Posts Tagged 'fisheries'

Transcriptome analysis of hepatopancreas in penaeus monodon under acute low pH stress

The decrease of seawater pH can affect the metabolism, acid-base balance, immune response and immunoprotease activity of aquatic animals, leading to aquatic animal stress, impairing the immune system of aquatic animals and weakening disease resistance, etc. In this study, we performed high-throughput sequencing analysis of the hepatopancreas transcriptome library of low pH stress penaeus monodon, and after sequencing quality control, a total of 43488612–56271828 Clean Reads were obtained, and GO annotation and KEGG pathway enrichment analysis were performed on the obtained Clean Reads, and a total of 395 DEGs were identified. we mined 10 differentially expressed and found that they were significantly enriched in the Metabolic pathways (ko01100), Biosynthesis of secondary metabolites (ko01110), Nitrogen metabolism (ko00910) pathways, such as PIGA, DGAT1, DGAT2, UBE2E on Metabolic pathways; UGT, GLT1, TIM genes on Biosynthesis of secondary metabolites; CA, CA2, CA4 genes on Nitrogen metabolism, are involved in lipid metabolism, induction of oxidative stress and inflammation in the muscular body of spot prawns. These genes play an important role in lipid metabolism, induction of oxidative stress and inflammatory response in the muscle of the shrimp. In summary, these genes provide valuable reference information for future breeding of low pH-tolerant shrimp.

Continue reading ‘Transcriptome analysis of hepatopancreas in penaeus monodon under acute low pH stress’

Sea surface carbonate dynamics at reefs of Bolinao, Philippines: seasonal variation and fish mariculture-induced forcing

Coral reefs are vulnerable to global ocean acidification (OA) and local human activities will continue to exacerbate coastal OA. In Bolinao, Philippines, intense unregulated fish mariculture has resulted in regional eutrophication. In order to examine the coastal acidification associated with this activity and the impact on nearby coral reefs, water quality and carbonate chemistry parameters were measured at three reef sites, a mariculture site and an offshore, minimally impacted control site during both the wet and dry season. Additionally, benthic community composition was characterized at reef sites, and both autonomous carbonate chemistry sampling and high-frequency pH measurements were used to characterize fine-scale (diel) temporal variability. Water quality was found to be poorer at all reefs during the wet season, when there was stronger outflow of waters from the mariculture area. Carbonate chemistry parameters differed significantly across the reef flat and between seasons, with more acidic conditions occurring during the dry season and increased primary production suppressing further acidification during the wet season. Significant relationships of both total alkalinity (TA) and dissolved inorganic carbon (DIC) with salinity across all stations may imply outflow of acidified water originating from the mariculture area where pH values as low as 7.78 were measured. This apparent mariculture-induced coastal acidification was likely due to organic matter respiration as sustained mariculture will continue to deliver organic matter. While TA-DIC vector diagrams indicate greater contribution of net primary production, net calcification potential in the nearest reef to mariculture area may already be diminished. The two farther reefs, characterized by higher coral cover, indicates healthier ecosystem functioning. Here we show that unregulated fish mariculture activities can lead to localized acidification and impact reef health. As these conditions at times approximate those projected to occur globally due to OA, our results may provide insight into reef persistence potential worldwide. These results also underscore the importance of coastal acidification and indicate that actions taken to mitigate OA on coral reefs should address not only global CO2 emissions but also local perturbations, in this case fish mariculture-induced eutrophication.

Continue reading ‘Sea surface carbonate dynamics at reefs of Bolinao, Philippines: seasonal variation and fish mariculture-induced forcing’

Impacts of seawater pH buffering on the larval microbiome and carry-over effects on later-life disease susceptibility in Pacific oysters

Ocean acidification upwelling events and the resulting lowered aragonite saturation state of seawater have been linked to high mortality of marine bivalve larvae in hatcheries. Major oyster seed producers along North America’s west coast have mitigated impacts via seawater pH buffering (e.g., addition of soda ash). However, little consideration has been given to whether such practice may impact the larval microbiome, with potential carry-over effects on immune competency and disease susceptibility in later-life stages. To investigate possible impacts, Pacific oysters (Crassostrea gigas) were reared under soda ash pH buffered or ambient pH seawater conditions for the first 24 h of development. Both treatment groups were then reared under ambient pH conditions for the remainder of the developmental period. Larval microbiome, immune status (via gene expression), growth, and survival were assessed throughout the developmental period. Juveniles and adults arising from the larval run were then subjected to laboratory-based disease challenges to investigate carry-over effects. Larvae reared under buffered conditions showed an altered microbiome, which was still evident in juvenile animals. Moreover, reduced survival was observed in both juveniles and adults of the buffered group under a simulated marine heatwave and Vibrio exposure compared with those reared under ambient conditions. Results suggest that soda ash pH buffering during early development may compromise later-life stages under stressor conditions, and illustrate the importance of a long-view approach with regard to hatchery husbandry practices and climate change mitigation.

Continue reading ‘Impacts of seawater pH buffering on the larval microbiome and carry-over effects on later-life disease susceptibility in Pacific oysters’

Effects of acidification on fish larval abundance at Teknaf coast, Bangladesh

The study aimed to investigate the effects of acidification on fish larvae abundance at the Teknaf coast. From January 8 to December 14, 2021, samples of fish larvae were collected at every month from the Teknaf coast. From the bottom to the surface, Bongo-Net with a 500 µm mesh size was being towed. A total of 1,120 larvae were gathered from the research area during the survey. In the study region, 93 larvae/1,000 m3 were found to be the mean density of all fish larvae. The hydrological parameters such as water temperature, pH, salinity, and total alkalinity were determined to find out the effects of these variables on the larvae abundance along the Teknaf coast. The average values of the parameters including water temperature, pH, salinity, and total alkalinity were found at 28.41°C, 8.36, 23.57 PSU, and 113.25 mg/l respectively. The ocean acidification factors including pCO2, HCO3-, CO32-, DIC, ΩAragonite, and ΩCalcite were also determined by using the “seacarb” package of R programming to find out the effects of these variables on the larvae abundance along the Teknaf coast. The average values of the factors including pCO2, HCO3-, CO32-, DIC, ΩAragonite, and ΩCalcite were found 128.72 µatm, 0.000751 mole/kg, 0.000138 mole/kg, 0.000892 mole/kg, 2.3544 and 3.7028 respectively. The results showed an insignificant relationship between pCO2 and fish larvae abundance throughout the Teknaf coast. However, there was a negative correlation between pCO2 and pH. The findings of this research indicate that OA affects fish larvae abundance at Teknaf coast. Regional fisheries management organizations will be better able to make decisions about the management of the extremely valuable fish larvae as a result of future population-level predictions of the impacts of ocean acidification.

Continue reading ‘Effects of acidification on fish larval abundance at Teknaf coast, Bangladesh’

Impacts of global environmental change on fish and fisheries of the Northeastern Pacific Ocean

Marine fishes’ intolerance to global change conditions can affect the abundance and distribution of ecologically and economically important species, reshape the structure of trophic webs, and profoundly impact the human communities that rely on fished species for their livelihood and culture. Only by understanding the vulnerability of fished species and fishing communities to global change can we take effective adaptive action and implement climate-ready fisheries management. In this dissertation, I investigate the vulnerability of eight commercially important fished species and one fishing community to global change in the Northeastern Pacific Ocean. In chapter one, I expose Lingcod (Ophiodon elongatus), a benthic egg layer, to temperature, oxygen, and pH conditions we expect to see in the Central California Current System (CCS) by the year 2050 and 2100. I examine both the lethal and sublethal effects of these two multistressor climate change scenarios by measuring differences in metabolic rate, hatching success, and larval quality between treatments. In chapter two, I use a species distribution modeling approach to evaluate how historical (1982-2019) and projected (2030 through end-of-century) warming in the Eastern Bering Sea (EBS), Alaska, affects predator-prey interactions for some of the most commercially valuable fisheries in the U.S. These species include: 1) Pacific Cod (Gadus macrocephalus), 2) Pacific Halibut (Hippoglossus stenolepis), 3) Arrowtooth Flounder, 4) Walleye Pollock (Gadus chalcogrammus), 5) Tanner Crab (Chionoecetes bairdi), 6) Snow Crab (Chionoecetes opilio), and 7) Alaskan Pink Shrimp (Pandalus eous). In chapter three, I use social network analyses to depict the resilience and adaptability of the California Market Squid fishery (Doryteuthis opalescens), the most valuable in the state, to climate perturbations and project changes in habitat suitability by the year 2100 in the CCS. By using all of these vulnerability assessment tools, we can begin to prepare U.S. west coast fisheries for global environmental change.

Continue reading ‘Impacts of global environmental change on fish and fisheries of the Northeastern Pacific Ocean’

Ocean acidification does not overlook sex: review of understudied effects and implications of low pH on marine invertebrate sexual reproduction

Sexual reproduction is a fundamental process essential for species persistence, evolution, and diversity. However, unprecedented oceanographic shifts due to climate change can impact physiological processes, with important implications for sexual reproduction. Identifying bottlenecks and vulnerable stages in reproductive cycles will enable better prediction of the organism, population, community, and global-level consequences of ocean change. This article reviews how ocean acidification impacts sexual reproductive processes in marine invertebrates and highlights current research gaps. We focus on five economically and ecologically important taxonomic groups: cnidarians, crustaceans, echinoderms, molluscs and ascidians. We discuss the spatial and temporal variability of experimental designs, identify trends of performance in acidified conditions in the context of early reproductive traits (gametogenesis, fertilization, and reproductive resource allocation), and provide a quantitative meta-analysis of the published literature to assess the effects of low pH on fertilization rates across taxa. A total of 129 published studies investigated the effects of ocean acidification on 122 species in selected taxa. The impact of ocean acidification is dependent on taxa, the specific reproductive process examined, and study location. Our meta-analysis reveals that fertilization rate decreases as pH decreases, but effects are taxa-specific. Echinoderm fertilization appears more sensitive than molluscs to pH changes, and while data are limited, fertilization in cnidarians may be the most sensitive. Studies with echinoderms and bivalve molluscs are prevalent, while crustaceans and cephalopods are among the least studied species even though they constitute some of the largest fisheries worldwide. This lack of information has important implications for commercial aquaculture, wild fisheries, and conservation and restoration of wild populations. We recommend that studies expose organisms to different ocean acidification levels during the entire gametogenic cycle, and not only during the final stages before gametes or larvae are released. We argue for increased focus on fundamental reproductive processes and associated molecular mechanisms that may be vulnerable to shifts in ocean chemistry. Our recommendations for future research will allow for a better understanding of how reproduction in invertebrates will be affected in the context of a rapidly changing environment.

Continue reading ‘Ocean acidification does not overlook sex: review of understudied effects and implications of low pH on marine invertebrate sexual reproduction’

Exposure of commercially exploited shellfish to changing pH levels: how to scale-up experimental evidence to regional impacts

Ocean acidification has become one of the most intensively studied climate change topics and it is expected to have both direct and indirect impacts on species, ecosystems, and economies. Experiments have been performed on different taxa, life stages, and at different pH levels. Despite this wealth of information, several key challenges remain, including (1) uncertainty about how to incorporate current pH ranges and variability experienced by organisms into experiments, and (2) how to bring this information together to support analysis and assessments at the broader ecosystem level. Sophisticated modelling tools are needed to ‘scale-up’ from experimental results to regional-scale insights. This paper highlights the challenges of combining information to determine how commercially exploited species may be affected under future pH levels, and how modelling and experimental results might be better aligned, using northwest Europe and the waters around the British Isles as an example. We argue that in most cases the current evidence does not offer sufficient information into impacts at projected pH levels, and that future experiments should be designed to consider the pH levels actually experienced by organisms, as well as variability in pH. These types of study are key in safeguarding commercially exploited shellfish stocks.

Continue reading ‘Exposure of commercially exploited shellfish to changing pH levels: how to scale-up experimental evidence to regional impacts’

How does climate change affect a fishable resource? The case of the royal sea cucumber (Parastichopus regalis) in the central Mediterranean Sea

Holothurians or sea cucumbers are key organisms in marine ecosystems that, by ingesting large quantities of sediments, provide important ecosystem services. Among them, Parastichopus regalis (Cuvier, 1817) is one of the living sea cucumbers in the Mediterranean actively fished for human consumption mainly in Spain, where it is considered a gastronomic delicacy. In the Strait of Sicily (central Mediterranean Sea), this species is not exploited for commercial use even if it is used as bait by longline fishery. P. regalis is frequently caught by bottom trawling and discarded at sea by fishers after catch, and because of its capacity to resist air exposition (at least in cold months), it is reasonable to consider that it is not affected by fishing mortality. Having observed a significant decrease in abundance since 2018, the possible effects of some ecological factors related to current climate change (i.e., temperature and pH) were sought. Generalized additive models (GAMs) were applied to investigate the relationship among the abundance of P. regalis and environmental variables and fishing effort. Long time series of P. regalis densities (2008–2021) were extracted from the MEDITS bottom trawling survey and modeled as function of environmental parameters (i.e., salinity, dissolved oxygen, ammonium, pH, and chlorophyll α) and fishing effort (i.e., total number of fishing days per gross tonnage). Our results showed that this species prefers the soft bottoms (50–200 m) of the Adventure Bank and Malta Plateau, and its distribution changed over time with a slight deepening and a rarefaction of spatial distribution starting from 2011 and 2017, respectively. In addition, a positive relationship with pH concentration in surface waters during the larval dispersal phase (3-year lag before the survey) and nutrient concentration at sea bottom (1-year lag) has been found, suggesting that this species is sensitive to climate change and food availability. This study adds new knowledge about the population dynamics of an unexploited stock of P. regalis under fishing impact and environmental under climate change in fisheries management.

Continue reading ‘How does climate change affect a fishable resource? The case of the royal sea cucumber (Parastichopus regalis) in the central Mediterranean Sea’

Ocean acidification and seasonal temperature extremes combine to impair the thermal physiology of a sub-Antarctic fish

Graphical abstract


  • Climate change stressors impaired the thermal physiology of Eleginops maclovinus.
  • Summer temperature and near-future pCO2 levels reduced its thermal tolerance.
  • Concomitant reductions occurred in fish aerobic scope at near-future pCO2.
  • An oxidative stress condition was detected in the gills and liver tissues.


To predict the potential impacts of climate change on marine organisms, it is critical to understand how multiple stressors constrain the physiology and distribution of species. We evaluated the effects of seasonal changes in seawater temperature and near-future ocean acidification (OA) on organismal and sub-organismal traits associated with the thermal performance of Eleginops maclovinus, a sub-Antarctic notothenioid species with economic importance to sport and artisanal fisheries in southern South America. Juveniles were exposed to mean winter and summer sea surface temperatures (4 and 10 °C) at present-day and near-future pCO2 levels (~500 and 1800 μatm). After a month, the Critical Thermal maximum and minimum (CTmax, CTmin) of fish were measured using the Critical Thermal Methodology and the aerobic scope of fish was measured based on the difference between their maximal and standard rates determined from intermittent flow respirometry. Lipid peroxidation and the antioxidant capacity were also quantified to estimate the oxidative damage potentially caused to gill and liver tissue. Although CTmax and CTmin were higher in individuals acclimated to summer versus winter temperatures, the increase in CTmax was minimal in juveniles exposed to the near-future compared to present-day pCO2 levels (there was a significant interaction between temperature and pCO2 on CTmax). The reduction in the thermal tolerance range under summer temperatures and near-future OA conditions was associated with a reduction in the aerobic scope observed at the elevated pCO2 level. Moreover, an oxidative stress condition was detected in the gill and liver tissues. Thus, chronic exposure to OA and the current summer temperatures pose limits to the thermal performance of juvenile E. maclovinus at the organismal and sub-organismal levels, making this species vulnerable to projected climate-driven warming.

Continue reading ‘Ocean acidification and seasonal temperature extremes combine to impair the thermal physiology of a sub-Antarctic fish’

Phenotypic plasticity in economically and ecologically important bivalves in response to changing environments

Marine bivalves are ecologically important, providing ecosystem services like filtering water, stabilizing substrate, and creating hard structure for epibionts. Cultured bivalves are also economically important, supporting thousands of aquaculture jobs nationwide and providing valuable protein sources for our growing human population. However, recent shifts in the environment such as temperature, ocean acidification, hypoxia, and extreme environmental variation have greatly affected bivalve physiology, reproduction, and survival across multiple lifestages. Bivalves in the Northeast Pacific are increasingly vulnerable climate change related stressors like intensifying upwelling and weather extremes, defined stratification, and unique geography which causes distinct spatial and seasonal variation. I seek to investigate if higher degrees of phenotypic plasticity and parental carryover will have the potential to improve bivalve’s fitness and tolerance as climate change progresses. My goal is to evaluate plastic capacity by taking a multi-method approach to assessing the physiological metrics of several important bivalve species, using both field and laboratory experiments. Early lifestages are greatly influenced by parental environmental history leading to carryover effects, favoring phenotypes that have a higher likelihood of surviving. In addition to natural selection in the wild, commercial and restoration aquaculturists may select for beneficial phenotypes in adults and offspring which would yield the most desirable characteristics. In our experiment, I focus on three different species: the purple-hinge rock scallop Crassadoma gigantea, the Mediterranean mussels Mytilus galloprovincialis, and the Olympia oyster Ostrea lurida. By choosing a suite of native and non-native, inter- and subtidal species, I hope to obtain a broad snapshot of physiological responses to help restore vulnerable species and maximize quality of farmed product. Chapter 1 examines physiological responses of the scallop C. gigantea to climate change related stressors in the laboratory. I conducted a full factorial laboratory experiment, manipulating pCO2 and temperature to mimic current and future ocean acidification and warming levels. After six weeks of acclimation, I found that stressors reduced shell strength and periostracum (outer shell layer) density. Only acidification affected lipids, and fatty acid content varied between treatments. I was the first to quantify microbial composition of a bivalve under multiple stressors and I found differences in the microbiome, especially with temperature stress. Chapter 2 explores physiological responses of C. gigantea and M. galloprovincialis in a six-month field acclimatation experiment. Shellfish were deployed in cages in Puget Sound, Washington at either 5 or 30 m below the surface. I found that environmental gradients varied seasonally and spatially and affected growth, shell strength, and isotopic signatures. There were differences between the two species, namely with shell strength and δ13C. I found that no one depth or time period yielded the most desirable traits for culturing, and I highlight the concerning patterns in Puget Sound’s most productive region. In Chapter 3, I took my research one step further by introducing a spatial component to a one-year field experiment. I outplanted O. lurida in cages at 5 m depth in three different locations in Puget Sound, one of which also had a 20 m depth. Each of these locations had an oceanographic monitoring buoy which allowed me to couple physiological data with high-resolution environmental data. I spawned the oysters to test parental carryover and found evidence in growth rates of larvae, which when acclimated to high temperatures, mirrored their parents. Interestingly, larval survival did not coincide with growth, and through respirometry, I found that 20°C may be a bottleneck for this lifestage. Adult oyster growth, isotopic signatures, and gametogenesis were affected by both seasonal and spatial field conditions. Metabolic responses to pH and temperature depending on recent acclimatization history. This research shows evidence of strong adaptive plasticity which was demonstrated by energetic trade-offs and parental carryover. Chapter 4 acclimatized M. galloprovincialis in the field in a similar fashion to O. lurida. Growth, shell strength, and isotopes were all affected by season and site. Similar to oysters, acute metabolic rate of each site and season was affected differently between pH and temperature. Shellfish covered in Chapter 3/4 have a high degree of plasticity and results are useful to restoration (oyster) and commercial (mussel) aquaculturists to create selective breeding programs that will withstand climate change. Results of this dissertation demonstrate the rapid degree of phenotypic plasticity and capacity for parental carryover in field and laboratory setting though a wide array of physiological analysis. Outcomes of this research add to the limited but growing body of literature about multiple-stressors and field experiments, and indents to assist aquaculturists as climate change progresses.

Continue reading ‘Phenotypic plasticity in economically and ecologically important bivalves in response to changing environments’

The effects of alkalinity on production performance and biochemical responses of spiny lobster Panulirus homarus reared in recirculating aquaculture system

Spiny lobsters (Panulirus sp.) were valuable and one of the most popular Indonesian export commodities. Some approaches were made to increase the quantity and quality of cultivated spiny lobsters. Land-based mariculture with Recirculating Aquaculture System (RAS) was applied to increase lobster harvesting and optimize environmental quality by adjusting water alkalinity. This study aimed to determine the optimum level of alkalinity for spiny lobsters Panulirus homarus rearing in RAS. This study investigated the effects of applying four water alkalinity levels (Control, 125, 200, and 275 mg L-1 CaCO3) on the biochemical responses of P. homarus observed in the hemolymph in terms of Total Hemocyte Count (THC), glucose, total protein, calcium, and pH levels.

Furthermore, we also studied the alkalinity effects on lobster production performance parameters in terms of body weight gain, body length, Survival Rate (SR), Specific Growth Rate (SGR), and Feed Conversion Ratio (FCR). Lobsters with an initial weight rate of 58.05±1.69 g and an initial total length rate of 115.33±1.52 mm were reared for 60 days in a recirculation system. Results of water quality parameters such as ammonia, nitrite, nitrate, dissolved oxygen, temperature, and salinity during the study were available for lobster rearing. Different alkalinity levels affected the biochemical responses and production performance of lobsters. The best alkalinity level to reared Panulirus sp. in the recirculation system during this study was 200 mg L-1 CaCO3 so that it could achieve the highest survival rate of 86.67% with SGR 0.60±0.01 % day-1.

Continue reading ‘The effects of alkalinity on production performance and biochemical responses of spiny lobster Panulirus homarus reared in recirculating aquaculture system’

Acidification and high-temperature impacts on energetics and shell production of the edible clam Ameghinomya antiqua

Warming and ocean acidification are currently critical global change drivers for marine ecosystems due to their complex and irreversible effects on the ecology and evolution of marine communities. Changes in the chemistry and the temperature of the ocean impact the biological performance of marine resources by affecting their energy budget and thus imposing energetic restrictions and trade-offs on their survival, growth, and reproduction. In this study, we evaluated the interplaying effects of increased pCO2 levels and temperature on the economically relevant clam Ameghinomya antiqua, an infaunal bivalve inhabiting a wide distributional range along the coast of Chile. Juvenile clams collected from southern Chile were exposed to a 90-day experimental set-up emulating the current and a future scenario projeced to the end of the current century for both high pCO2/low-pH and temperature (10 and 15°C) projected for the Chilean coast. Clams showed physiological plasticity to different projected environmental scenarios without mortality. In addition, our results showed that the specimens under low-pH conditions were not able to meet the energetic requirements when increased temperature imposed high maintenance costs, consequently showing metabolic depression. Indeed, although the calcification rate was negative in the high-pCO2 scenario, it was the temperature that determined the amount of shell loss. These results indicate that the studied clam can face environmental changes for short-term periods modifying energetic allocation on maintenance and growth processes, but with possible long-term population costs, endangering the sustainability of an important benthic artisanal fisheries resource.

Continue reading ‘Acidification and high-temperature impacts on energetics and shell production of the edible clam Ameghinomya antiqua

Vulnerability of exploited deep-sea demersal species to ocean warming, deoxygenation, and acidification

Vulnerability of marine species to climate change (including ocean acidification, deoxygenation, and associated changes in food supply) depends on species’ ecological and biological characteristics. Most existing assessments focus on coastal species but systematic analysis of climate vulnerability for the deep sea is lacking. Here, we combine a fuzzy logic expert system with species biogeographical data to assess the risks of climate impacts to the population viability of 32 species of exploited demersal deep-sea species across the global ocean. Climatic hazards are projected to emerge from historical variabilities in all the recorded habitats of the studied species by the mid-twenty-first century. Species that are both at very high risk of climate impacts and highly vulnerable to fishing include Antarctic toothfish (Dissostichus mawsoni), rose fish (Sebastes norvegicus), roughhead grenadier (Macrourus berglax), Baird’s slickhead (Alepocephalus bairdii), cusk (Brosme brosme), and Portuguese dogfish (Centroscymnus coelepis). Most exploited deep-sea fishes are likely to be at higher risk of local, or even global, extinction than previously assessed because of their high vulnerability to both climate change and fishing. Spatially, a high concentration of deep-sea species that are climate vulnerable is predicted in the northern Atlantic Ocean and the Indo-Pacific region. Aligning carbon mitigation with improved fisheries management offers opportunities for overall risk reduction in the coming decades. Regional fisheries management organizations (RFMOs) have an obligation to incorporate climate change in their deliberations. In addition, deep-sea areas that are not currently managed by RFMOs should be included in existing or new international governance institutions or arrangements.

Continue reading ‘Vulnerability of exploited deep-sea demersal species to ocean warming, deoxygenation, and acidification’

Chapter 84 – ocean acidification

The problem with climate change which increases the concentration of carbon dioxide in the atmosphere is that it promotes acidification of the oceans. This acidification impairs the ability of bivalve mollusks living in acidified waters to have normal reproduction and growth. The climate issue has broad implications for aquacultured species with alterations in water temperature (increases), disease patterns, harmful algal blooms, rainfall patterns, sea surface salinity, or severe weather events which may have an overall net negative impact on aquaculture production. This chapter discusses the implications of climate ocean acidification on the health of mollusks.

Continue reading ‘Chapter 84 – ocean acidification’

Climate resilience and adaptation in West African oyster fisheries: an expert-based assessment of the vulnerability of the oyster Crassostrea tulipa to climate change

Graphical abstract

Globally, over 85% of oyster reefs have been lost, and the combined effects of climate change, ocean acidification, and environmental degradation, including pollution and mangrove overharvesting, could further reduce global oyster fisheries in the coming decades. To understand the level of impact of climate change on the oyster fishery in West Africa, an expert-based vulnerability assessment to climate change was conducted for the West African mangrove oyster (Crassostrea tulipa, Lamarck 1819). Using a combination of the exposure of the oyster to climatic stressors (estuarine temperature, salinity, river flow, surface run-off, sea level rise, and estuarine circulation) together with an assessment of sensitivity to these stressors, we estimate the overall vulnerability of C. tulipa to climate change. A very high overall climate vulnerability score of 12 on a scale of 16 was calculated for C. tulipa. While the overall climate exposure score in the West African coastal region remained high, the high sensitivity of C. tulipa to hydrographic conditions of its habitat, in particular salinity, coupled with its sessile and habitat-specific nature, pushed the overall vulnerability to very high. Early life history settlement requirements, adult mobility, and sensitivity to salinity were the three most important biological and sensitivity attributes that determined the vulnerability score. By leaving each of these three sensitivity attributes out of the analysis, the overall vulnerability score was reduced to 9 (i.e., from very high to high). A negative directional effect of climate change, coupled with a low potential for change in distribution, threatens the C. tulipa fishery in a long-term adverse climate scenario. We recommend management efforts that incorporate climate resilience and adaptation practices to prioritize recruitment success, as well as the development of breeding lines with climate-resilient traits.

Continue reading ‘Climate resilience and adaptation in West African oyster fisheries: an expert-based assessment of the vulnerability of the oyster Crassostrea tulipa to climate change’

Toward a decade of ocean science for sustainable development through acoustic animal tracking

The ocean is a key component of the Earth’s dynamics, providing a great variety of ecosystem services to humans. Yet, human activities are globally changing its structure and major components, including marine biodiversity. In this context, the United Nations has proclaimed a Decade of Ocean Science for Sustainable Development to tackle the scientific challenges necessary for a sustainable use of the ocean by means of the Sustainable Development Goal 14 (SDG14). Here, we review how Acoustic animal Tracking, a widely distributed methodology of tracking marine biodiversity with electronic devices, can provide a roadmap for implementing the major Actions to achieve the SDG14. We show that acoustic tracking can be used to reduce and monitor the effects of marine pollution including noise, light, and plastic pollution. Acoustic tracking can be effectively used to monitor the responses of marine biodiversity to human-made infrastructures and habitat restoration, as well as to determine the effects of hypoxia, ocean warming, and acidification. Acoustic tracking has been historically used to inform fisheries management, the design of marine protected areas, and the detection of essential habitats, rendering this technique particularly attractive to achieve the sustainable fishing and spatial protection target goals of the SDG14. Finally, acoustic tracking can contribute to end illegal, unreported, and unregulated fishing by providing tools to monitor marine biodiversity against poachers and promote the development of Small Islands Developing States and developing countries. To fully benefit from acoustic tracking supporting the SDG14 Targets, trans-boundary collaborative efforts through tracking networks are required to promote ocean information sharing and ocean literacy. We therefore propose acoustic tracking and tracking networks as relevant contributors to tackle the scientific challenges that are necessary for a sustainable use of the ocean promoted by the United Nations.

Continue reading ‘Toward a decade of ocean science for sustainable development through acoustic animal tracking’

Observations to underpin policy: examples of ocean and coastal observations in support of the Sendai Framework, the Paris Agreement, and Sustainable Development Goal 14

The ocean impacts human well-being and sustainability by influencing weather, climate, the economy, health and safety. Ocean and coastal observations play a critical role in enabling decision-makers to understand ocean and coastal issues and shape effective policies. This chapter explores how ocean and coastal observations relate to the development and achievement of three of the Group on Earth Observation’s engagement priority areas: the Sendai Framework for Disaster Risk Reduction, the Paris Climate Agreement, and the United Nations 2030 Agenda for Sustainable Development. Observing systems and outputs covered in this chapter include tsunami warning, storm surge monitoring and forecasting, monitoring ocean heat content, informing climate adaptation, monitoring of marine pollution and ocean acidification and safety at sea alters for fishers.

Continue reading ‘Observations to underpin policy: examples of ocean and coastal observations in support of the Sendai Framework, the Paris Agreement, and Sustainable Development Goal 14’

Higher survival but smaller size of juvenile Dungeness crab (Metacarcinus magister) in high CO2


  • Ocean acidification conditions do not affect Dungeness crab megalopae survival.
  • Dungeness crab juveniles reared in high CO2 have higher survival but are smaller.
  • Dungeness crab zoea more susceptible to ocean acidification than juveniles.


Dungeness crab (Metacarcinus magister) are the most valuable fishery on the U.S. West Coast and both larval and adult Dungeness crabs are important components of regional food webs. Previous experiments have shown decreased survival and a slower development rate for Dungeness crab zoea reared in water with high CO2, indicating a susceptibility to ocean acidification. In this study we reared late-stage megalopae and juvenile Dungeness crabs in both ambient and high CO2 conditions for over 300 days. Counter to expectations, crabs reared in high CO2 had a higher survival rate than those reared in ambient conditions and crabs in high CO2 transitioned more quickly in one of the stages (J5 to J6). However, crabs reared in high CO2 were generally smaller and had a higher resting metabolic rate than crabs in ambient CO2. We hypothesized that two separate mechanisms were in effect, with one process driving survival and a second process driving size and respiration rate. We further hypothesized that increased mortality in ambient CO2 could be caused by a CO2-sensitive microbial pathogen, but that size and respiration differences were caused by the direct effects of CO2 on the crabs themselves. Overall, the zoea stages seem more sensitive to CO2 than the megalopae and juvenile stages.

Continue reading ‘Higher survival but smaller size of juvenile Dungeness crab (Metacarcinus magister) in high CO2’

Impacts of ocean warming and acidification on the energy budget of three commercially important fish species

Using experimental data of three commercially important marine fish species (Diplodus sargus, Diplodus cervinus and Solea senegalensis), a model based on Dynamic Energy Budget theory was parametrized. The model was used to produce projections of growth and reproduction for these species, under different scenarios of ocean warming and acidification.

A mechanistic model based on Dynamic Energy Budget (DEB) theory was developed to predict the combined effects of ocean warming, acidification and decreased food availability on growth and reproduction of three commercially important marine fish species: white seabream (Diplodus sargus), zebra seabream (Diplodus cervinus) and Senegalese sole (Solea senegalensis). Model simulations used a parameter set for each species, estimated by the Add-my-Pet method using data from laboratory experiments complemented with bibliographic sources. An acidification stress factor was added as a modifier of the somatic maintenance costs and estimated for each species to quantify the effect of a decrease in pH from 8.0 to 7.4 (white seabream) or 7.7 (zebra seabream and Senegalese sole). The model was used to project total length of individuals along their usual lifespan and number of eggs produced by an adult individual within one year, under different climate change scenarios for the end of the 21st century. For the Intergovernmental Panel on Climate Change SSP5-8.5, ocean warming led to higher growth rates during the first years of development, as well as an increase of 32-34% in egg production, for the three species. Ocean acidification contributed to reduced growth for white seabream and Senegalese sole and a small increase for zebra seabream, as well as a decrease in egg production of 48-52% and 14-33% for white seabream and Senegalese sole, respectively, and an increase of 4-5% for zebra seabream. The combined effect of ocean warming and acidification is strongly dependent on the decrease of food availability, which leads to significant reduction in growth and egg production. This is the first study to assess the combined effects of ocean warming and acidification using DEB models on fish, therefore, further research is needed for a better understanding of these climate change-related effects among different taxonomic groups and species.

Continue reading ‘Impacts of ocean warming and acidification on the energy budget of three commercially important fish species’

Ramifications of climate change induced by anthropogenic factors on global fish population scenario

One of the important consequences of climate change is its effect on the global fish population. Though not very highly pronounced each year, the effect of climate change is of cumulative nature. Global aquaculture is being affected by temperature changes of both water and air. Fluctuations in the ocean surface temperatures, ocean current patterns, wind speeds, and wave directions, all have its impact on aquaculture. Each year we see more and more incidences of extreme weather conditions in different parts of the world, be it in the form of hurricanes, heavy floods, etc. Fishes are subjected to various stress factors which in turn take a toll on its growth and development. This can lead to lower weight gain and increased mortality due to higher susceptibility to diseases. This, coupled with direct unsustainable anthropogenic activities in the oceans and rivers may lead to collapse of the marine and freshwater ecosystem. Recent studies have identified specific regions where marine aquaculture production will be positively and negatively affected. One of the sustainable ways of developing aquaculture in the coming decades would be by developing region-wise strategies to maintain or increase fish population levels and thus meet the global seafood demands even in 2050. The current review is an attempt to assess the effects of ocean warming, ocean acidification, and ocean deoxygenation on the growth, survival, and diversity of marine lifeforms and suggest ways to stop a complete collapse of marine fish population by 2050, the year for which the complete collapse is predicted based on projections.

Continue reading ‘Ramifications of climate change induced by anthropogenic factors on global fish population scenario’

  • Reset


OA-ICC Highlights

%d bloggers like this: