Management Of Marine Ecosystems Research Articles

Improving Satellite Chlorophyll-a Retrieval in the Turbid Waters of the Bay of Fundy, Canada

AbstractThe Bay of Fundy is a highly productive ecosystem within the Northwest Atlantic where extreme tides and strong currents result in a large gradient of sediment concentrations across and along the bay. We processed daily satellite data from the MODerate resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite from 2003 to 2021 at 300-m resolution to understand and quantify spatial and temporal trends in chlorophyll-a concentration (chl-a, a measure of phytoplankton biomass), and suspended particulate matter concentration (SPM) in the Bay of Fundy surface waters. To account for high sediment loading (up to 100’s g m−3) and moderate chl-a (median in situ chl-a of 1.5 mg m−3 from 2003 to 2021), coefficients of the OC3M chl-a algorithm were regionally tuned using in situ chl-a data, and satellite-derived SPM was incorporated within the chl-a retrieval algorithm to account for possible bias. The updated new algorithm was denoted as OCX-SPMCor. Chl-a computed using OCX-SPMCor showed better performance against in situ chl-a than the generic OC3M with a coefficient of determination that increased from 0.01 to 0.28 and a root mean square logarithmic error that decreased by 35%. Unlike previous remote sensing studies, OCX-SPMCor correctly predicted the particular chl-a seasonality in the Bay of Fundy, which does not follow the typical occurrence of spring/fall blooms as observed in the adjacent Gulf of Maine and Scotian Shelf. For the first time, satellite-predicted chl-a aligned with the phenology of in situ chl-a, where chl-a continually increased from April to June and remained high all summer, with a small secondary summer peak before decreasing in the fall. SPM seasonality followed an opposite trend where SPM reached a maximum in winter and a minimum in summer. A small number of matchups and high temporal variability on the hourly time scale precluded a robust assessment of the satellite-derived SPM. However, comparisons between time series of remotely sensed and in situ SPM demonstrated the ability of the satellite-derived SPM to capture temporal variations, though the absolute values may be slightly underestimated. Accurate maps of phytoplankton biomass and sediment concentrations are essential variables required for effective management and conservation of marine ecosystems in the Bay of Fundy.

Catalyzing Conservation: An Analysis of Fish Stock Dynamics in a Marine Protected Area before and after Artificial Reef Deployment

The marine ecosystem’s balance is crucial for sustaining biodiversity and supporting fisheries. Marine protected areas have been increasingly used to enhance marine habitats, yet their impact on fish populations remains a topic of debate. This study focuses on a marine protected area in Kitros, Pieria, in Greece, where an artificial reef was constructed, to understand its influence on coastal fish populations. The objectives were to investigate the changes in fish biomass and abundance, comparing the data from periods before and after the construction of an artificial reef. This research compares the data between 2007 and 2008 with the data between 2016 and 2017, collected with bottom trawl surveys strategically executed prior to and after the artificial reef’s installation. Fish species captured were identified, with their lengths and masses measured. The findings indicate an increase in the biomass and abundance of certain fish species after artificial reef deployment, notably the commercially significant Mullus barbatus and Pagellus erythrinus. The artificial reef in Kitros, Pieria, with its surrounding marine protected area appears to have had a positive impact on the local fish populations over the years, suggesting that it can contribute to marine conservation and fishery enhancement. These results underscore the potential of artificial reefs as tools for marine ecosystem management, offering insights for policymakers and environmentalists into coastal resource management.

INCREASING MARINE TOURISM WITH MARINE SPATIAL PLANNING METHOD AND GROWTH OF MARINE ECOSYSTEM MANAGEMENT OF UNUSED MARINE AREAS

The current state of the art of ecosystem-based marine spatial management (EB-MSM), a new approach to ocean management that is being supported all over the world as the best means of ensuring the sustainability of marine ecosystems. It aims to sustain robust, fruitful, and resilient ecosystems that supply essential products and services while withstanding human influences. It concentrates on all interactions within a marine ecosystem, including human interactions. The most cutting-edge science and innovative methods are needed for successful implementation. Focusing on the role of marine spatial planning (MSP) in marine ecosystem management and discussing the use of MSP to manage the risks associated with geohazards and climate change. Including creation of networks of marine protected areas (MPAs), how maritime activities are distributed both spatially and temporally, flexibility in fisheries management, actions to promote coastal resilience, the restoration of vital coastal ecosystems, the establishment of buffer zones between permanent structures and the coastline, and the implementation of risk-mitigation tools like monitoring programs and warning systems. More responsive demands of coastal countries and more actively supporting the economic integration of foreign operators and tourism. Even during disputes or cancellations, innovative ideas and agreements can stimulate the economy. For instance, a third party can create jobs in sub-Saharan West Africa, while a recreation area could increase tourist in Indonesia.

What next for marine ecosystem management in Vietnam: assessment of coastal economy, climate change, and policy implication

Vietnam is a coastal country with a coastline stretching more than 3,260 km. Marine resources are important for the development of Vietnam. In Vietnamese seas, there are about 20 typical ecosystems spreading over 1 million square kilometers in the East Sea consisting of mangrove forests, coral reefs, lagoons, seagrasses in intertidal areas and estuaries, and living species in 155,000 hectares, 1,300 square kilometers, 500 square kilometers, 16,000 hectares, and 11,000 living species, respectively. At present, the impact of climate change, socio-economic development, and environmental pollution are considered as the main causes of degradation of Vietnam’s marine ecosystems. This paper presents and discusses the pressure of socio-economic activities including industry, tourism, marine transportation and services, aquaculture and fishery on marine ecosystems. In Vietnam, compared to the early 2000s a total of 12% of coral reefs, and 48% of other coral reefs are vulnerable to degradation. So far, about 100 species of marine life in Vietnam are at risk of being threatened due to over-exploitation and fishing. The seagrass-bed ecosystem is currently being degraded with only over 5,580 ha remaining. In some areas, such as Cat Ba, Ha Long, and Quang Nam, seagrass beds have almost no chance to recover naturally due to serious impacts from tourism and aquaculture activities. From the findings, orientations that aim at effective management and protection of marine ecosystems to cope with adverse impacts of anthropogenic activities, climate change, and the pressure of socioeconomic development were proposed.

Regional variability in remotely sensed data with respect to the distribution of some snapper fishes (Family: Lutjanidae) between the Red Sea and the Arabian Gulf

Geographically dissimilar aquatic ecosystems from similar origin promote our comprehensive understanding of the role of abiotic factors in the distribution of biodiversity from one extreme, and they provide outstanding examples of convergent evolution in biological diversity on the other extreme. A new approach to monitoring and management of fisheries and marine ecosystems is required. Sea Surface Temperature (SST) and Chlorophyll-a (Chl-a) concentration are both crucial environmental variables that have significant impacts on marine ecosystems, particularly for fishes and overall aquatic life. These factors play important roles in shaping the health, distribution, behavior, and productivity of marine organisms. In the current study, Modis-aqua daily SST and Chl-a derived data from 2002 to 2022 were loaded into MATLAB, analyzed, and compared between the Arabian Gulf and Red Sea (Egyptian territory). Additionally, the catch of the family Lutjanidae (snapper fish) was recorded in 2002 to determine the distribution of napper fish species and compare production (based on data available from 2002 to 2022) in relation to SST and Chl-a variabilities. According to the current study, Chl-a in the Arabian Gulf showed narrow fluctuations during the winter and spring months, but higher than the Red Sea, and had a significant increase in sea surface temperature (SST) throughout the summer compared to the Red Sea. Spatial and temporal interaction between the means of Chl-a and SST was significantly different (P < 0.01). On the other hand, the results showed that different thermal stresses were experienced by the Arabian Gulf and the Red Sea, as shown by the total positive SST anomaly and by events occurring in different trends. Both the total catch of lutjanid snappers and the species identified by DNA barcoding varied significantly between the two geographical regions. The current work suggests using large-scale, fisheries-independent data to map the main gradients in marine fish community and species abundance and forecast their future distribution in connection to climate change.

Offshore wind energy potential along the Indian Coast considering ecological safeguards

This study focuses on assessing the offshore wind energy potential along the Indian Coast over a 10-year period (2005–2014) using high-resolution data from the simulation of the Weather Research and Forecasting (WRF) model. The predicted wind fields are utilized to identify potential sites, estimate offshore wind technical potential at different depths (ranging from 30 to 200 meters), and develop wind energy blocks within the Indian Exclusive Economic Zone. To ensure environmental protection, environmentally sensitive areas have been excluded from the offshore wind potential sites. The gross technical offshore wind potential was estimated to be 3941 GW within depths of 30–200 meters, excluding environmentally sensitive areas within the 0 to 30-m depth range. High-potential sites have been identified in the coastal states of Gujarat, Maharashtra, Kerala, and Tamil Nadu. The environmental offshore wind potential across these identified sites (feasible OWE sites) along the Indian coast is estimated at 432.34 GW within the 30 to 200-m depth range (at 140 m AGL).According to the report by the Central Electricity Authority (CEA), the predicted offshore wind power has the potential to significantly contribute to the country's total electrical power requirement for 2020–21. This study encourages exploration of offshore wind energy possibilities along the Indian coast and highlights the management challenges at suitable sites, including addressing potential conflicts between offshore wind energy development and other marine uses. The findings of this study can assist in the assessment of offshore wind resources and provide decision-makers with scientific evidence for the development of offshore wind energy in India, while also considering the management and conservation of marine ecosystems.

Geomorphometric maps of Australia’s Marine Park estate and their role in improving the integrated monitoring and management of marine ecosystems

The loss of marine biodiversity is a major global issue that needs to be prioritised. In Australia, a considerable proportion (48%) of its Exclusive Economic Zone is dedicated to marine protected areas. To effectively manage this network of marine protected areas Australia has recently introduced a Management Effectiveness system. This system is designed to identify, monitor, and manage natural values and the various activities and pressures affecting the Australian Marine Parks (AMPs). Key to this approach is the identification and accurate mapping of the location of these values and pressures acting on the seabed. The AusSeabed program is a national initiative in Australia aimed at improving access to bathymetric data and coordinating efforts to collect such data in Australian waters. This manuscript proposes a novel systematic processing method to create detailed and scalable geomorphometric maps from AusSeabed’s bathymetric data holdings, intended as a standard operating procedure for initial bathymetric data interpretation in the AMPs. Utilising this workflow, we produce seafloor geomorphometry maps across 37 AMPs within which sufficient bathymetric data has been collected. These maps can be used 1) for predictive mapping of biological assemblages; 2) in field sampling design for the collection of ‘ground truthing’ data (e.g. underwater imagery and sediment samples) to validate habitat maps from bathymetric datasets; and 3) as input datasets for subsequent geomorphological mapping with a deeper understanding of seafloor processes. This research highlights the importance of robust geomorphometry classification standards to ensure consistency in mapping Australia’s marine estate in preparation for the Decade of Oceans plans. The Seamap Australia program provides a stepwise approach to advancing Australia’s national collection of bathymetric data into derived products that can enable habitat mapping of Australian waters, providing a foundational tool for the adaptive management of AMPs.

“Green Finance towards Achieving SDG14 – An Overview of the Challenges &amp; Opportunities in the Context of Bangladesh”

Green Finance, alternatively Sustainable Finance, is one of the fastest growing economic sectors in the world now a day. This paper provides an outline of green financing status of Bangladesh, endows with a portrayal on the different sources of green finance available in Bangladesh, provides an insight into the green finance landscape in the country in general and represents the challenges and prospective for greening growth of Bangladesh towards achieving SDG14. Greening the economy involves improving environmental quality and combating climate change which poses political, economic and financial challenges. Major challenges are about financing climate protection and climate change adaptation and how we can fill the funding gap. The goal of SDG 14 is to prevent and reduce ocean pollution, promote sustainable management and protection of marine and coastal ecosystems. Green finance faces many challenges as such in achieving SDGs created a huge financial gap in Bangladesh. This requires the mobilization and use of a variety of financial sources, including domestic revenue, development assistance, private sector investment, and public-private partnerships. The global economic downturn, violent conflict in some countries, biodiversity loss, water, dry land, forest degradation, and climate change pose challenges to peace and prosperity. Due to lack of capacities of banks and financial institutions, the lack of a proper understanding of the risks and returns of green projects, and the underdeveloped equity and bond markets decelerating the expected growth of green projects in Bangladesh. Lack of coordination among the respective agencies, poor financial governance, and the absence of a national policy oversight body and mainstreaming green finance toward SDG14 are some of the key policy issues that Bangladesh needs to address and to promote green financing to achieve sustainable development goals (i.e. SDG14) for reinstallation of coastal and marine ecosystem.

UAV photogrammetry for red tide monitoring and geo-localization via onboard GNSS/IMU data

As one of the worst ecological disasters in the world’s oceans, red tide seriously threatens marine ecology. Red tide monitoring is essential for preserving the ocean ecosystem. However, traditional photogrammetric processing workflows, e.g. SfM (Structure from Motion) and MVS (Multi-view Stereo) based image orientation and dense matching, do not apply to offshore images due to the low texture of ocean color. The primary contribution of this study is a UAV (Unmanned Aerial Vehicle)-based photogrammetric solution for red tide monitoring and direct geo-localization. First, a direct geo-localization model has been created, which solely uses onboard sensor data for the 3D coordinate calculation of 2D image targets based on the collinear equation. Second, two UAVs are chosen as photogrammetric systems that can supply the necessary data for the direct geo-localization model, including high-resolution images, camera intrinsic and extrinsic parameters. Third, a human annotation technique has been utilized to identify red tide regions whose ground polygons can be further estimated using the direct geo-localization model, taking into account how difficult it is to detect red tides automatically. Finally, the accuracy of direct geo-localization and the viability of the proposed solution has been evaluated and verified using real UAV datasets. The experimental results show that the direct geo-localization precision is better than 20 m when only onboard sensor data is used. The suggested workflow is appropriate for monitoring red tides, which can provide critical information for managing marine ecosystems. The executable toolkit would be made publicly available at https://github.com/json87/PhotoDigitizer.

Native Canadian daily life in the Northwest Passage context

This article explores the connection between the indigenous populations of the North and the Canadian government regarding the Northwest Passage in the Arctic region. The significance of indigenous representation in managing the Northwest Passage is emphasized. The challenges faced by small indigenous groups of the Canadian Arctic are addressed, as well as possible solutions through series of mutually beneficial economic and political proposals. Inuit involvement in the management of marine ecosystem goes beyond Canada’s borders. The Arctic Council has demonstrated that permanent participants from Northern Indigenous communities can significantly influence government, especially on Arctic issues. The days when the Arctic was on the outskirts of global political affairs are gone, as are the days of Canada’s previous passive stance towards its assertions of historically internal waters within the Northwest Passage. Advancing the interests of Indigenous peoples of the North is a well-established Canadian position. The utilization of the Arctic territory by these peoples serves as the backbone of Canada’s Arctic State Policy, consistently articulated by the Government of Canada.

A Comparative Analysis of Sparisoma cretense in Island Environments: Unraveling Metal Accumulation Differences in the Canary Islands (Spain, NW African Waters).

This study investigates the impact of varying environmental conditions on the metal composition within the tissues of Sparisoma cretense, contributing to the understanding necessary to offer scientifically sound advice regarding the health status of this species. This knowledge extends beyond fishery production, encompassing implications for food security. The data span the years 2022 and 2023, encompassing both cold and warm climatic seasons. The concentrations of various metals, such as Al, Zn, Cd, Pb, Fe, and Cu, exhibited noteworthy variations across the islands, with significant increases recorded in 2023, particularly during the warm season. The intricate interplay between multiple factors shaped the availability of the analyzed elements in S. cretense. Factors such as rising temperatures during the warm season increased biological activity in marine ecosystems, seasonal fluctuations in weather conditions, water quality, and anthropogenic influences, all contributing to the observed variations in metal concentrations. Additionally, the geological composition of each island and the patterns of marine currents and sediment transport play pivotal roles in these differences. Comprehensive scientific research, monitoring, and environmental surveillance are essential for a holistic understanding of this variability and providing valuable insights for the conservation and management of marine ecosystems in the Canary archipelago.

Understanding the compound marine heatwave and low-chlorophyll extremes in the western Pacific Ocean

The western Pacific Ocean is the global center for marine biodiversity, with high vulnerability to climate change. A better understanding of the spatiotemporal characteristics and potential drivers of compound marine heatwaves (MHWs) and low-chlorophyll (LChl) extreme events is essential for the conservation and management of local marine organisms and ecosystems. Here, using daily satellite sea surface temperature and model-based chlorophyll concentration, we find that the climatological spatial distribution of MHW-LChl events in total days, duration, and intensity exhibits heterogeneous distributions. The southwest sections of the South China Sea (WSCS) and Indonesian Seas are the hotspots for compound events, with total MHW-LChl days that are more than 2.5 times higher than in the other sub-regions. Notably, there is a trend toward more frequent (&amp;gt; 4.2 d/decade), stronger (&amp;gt; 0.5), and longer-lasting (&amp;gt; 1.4 d/decade) MHW-LChl occurrences in the WSCS. The occurrence of compound MHW-LChl extremes exhibits remarkable seasonal differences, with the majority of these events transpiring during winter. Moreover, there are generally statistically significant increasing trends in MHW-LChl events for all properties on both seasonal and inter-annual timescales. Furthermore, we reveal that the total days of compound MHW-LChl extremes are strongly modulated by large-scale climate modes such as the El Niño-Southern Oscillation and Dipole Mode Index. Overall, pinpointing MHW-LChl hotspots and understanding their changes and drivers help vulnerable communities in better preparing for heightened and compounded risks to marine organism and ecosystems under climate change.

Data-driven modelling for assessing trophic status in marine ecosystems using machine learning approaches

Assessing eutrophication in coastal and transitional waters is of utmost importance, yet existing Trophic Status Index (TSI) models face challenges like multicollinearity, data redundancy, inappropriate aggregation methods, and complex classification schemes. To tackle these issues, we developed a novel tool that harnesses machine learning (ML) and artificial intelligence (AI), enhancing the reliability and accuracy of trophic status assessments. Our research introduces an improved data-driven methodology specifically tailored for transitional and coastal (TrC) waters, with a focus on Cork Harbour, Ireland, as a case study.Our innovative approach, named the Assessment Trophic Status Index (ATSI) model, comprises three main components: the selection of pertinent water quality indicators, the computation of ATSI scores, and the implementation of a new classification scheme. To optimize input data and minimize redundancy, we employed ML techniques, including advanced deep learning methods. Specifically, we developed a CHL prediction model utilizing ten algorithms, among which XGBoost demonstrated exceptional performance, showcasing minimal errors during both training (RMSE = 0.0, MSE = 0.0, MAE = 0.01) and testing (RMSE = 0.0, MSE = 0.0, MAE = 0.01) phases.Utilizing a novel linear rescaling interpolation function, we calculated ATSI scores and evaluated the model's sensitivity and efficiency across diverse application domains, employing metrics such as R2, the Nash-Sutcliffe efficiency (NSE), and the model efficiency factor (MEF). The results consistently revealed heightened sensitivity and efficiency across all application domains. Additionally, we introduced a brand new classification scheme for ranking the trophic status of transitional and coastal waters. To assess spatial sensitivity, we applied the ATSI model to four distinct waterbodies in Ireland, comparing trophic assessment outcomes with the Assessment of Trophic Status of Estuaries and Bays in Ireland (ATSEBI) System. Remarkably, significant disparities between the ATSI and ATSEBI System were evident in all domains, except for Mulroy Bay.Overall, our research significantly enhances the accuracy of trophic status assessments in marine ecosystems. The ATSI model, combined with cutting-edge ML techniques and our new classification scheme, represents a promising avenue for evaluating and monitoring trophic conditions in TrC waters. The study also demonstrated the effectiveness of ATSI in assessing trophic status across various waterbodies, including lakes, rivers, and more. These findings make substantial contributions to the field of marine ecosystem management and conservation.

Typology of planktonic food webs and associated emerging properties as indicators of the ecological status of a permanently disturbed Gulf of Gabès

This study highlights the importance of coupling the typology of planktonic food webs and their emerging properties to better describe the ecological status of an ecosystem under permanent disturbance mainly caused by phosphate industry. Linear inverse models were built to describe four stations under various levels of nutrient pressure, using the Markov Chain Monte Carlo method to estimate known and unknown carbon flows, later used to calculate food web typology ratios. Ecological network analysis (ENA) was used to describe the structural and functional properties of each food web. Based on the food web typology ratios, three planktonic trophic pathways (PTP) with different functional indices were distinguished according to nutrient stress. The microbial food web dominated in the least nutrient-rich environment. It mainly relied on phytoplankton production (picophytoplankton <2 μm) that was mainly transferred by the high microbivory of protozooplankton. In contrast, the herbivorous food web developed in the most nutrient-rich environment, where biogenic carbon was mainly produced by large phytoplankton (microphytoplankton >10 μm) and channeled to higher trophic levels by herbivorous protozooplankton and metazooplankton. In the other two stations – moderately nutrient-rich systems – the PTP acted as a multivorous food web. Phytoplankton (small and large size fractions) and non-living components (detritus and dissolved organic carbon) played a significant role in carbon production, and competed with protozooplankton and metazooplankton for its transport. ENA indices revealed that the herbivorous food web, with the highest total system throughput and lowest relative Ascendency and cycling, was the most active but the least organized and stable system. In contrast, the microbial food web, with the lowest total system flux and highest Ascendency, was least active but more organized than the herbivorous food web. The multivorous food web displayed the most recycling and most organized system, with high values of the detritivory-to-herbivory ratio, cycling and Ascendency. In addition to ENA indices, which are considered effective tools for studying the structural and functional properties of food webs, marine ecosystem management efforts heavily focus on using the “marine food web” as a descriptor of the system's ecological status. However, we suggest that the combination of food web typology and ecological indices could be used as an effective tool for the management and assessment of ecosystem health wherever possible, as well as for the study of anthropogenic pressures.

Species Identification of Sea Bamboo (Isis hippuris) using COI-based DNA Barcoding

Conservation and effective management of marine ecosystems and biodiversity requires accurate species identification. This study classifies sea bamboo (Isis hippuris) specimens using DNA barcoding, a technique widely recognized for its speed, accuracy, and objectivity. This study examines the cytochrome c oxidase subunit I (COI) gene analysis for species identification. Isis hippuris was collected from two stations (coral and seagrass areas) of Tanjung Tiram Waters, South Konawe, Southeast Sulawesi. Genomic DNA was extracted from the base, main, and lateral stem of I. hippuris. Polymerase chain reaction (PCR) was used to amplify the mtDNA of I. hippuris with HCO2198 and LCO1490 primers. The highest quality PCR product based on the COI gene was chosen for sequencing analysis. The study revealed that COI gene analysis could only be performed on the base and main stem of the I. hippuris. Samples from coral and seagrass-coral areas on lateral stems were not further analyzed due to low concentration and purity values, which could potentially fail DNA sequencing. Each part of I. hippuris may have unique genetic differences. This study highlights the advantages of DNA sequencing in providing a unique genetic fingerprint for each species, enabling accurate species identification. This research provides insight into using DNA barcoding for sea bamboo species identification.

Intercomparison of marine tracer and catchment-based submarine groundwater discharge estimates for a karst aquifer

Submarine groundwater discharge (SGD) is a major source of solutes to the ocean. Consequently, the accuracy of estimates of the magnitude and seasonal variability of SGD is critical for the management of coastal marine ecosystems. However, very few intercomparison studies between different conceptual approaches have been made to assess the reliability and consistency of SGD flow estimates while simultaneously gauging the applicability of underlying models and budget assumptions in real-world scenarios. To date, intercomparison efforts have focused on homogeneous aquifers, and less so on highly heterogeneous aquifers such as karst systems. Here we compare the results of tracer-based (salt mass balance, tidal prism and radon mass balances) and catchment-based methods (water balance, semi-distributed karst network model) to assess SGD at a data-rich coastal location. All approaches tested here reveal a positive relationship between SGD fluxes and groundwater level measured close to the preferential groundwater flow pathways in the phreatic karst aquifer (e.g. water-saturated conduits or fracture network). We use this finding to derive site-specific relationships between groundwater level and SGD flow rates. We derive these relationships from least square fitting of Darcian and Non-Darcian models and regression analysis. The relationships validate the findings derived independently from hydraulic/hydrogeological modelling of the complex karst networks. By combining various estimates made with distinct assumptions, this method produces robust estimates of the SGD seasonal variability, essential to develop optimal management strategies of SGD resources in coastal karstic regions. Where direct measurements of SGD are not possible, monitoring of coastal groundwater level close to preferential phreatic groundwater pathways can be thus used as a useful indicator to compare past groundwater flow measurements and derive site-specific relationships, particularly in settings where large flow rate changes are present such as karst aquifers.

Ecosystem-based fishery management that accounts for trade-offs between fishing and enhancement stocking: A case study of Juehua Island in the Bohai Sea

The implementation of marine ecosystem management requires modeling that accounts for the trade-off between exploitation in fisheries and protection activities (e.g., enhancement and release, artificial reefs). Researchers are increasingly interested in the trends of fishery resources under these joint driving forces due to the negative impacts of resource exploitation and the positive impacts of marine protection. Using the sea around Juehua Island in China’s Bohai Sea as a case study, we developed a marine ecosystem model based on the Ecopath with Ecosim software to analyze the trends in fishery resources driven both by fishing and stock enhancement. When the fishing effort exceeded 42 % of the 2019 value, the biomass of top predator Platycephalus indicus decreased by 50 %, indicating a regime shift. When the fishing effort increased to 340 % of the 2019 level, the ecosystem shifts to an alternative stable state occurs, indicating destabilization of the marine ecosystem. The impact of fishing effort on the marine ecosystem was not well compensated by release of a single target species. We also designed an orthogonal experiment with three factors (the key species Fenneropenaeus chinensis, Paralichthys olivaceus, and Charybdis japonica) and four restocking release levels to determine both the optimal release rate for each species individually and the optimal combination of different species. If the 2019 fishing effort is maintained, the release of 125 × 106 juvenile F. chinensis, 400 × 103 juvenile P. olivaceus, and 15 × 106 juvenile C. japonica would be an optimal solution to improve the marine biomass, trophic level, and biodiversity. Our results provide insights into ecosystem-based management strategies for implementing a policy to limit fishing in the study area and for scientifically determining the restocking release rates.

Comparative changes in seasonal marine heatwaves and cold spells over the Tropical Indian Ocean during recent decades and disentangling the drivers of highly intense events

AbstractThe unprecedented increase in the Sea Surface Temperature (SST) in the warming climate yield stress to the system and pose severe threats to the marine ecosystem. Marine Heatwaves (MHWs) and Marine Cold Spells (MCSs) are two extreme events related to SST variability. For better management of ocean productivity, marine ecosystem, marine services, and fisheries, the understanding of seasonal discrepancies rather than annual documentation of MHWs and MCSs metrics is more utilitarian. This study documents the decadal changes in the MHWs and MCSs over the Tropical Indian Ocean (TIO) for all seasons. Additionally, highly intense events (based on intensity and duration) are identified and demonstrate the associated drivers. During the past two decades (1982–1990, 1991–2000), the MCSs were more frequent than MHWs in every season. However, in the recent two decades (2001–2010, 2011–2020), TIO become more prone to MHWs with considerably more frequent and prolonged events in JJAS months. Moreover, MCSs are disappearing from the TIO. It was noted that the choice of baseline period has an impact on the magnitude of MHWs and MCSs changes, but the spatial pattern (regions with high/low magnitude MHWs and MCSs) stays fairly constant in all baseline period sensitivity checks. The investigation of highly intense events reveals that MHWs and MCSs are produced and sustained by the same drivers when they are at their opposing edges. In general, the coherence effort from winds, net heat fluxes (shortwave radiation, longwave radiation, latent heat flux, and sensible heat flux), mixed level depth, and mean sea level pressure contribute to the genesis of seasonal MHWs or MCSs events. Additionally, in some cases, a single driver (e.g., wind) may also play a crucial role in these extreme events. The remote climate modes of variability, such as El Niño–Southern Oscillation, also contribute significantly to the MHWs and MCSs. El Niño (La Niña) events not only increase the spatial coverage of MHWs (MCSs) but also increases the intensity.

The similarities of sustainable marine ecosystem management and circular economy in industry 4.0

The similarities of sustainable marine ecosystem management and circular economy in industry 4.0

Knowledge-based science in support of the blue growth ambition for small island developing states

Abstract The “blue economy” idea promotes the responsible and sustainable use of coastal and marine resources. The need to balance the exploitation and economic use of these resources has moved to the top of the research agenda and management priorities for small island developing states (SIDS). SIDS face unique challenges due to their geographic, economic, and environmental characteristics. While the specific challenges can vary based on the individual SIDS, some common future challenges include (i) climate change and sea-level rise resulting from the increased frequency and intensity of storms and coastal erosion; (ii) natural disasters such as hurricanes, cyclones, tsunamis, and earthquakes, resulting in extensive damage, disruption of essential services, and lead to loss of lives and livelihoods; (iii) lack of sustainable development and economic diversification leading to reliance on few key sectors, such as tourism and agriculture, which are vulnerable to market fluctuations; (iv) energy security and renewable energy transition; as there is dependency on imported fossil fuels for their energy needs, price fluctuations and supply disruptions occurs; (v) biodiversity conservation and marine resource management; they host unique ecosystems and rich biodiversity, including coral reefs, mangroves, and marine species; and (vi) access to finance and technology; there are direct opportunities, for accessing funds to support technology development under sustainable finance projects. This themed article set attracted 14 submissions, 7 of which were accepted for publication. The topics covered fisheries, climate change effects, marine litter, and development of new technologies and finance mechanisms to support the SIDS. Overall, these contributions have emphasized the remarkable role that SIDS play in the protection and management of coastal and marine ecosystems, but also highlighted several needs and key priorities.