Development and application of an online tool to quantify nitrogen removal associated with harvest of cultivated eastern oysters

Shellfish aquaculture can provide important ecosystem services to coastal communities, yet these benefits are not typically considered within the aquaculture permit review process. Resource managers have expressed interest in easy-to-use tools, based on robust science, that produce location and operation-appropriate values for beneficial services. These values need to be produced in a format that aligns with existing regulatory processes to facilitate seamless integration with permit review. The removal of excess nitrogen from coastal waters by shellfish farms is well documented in the literature and has been incorporated into nutrient management in the USA. Shellfish assimilate nitrogen into their tissue and shell as they grow, and this nitrogen is removed from the environment upon harvest. We have assembled a dataset of nitrogen concentration and morphometric measurements from farmed eastern oysters across the US Northeast, and adapted methodology used by existing nutrient management programs to quantify harvest-associated removal of nitrogen. Variability in oyster tissue and shell nutrient concentration was low within the dataset, and an assessment of farm location, ploidy, and three common cultivation practices (floating gear, bottom gear, no gear) suggested that a simple regression-based calculation could be applied across all farms within the region. We designed the new, publicly available online Aquaculture Nutrient Removal Calculator tool https://connect.fisheries.noaa.gov/ANRC/ based on this analysis, which uses inputs related to oyster size and harvest number to predict harvest-based nitrogen removal from an eastern oyster farm located within the geographic range of North Carolina to Maine, USA. The tool also produces a report that has been designed to integrate with the US Army Corps of Engineers public interest review process, and similar state-level permitting processes, and provides a succinct summary of the ecological services associated with nutrient removal in eutrophic locations, project-specific values, and citations supporting the calculation of those values.

Prediction and assessment of marine fisheries carbon sink in China based on a novel nonlinear grey Bernoulli model with multiple optimizations

The vigorous development of marine fisheries carbon sinks (MFCS) has become a momentous pathway to mitigate global warming and effectively cope with the climate crisis. Deservedly, based on clarifying mechanism of carbon sequestration, this paper designs a research paradigm for predicting and evaluating the potential of MFCS. Specifically, a novel nonlinear grey Bernoulli model, namely MFCSNGBM(1,1), is proposed by innovatively mining the original data law through adaptive cumulative series and introducing the compound Simpson formula to optimize background values. More precisely, we utilize a heuristic Grey Wolf Optimization algorithm to find the best power index, which enhances the adaptability. To prove usefulness and robustness of MFCSNGBM(1,1) model, yields of seven common shellfishes (oyster, clam, mussel, scallop, razor clam, bloody clam, and snail) and three main algae (kelp, pinnatifid undaria, and laver) are predicted and compared with six competing models. Based on prediction results, new model has the most accurate predictions, with all prediction errors being <10 %, and thus can achieve effective prediction of shellfish and algae production from 2022 to 2025. Further, the capacity and potential of MFCS in China are scientifically evaluated using a removable carbon sink model, considering various yield levels and biological parameters of shellfish and algae. The assessment results show that during the sample period, China's marine fisheries carbon sinks steadily increased with an annual growth rate of 57,000 tons. From 2022 to 2025, with support of policy of MFCS and improvement of disaster prevention and mitigation capacity, the potential of MFCS will be further released. The growth rate of MFCS will be increased to 94,000 tons per year, and its overall scale is expected to reach 2,198,245 tons by 2025, equivalent to fixing 8.06 million tons of CO2. The carbon sink's economic value is significantly estimated to be over 400 billion yuan.

Achieving conservation and restoration outcomes through ecologically beneficial aquaculture

A range of conservation and restoration tools are needed to safeguard the structure and function of aquatic ecosystems. Aquaculture, the culturing of aquatic organisms, often contributes to the numerous stressors that aquatic ecosystems face, yet some aquaculture activities can also deliver ecological benefits. We reviewed the literature on aquaculture activities that may contribute to conservation and restoration outcomes, either by enhancing the persistence or recovery of one or more target species or by moving aquatic ecosystems toward a target state. We identified 12 ecologically beneficial outcomes achievable via aquaculture: species recovery, habitat restoration, habitat rehabilitation, habitat protection, bioremediation, assisted evolution, climate change mitigation, wild harvest replacement, coastal defense, removal of overabundant species, biological control, and ex situ conservation. This list may be expanded as new applications are discovered. Positive intentions do not guarantee positive ecological outcomes, so it is critical that potentially ecologically beneficial aquaculture activities be evaluated via clear and measurable indicators of success to reduce potential abuse by greenwashing. Unanimity on outcomes, indicators, and related terminology will bring the field of aquaculture-environment interactions into line with consensus standards in conservation and restoration ecology. Broad consensus will also aid the development of future certification schemes for ecologically beneficial aquaculture.

Untangling the Gordian Knot of Aplysia sea hare egg masses: An integrated open-hardware system for standardized egg strand sizing and packaging for cryopreservation research and application

The California sea hare (Aplysia californica) provides a powerful biomedical model system for studying aspects of neurological development and damage, behavior, aging, and hypoxia. Aplysia encapsulate their zygotes within strands that result in tangled egg masses that greatly complicate culture and experimentation. The historical and current importance of Aplysia for biomedical research and the mounting climate crisis necessitates protection of Aplysia genetic resources. The goal of this work was to prototype open-hardware sizing, processing, and packaging devices for A. californica early life stages suitable for integration into a cryopreservation pathway. The Strand Centi-Sizer was a low-cost, fused filament fabrication 3-D printable device that increased experiment preparation efficiency and standardized the cutting of egg strands customizable to user needs. A downstream system of 3-D printed devices was also prototyped to address inefficiencies in handling of egg strand sections for processing and packaging into existing cryopreservation straw platforms. Time studies were conducted comparing manual methods (i.e., no specialized equipment) with open hardware to demonstrate utility of the devices and to encourage community members to design and prototype new devices to address recurrent and novel problems in other aquatic animals that produce egg strands. Improvements in design could further increase efficiency, standardization, and reproducibility, and extend the application of these devices to other research communities, such as shrimp or salamander spermatophores, sea anemone body part (e.g., pedal lacerate) cryopreservation, or study areas such as vitrification.

Tropical Red Macroalgae Cultivation with a Focus on Compositional Analysis

To create carbon efficient sources of bioenergy feedstocks and feedstuff for aquaculture and terrestrial livestock, it is critical to develop and commercialize the most efficient seaweed cultivation approach with a sustainable nutrient input supply. Here, we present data for a novel, onshore tropical macroalgae cultivation system, based on influent deep seawater as the nutrient and carbon sources. Two red algal species were selected, Agardhiella subulata and Halymenia hawaiiana, as the basis for growth optimization. Highest productivity in small-scale cultivation was demonstrated with A. subulata in the 10% deep seawater (64.7 µg N L-1) treatment, growing at up to 26% specific growth rate day-1 with highest yields observed at 247.5 g m-2 day-1 fresh weight. The highest yields for H. hawaiiana were measured with the addition of 10% deep seawater up to 8.8% specific growth rate day-1 and yields at 63.3 g fresh weight m-2 day-1 equivalent. Biomass should be culled weekly or biweekly to avoid density limitations, which likely contributed to a decrease in SGR over time. With a measured 30-40% carbon content of the ash-free dry weight (20-30% of the dry weight) biomass, this translates to an almost 1:1 CO2 capture to biomass ratio. The compositional fingerprint of the high carbohydrate content of both Agardhiella and Halymenia makes for an attractive feedstock for downstream biorefinery applications. By focusing on scaling and optimizing seaweed farming technologies for large-scale onshore farms, the opportunities for yield potential, adaptability to cultivation conditions, and meeting global sustainability goals through novel, carbon-negative biomass sources such as seaweed can be realized.

Supporting ecosystem services of habitat and biodiversity in temperate seaweed (Saccharina spp.) farms

Habitat provisioning, and the biodiversity within, is considered a type of "supporting" ecosystem service. Ecosystem services are the benefits humans receive from healthy ecosystems. We assess whether kelp (Saccharina spp.) farms provide seasonal habitat for wild organisms. Contrary to other studies conducted in tropic seaweed farms, we did not observe habitat provisioning or increased biodiversity at seasonal temperate seaweed farm sites compared to neighboring non-farm sites, which is encouraging news for the aquaculture industry given that most farm gear is removed from the water after the spring harvest. We quantified fish and crustaceans interacting with kelp farms using GoPro cameras. We also assessed small (<5 mm) invertebrates using mesh settling devices suspended at the same depth as kelp lines (2m). Visual surveys were paired with eDNA. There was coherence in the conclusions drawn from observational and eDNA methods, despite weak coherence in the specific species identified between the methods. Both farm and non-farm sites exhibited higher species richness and biodiversity in the summer non-growing season compared to the winter growing season, attributed to expected seasonal species movements.

Detecting sediment recovery below an offshore longline mussel farm: A macrobenthic Biological Trait Analysis (BTA)

Expansion of bivalve aquaculture offshore reports lower environmental impacts compared to inshore farms. Taking a Before-After Control-Impact approach, this study presents the first functional diversity analysis and long-term Biological Trait Analysis (BTA) of infauna functional traits following the development of the United Kingdom's first large-scale, offshore longline mussel farm. Located in an area historically impacted by mobile fishing gear, farm sites had the greatest number of taxa and abundance compared to control sites. Functional diversity varied significantly across treatments (farm, near control, far control); while Functional Diversity, Richness, Divergence and Dispersion increased over time within the farm, Functional Evenness and Redundancy decreased. Bioturbation, body size, diet, feeding mode, life span, motility, sediment position, sensitivity and substrate type were chosen for Community-level Weighted Mean analysis, depicting the most frequently affected biological traits by shellfish farming. Farm sites developed a wider range of traits enhancing ecosystem function and habitat recovery after years of seabed damage. Outcomes support the use of functional diversity and BTA analysis to perform ecosystem assessment, supporting decision-makers implement policy and management.

Does experimental seaweed cultivation affect benthic communities and shorebirds? Applications for extensive aquaculture

Extensive seaweed aquaculture is a growing industry expected to expand globally due to its relatively low impact and benefits in the form of ecosystem services. However, seaweeds are ecosystem engineers that may alter coastal environments by creating complex habitats on previously bare mudflats. These changes may scale up to top-consumers, particularly migratory shorebirds, species of conservation concern that regulate trophic webs at these habitats. Understanding how habitats are transformed and how this affects different species is critical to direct ecological applications for commercial seaweed management. We experimentally assessed through a Before-After Control-Impact design the potential changes exerted by Gracilaria chilensis farming on bare mudflats on the abundance, biomass, and assemblage structure of benthic macroinvertebrates, and their scaled-up effects on shorebirds' habitat use and prey consumption. As predicted, experimental cultivation of G. chilensis significantly affects different components of biodiversity that scale-up from lower to upper trophic levels. The total biomass of benthic macroinvertebrates increased with seaweed cultivation and remained high for at least 2 months after harvest, boosted by an increase in the median size of polychaetes, particularly Nereids. Tactile-foraging shorebirds tracked these changes at the patch level increasing their abundance and spending more time foraging at seaweed cultivated plots. These results suggest that seaweed farming has the potential to impact shorebird populations by favoring tactile-foraging species which could lead to a competitive disadvantage to species that rely on visual cues. Therefore, the establishment of new seaweed farms in bare mudflats at key sites for shorebirds must be planned warranting habitat heterogeneity (i.e., cultivated and non-cultivated areas) at the landscape level and based on a previous experimental approach to account for local characteristics. Fostering properly designed extensive seaweed farming over other aquaculture industries with greater negative environmental impacts would provide benefits for human well-being and for ecosystem functions.

Development and Diversity of Epibiont Assemblages on Cultivated Sugar Kelp (Saccharina latissima) in Relation to Farming Schedules and Harvesting Techniques

Seaweed farming in Europe is growing and may provide environmental benefits, including habitat provisioning, coastal protection, and bioremediation. Habitat provisioning by seaweed farms remains largely unquantified, with previous research focused primarily on the detrimental effects of epibionts, rather than their roles in ecological functioning and ecosystem service provision. We monitored the development and diversity of epibiont assemblages on cultivated sugar kelp (Saccharina latissima) at a farm in Cornwall, southwest UK, and compared the effects of different harvesting techniques on epibiont assemblage structure. Increases in epibiont abundance (PERMANOVA, F4,25 = 100.56, p < 0.001) and diversity (PERMANOVA, F4,25 = 27.25, p < 0.001) were found on cultivated kelps over and beyond the growing season, reaching an average abundance of >6000 individuals per kelp plant with a taxonomic richness of ~9 phyla per kelp by late summer (August). Assemblages were dominated by crustaceans (mainly amphipods), molluscs (principally bivalves) and bryozoans, which provide important ecological roles, despite reducing crop quality. Partial harvesting techniques maintained, or increased, epibiont abundance and diversity beyond the farming season; however, these kelp plants were significantly fouled and would not be commercially viable in most markets. This paper improves understanding of epibiont assemblage development at European kelp farms, which can inform sustainable, ecosystem-based approaches to aquaculture.

Experimental design and field deployment of an artificial bio-reef produced by mollusk shell recycling

Shellfish farming is considered a highly sustainable form of aquaculture that has developed rapidly worldwide. Unfortunately, today biological and chemical pollution of the oceans and marine waters is widespread and has multiple negative impacts on marine ecosystems, which are exacerbated by global climate changes. In addition, such impacts on fisheries and aquaculture are significant in inducing socio-economic losses. Therefore, it is necessary to develop innovative solutions to improve productivity and environmental performance in line with the blue sustainable economy (European Green Deal). However, one upcoming problem associated with shellfish consumption is shell waste and its disposal. In addition, the percentage of wasted shells destined for reuse is much lower than the one accumulated in landfills or in more or less well-managed sites. This represents a weakness of the shellfish farming sector that can only be mitigated through a project of shellfish waste recycling moving towards the circular economy, with undoubted environmental and economic advantages. In the present study, we present a possible solution for recycling clam shells coming from the waste of the fishing industry (circular economy). Indeed, three eco-friendly bio-reefs for the stabilization and implementation of marine biodiversity (blue economy) were realized using additive manufacturing technology (3D printing) for large dimensions (technological innovation). Furthermore, before deploying the reefs on the sea bottom, they were colonized with oysters to promote repopulation.

CAPOT: A flexible rapid assessment model to estimate local deposition of fish cage farm wastes

The Cage Aquaculture Particulate Output and Transport (CAPOT) model is an easy to use and flexible farm-scale model that can rapidly estimate particulate waste deposition from fish cage production. This paper describes and tests the model and demonstrates its use for Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua). The spreadsheet-based model gives outputs for waste distribution in a variety of spatial modelling software formats, used for further analysis. The model was tested at a commercial Atlantic cod farm and commercial Atlantic salmon farm under full production conditions. Sediment trap data showed predictions, using actual recorded feed and biomass data, to be 96% (±36%) similar for Atlantic cod beyond 5 m from the cage edge, giving a satisfactory estimate of local benthic impact in the vicinity of the farm. For Atlantic salmon, using estimated production biomass and FCR (Feed Conversion Ratio) to calculate feed input, the model overestimated wastes directly beneath the cages (120% ± 148%) and underestimated beyond 5 m from the cage edge, being 48% (±42%) similar to sediment trap data. CAPOT is a suitable initial, rapid assessment model to give an overview of potential impact of particulate waste from new or expanded fish cage farms, with little operator expertise by a wide range of stakeholders.

Climate-Friendly Seafood: The Potential for Emissions Reduction and Carbon Capture in Marine Aquaculture

Aquaculture is a critical food source for the world's growing population, producing 52% of the aquatic animal products consumed. Marine aquaculture (mariculture) generates 37.5% of this production and 97% of the world's seaweed harvest. Mariculture products may offer a climate-friendly, high-protein food source, because they often have lower greenhouse gas (GHG) emission footprints than do the equivalent products farmed on land. However, sustainable intensification of low-emissions mariculture is key to maintaining a low GHG footprint as production scales up to meet future demand. We examine the major GHG sources and carbon sinks associated with fed finfish, macroalgae and bivalve mariculture, and the factors influencing variability across sectors. We highlight knowledge gaps and provide recommendations for GHG emissions reductions and carbon storage, including accounting for interactions between mariculture operations and surrounding marine ecosystems. By linking the provision of maricultured products to GHG abatement opportunities, we can advance climate-friendly practices that generate sustainable environmental, social, and economic outcomes.

Seaweed Aquaculture in Indonesia Contributes to Social and Economic Aspects of Livelihoods and Community Wellbeing

Seaweed farming in Indonesia is carried out throughout much of the archipelago and is mainly undertaken by smallholder farmers. Indonesia is the largest global producer of the red seaweeds Kappaphycus and Eucheuma, which are used to produce carrageenan, and is a major producer of Gracilaria, which is used to produce agar. Seaweed farming is attractive to farmers in rural coastal communities because capital and operating costs are low, farming techniques are not technically demanding, labour requirements are relatively low (allowing farmers to engage in other livelihoods), and production cycles are short (30–45 days), providing regular income. Using reported values for seaweed-farming income, we conclude that seaweed farming can, but does not always, lift rural households above the Indonesian poverty line. In addition to direct financial benefits, seaweed farming also contributes to human and social capital within seaweed farming households and communities. Achieving continued economic and social benefits from seaweed farming will require additional policy development, as well as research and development to support improved and more consistent seaweed productivity and improved product quality at the farm level, provision of effective extension and technical support services, and diversification of the existing value chains in order to reduce the impacts of price fluctuations that are associated with limited global commodity chains.

Seaweed farms provide refugia from ocean acidification

Seaweed farming has been proposed as a strategy for adaptation to ocean acidification, but evidence is largely lacking. Changes of pH and carbon system parameters in surface waters of three seaweed farms along a latitudinal range in China were compared, on the weeks preceding harvesting, with those of the surrounding seawaters. Results confirmed that seaweed farming is efficient in buffering acidification, with Saccharina japonica showing the highest capacity of 0.10 pH increase within the aquaculture area, followed by Gracilariopsis lemaneiformis (ΔpH = 0.04) and Porphyra haitanensis (ΔpH = 0.03). The ranges of pH variability within seaweed farms spanned 0.14-0.30 unit during the monitoring, showing intense fluctuations which may also help marine organisms adapt to enhanced pH temporal variations in the future ocean. Deficit in pCO₂ in waters in seaweed farms relative to control waters averaged 58.7 ± 15.9 μatm, ranging from 27.3 to 113.9 μatm across farms. However, ΔpH did not significantly differ between day and night. Dissolved oxygen and Ω_arag were also elevated in surface waters at all seaweed farms, which are benefit for the survival of calcifying organisms. Seaweed farming, which unlike natural seaweed forests, is scalable and is not dependent on suitable substrate or light availability, could serve as a low-cost adaptation strategy to ocean acidification and deoxygenation and provide important refugia from ocean acidification.

Conservation aquaculture as a tool for imperiled marine species: Evaluation of opportunities and risks for Olympia oysters, Ostrea lurida

Conservation aquaculture is becoming an important tool to support the recovery of declining marine species and meet human needs. However, this tool comes with risks as well as rewards, which must be assessed to guide aquaculture activities and recovery efforts. Olympia oysters (Ostrea lurida) provide key ecosystem functions and services along the west coast of North America, but populations have declined to the point of local extinction in some estuaries. Here, we present a species-level, range-wide approach to strategically planning the use of aquaculture to promote recovery of Olympia oysters. We identified 12 benefits of culturing Olympia oysters, including identifying climate-resilient phenotypes that add diversity to growers’ portfolios. We also identified 11 key risks, including potential negative ecological and genetic consequences associated with the transfer of hatchery-raised oysters into wild populations. Informed by these trade-offs, we identified ten priority estuaries where aquaculture is most likely to benefit Olympia oyster recovery. The two highest scoring estuaries have isolated populations with extreme recruitment limitation—issues that can be addressed via aquaculture if hatchery capacity is expanded in priority areas. By integrating social criteria, we evaluated which project types would likely meet the goals of local stakeholders in each estuary. Community restoration was most broadly suited to the priority areas, with limited commercial aquaculture and no current community harvest of the species, although this is a future stakeholder goal. The framework we developed to evaluate aquaculture as a tool to support species recovery is transferable to other systems and species globally; we provide a guide to prioritizing local knowledge and developing recommendations for implementation by using transparent criteria. Our collaborative process engaging diverse stakeholders including managers, scientists, Indigenous Tribal representatives, and shellfish growers can be used elsewhere to seek win-win opportunities to expand conservation aquaculture where benefits are maximized for both people and imperiled species.

Maximizing Benefits to Nature and Society in Techno-Ecological Innovation for Water

Nature-based solutions (NbS) build upon the proven contribution of well-managed and diverse ecosystems to enhance resilience of human societies. They include alternatives to techno-industrial solutions that aim to enhance social-ecological integration by providing simultaneous benefits to nature (such as biodiversity protection and green/blue space) and society (such as ecosystem services and climate resiliency). Yet, many NbS exhibit aspects of a technological or engineered ecosystem integrated into nature; this techno-ecological coupling has not been widely considered. In this work, our aim is to investigate this coupling through a high-level and cross-disciplinary analysis of NbS for water security (quantity, quality, and/or water-related risk) across the spectrums of naturalness, biota scale, and benefits to nature and society. Within the limitations of our conceptual analysis, we highlight the clear gap between “nature” and “nature-based” for most NbS. We present a preliminary framework for advancing innovation efforts in NbS towards maximizing benefits to both nature and society, and offer examples in biophysical innovation and innovation to maximize techno-ecological synergies (TES).

A Cursory Look at the Fishmeal/Oil Industry From an Ecosystem Perspective

By supporting the fishmeal industry, are we competing with marine predators? Should we be taking away food from marine predators to subsidize agriculture? If not for human consumption, should forage fish be left in the sea for predators? Are there more sustainable alternatives to fishmeal; can the fishing industry be part of developing these? These are all pressing questions being posed by marine scientists, particularly in the light of the increasing aquaculture industry and associated increasing demand in recent decades for fishmeal and oil to sustain cultured fish. We concisely summarize the global context of marine sourced fishmeal and then use the South African marine ecosystem as a working example. This article draws on research into the trophic role of forage fish in marine ecosystems and ponders whether a reduced demand for fishmeal, given increasing global pressures such as climate change, could benefit marine ecosystems, fisheries on predatory species, and vulnerable marine predators.

Aquaculture and Restoration: Perspectives from Mediterranean Sea Experiences

In this paper, the different possibilities and innovations related to sustainable aquaculture in the Mediterranean area are discussed, while different maricultural methods, and the role of Integrated Multi-Trophic Aquaculture (IMTA) in supporting the exploitation of the ocean’s resources, are also reviewed. IMTA, and mariculture in general, when carefully planned, can be suitable for environmental restoration and conservation purposes. Aquaculture, especially mariculture, is a sector that is progressively increasing in parallel with the increase in human needs; however, several problems still affect its development, mainly in relation to the choice of suitable sites, fodder production, and the impact on the surrounding environment. A current challenge that requires suitable solutions is the implementation of IMTA. Unfortunately, some criticisms still affect this approach, mostly concerning the commercialization of new products such as invertebrates and seaweeds, notwithstanding their environmentally friendly character. Regarding the location of a suitable site, mariculture plans are currently displaced from inshore to offshore, with the aim of reducing the competition for space with other human activities carried out within coastal waters. Moreover, in open water, waste loading does not appear to be a problem, but high-energy waters increase maintenance costs. Some suggestions are given for developing sustainable mariculture in the Mediterranean area, where IMTA is in its infancy and where the scarce nutrients that characterize offshore waters are not suitable for the farming of both filter feeder invertebrates and macroalgae. From the perspective of coupling mariculture activity with restoration ecology, the practices suggested in this review concern the implementation of inshore IMTA, creating artificially controlled gardens, as well as offshore mussel farming coupled with artificial reefs, while also hypothesizing the possibility of the use of artificially eutrophized areas.

A 20-year retrospective review of global aquaculture

The sustainability of aquaculture has been debated intensely since 2000, when a review on the net contribution of aquaculture to world fish supplies was published in Nature. This paper reviews the developments in global aquaculture from 1997 to 2017, incorporating all industry sub-sectors and highlighting the integration of aquaculture in the global food system. Inland aquaculture-especially in Asia-has contributed the most to global production volumes and food security. Major gains have also occurred in aquaculture feed efficiency and fish nutrition, lowering the fish-in-fish-out ratio for all fed species, although the dependence on marine ingredients persists and reliance on terrestrial ingredients has increased. The culture of both molluscs and seaweed is increasingly recognized for its ecosystem services; however, the quantification, valuation, and market development of these services remain rare. The potential for molluscs and seaweed to support global nutritional security is underexploited. Management of pathogens, parasites, and pests remains a sustainability challenge industry-wide, and the effects of climate change on aquaculture remain uncertain and difficult to validate. Pressure on the aquaculture industry to embrace comprehensive sustainability measures during this 20-year period have improved the governance, technology, siting, and management in many cases.

The Aichi Biodiversity Targets: achievements for marine conservation and priorities beyond 2020

In 2010 the Conference of the Parties (COP) for the Convention on Biological Diversity revised and updated a Strategic Plan for Biodiversity 2011–2020, which included the Aichi Biodiversity Targets. Here a group of early career researchers mentored by senior scientists, convened as part of the 4th World Conference on Marine Biodiversity, reflects on the accomplishments and shortfalls under four of the Aichi Targets considered highly relevant to marine conservation: target 6 (sustainable fisheries), 11 (protection measures), 15 (ecosystem restoration and resilience) and 19 (knowledge, science and technology). We conclude that although progress has been made towards the targets, these have not been fully achieved for the marine environment by the 2020 deadline. The progress made, however, lays the foundations for further work beyond 2020 to work towards the 2050 Vision for Biodiversity. We identify key priorities that must be addressed to better enable marine biodiversity conservation efforts moving forward.

Farming fish in the sea will not nourish the world

Recent literature on marine fish farming brands it as potentially compatible with sustainable resource use, conservation, and human nutrition goals, and aligns with the emerging policy discourse of ‘blue growth’. We advance a two-pronged critique. First, contemporary narratives tend to overstate marine finfish aquaculture’s potential to deliver food security and environmental sustainability. Second, they often align with efforts to enclose maritime space that could facilitate its allocation to extractive industries and conservation interests and exclude fishers. Policies and investments that seek to increase the availability and accessibility of affordable and sustainable farmed aquatic foods should focus on freshwater aquaculture.

Marine aquaculture is widely proposed as compatible with ocean sustainability, biodiversity conservation, and human nutrition goals. In this Perspective, Belton and colleagues dispute the empirical validity of such claims and contend that the potential of marine aquaculture has been much exaggerated.

Eliciting expert judgment to inform management of diverse oyster resources for multiple ecosystem services

This study presents the most comprehensive set of ecosystem service provision estimates for diverse oyster-based resources to date. We use expert elicitation methods to derive estimates of five ecosystem services provided by oysters: oyster harvest (as indicated by oyster density), improved water quality (net nitrogen assimilation), shoreline protection (net erosion), and other fish habitat (blue crab and red drum density). Distributions are estimated for three distinct resources: on-bottom production, off-bottom farms, and non-harvested restoration/conservation efforts, under twelve distinct scenarios according to varying environmental conditions (eutrophication, sedimentation, and salinity regimes). Our expert-derived estimates of ecosystem services provide useful comparisons across oyster resources of both expected ecosystem service delivery levels and the amount of variation in those levels. These estimates bridge an information gap regarding relative performance of diverse oyster resources along multiple dimensions and should serve as a useful guide for resource managers facing competing interests.

A global assessment of the vulnerability of shellfish aquaculture to climate change and ocean acidification

Human-induced climate change and ocean acidification (CC-OA) is changing the physical and biological processes occurring within the marine environment, with poorly understood implications for marine life. Within the aquaculture sector, molluskan culture is a relatively benign method of producing a high-quality, healthy, and sustainable protein source for the expanding human population. We modeled the vulnerability of global bivalve mariculture to impacts of CC-OA over the period 2020-2100, under RCP8.5. Vulnerability, assessed at the national level, was dependent on CC-OA-related exposure, taxon-specific sensitivity and adaptive capacity in the sector. Exposure risk increased over time from 2020 to 2100, with ten nations predicted to experience very high exposure to CC-OA in at least one decade during the period 2020-2100. Predicted high sensitivity in developing countries resulted, primarily, from the cultivation of species that have a narrow habitat tolerance, while in some European nations (France, Ireland, Italy, Portugal, and Spain) high sensitivity was attributable to the relatively high economic value of the shellfish production sector. Predicted adaptive capacity was low in developing countries primarily due to governance issues, while in some developed countries (Denmark, Germany, Iceland, Netherlands, Sweden, and the United Kingdom) it was linked to limited species diversity in the sector. Developing and least developed nations (n = 15) were predicted to have the highest overall vulnerability. Across all nations, 2060 was identified as a tipping point where predicted CC-OA will be associated with the greatest challenge to shellfish production. However, rapid declines in mollusk production are predicted to occur in the next decade for some nations, notably North Korea. Shellfish culture offers human society a low-impact source of sustainable protein. This research highlights, on a global scale, the likely extent and nature of the CC-OA-related threat to shellfish culture and this sector enabling early-stage adaption and mitigation.

A global spatial analysis reveals where marine aquaculture can benefit nature and people

Aquaculture of bivalve shellfish and seaweed represents a global opportunity to simultaneously advance coastal ecosystem recovery and provide substantive benefits to humanity. To identify marine ecoregions with the greatest potential for development of shellfish and seaweed aquaculture to meet this opportunity, we conducted a global spatial analysis using key environmental (e.g., nutrient pollution status), socioeconomic (e.g., governance quality), and human health factors (e.g., wastewater treatment prevalence). We identify a substantial opportunity for strategic sector development, with the highest opportunity marine ecoregions for shellfish aquaculture centered on Oceania, North America, and portions of Asia, and the highest opportunity for seaweed aquaculture distributed throughout Europe, Asia, Oceania, and North and South America. This study provides insights into specific areas where governments, international development organizations, and investors should prioritize new efforts to drive changes in public policy, capacity-building, and business planning to realize the ecosystem and societal benefits of shellfish and seaweed aquaculture.

Farming the Sea: The Only Way to Meet Humanity's Future Food Needs

A major change began 10,000-12,000 years ago when humans began to practice agriculture. A series of "green revolutions" enabled the human population to explode, but these advancements have dramatically changed the planet. The United Nations predicts that we will need to produce 50% more food by 2050 to feed another 2.5 billion people, but this will be challenging with tighter land and water resources and a changing climate. Responsible marine aquaculture can complement responsible land-based agriculture and aquaculture and well-managed fisheries to increase the global supply of nutritious food.