Interest in understanding the extent of plastic and specifically microplastic pollution has increased on a global scale. However, we still know relatively little about how much plastic pollution has found its way into the deeper areas of the world’s oceans. The extent of microplastic pollution in deep-sea sediments remains poorly quantified, but this knowledge is imperative for predicting the distribution and potential impacts of global plastic pollution. To address this knowledge gap, we quantified microplastics in deep-sea sediments from the Great Australian Bight using an adapted density separation and dye fluorescence technique. We analyzed sediment cores from six locations (1–6 cores each, n = 16 total samples) ranging in depth from 1,655 to 3,062 m and offshore distances ranging from 288 to 356 km from the Australian coastline. Microplastic counts ranged from 0 to 13.6 fragments per g dry sediment (mean 1.26 ± 0.68; n = 51). We found substantially higher microplastic counts than recorded in other analyses of deep-sea sediments. Overall, the number of microplastic fragments in the sediment increased as surface plastic counts increased, and as the seafloor slope angle increased. However, microplastic counts were highly variable, with heterogeneity between sediment cores from the same location greater than the variation across sampling sites. Based on our empirical data, we conservatively estimate 14 million tonnes of microplastic reside on the ocean floor.
Non-compliance with regulations is a complex problem in recreational fisheries management, having the potential to evoke uncertainty for conservation and socio-ecological outcomes and to undermine management efforts. While we know that in fisheries people make trade-offs between following or breaking rules, it is of interest to determine how people respond to different management incentives to curtail non-compliance. The overall aim of this study is to examine what individual psycho-social characteristics are associated with responses to instrumental and normative management incentives in a recreational fisheries context through the use of an economic experiment. We examined five psycho-social characteristics, three of which (expectation of behavior of others, social norms, and risk preferences) have separately been explored within the fisheries compliance literature, while two factors (ecological values and personality types) have yet to be explored. While information about these two latter characteristics is limited within the fisheries compliance literature, our results suggest that they are relevant predictors for certain compliance groups across compliance incentives. The findings underline that there is significant heterogeneity in the associations between psycho-social make-up and compliance behaviors. Knowledge of this behavioral relationship can progress fisheries management toward increased innovation by encouraging the management of the individual fisher rather than the average fisher.
The marine ecosystem off British Columbia (BC), Canada, has experienced various changes in the last two decades, including reduced lipid-rich zooplankton biomass, increased marine mammals, and deteriorated commercial fisheries, particularly those targeting pelagic species such as Pacific Herring (Clupea pallasii). Understanding how stressors interactively and cumulatively affect commercially important fish species is key to moving toward ecosystem-based fisheries management. Because it is challenging to assess the cumulative effects of multiple stressors by using empirical data alone, a dynamic, individual-based spatially explicit ecosystem modeling platform such as Object-oriented Simulator of Marine Ecosystems (OSMOSE) represents a valuable tool to simulate ecological processes and comprehensively evaluate how stressors cumulatively impact modeled species. In this study, we employed OSMOSE to investigate the cumulative effects of fishing, plankton biomass change, and marine mammal consumption on the dynamics of some fish species and the BC marine ecosystem as a whole. We specifically simulated ecosystem dynamics during the last 20 years under two sets of scenarios: (1) unfavorable conditions from the perspective of commercial fish species (i.e., doubling fishing mortality rates, halving plankton biomass, and doubling marine mammal biomass, acting individually or collectively); and (2) favorable conditions with the three factors having opposite changes (i.e., halving fishing mortality rates, doubling plankton biomass, and halving marine mammal biomass, acting individually or collectively). Our results indicate that, under unfavorable conditions, the degree to which species biomass was reduced varied among species, and that negative synergistic and negative dampened effects were dominant under historical and doubled fishing mortality rates, respectively. Under favorable conditions, species biomasses did not increase as much as expected due to the existence of complex predator-prey interactions among fish species, and positive synergistic and positive dampened effects were prevailing under historical and halved fishing mortality rates, respectively. The ecosystem total biomass and the biomass to fisheries yield ratio were found to be good ecological indicators to represent ecosystem changes and track the impacts from the multiple drivers of change. Our research provides insights on how fisheries management should adapt to prepare for potential future impacts of climate change.
In 2015 the Sustainable Development Goals of the United Nations stipulated that certain forms of subsidies that the fishing sector receive must be prohibited. However, the global fishing sector is complex and varied, and as such there remains a need for information on the distribution of subsidies between the different regions and their sub-sectors. This bottom-up study therefore provides up-dated and improved analyses of the financial support fishing sub-sectors receive from public entities. Estimates show that of the USD 35.4 billion of global fisheries subsidies provided in 2018, 19% went to the small-scale fishing sub-sector (SSF), including artisanal, and subsistence fisheries. Whilst more than 80% went to the large-scale (industrial) fishing sub-sector (LSF). Analysis by subsidy category and type shows, for example, that the majority of the subsidies that the LSF receive are in the form of capacity-enhancing subsidies (USD 18.3 billion) with fuel subsidies being the highest overall subsidy type (USD 7.2 billion). Fuel subsidies are especially harmful as they perpetuate fuel inefficient technology. Since the last estimate of the global fisheries subsidies divide, the percentage of capacity-enhancing subsidies within the SSF has increased from 41% in 2009 to 59% in 2018. When assessing the level of subsidization per active fisher at the global scale, a fisher involved in LSF receives disproportionally (3.5 times) more subsidies than a fisher involved in SSF and in terms of subsidies per landed value LSF receive twice as many subsidies per dollar landed than SSF. This unequal distribution of government support exacerbates the ongoing political and economic marginalization of SSF, globally. The Sustainable Development Goals and the supporting science are quite clear, we must remove all capacity-enhancing subsidies across all sub-sectors and regions which exacerbate overcapacity and overfishing, in order to ensure the sustainability of our fish stocks. Our recommendation is that capacity-enhancing subsidies be removed and instead used to support fishers through coastal fishing community projects that focus on fisheries sustainability, social justice and food security, rather than on reducing the cost of fishing or artificially enhancing profits through the provision of harmful subsidization.
Increasing sea surface temperature and extreme heat events pose the greatest threat to coral reefs globally, with trends exceeding previous norms. The resultant mass bleaching events, such as those evidenced on the Great Barrier Reef in 2016, 2017, and 2020 have substantial ecological costs in addition to economic and social costs. Advancing remote (nanosatellites, rapid revisit traditional satellites) and in-field (drones) technological capabilities, cloud data processing, and analysis, coupled with existing infrastructure and in-field monitoring programs, have the potential to provide cost-effective and timely information to managers allowing them to better understand changes on reefs and apply effective remediation. Within a risk management framework for monitoring coral bleaching, we present an overview of how remote sensing can be used throughout the whole risk management cycle and highlight the role technological advancement has in earth observations of coral reefs for bleaching events.
A comprehensive, high resolution, ground truthed benthic habitat map has been completed for Qatar's coastal zone and Halul Island. The objectives of this research were to; 1. Systematically compare and contrast pixel- and object-based classifiers for benthic mapping in a limited focus area and then to, 2. Apply these learnings to develop an accurate high resolution benthic habitat map for the entirety of the Qatari coastal zone. Results indicate object-based methods proved more efficient and accurate when compared to pixel based classifiers. The developed country-wide map covers 4500 km2 and underscores the complex interplay of seagrass, macroalgal, and reefal habitats, as well as areas of expansive mangrove forests and microbial mats. The map developed here is a first of its kind in the region. Many potential applications exist for the datasets collected to provide fundamental information that can be used for ecosystem-based management decision making.
The increasing amount of marine plastic waste poses challenges including, not only the collection, but also the subsequent recyclability of the plastic. An artificial accelerated weathering procedure was developed, which modelled the marine environment and investigated the recyclability of weathered and non-weathered PET. Marine conditions were simulated for poly(ethylene terephthalate) (PET) bottle material and high-density polyethylene (HDPE) cap material. It consisted of 2520 h cyclical weathering, alternating the sample between a salt spray and a Xenon-chamber—this corresponds to roughly 3–4 years on the surface of an ocean.
It was proved that the molecular weight of PET is a function of weathering time and can be described mathematically. Microscopic examination of the surface of the PET bottles and HDPE caps proved that these surfaces were damaged. After weathering, manufacturing tests were performed on the PET material by extrusion, injection moulding, 3D printing and thermoforming. Quantitative comparison between products manufactured by the same technology was performed in order to compare the qualities of products made from original PET, non-weathered PET waste, which was the example of classical recycling, and weathered PET. In the case of products made from weathered PET, certain mechanical and optical properties (e.g. impact strength and transparency) were significantly impaired compared to the original PET and the recycled, non-weathered PET. Certain other properties (e.g. strength and rigidity) did not change significantly. It was proved that the samples from weathered plastic material can be successfully recycled mechanically and used to manufacture plastic products.
As plastic waste accumulates in the ocean at alarming rates, the need for efficient and sustainable remediation solutions is urgent. One solution is the development and mobilization of technologies that either 1) prevent plastics from entering waterways or 2) collect marine and riverine plastic pollution. To date, however, few reports have focused on these technologies, and information on various technological developments is scattered. This leaves policymakers, innovators, and researchers without a central, comprehensive, and reliable source of information on the status of available technology to target this global problem. The goal of this study was to address this gap by creating a comprehensive inventory of technologies currently used or in development to prevent the leakage of plastic pollution or collect existing plastic pollution. Our Plastic Pollution Prevention and Collection Technology Inventory (https://nicholasinstitute.duke.edu/plastics-technology-inventory) can be used as a roadmap for researchers and governments to 1) facilitate comparisons between the scope of solutions and the breadth and severity of the plastic pollution problem and 2) assist in identifying strengths and weaknesses of current technological approaches. We created this inventory from a systematic search and review of resources that identified technologies. Technologies were organized by the type of technology and target plastics (i.e., macroplastics, microplastic, or both). We identified 52 technologies that fall into the two categories of prevention or collection of plastic pollution. Of these, 59% focus specifically on collecting macroplastic waste already in waterways. While these efforts to collect plastic pollution are laudable, their current capacity and widespread implementation are limited in comparison to their potential and the vast extent of the plastic pollution problem. Similarly, few technologies attempt to prevent plastic pollution leakage, and those that do are limited in scope. A comprehensive approach is needed that combines technology, policymaking, and advocacy to prevent further plastic pollution and the subsequent damage to aquatic ecosystems and human health.
Many marine animals have evolved sensory abilities to use electric and magnetic cues in essential aspects of life history, such as to detect prey, predators and mates as well as to orientate and migrate. Potential disruption of vital cues by human activities must be understood in order to mitigate potential negative influences. Cable deployments in coastal waters are increasing worldwide, in capacity and number, owing to growing demands for electrical power and telecommunications. Increasingly, the local electromagnetic environment used by electro- and magneto-sensitive species will be altered. We quantified biologically relevant behavioural responses of the presumed, magneto-receptive American lobster and the electro-sensitive Little skate to electromagnetic field (EMF) emissions of a subsea high voltage direct current (HVDC) transmission cable for domestic electricity supply. We demonstrate a striking increase in exploratory/foraging behaviour in skates in response to EMF and a more subtle exploratory response in lobsters. In addition, by directly measuring both the magnetic and electric field components of the EMF emitted by HVDC cables we found that there were DC and unexpectedly AC components. Modelling, restricted to the DC component, showed good agreement with measured results. Our cross-disciplinary study highlights the need to integrate an understanding of the natural and anthropogenic EMF environment together with the responses of sensitive animals when planning future cable deployments and predicting their environmental effects.
Marine debris on the seafloor has not been thoroughly investigated, and there is little information compared to other types of marine debris. We conducted bottom trawl surveys to determine the present situation of marine debris on the seafloor in offshore areas around Japan. The survey was conducted in three sea areas with different characteristics. As a result, it was found that the amount of marine debris in submarine canyons (2926.1 items/km2) was higher than on the continental shelf. It was revealed that most marine debris on the seafloor is comprised of plastic products, and that debris on the seafloor retains its condition for a long time (over 30 years) without deterioration. In addition, the type of marine debris is affected by the industries operating in each area. Continuing to investigate marine debris on the seafloor in more areas will contribute to solving the problem of marine debris.
Globally, shrimp aquaculture has undergone a rapid development in the last decades, as it can help to satisfy the increasing food demand of a growing population. However, shrimp production can be accompanied by environmental impacts, such as land cover changes associated with pond construction, or the degradation of coastal areas through pollution. Environmental footprinting, has proven to be a valuable tool for tracing environmental impacts from human consumption back to their location and sector of origin. Here, we focus on the land footprint, which quantifies the area of required land resources to satisfy human consumption (of shrimp production). However, today’s footprinting tools often lack spatially explicit land cover information for land footprint assessments. In this study we developed a new method, which allows us to identify the land cover change caused by shrimp pond construction in Thailand without using sample shrimp pond shape polygons as input data. We use the global water surface explorer (using globally 3 million Landsat 5 TM, Landsat 7 ETM and Landsat 8 OLI images, acquired between 1984 and 2015), aerial photographs and land cover maps in combination with known aquaculture locations, to identify water areas in Thailand that have a high likelihood to be a shrimp pond and to assess the corresponding land cover change. We estimated that in 2015 an area of 377 km2 had a high likelihood of being shrimp pond water area. Further, we show that the construction of shrimp ponds in Thailand was responsible for the transformation of 552 km2 primary habitat, such as mangrove areas. Our results support the environmental footprint assessment of shrimp ponds in Thailand, while our proposed method allows identifying possible shrimp pond areas on a global scale.
We report archaeological findings from a significant new cave site on Alor Island, Indonesia, with an in situ basal date of 40,208–38,454 cal BP. Twenty thousand years older than the earliest Pleistocene site previously known from this island, Makpan retains dense midden deposits of marine shell, fish bone, urchin and crab remains, but few terrestrial species; demonstrating that protein requirements over this time were met almost exclusively from the sea. The dates for initial occupation at Makpan indicate that once Homo sapiens moved into southern Wallacea, settlement of the larger islands in the archipelago occurred rapidly. However, the Makpan sequence also suggests that the use of the cave following initial human arrival was sporadic prior to the terminal Pleistocene about 14,000 years ago, when occupation became intensive, culminating in the formation of a midden. Like the coastal sites on the larger neighbouring island of Timor, the Makpan assemblage shows that maritime technology in the Pleistocene was highly developed in this region. The Makpan assemblage also contains a range of distinctive personal ornaments made on Nautilus shell, which are shared with sites located on Timor and Kisar supporting connectivity between islands from at least the terminal Pleistocene. Makpan’s early inhabitants responded to sea-level change by altering the way they used both the site and local resources. Marine food exploitation shows an initial emphasis on sea-urchins, followed by a subsistence switch to molluscs, barnacles, and fish in the dense middle part of the sequence, with crabs well represented in the later occupation. This new record provides further insights into early modern human movements and patterns of occupation between the islands of eastern Nusa Tenggara from ca. 40 ka.
Knowledge mobilisation is required to “bridge the gap” between research, policy and practice. This activity is dependent on the amount, richness and quality of the data published. To understand the impact of a changing climate on commercial species, stakeholder communities require better knowledge of their past and current situations. The common cockle (Cerastoderma edule) is an excellent model species for this type of analysis, as it is well-studied due to its cultural, commercial and ecological significance in west Europe. Recently, C. edule harvests have decreased, coinciding with frequent mass mortalities, due to factors such as a changing climate and diseases. In this study, macro and micro level marine historical ecology techniques were used to create datasets on topics including: cockle abundance, spawning duration and harvest levels, as well as the ecological factors impacting those cockle populations. These data were correlated with changing climate and the Atlantic Multidecadal Oscillation (AMO) index to assess if they are drivers of cockle abundance and harvesting. The analyses identified the key stakeholder communities involved in cockle research and data acquisition. It highlighted that data collection was sporadic and lacking in cross-national/stakeholder community coordination. A major finding was that local variability in cockle populations is influenced by biotic (parasites) and abiotic (temperature, legislation and harvesting) factors, and at a global scale by climate (AMO Index). This comprehensive study provided an insight into the European cockle fishery but also highlights the need to identify the type of data required, the importance of standardised monitoring, and dissemination efforts, taking into account the knowledge, source, and audience. These factors are key elements that will be highly beneficial not only to the cockle stakeholder communities but to other commercial species.
Farming of marine organisms (mariculture) represented 36% of global aquaculture, with mollusks representing 58.8% in live weight. Mollusk populations in some locations are, however, threatened by degradation of the ecosystems and/or over-fishing. This threat is increasingly being addressed through Restorative Shellfish Mariculture (RSM), as opposed to mariculture alone. There is no general consensus in the literature on what can and cannot be considered RSM. While maximization of benefits other than provisioning services is often considered a prerequisite, in other cases the maximization of fisheries yields is prioritized. Here we define RSM as the farming of marine shellfish, implying some form of intervention during the species life cycle, in order to address negative socio-ecological issues arising from the unsustainable use of marine ecosystems, independent of the final ownership regime of the resource. Strategies for developing RSM were reviewed and classified along a gradient from the most conservation-oriented (e.g., habitat restoration, reintroduction of locally extinct endangered species), to the most fisheries-oriented (including some forms of fisheries enhancement), and classified as Non-hatchery Dependent or Hatchery Dependent strategies. We reviewed the targeted species and strategies implemented across 584 individual projects developed in the last decades in North America, Europe, Asia, Oceania and South America. We found that some 48 species, including 34 bivalves and 15 gastropods were targets of RSM in 34 countries. US projects accounted for ca. three quarters of the total (N = 438), with Philippines, Japan and Australia also being home to a large number. More than 90% of the projects involved five species, namely the eastern oyster (Crassostrea virginica, N = 379), the giant clam (Tridacna gigas, N = 65), the Olympia oyster (Ostrea lurida, N = 25), the bay scallop (Argopecten irradians, N = 25) and the hard clam (Mercenaria mercenaria, N = 15). Of the RSM projects, 51% used Non-hatchery dependent methods, mostly habitat restoration providing substrata for settlement, whereas some 49% involved hatcheries. 3% of the projects combined both methods. This review provides an overview of the breadth, depth and aims of RSM globally, develops a broad definition of the activity, and proposes a structure for classifying RSM.
New Zealand has a large exclusive economic zone (EEZ) of which the area between the 30 and 50 m bathymetric zone offers the most prospects for shellfish production. Only 0.3% of this zone would be required to increase New Zealand’s shellfish production by 150,000 t. The Enabling Open Ocean Aquaculture Program, funded by the New Zealand Ministry of Business, Innovation and Employment, is a collaboration aiming to develop technologies that will enable the extension of aquaculture into New Zealand’s harsh and challenging open ocean conditions, and facilitate adaptation to the escalating effects of climate change in inner shore environments. New Zealand has started expanding aquaculture into exposed environments, allowing farm expansion to meet increasing demand for aquaculture products but also enabling ventures into new aquatic products. Expansion into offshore developments is in direct response to mounting stakeholder interaction in inshore coastal areas. This document presents a brief overview of the potential zones for open ocean aquaculture, the influence of climate change, and two potential shellfish operational systems that may facilitate the expansion of shellfish aquaculture onto New Zealand’s exposed ocean sites.
Harp seals are the most abundant marine mammal in the north Atlantic. As an ice obligatory predator, they reflect changes in their environment, particularly during a period of climatic change. As the focus of a commercial hunt, a large historic data set exists that can be used to quantify changes. There are three populations of harp seals: White Sea/Barents Sea, Greenland Sea and Northwest Atlantic. The objective of this paper is to review their current status and to identify the factors that are influencing population dynamics in different areas. Although important historically, recent catches have been low and do not appear to be influencing trends in either of the two northeast Atlantic populations. Massive mortalities of White Sea/Barents Sea seals occurred during the mid 1980s due to collapses in their main prey species. Between 2004 and 2006, pup production in this population declined by 2/3 and has remained low. Body condition declined during the same period, suggesting that ecosystem changes may have resulted in reduced reproductive rates, possibly due to reduced prey availability and/or competition with Atlantic cod. The most recent estimate of pup production in the Greenland Sea also suggests a possible decline during a period of reduced hunting although the trend in this population is unclear. Pupping concentrations are closer to the Greenland coast due to the reduction in ice in the traditional area and increased drift may result in young being displaced from their traditional feeding grounds leading to increased mortality. Reduced ice extent and thickness has resulted in major mortality of young in the Northwest Atlantic population in some years. After a period of increase, the population remained relatively stable between 1996 and 2013 due to increased hunting, multiple years with increased ice-related mortality of young seals, and lower reproductive rates. With a reduction in harvest and improved survival of young, the population appears to be increasing although extremely large interannual variations in body condition and fecundity have been observed which were found to be influenced by variations in capelin biomass and ice conditions. Each of these populations has been impacted differently by changes in their ecosystems and hunting practices. By identifying the factors influencing these three populations, we can gain a better understanding of how species may respond to changes that are occurring in their ecosystems.
Autonomous platforms already make observations over a wide range of temporal and spatial scales, measuring salinity, temperature, nitrate, pressure, oxygen, biomass, and many other parameters. However, the observations are not comprehensive. Future autonomous systems need to be more affordable, more modular, more capable and easier to operate. Creative new types of platforms and new compact, low power, calibrated and stable sensors are under development to expand autonomous observations. Communications and recharging need bandwidth and power which can be supplied by standardized docking stations. In situ power generation will also extend endurance for many types of autonomous platforms, particularly autonomous surface vehicles. Standardized communications will improve ease of use, interoperability, and enable coordinated behaviors. Improved autonomy and communications will enable adaptive networks of autonomous platforms. Improvements in autonomy will have three aspects: hardware, control, and operations. As sensors and platforms have more onboard processing capability and energy capacity, more measurements become possible. Control systems and software will have the capability to address more complex states and sophisticated reactions to sensor inputs, which allows the platform to handle a wider variety of circumstances without direct operator control. Operational autonomy is increased by reducing operating costs. To maximize the potential of autonomous observations, new standards and best practices are needed. In some applications, focus on common platforms and volume purchases could lead to significant cost reductions. Cost reductions could enable order-of-magnitude increases in platform operations and increase sampling resolution for a given level of investment. Energy harvesting technologies should be integral to the system design, for sensors, platforms, vehicles, and docking stations. Connections are needed between the marine energy and ocean observing communities to coordinate among funding sources, researchers, and end users. Regional teams should work with global organizations such as IOC/GOOS in governance development. International networks such as emerging glider operations (EGO) should also provide a forum for addressing governance. Networks of multiple vehicles can improve operational efficiencies and transform operational patterns. There is a need to develop operational architectures at regional and global scales to provide a backbone for active networking of autonomous platforms.
Marine coastal (or “blue”) ecosystems provide valuable services to humanity and the environment, but global loss and degradation of blue ecosystems necessitates ecological restoration. However, blue restoration is an emerging field and is still relatively experimental and small-scale. Identification of the key barriers to scaling-up blue restoration will enable targeted problem solving and increase the likelihood of success. Here we describe the environmental, technical, social, economic, and political barriers to restoration of blue ecosystems, including saltmarsh, mangroves, seagrass, shellfish reefs, coral reefs, and kelp forests. We provide managers, practitioners, and decision-makers with solutions to construct barrier-informed blue restoration plans and illustrate these solutions through the use of case studies where barriers were overcome. We offer a way forward to build confidence in blue restoration for society, government, and restoration practitioners at larger and more ambitious scales.
Marine and coastal activities are closely interrelated, and conflicts among different sectors can undermine management and conservation objectives. Governance systems for fisheries, power generation, irrigation, aquaculture, marine biodiversity conservation, and other coastal and maritime activities are typically organized to manage conflicts within sectors, rather than across them. Based on the discussions around eight case studies presented at a workshop held in Brest in June 2019, this paper explores institutional approaches to move beyond managing conflicts within a sector. We primarily focus on cases where the groups and sectors involved are heterogeneous in terms of: the jurisdiction they fall under; their objectives; and the way they value ecosystem services. The paper first presents a synthesis of frameworks for understanding and managing cross-sectoral governance conflicts, drawing from social and natural sciences. We highlight commonalities but also conceptual differences across disciplines to address these issues. We then propose a novel analytical framework which we used to evaluate the eight case studies. Based on the main lessons learned from case studies, we then discuss the feasibility and key determinants of stakeholder collaboration as well as compensation and incentive schemes. The discussion concludes with future research needs to support policy development and inform integrated institutional regimes that consider the diversity of stakeholder interests and the potential benefits of cross-sectoral coordination.
Over 85% of the world's oyster reefs have been lost in the past two centuries, triggering a global effort to restore shellfish reef ecosystems and the ecosystem services they provide. While there has been considerable success in re-establishing oyster reefs, many challenges remain. These include: high incidence of failed restoration, high cost of restoration per unit area, and increasing stress from climate change. In order to leverage our past successes and progress the field, we must increase restoration efficiencies that not only reduce cost per unit area, but also increase the resilience of restored ecosystems. To help address this need, we qualitatively review the literature associated with the structure and function of oyster reef ecosystems to identify key positive species interactions (i.e., those species interactions where at least one partner benefits and no partners are harmed). We classified positive inter- and intraspecific interactions between oysters and organisms associated with oyster ecosystems into the following seven functional categories: (1) physical reef creation, (2) positive density dependence, (3) refugia from physical stress, (4) refugia from biological stress, (5) biodiversity enhancement, (6) settlement improvement, and (7) long-distance facilitation. We discuss each category of positive interaction and how restoration practitioners can use knowledge of such processes to enhance restoration success. We propose that systematic incorporation of positive species interactions into restoration practice will both enhance ecological services provided by restored reefs and increase restoration success.