The exponential rise in atmospheric CO₂ driven by human activities is accelerating climate change and causing ocean acidification (OA). While the effects of elevated CO₂ on a wide range of marine species have been well documented, the implications of OA for bivalve aquaculture have received comparatively little attention. Using a multi-level meta-analytical approach, we evaluated the impacts of two elevated pCO₂ levels—classified as high and extreme—on cultured bivalves, based on 266 observations from 24 species across tropical and temperate regions. Overall, both elevated pCO₂ levels negatively affected bivalves, reducing survival, growth, feeding rates, development, and calcification. Larvae were generally more vulnerable than juveniles and adults. Our analyses further indicated that temperate bivalves were more sensitive to OA than tropical and subtropical counterparts. Among taxa, clams were the most vulnerable under high CO₂ emission scenarios, whereas scallops were the most sensitive under extreme pCO₂ levels. We also discuss potential mitigation strategies for the bivalve aquaculture industry. With advancements in local and regional monitoring, coupled with targeted measures such as buffering sites, selective breeding, and integrated multi-trophic aquaculture, the adverse effects of OA on bivalve farming could be mitigated.
Continue reading ‘A global meta-analysis reveals consistently negative effects of ocean acidification on marine cultured bivalves: implications for future bivalve aquaculture’Posts Tagged 'fisheries'
A global meta-analysis reveals consistently negative effects of ocean acidification on marine cultured bivalves: implications for future bivalve aquaculture
Published 16 December 2025 Science Leave a CommentTags: biological response, calcification, fisheries, growth, mitigation, mollusks, mortality, performance, physiology, reproduction, review
Saving oysters from ocean acidification with seaweed
Published 3 December 2025 Web sites and blogs ClosedTags: fisheries
Oyster farms are one of the most environmentally sustainable farms in the world. As filter-feeders, oysters and other bivalve mollusks like clams, mussels, and scallops, require no additional feed or fertilizers. They simply eat plankton from their surroundings, leaving cleaner shallows for the rest of the ecosystem to enjoy.
However, the late 2000’s brought a concerning trend of oyster farm mortality events. One culprit is higher levels of carbon dioxide absorbed into our waters, which creates a more acidic environment. As climate change progresses, the oceans grow more acidic and less hospitable for shellfish.
“It affects many ocean organisms, but especially animals that build shells and skeletons,” says graduate student Leah Wessler. “It’s a big barrier for aquaculture and wild fisheries.”
Wessler is in the MSc program Applied Animal Biology studying how ocean acidification affects shellfish farms and how we can mitigate or even reverse the damage. From coral reefs in the Caribbean to beluga whales in Alaska, Wessler has worked in marine conservation and research around the world. She was drawn back home to the Pacific North West by a growing sense of optimism and momentum in the shellfish aquaculture sector.
“Here’s an avenue of farming that’s sustainable, produces high-quality protein, and is already quite common in many areas of the world,” Wessler says.
Continue reading ‘Saving oysters from ocean acidification with seaweed’Acidification-mediated perturbations of developmental pathways and life-stage transitions in Artemia salina
Published 27 November 2025 Science ClosedTags: biological response, crustaceans, fisheries, laboratory, mortality, reproduction
Projected increases in atmospheric carbon dioxide are anticipated to induce a 0.3–0.5 unit decline in oceanic pH by the year 2100, posing a significant threat to marine ecosystems. This study investigated the sub lethal effects of simulated ocean acidification on the ontogenetic success of Artemia salina, a key trophic link in aquaculture systems. A controlled, in vitro experiment employing a Completely Randomized Design (CRD) was conducted, maintaining constant temperature, salinity, and dissolved oxygen. Embryonic development and larval survival were assessed across a gradient of pH levels, representing projected future ocean acidification scenarios. Preliminary data indicate a negative correlation between decreasing pH and both hatching success and larval survivorship. Further investigations are warranted to elucidate the long-term ecological consequences of ocean acidification on Artemia salina populations and their role in aquaculture.
Continue reading ‘Acidification-mediated perturbations of developmental pathways and life-stage transitions in Artemia salina’Perceptions of oyster farmers on adopting environmental monitoring technologies to mitigate ocean acidification: a case study in Bahía San Quintín, México
Published 19 November 2025 Science ClosedTags: fisheries, mitigation, North Pacific, socio-economy
Coastal ecosystems face multiple stressors, and their responses are magnified by global stressors associated with climate change, such as warming and ocean acidification (OA). Oyster farming are vulnerable to the effects of these stressors. Environmental monitoring technologies have been proposed as an adaptive strategy to OA. This study examined the perceptions of the oyster farmers in Bahía San Quintín, Mexico, toward this strategy. Through surveys and workshops, we identified the main challenges oyster farmers face in their industry, their level of awareness about OA, and their openness to adopting new technologies. Most respondents (66 %) did not recognize OA, which suggests that they had a low perception of its risks and its potential consequences for their activities. The most frequent problems were environmental issues (48 %), such as extreme temperature events, biofouling, and predation, followed by limited technical and financial resources (34 %). Recognizing the negative effect that high temperatures have on their activity, especially during El Niño Southern Oscillation (ENSO) events, is a positive outcome, as it allows them to adopt strategies to cope with OA. The main barriers to adopt new technologies were related to management issues (56 %), including a lack of economic resources. We recommend that interactions between oyster producers, academia, and governmental actors must be strengthened to promote environmental monitoring, thus improving their adaptive capacity and reducing potential impacts of stressors on their industry, such as climate change and OA. This study case is a valuable reference for other oyster farming communities in similar environmental and socio-economic contexts.
Continue reading ‘Perceptions of oyster farmers on adopting environmental monitoring technologies to mitigate ocean acidification: a case study in Bahía San Quintín, México’Mothers know best: maternal signaling boosts larval resilience under ocean acidification conditions
Published 12 November 2025 Science ClosedTags: adaptation, biological response, fisheries, molecular biology, mollusks, morphology, mortality, otherprocess, physiology, reproduction
Highlights
- Environmental priming effectively rescued larval phenotype under OA conditions.
- Egg ‘omics were investigated to elucidate mechanism of priming across generations.
- Clam egg lipidomes were largely unperturbed by maternal low-pH exposure.
- Differentially expressed genes were identified in eggs of low-pH primed clams.
Abstract
Bivalve aquaculture is a growing sector worldwide, producing sustainable animal protein to meet growing demand from consumers. Yet, the industry remains vulnerable to environmental changes that can impact their product across life stages, especially at the larval stage. Parental priming, or the exposure of broodstock to adverse environmental conditions as they undergo gametogenesis, holds promise as a method to increase resilience in bivalve offspring. We exposed Manila clam (Ruditapes philippinarum) broodstock to low pH conditions (pH 7.4 for 78 days during gametogenesis). Larvae were produced from primed (low pH) and unprimed (ambient pH) broodstock and exposed to ambient or low pH conditions in a full factorial design. Larval phenotype in response to low pH was partially rescued by broodstock priming: larvae from low pH-exposed broodstock had better survival and growth than larvae from broodstock held under ambient conditions. Clam egg lipidomic and transcriptomic analyses were performed to determine the physiological differences associated with broodstock environmental conditions. Egg lipid abundance profiles were not significantly different between parental treatments. The egg transcriptome revealed 48 differentially expressed transcripts associated with parental environmental conditions. These genes are involved in important processes for early larval physiology, including metabolism, cell cycle, and transcriptional regulation. Broodstock clams were minimally impacted by their exposure to low pH for 78 days, however we show here that subtle maternal signals may contribute to the vastly improved larval performance observed under low pH conditions.
Continue reading ‘Mothers know best: maternal signaling boosts larval resilience under ocean acidification conditions’Transcriptomic analysis of the hepatopancreas response to low-pH stress in kuruma shrimp (Marsupenaeus japonicus)
Published 6 November 2025 Science ClosedTags: biological response, crustaceans, fisheries, laboratory, molecular biology, North Pacific, physiology
Highlights
- Low-pH stress disrupted oxidative balance in M. japonicus, suppressing SOD and CAT activities while increasing MDA levels.
- Low-pH stress triggered 2705 DEGs in hepatopancreas linked to immunity, oxidative stress, and energy metabolism.
- CTSD, GLB1, and LGI4 are implicated in long-term immune adaptation to low pH.
- Key pathways—lysosome, Toll-like receptor, AMPK, and PPAR signaling—were activated under low pH stress.
- Hub genes such as NADH-GOGAT and MDHM were identified as central regulators of antioxidant defense and energy metabolism.
Abstract
Ocean acidification has emerged as a globally recognized environmental issue, posing a serious threat to marine ecosystems. To elucidate the adaptive mechanisms of Marsupenaeus japonicus under acidified conditions, both biochemical and transcriptomic analyses were performed following low-pH exposure. Biochemical assays revealed that low pH stress significantly SOD and CAT activities while markedly elevating MDA levels, indicating oxidative damage. T-AOC exhibited a transient rise followed by a sharp decline at later stages, suggesting initial activation and subsequent exhaustion of antioxidant defense. Transcriptomic profiling identified 2705 DEGs that were primarily enriched in pathways related to immune regulation, redox balance, apoptosis, and energy metabolism, including the lysosome, Toll-like receptor, and PPAR signaling pathways. Protein interaction analysis identified 9 hub genes, including NADH-GOGAT and MDHM, which may play key roles in antioxidant defense and metabolic regulation. The integration of enzyme activity and transcriptomic data indicates that acid stress initially induces oxidative imbalance, followed by compensatory activation of antioxidant and immune systems to restore cellular homeostasis. These findings provide comprehensive insights into the oxidative stress adaptation of M. japonicus and offer a genetic and physiological foundation for breeding acid-tolerant shrimp strains.
Continue reading ‘Transcriptomic analysis of the hepatopancreas response to low-pH stress in kuruma shrimp (Marsupenaeus japonicus)’Japan shellfish farmer perceptions of ocean acidification, adaptive strategies and comparison with global shellfish farmers
Published 24 October 2025 Science ClosedTags: fisheries, mitigation, North Pacific, policy, socio-economy
Ocean acidification (OA) poses significant threats to shellfish aquaculture. Although governments and organizations around the globe are taking actions to mitigate the impacts of OA, few studies directly report shellfish farmer perceptions of OA and corresponding responses. In this study, we document Japanese shellfish (oyster) commercial farmer perceptions of, and adaptive strategies for OA with respect to oyster aquaculture. We also review and compare our results with existing studies of shellfish commercial farmer perceptions of OA in three regions, including the United States (U.S.), the Mediterranean region and British Columbia, Canada. We found variation in the perceptions of OA around the globe; it is common among all shellfish farmers to have difficulty distinguishing OA from other environmental stressors. OA adaptive strategies from shellfish farmers were only reported for the U.S. (in the literature), and Japan (this study). Acknowledging the diverse geographical and cultural backgrounds, we discussed the similarity and difference of adaptive strategies between the U.S. (as a post-event case with documented OA-related shellfish mortality) and Japan (as a pre-event case) to cope with OA. For example, farmers from both countries suggest, or are already utilizing flexibility in farm management and applying knowledge through hands-on learning. While U.S. farmers rely on networking with different stakeholders to learn about OA knowledge and solutions while Japanese farmers do not. Learning from the strategies that U.S. farmers applied to adapt to OA events, several areas of policies and actions (e.g., financial support, collaboration with scientists and OA awareness enhancement) were identified to better support and empower Japanese shellfish farmers to adapt to future OA scenarios. However, future study on suitability and transferability of implementing policies and actions in Japan is required due to different geographical and cultural contexts.
Continue reading ‘Japan shellfish farmer perceptions of ocean acidification, adaptive strategies and comparison with global shellfish farmers’Macroalgae farming increases DO and pH, reduces pCO2 and nutrients, and enhances blue carbon potential
Published 17 October 2025 Science ClosedTags: algae, biogeochemistry, biological response, chemistry, field, fisheries, mitigation, North Pacific
Edible macroalgal cultivation is increasingly promoted as a nature-based solution to mitigate coastal eutrophication and improve seawater quality. However, the species-specific impacts and spatial extent of these ecological effects remain poorly understood, particularly in semi-enclosed bays with complex hydrodynamics. This study aims to quantify the biogeochemical influence of two widely cultivated species—Porphyra haitanensis and Hizikia fusiformis—on seawater carbonate chemistry and nutrient levels in Yueqing Bay, eastern China. High-resolution field surveys were conducted at 52 stations, enabling direct comparisons between cultivated and non-cultivated waters. Geostatistical modeling, including spherical semivariograms and Empirical Bayesian Kriging, was applied to delineate species-specific influence zones and quantify changes in key water quality parameters. P. haitanensis farming induced broad, kilometer-scale improvements in seawater chemistry, including elevated dissolved oxygen (DO) (+ 2.72%) and pH (+ 0.09 units), and significantly lower partial pressure of CO2 (pCO2) (− 118 µatm), relative to distant reference sites (all p < 0.05). A slight increase in total phosphorus (TP) (+ 0.007 mg L− 1) was also observed, likely reflecting nearby riverine inputs. In contrast, H. fusiformis cultivation produced more localized (< 100 m) but significant changes, including reductions in dissolved inorganic carbon (DIC) (− 1.84 mg L− 1) and pCO2 (− 82.6 µatm), alongside increases in DO (+ 1.72%), pH (+ 0.02 units), and chlorophyll-a (Chl-a) (+ 0.72 µg L− 1) (all p < 0.05). These results provide the first fine-scale, species-resolved spatial assessment of macroalgal farming effects on water quality in a semi-enclosed bay. By quantifying distance-dependent ecological responses, this study offers science-based guidance for spatial planning, nutrient management, and blue carbon integration—particularly as the routine harvest of biomass facilitates net carbon export from coastal waters. These findings highlight the potential of macroalgal farming as a scalable, multifunctional nature-based solution for sustainable aquaculture and climate mitigation.
Continue reading ‘Macroalgae farming increases DO and pH, reduces pCO2 and nutrients, and enhances blue carbon potential’Warming, but not acidification, increases metabolism and reduces growth of redfish (Sebastes fasciatus) in the Gulf of St. Lawrence
Published 16 October 2025 Science ClosedTags: biological response, fish, fisheries, growth, laboratory, multiple factors, performance, physiology, temperature
Understanding the effects of global change, including temperature, pH, and oxygen availability, on commercially important species is crucial for anticipating consequences for these resources and their ecosystems. In the Gulf of St. Lawrence (GSL), redfish (Sebastes spp.) were under moratorium from 1995 to 2023, but the fishery has reopened in 2024 following massive recruitment observed in 2011–2013. Despite current high abundance, little is known about their metabolic and thermal physiology. To address this, we quantified the effects of four acclimation temperatures (2.5, 5.0, 7.5, and 10.0 °C) and two ocean acidification scenarios (current and future) on standard and maximum metabolic rates (SMR and MMR), aerobic scope (AS), factorial aerobic scope, hypoxia tolerance (O2crit), food consumption, growth and food conversion efficiency (FCE) in redfish (Sebastes fasciatus Storer, 1854). SMR, MMR, and AS increased with temperature, but growth and FCE decreased with temperature, likely due to increased cost of maintenance. Food consumption was lower at 2.5 °C, but similar at higher temperatures. Redfish were less hypoxia-tolerant at higher temperatures. Except for SMR, no significant effect of pH was observed. These results suggest that future changes in the GSL will challenge redfish, with potential long-term effects on growth due to increased energy requirements.
Continue reading ‘Warming, but not acidification, increases metabolism and reduces growth of redfish (Sebastes fasciatus) in the Gulf of St. Lawrence’Riverine-coastal carbon dynamics, acidification, and CO2 outgassing in an intensive mariculture bay
Published 17 September 2025 Science ClosedTags: chemistry, field, fisheries, modeling, North Pacific, regionalmodeling
Highlights
- Coupled DIC and δ13CDIC analysis enabled quantification of carbonate system alteration.
- Organic matter degradation dominated the main channel, causing acidification.
- Summer phytoplankton production buffered acidification in western bay waters.
- Remineralized exogenous nitrogen and nitrification intensified oxygen consumption.
- Net carbon dioxide outgassing occurred throughout Sansha Bay in winter and summer.
Abstract
Semi-enclosed bays offer hydrodynamic conditions favorable for mariculture, yet this activity can greatly alter coastal carbon dynamics and may transform coastal waters into bioreactors that modulate the carbonate system by stimulating organic matter (OM) inputs, respiration, primary production, and coupled oxygen consumption-acidification. We investigate seasonal variability in carbonate system dynamics and dissolved inorganic carbon stable isotopic composition (δ13CDIC) in Sansha Bay, the largest large yellow croaker culture site in China, which is flushed by rivers and varying coastal water masses. Adopting a semi-analytical framework that uses a two end-member mixing model, we found that along the main channel, DIC concentrations were elevated by ∼5.3–87.5 μmol kg−1, along with pH reduction of ∼0.05–0.07 units. Instead, western off-main channel with longer residence times exhibited opposing trends: winter DIC accumulation (up to 167 μmol kg−1) and summer net removal (up to −75 μmol kg−1), accompanying a pH decrease/increase of ∼0.12/∼0.19 units, respectively. Excess DIC was mainly attributable to OM remineralization and partially removed by phytoplankton production. The bay supplied a net CO2 source, supported by high pCO2 (mean: 811/562 μatm in winter/summer, respectively). Box model analysis showed that marine-derived OM remineralization combined with mariculture feed inputs caused DIC enrichment and declining oxygen consumption and pH evidenced by a −16.6 ‰ δ13Cox value and 0.43–0.70 carbon/oxygen stoichiometry. Results underscore the role of interacting water masses and mariculture in modulating the carbonate system and its coupling with oxygen and pH dynamics. They provide critical insights into biogeochemical processes driving hypoxia and acidification in intensively farmed coastal ecosystems.
Continue reading ‘Riverine-coastal carbon dynamics, acidification, and CO2 outgassing in an intensive mariculture bay’A policy analysis for climate adaptation in Japanese fisheries
Published 16 September 2025 Newsletters and reports ClosedTags: fisheries, North Pacific, policy
Japan plays a key role in the world’s production and consumption of seafood. In 2021, the fishing industry is estimated to have generated over 637 billion Japanese yen for the country’s GDP (Klein, 2024), and the Japanese government ranks as one of the top spenders globally in terms of public sector support for the fisheries sector (OECD, 2022). Additionally, Japan ranks the highest in per capita seafood consumption globally, constituting one of the top three markets for seafood (Guillen et al., 2019; Swartz et al., 2010).
Climate change is rapidly changing Japanese fisheries, which have long been a significant economic and cultural part of Japanese life. This time of change presents an opportunity for the Japanese government to reconsider its approach to fisheries management. Particularly, it presents an opportunity to center equity values in fisheries management, which have traditionally been overlooked relative to other public values such as economy, effectiveness, and efficiency. As climate impacts disproportionately disadvantage marginalized populations in fisheries, it is crucial to incorporate an environmental justice perspective into policymaking. This time of change serves as an opportunity to dismantle long-standing institutions that have been perpetuating social inequities.
This report presents a policy analysis for climate adaptation in Japanese fisheries. The policy analysis report is prepared for the Fisheries Agency of Japan. The objective is to provide the Japanese government with an assessment of policy options that they can consider for climate change adaptation. Findings are discussed in the form of tradeoffs between policy options. We seek to promote equitable policymaking by incorporating equity assessments into our policy analysis.
Continue reading ‘A policy analysis for climate adaptation in Japanese fisheries’Identifying and reducing climate uncertainty in fisheries management reference points
Published 15 September 2025 Science ClosedTags: biological response, communitymodeling, crustaceans, fisheries, modeling, socio-economy
Modelling has predicted that reductions in ocean pH and increases in temperature will reduce vital rates (survival and growth) of North Pacific crab stocks and hence the target levels of fishing mortality consistent with sustainable harvesting. However, these predictions have been based on the best estimates of the effects of changes in ocean pH and temperature on vital rates from laboratory experiments. We quantified the effects of several climate and market sources of variability in Alaskan red king and southern Tanner crab fisheries on predicted optimal fishing mortality rates, including changes in ocean chemistry and temperature on vital rates, non-linear relationships between prices, costs and catch, and the uncertainty in population dynamics models. The declines in survival consistently lead to predictions of a reduction in productivity and hence the optimal level of fishing intensity over time, but the extent of change is uncertain. Uncertainty related to the effects of ocean pH and temperature on vital rates and variability among Earth System Models and future emission scenarios are the dominant sources of uncertainty, although potential fluctuations in prices and costs are also consequential. Further, simulations are used to explore the relationship between changes in ocean pH or temperature and vital rates (additional experimental replicates and a wider range of levels of ocean pH in experiments) and hence identify approaches to reduce the uncertainty in estimates of future projections of target fishing mortality rates. Importantly, we demonstrate that optimal approaches to reducing uncertainty depend on life stage (juvenile growth for red king crab and larval survival for southern Tanner crab), and the optimal experiment depends on species (increasing the range of pH levels for red king crab vs increasing sample sizes for southern Tanner crab). The results of this study can inform priorities for future ocean acidification-related laboratory experiments and provide a basis for evaluating “investment in research” more broadly.
Continue reading ‘Identifying and reducing climate uncertainty in fisheries management reference points’Cumulative impacts to global marine ecosystems projected to more than double by midcentury
Published 12 September 2025 Science ClosedTags: biological response, fisheries, globalmodeling, modeling
Pressures from human activities are expected to increase significantly, impacting marine ecosystems globally. To plan for a sustainable future, we need to forecast distributions of cumulative impacts from multiple pressures. Here we mapped (10km resolution) future cumulative impacts of ten climate, land-based, fishing and other pressures on twenty marine habitats under two climate scenarios at midcentury (~2050). We found cumulative impacts are projected to increase 2.2 to 2.6 times globally, with coastal habitats facing higher impacts but offshore regions facing faster increases, especially in equatorial regions. Furthermore, many countries dependent on marine resources will have large increases in impacts. Incorporating these results into strategic policy and management will support more sustainable use and protection of marine ecosystems and the services provided to people.
Continue reading ‘Cumulative impacts to global marine ecosystems projected to more than double by midcentury’Selective breeding boosts oyster resilience to ocean acidification via energy budget modulation
Published 12 September 2025 Science ClosedTags: biological response, fisheries, growth, laboratory, mitigation, mollusks, mortality, North Pacific, physiology
Natural pH variability in coastal-estuarine systems exacerbates OAX events through frequent pCO2 spikes, posing severe threats to bivalves and ecosystems they support. While selective breeding has improved growth performance in oysters, its capacity to enhance tolerance to acidic stress remains poorly understood. Here, we evaluated the physiological performance of wild and recently selectively bred oyster variety (Guihao No. 1) under the simulation of recurrent OAX scenarios. In comparison to wild oysters, selectively bred oysters exhibited significantly higher survival rates, fast shell growth, and improved condition index. Energy metabolism suggests that selective breeding confers enhanced stress resilience in oysters by optimizing feeding capacity, increasing oxygen uptake, and reducing ammonia excretion rates. This metabolic efficiency supports more effective protein and glycogen turnover, as evidenced by elevated O:N ratios, and ultimately results in higher SFG. PCA analysis demonstrated that enhanced energy metabolism (CMA, NKA), antioxidant capacity (low MDA), and immune activity (high ACP, AKP) contributed to improved growth and resilience of selectively bred oysters when exposed to OAX, whereas wild oysters showed metabolic suppression and oxidative damage. These results highlight the role of selective breeding in promoting stress tolerance through optimized energy allocation and defense mechanisms, offering valuable guidance for climate-resilient oyster aquaculture in acidifying oceans.
Continue reading ‘Selective breeding boosts oyster resilience to ocean acidification via energy budget modulation’Ocean acidification: impacts on marine ecosystems and deep-sea carbon sequestration
Published 10 September 2025 Science ClosedTags: biogeochemistry, biological response, fisheries, mitigation, review
Carbon dioxide (CO₂) is a major greenhouse gas that plays an essential role in Earth’s climate system. Oceans help climate stability by absorbing about 30% of the anthropogenic CO₂ emissions. However, this process leads to ocean acidification (OA) and reduces the availability of carbonate ions, which are necessary for organisms that build shells and skeletons, such as corals, mollusks, and certain plankton. Since the Industrial Revolution, ocean pH has dropped by approximately 0.1 units, a significant shift that threatens marine ecosystems. OA affects marine organisms in multiple ways. Calcifying species struggle to form shells, leading to reduced survival and disrupted food webs. Coral reefs, often called the “rainforests of the sea” due to their exceptional biodiversity, are particularly vulnerable, and their decline results in biodiversity and habitat loss. Phytoplankton, the foundation of the marine food web and the ocean’s biological carbon pump, also respond in mixed ways; some benefit from higher CO₂, while others are negatively affected, reducing ocean productivity and carbon cycling. OA weakens the ocean’s biological carbon pump, reducing long-term carbon storage in the deep sea. It also contributes to harmful algal blooms, which can contaminate seafood and pose human health risks. Economically, OA threatens global seafood production, especially shellfish and crustaceans, jeopardizing food security and coastal livelihoods. This paper explores the biological, ecological, and economic impacts of OA and discusses mitigation strategies such as reducing CO₂ emissions, protecting blue carbon ecosystems, controlling coastal pollution, and supporting adaptive aquaculture. Addressing OA is essential to protect marine biodiversity, sustain seafood resources, and maintain climate stability.
Continue reading ‘Ocean acidification: impacts on marine ecosystems and deep-sea carbon sequestration’Impacts of ocean acidification on survival of the brown mussel (Perna perna) in Brazil
Published 27 August 2025 Science ClosedTags: adaptation, biological response, fisheries, growth, laboratory, mollusks, morphology, mortality, otherprocess, South Atlantic
The impacts of ocean acidification (OA) on seafood are recognized globally as a major threat, and OA is explicitly mentioned in the United Nations 2030 Agenda for Sustainable Development. One target of Goal 14 (SDG 14.3), life below water, is to minimize and address the impacts of OA using all levels of scientific cooperation. In 2018, the International Atomic Energy Agency launched a Coordinated Research Project (CRP), which gathered researchers from 13 different countries and aimed to evaluate the quantitative and qualitative impacts of OA on seafood. The Brazilian brown mussel Perna perna (Linné, 1858) was selected as the target species for these experiments. Low pH can disrupt the life cycle, affect survival and growth rates, and lead to a decline in mussel populations over time. Based on an agreed protocol within the CRP network, brown mussels were exposed to pH scenarios covering the present and future range of pH variability at the sampling site. The impacts on mortality, growth rate, and morphological parameters of juvenile mussels (seed) were evaluated after a 15-wk exposure in the laboratory, followed by an 8-wk recovery period in situ. Although no effect was detected for growth rate and allometric relationships during the laboratory experiment, mussel mortality was significantly higher at low pH. This effect on mortality disappeared when mussels were transferred to the field for a recovery period, and the acclimation to low pH had no carry-over effect on growth, allometric relationships, or sensory quality. Evidence of impacts from chronic lowering of pH is still needed to address species adaptation for long-term changes, which limit the prognostic power of short-term experiments.
Continue reading ‘Impacts of ocean acidification on survival of the brown mussel (Perna perna) in Brazil’Emergent seasonal hypoxia and acidification risks induced by seaweed and fish polyculture in the world’s largest seaweed farm
Published 26 August 2025 Science ClosedTags: chemistry, field, fisheries, mitigation, North Pacific
Scientific Significance Statement
Seaweed farming is increasingly recognized as a promising strategy for marine carbon dioxide removal (mCDR). However, its ecological sustainability, particularly in semi-enclosed bays, remains uncertain. Using data collected from Sansha Bay, Fujian, China, the world’s largest seaweed farming site, our study reveals an inherent trade-off: in highly sheltered coastal environments, especially when integrated with algae-fish polyculture, seaweed farming can induce significant hypoxia and acidification risks through organic carbon degradation. Carbon isotopic tracing further demonstrates that seasonal shifts in organic carbon sources—from fish feed in autumn to macroalgal detritus in spring—diminish the potential of macroalgal-based carbon sequestration. These findings emphasize the complexity of coastal carbon management and highlight the critical importance of considering ecosystem health—including the system’s capacity to maintain oxygen and pH stability and sustain biogochemical functioning—when implementing seaweed-based carbon sequestration strategies.
Abstract
Seaweed farming is increasingly promoted as a carbon sequestration strategy, but its effectiveness relies on carbon burial and export to deep waters. Seaweed farms commonly occupy semi-enclosed bays, causing continuous accumulation of organic carbon (OC) and its degradation products, potentially undermining carbon sequestration and driving hypoxia and acidification. These ecological impacts may be amplified in fish–algae polyculture systems, yet they remain unclear. We investigated carbon cycling in Sansha Bay, China, the world’s largest seaweed farm and intensive algae–fish polyculture site. During aquaculture seasons, bottom waters experienced rapid OC decomposition, causing severe oxygen depletion and acidification. Vertical mixing spread these effects throughout the water column, turning surface waters into net CO2 sources. δ13CDIC carbon isotopic analyses indicated seasonal shifts in dominant OC sources, from fish feed in autumn to macroalgal detritus in spring. These findings underscore the importance of evaluating the sustainability of coastal systems when pursuing seaweed-based carbon sequestration.
Metabolomics analysis provides new insights into the impacts of long-term ocean acidification and warming on the sensory qualities of sea urchin (Strongylocentrotus intermedius) gonads
Published 26 August 2025 Science ClosedTags: biological response, echinoderms, fisheries, laboratory, morphology, multiple factors, North Pacific, physiology, temperature
Highlights
- Ocean acidification and warming (OAW) alter the color of sea urchin gonads.
- OAW reduce the size and weight of sea urchin gonads.
- OAW alter contents of flavor and odor-related compounds in sea urchin gonads.
- OAW affect the quality of female gonads more seriously than that of males.
Abstract
Sea urchin gonads are popular raw, ready-to-eat seafood known for their fresh, sweet taste and high nutritional value. To investigate the impacts of ocean acidification and warming (OAW) on the sensory qualities of sea urchin gonads, farmed Strongylocentrotus intermedius were incubated separately and jointly in acidic (ΔpHNBS = −0.5 units) and thermal (ΔT = +3.0 °C) seawater for 90 days under lab-controlled conditions based on the ocean pH and temperature for 2100 projected by the Intergovernmental Panel on Climate Change (IPCC). Sensory properties (gonad size, color, and flavor-related metabolites) were subsequently determined and compared between groups. The results showed that: 1) The gonad size and gonad index (GI) decreased sharply (−49 % in female; −46 % in male) under OAW conditions in both sexes of adult S. intermedius. There were significant negative additive effects of acidification and high temperature on the GI. 2) OAW had no significant interaction effects on five gonadal color-related parameters; however, the redness (a*) of male gonads was significantly less than that of female gonads in both the separate and joint OAW groups. 3) Significant alterations to metabolome profiles, exhibiting sex-specific variations, were observed in adult S. intermedius incubated under separate/joint OAW conditions. Twenty-two significantly differentially expressed metabolites (SDMs) related to color, odor, and flavor were identified, primarily enriched in metabolic pathways associated with the biosynthesis and accumulation of odor and flavor compounds. To sum up, the data from this study indicate that OAW affect sensory qualities of sea urchin gonads negatively especially the gonads of females.
Continue reading ‘Metabolomics analysis provides new insights into the impacts of long-term ocean acidification and warming on the sensory qualities of sea urchin (Strongylocentrotus intermedius) gonads’A collaborative climate vulnerability assessment of California marine fishery species
Published 20 August 2025 Science ClosedTags: biological response, crustaceans, fish, fisheries, mollusks, North Pacific, policy, review
Climate change and the associated shifts in species distributions and ecosystem functioning pose a significant challenge to the sustainability of marine fisheries and the human communities dependent upon them. In the California Current, as recent, rapid, and widespread changes have been observed across regional marine ecosystems, there is an urgent need to develop and implement adaptive and climate-ready fisheries management strategies. Climate Vulnerability Assessments (CVA) have been proposed as a first-line approach towards allocating limited resources and identifying those species and stocks most in need of further research and/or management intervention. Here we perform a CVA for 34 California state-managed fish and invertebrate species, following a methodology previously developed for and applied to federally managed species. We found Pacific herring, warty sea cucumber, and California spiny lobster to be three of the species expected to be the most sensitive to climate impacts with California halibut, Pacific bonito, and Pacific hagfish expected to be the least sensitive. When considering climate sensitivity in combination with environmental exposure in both Near (2030–2060) and Far (2070–2100) Exposure climate futures, red abalone was classified as a species with Very High climate vulnerability in both periods. Dungeness and Pacific herring shifted from High to Very High climate vulnerability and Pismo clam and pink shrimp shifted from Moderate to Very High climate vulnerability as exposure conditions progressed. In providing a relative and holistic comparison of the degree to which state-managed marine fishery species are likely to be impacted as climate change progresses, our results can help inform strategic planning initiatives and identify where gaps in scientific knowledge and management capacity may pose the greatest risk to California’s marine resource dependent economies and coastal communities.
Continue reading ‘A collaborative climate vulnerability assessment of California marine fishery species’A self-powered pH sensing method based on a triboelectric nanogenerator: an innovative application in marine ranch water quality monitoring
Published 15 August 2025 Science ClosedTags: chemistry, fisheries, methods
To achieve intelligent aquaculture and ensure environmental health, water quality monitoring is indispensable in marine ranching. However, the energy supply for widely deployed sensors remains a critical challenge. Self-powered sensing technology is one of the core solutions to address this bottleneck. In this research, a capsule-structured, solid–solid/solid–liquid mixed-mode triboelectric nanogenerator (TENG) is proposed, which addresses the limitations of the existing TENG technology in marine environments. The proposed TENG collects wind and wave energy by coupling solid–solid contact electrification with the bilayer effect at the solid–liquid interface under complex marine conditions. A theoretical model of triboelectric energy conversion and solid–liquid pH sensing is developed. Additionally, the TENG self-powered sensing structure is optimized to improve its performance for pH monitoring under a range of conditions in marine ranches. The experimental results demonstrate that the capsule-type dual-mode TENG (CD-TENG) achieves an open-circuit voltage of 50 V and a short-circuit current of 25 μA under optimal conditions. The peak power density of 0.35 W/m2 enables sustained operation of low-power microelectronics, which is beneficial for real-time water quality monitoring in marine ranching.
Continue reading ‘A self-powered pH sensing method based on a triboelectric nanogenerator: an innovative application in marine ranch water quality monitoring’
