group composition are easily tracked through photographs and offer the best potential for research conducted by citizen scientists.
Spatial fragmentation is a near-ubiquitous characteristic of marine canopies. Biophysical interactions with fragmented canopies are multi-faceted and have many significant implications at multiple scales. The aims of this paper are to review research on biophysical interactions in fragmented marine canopies, identify current gaps in knowledge and understanding, and propose ways forward. The review starts at the patch/gap scale and focuses initially on hydrodynamic interactions. It then considers the consequences of these interactions for particulate and dissolved material, and distributions of canopy-associated organisms. Finally, it addresses issues of upscaling to landscape-scale and ways in which this research can be applied to marine landscape management. Work on a broad range of canopy types is considered, including micro-algal biofilms and turf algae; macro-algae, seagrasses and coral reefs; saltmarsh vegetation and mangroves. Although the focus is on marine canopies, insights from studies of fragmented canopies in other contexts are drawn on where relevant. These include freshwater environments and terrestrial forests, grasslands, crop canopies, and urban areas. Specific areas requiring greater attention are highlighted. As a result of this meta-analysis, the following recommendations are made for further research. A lack of basic data is identified across all canopy types regarding the formation, fate and spatial and temporal characteristics of canopy patches, gaps, and spatial structure. Studies of hydrodynamics with fragmented canopies would benefit from shifting focus toward more non-uniform, realistic configurations, while ecological research in this area would benefit from a move toward configurations that are more controlled and tractable for quantitative modeling. More comparative studies across canopy types would enable understanding of their biophysical interactions and their consequences to be more fully tested and developed. A greater incorporation of chemical aspects of canopy systems into work that has hitherto focused on biophysical interactions would also be pertinent. Upscaling of patch and gap-scale phenomena to landscape-scale is identified as a crucial topic, since it is at the latter scale that management efforts are most readily carried out. Overall, an approach that balances hydrodynamics, marine canopy ecology, spatial analysis of landscapes, biogeochemistry, and socio-environmental interactions is recommended.
Assessment of environmental literacy and ocean literacy focus on increasing knowledge and awareness. The goal of ocean literacy initiatives is ultimately to enable behavior change (whereby citizens take direct and sustainable action) to achieve sustainable solutions to marine environment issues. The application of social and behavioral research methods provides powerful tools for assessing if ocean literacy initiatives are effective at increasing participant's knowledge and awareness of an issue, its causes and consequences and behaviors or actions required to enable sustainable solutions. Social and behavioral research methods also provide a means of assessing changes in attitude, a key predictor of behavior change, and ultimately a means of assessing changes in a participants intended and reported behaviors. We present a framework to integrate social and behavioral research methods within assessment of the effectiveness of ocean literacy initiatives. The before and after assessment we undertake develops existing environmental literacy and ocean literacy assessment approaches by integrating social and behavioral research methods to assess key predictors of behavior change. We structured the assessment methodology within a Theory of Change logic model, to provide a protocol for systematic evaluation of ocean literacy initiatives and tools. Specifically those aimed at promoting specific behavior change objectives for pre-identified actors. Assessment of educational training courses for professionals entering the shipping industry (targeting behaviors to reduce the spread of invasive species), and educational workshops for school students (aged 11–15 and 16–18), on problems related to marine litter and microplastics and potential solutions were assessed using the framework. Through before and after surveys, an increase in awareness, knowledge and an increase in attitudes supporting action to reduce impacts on the marine environment were reported by participants, after interaction with sets of tools developed by the Horizon 2020 Ocean Literacy project ResponSEAble. Results supported the importance of targeting specific audiences with tailored ocean literacy tools and the importance of informing actors of issues and solutions within the context of wider ocean literacy principles.
Coastal habitats (e.g., seagrass beds, shallow mud, and sand flats) strongly influence survival, growth, and reproduction of marine fish and invertebrate species. Many of these species have declined over the past decades, coincident with widespread degradation of coastal habitats, such that an urgent need exists to model the quantitative value of coastal habitats to their population dynamics. For exploited species, demand for habitat considerations will increase as fisheries management contends with habitat issues in stock assessments and management in general moves toward a more ecosystem-based approach. The modeling of habitat function has, to date, been done on a case-by-case basis involving diverse approaches and types of population models, which has made it difficult to generalize about methods for incorporating habitat into population models. In this review, we offer guiding concepts for how habitat effects can be incorporated in population models commonly used to simulate the population dynamics of fish and invertebrate species. Many marine species share a similar life-history strategy as long-lived adults with indeterminate growth, high fecundity, a planktonic larval form, and benthic juveniles and adults using coastal habitats. This suite of life-history traits unites the marine species across the case studies, such that the population models can be adapted for other marine species. We categorize population models based on whether they are static or dynamic representations of population status, and for dynamic, further into unstructured, age/size class structured, and individual-based. We then use examples, with an emphasis on exploited species, to illustrate how habitat has been incorporated, implicitly (correlative) and explicitly (mechanistically), into each of these categories. We describe the methods used and provide details on their implementation and utility to facilitate adaptation of the approaches for other species and systems. We anticipate that our review can serve as a stimulus for more widespread use of population models to quantify the value of coastal habitats, so that their importance can be accurately realized and to facilitate cross-species and cross-system comparisons. Quantitative evaluation of habitat effects in population dynamics will increasingly be needed for traditional stock assessments, ecosystem-based management, conservation of at-risk habitats, and recovery of overexploited stocks that rely on critical coastal habitats during their life cycle.
Managing invasive alien species is particularly challenging in the ocean mainly because marine ecosystems are highly connected across broad spatial scales. Eradication of marine invasive species has only been achieved when species were detected early, and management responded rapidly. Generalized approaches, transferable across marine regions, for prioritizing actions to control invasive populations are currently lacking. Here, expert knowledge was elicited to prioritize 11 management actions for controlling 12 model species, distinguished by differences in dispersion capacity, distribution in the area to be managed, and taxonomic identity. Each action was assessed using five criteria (effectiveness, feasibility, acceptability, impacts on native communities, and cost), which were combined in an ‘applicability’ metric. Raising public awareness and encouraging the commercial use of invasive species were highly prioritized, whereas biological control actions were considered the least applicable. Our findings can guide rapid decision-making on prioritizing management options for the control of invasive species especially at early stages of invasion, when reducing managers' response time is critical.
Fish stocks are managed within national boundaries and by regional organizations, but the interdependence of stocks between these jurisdictions, especially as a result of larval dispersal, remains poorly explored. We examined the international connectivity of 747 commercially fished taxonomic groups by building a global network of fish larval dispersal. We found that the world’s fisheries are highly interconnected, forming a small-world network, emphasizing the need for international cooperation. We quantify each country’s dependence on its neighbors in terms of landed value, food security, and jobs. We estimate that more than $10 billion in annual catch from 2005 to 2014 is attributable to these international flows of larvae. The economic risks associated with these dependencies is greatest in the tropics.
Community marine reserves are geographical areas closed to fishing activities, implemented and enforced by the same fishermen that fish around them. Their main objective is to recover commercial stocks of fish and invertebrates. While marine reserves have proven successful in many parts of the world, their success near important marine predator colonies, such as the California sea lion (Zalophus californianus) and the Pacific harbor seal (Phoca vitulina richardii), is yet to be analyzed. In response to the concerns expressed by local fishermen about the impact of the presence of pinnipeds on their communities’ marine reserves, we conducted underwater surveys around four islands in the Pacific west of the Baja California Peninsula: two without reserves (Todos Santos and San Roque); one with a recently established reserve (San Jeronimo); and, a fourth with reserves established eight years ago (Natividad). All these islands are subject to similar rates of exploitation by fishing cooperatives with exclusive rights. We estimated fish biomass and biodiversity in the seas around the islands, applying filters for potential California sea lion and harbor seal prey using known species from the literature. Generalized linear mixed models revealed that the age of the reserve has a significant positive effect on fish biomass, while the site (inside or outside of the reserve) did not, with a similar result found for the biomass of the prey of the California sea lion. Fish biodiversity was also higher around Natividad Island, while invertebrate biodiversity was higher around San Roque. These findings indicate that marine reserves increase overall fish diversity and biomass, despite the presence of top predators, even increasing the numbers of their potential prey. Community marine reserves may help to improve the resilience of marine mammals to climate-driven phenomena and maintain a healthy marine ecosystem for the benefit of both pinnipeds and fishermen.
Examining stakeholder's knowledge, perception and attitudes are necessary for effective implementation of laws that are designed to protect and conserve marine biodiversity. In order to understand knowledge, awareness and perception about the law and the species that are protected under the Indian Wildlife (Protection) Act, 1972, I interviewed (N = 159) stakeholders (77 fishermen, 39 authorities and 41 middlemen/traders) in the Andaman Islands, India. Within respondents, mean awareness about different protected marine species was (80%) amongst authorities, followed by (63%) amongst traders/middlemen and (59%) amongst fishermen. The awareness about a few charismatic groups i.e., mammals, reptiles and cnidarians high; whereas awareness about elasmobranchs, fish, sea cucumbers and molluscs low amongst the respondent groups. Amongst several species traded in the islands, the sea cucumber, the trochus and the turbo are in high demand, and there is demand from middlemen and fishers to delist these species. Generalised model revealed that the years of fishing experience, occupation, annual income and age of respondents are important factors in determining awareness of locals towards protected species. Solutions suggested by stakeholders are strict enforcement of the law, education and awareness of protected species, a special task force for dealing with the Indian Wildlife Protection Act, need to curb poaching from foreigners etc. All fishers sell their catch to middlemen/traders who in turn send their catch to mainland India (Tamil Nadu and Kolkata). The knowledge about which government department is responsible for implementation and monitoring of the law is limited amongst all stakeholder groups.The study demonstrates that stakeholder's knowledge, perception and attitude can offer valuable insights towards strengthening the law that protects marine species. Similar studies should be carried out across different coastal states to understand the level of awareness of stakeholders towards protected marine species. Creating awareness, inclusiveness of local stakeholders in decision making, empowering authorities in monitoring can help in strengthening the existing law framework for protected marine species.
We present a study of small microplastic particles (S-MPPs) in the sediments of mangrove ecosystem of Khor-e- Khoran, a Ramsar site in Iran. The spatial distribution of S-MPPs (<1 mm) in mangrove surface sediments were investigated, which provided new insights into the detection and composition of S-MPPs in the study area. S-MPPs were extracted via the air-induced overflow (AIO) extraction procedure, and then they were counted and categorized according to the particle shape, color and size. The mean number of S-MPPs at the five sampling sites ranged from 19.5 to 34.5 particles per kg dry sediment in Bandar Gelkan and Bandar Lengeh, respectively. In general, microfibres followed by fragments were the most common type of S-MPPs isolated in each site (>56% and ~35%, respectively). Sewage discharge is probably the main source of extracted fibres in almost all the sites. The observed S-MPPs were classified into two size groups (10–300 μm and 300–1000 μm). The majority of S-MPPs fell into the smallest size group which accounted for 70–97% of the total S-MPPs. Fourier transform infrared (FTIR) analysis of some subsamples showed that polyethylene (PE) was the most common recovered polymer. Some non-plastic particles were also isolated from plastic-like particles of suspected S-MPPs in the mangrove sediments using a Scanning Electron Microscope (FE-SEM). This study provided the first evidence of S-MPPs contamination in the mangroves of the Iranian coast of the Persian Gulf. Long-term studies are required to understand, monitor and prevent further microplastics pollution in the region.
Over the last 35 years, at both European and Italian level, great efforts have been made to increase the number of Marine Protected Areas (MPAs), as they are considered an effective tool for protecting oceans and biodiversity. In recent years, MPAs have become more than simply a tool to improve marine conservation. In fact, their management agencies are actively involved in the sustainable development of nearby communities through the promotion of recreational activities (boating, snorkelling, diving). Even if the recreational uses of the marine environment are generally considered benign, they can potentially be highly detrimental for species and their habitats. As a result, these activities should be controlled through the spatial zoning and the regulations of the MPAs. Thus, the achievement of the conservation goals of the MPAs depends primarily on compliance with the regulations of recreational uses inside their boundaries. The objective of this study was to estimate boating usage and the level of compliance inside the Capo Gallo and Isola delle Femmine (Italy) MPA. The spatial and temporal trend of boating and the behaviours of boaters were measured through direct observation over a period of two summer months. The study highlighted a weakness in the effectiveness of this MPA, linked to a social component and compliance with the regulation. Solutions for effective management plans are outlined thanks to an understanding of the limitations and potential of existing MPA policies.
The fin whale is a globally endangered species and is listed as threatened in Australia, however no peer-reviewed studies are available to indicate the migratory movements of the species in Australian waters. This study uses passive acoustic monitoring as a tool to identify the migratory movements of fin whales in Australian waters. Sampling was conducted from eight locations around Australia between 2009 and 2017, providing a total of 37 annual migratory records. Taken together, our observations provide evidence of fin whale migration through Australian waters, with earliest arrival of the animals recorded on the Western Australian coast, at Cape Leeuwin in April. The whales travel through Cape Leeuwin, migrating northward along the Western Australian coast to the Perth Canyon (May to October), which likely acts as a way-station for feeding. Some whales continue migrating as far north as Dampier (19°S). On Australia’s east coast, at Tuncurry, fin whale seasonal presence each year occurred later, from June to late September/October. A total of only 8,024 fin whale pulses were recorded on the east coast, compared to 177,328 pulses recorded at the Perth Canyon. We suggest these differences, as well as the spatial separation between coasts, provide preliminary evidence that the fin whales present on the east and west coasts constitute separate sub-populations.
Regional ocean governance has been flagged as critical for successful achievement on SDG14 and other ocean related SDGs. The 20 ocean regions of the world are characterized by clusters of multilevel intergovernmental arrangements relating to EBM. Among the many needs for strengthening ocean governance in these regions is the development of effective regional integrating and coordinating mechanisms. These have been emerging somewhat organically. This study explores the clusters of regional agreements in the 20 regions to determine the extent to which integration mechanisms are in place or planned. It also looks at the extent to which the concept of governance polycentricity can be applied in these regions. Only four regions have established regional integration mechanisms thought to be needed for ecosystem-based management; while such mechanisms are planned in five others. Seven regions do have some level of intersectoral coordination such as within fisheries or environment or at a subregional level in a Large Marine Ecosystem (LME). Four regions show no sign of regional coordination. The study also the extent to which regional clusters of arrangements actually meet criteria for polycentricity based on governance theory. Regions have taken different approaches to regional integration mechanisms, but mostly based on working with a polycentric multilevel system of governance, rather than trying to tame it. There is both the need, and an untapped potential, for increased learning among regions regarding integration mechanisms and the polycentric structure and function of the regional clusters that they are seeking to integrate.
Cold water coral and sponge communities (CWCS) are important indicators of vulnerable marine ecosystems (VMEs) and are used to delineate areas for marine conservation and fisheries management. Although the Northeast Pacific region of Canada (NEPC) is notable for having unique CWCS assemblages and is the location of >80% of Canadian seamounts, the extent of potential CWCS-defined VMEs in this region is unknown. Here, we used a diverse set of environmental data layers (n=30) representing a range of bathymetric derivatives, physicochemical variables, and water column properties to assess the primary factors influencing the niche separation and potential distributions of six habitat-forming groups of CWCS in the NEPC (sponge classes: Hexactinellida, Demospongiae; coral orders: Alcyonacea, Scleractinia, Antipatharia, Pennatulacea). The primary environmental gradients that influence niche separation among CWCS are driven by total alkalinity, dissolved inorganic carbon, and dissolved oxygen. Significant niche separation among groups indicates CWCS to be primarily specialists occurring in rare habitat conditions in the NEPC. Species distribution models (SDMs) developed for each CWCS group shared severely low dissolved oxygen levels ([O2] < 0.5 ml L−1) as a top predictor for habitat suitability in the NEPC. Niche separation is further emphasized by differences in the model-predicted areas of suitable habitat among CWCS groups. Although niches varied among taxa, the general areas of high habitat suitability for multiple CWCS groups in the NEPC occurred within the 500–1400 m bottom depth range which is strongly associated with the extensive oxygen minimum zone (OMZ) characterizing this region. As a result, the largest continuous area of potential CWCS habitat occurred along the continental slope with smaller, isolated patches also occurring at several offshore seamounts that have summits that extend into OMZ depths. Our results provide insight into the factors that influence the distributions of some of the most important habitat-forming taxa in the deep ocean and create an empirical foundation for supporting cold-water coral and sponge conservation in the NEPC.
The importance of regional and subregional levels in global ocean governance is being increasingly recognised. Regional approaches are prominent in the 2030 Sustainable Development Agenda. The UN Environment Regional Seas Programme bodies focusing on pollution and biodiversity and the UN Food and Agriculture Organisation (FAO) regional fisheries bodies focusing on fisheries are the best known regional arrangements. However, there are other regional and subregional multilateral agreements that should be considered in building comprehensive regional ocean governance; in particular ‘indigenous’ agreements developed by the countries of the regions. This study examined 165 regional arrangements related to ecosystem-based management of oceans and allocated them into 20 regional clusters covering most of the world's oceans. The study explores the characteristics of these regional clusters which exhibit characteristics of polycentric systems. The suite of 20 regional clusters as well as global level oceans arrangements raises the question of whether there is an overall governance structure that should be pursued to strengthen ocean governance as envisaged in the Sustainable Development Goals and provide a holistic context for improving regional ocean governance. This study poses the question as to whether polycentric regional clusters can provide the ‘missing link’ for achieving global ocean governance objectives and whether these clusters are more than just the sum of their arrangements.
With the advent of DNA forensics, research on seafood fraud has increased drastically. The documentation of mislabeling has raised concern over the identity, value, and safety of seafood. However, the general characterization of mislabeling is limited. We conduct a Bayesian meta-analysis to estimate global mislabeling rates and their uncertainty across several factors. While the effort to document mislabeling is impressive, it is highly skewed toward certain taxa and geographies. For most products, including all invertebrates, there is insufficient data to produce useful estimates. For others, the uncertainty of estimates has been underappreciated. Mislabeling is commonly characterized by study-level means. Doing so often overestimates mislabeling, masks important product information, and is of limited utility—particularly given that studies often lack adequate sampling designs for parameter estimation. At the global level, overall mislabeling rates do not differ statistically across supply chain locations, product forms, or countries. Product-level estimates are the most informative. The majority of products, for which there is sufficient data, have mislabeling estimates lower than commonly reported. The most credible average mislabeling rate at the product-level is 8% (95% HDI: 4–14%). Importantly, some products have high estimates, which should be priorities for research and interventions. Estimates must be combined with other data in order to understand the extent and potential consequences of mislabeling, which is likely to vary drastically by product. Our meta-analysis, which can be updated with new data, provides a foundation for prioritizing research to inform programs and policies to reduce seafood fraud.
Perceptions of coastal hazards and risks and support for mitigation strategies among three different stakeholder groups (experts, businesses, and community members) are compared and analyzed in Waikiki, Hawaii. A justification for research on Waikiki, a world renown tourist destination and its relevance to other coastal communities is provided. It is shown that the three groups perceive risks, such as hurricanes, storm surge, erosion, tsunamis, and other natural and man-made hazards, differently which in turn influences support for mitigation strategies such as sea walls, beach nourishment, elevating or relocating at-risk structures and the preferences as to who should pay for risk reduction strategies. Data were analyzed using basic inferential statistics, GLM regression and correspondence analysis. Correspondence analysis is a novel technique for studying the relationships between stakeholder attributes (demographic, political, etc.) and the level of support for coastal interventions. The implications for researchers, engineers and coastal planners working in at-risk coastal communities are described.