Pub Date : 2024-12-01DOI: 10.1016/j.seares.2024.102554
Lang Xu , Yajing Shen , Jihong Chen , Guangnian Xiao , Liying Liu
The COVID-19 pandemic severely disrupted global maritime transport, while Chinese coastal ports demonstrated remarkable resilience, continuing to play a pivotal role in the shipping industry. This study categorizes resilience into five key properties (redundancy, flexibility, stability, recoverability, and scalability) using tier-1 and tier-2 indicators to evaluate the resilience performance of 16 ports from 2013 to 2022. To standardize the data, we apply the min-max normalization, followed by entropy weighting to evaluate the performance of various resilience indicators, then construct a DBN model to reflect the state transitions of resilience indicators. The findings reveal strong financial health is crucial for maintaining port resilience. Enhancing financial management and improving profitability provide a robust economic foundation for the sustainable development of ports. Additionally, cargo throughput and import-export trade are highly sensitive to port resilience.
{"title":"Assessing the impact of the Covid-19 epidemic on the resilience of Chinese coastal ports","authors":"Lang Xu , Yajing Shen , Jihong Chen , Guangnian Xiao , Liying Liu","doi":"10.1016/j.seares.2024.102554","DOIUrl":"10.1016/j.seares.2024.102554","url":null,"abstract":"<div><div>The COVID-19 pandemic severely disrupted global maritime transport, while Chinese coastal ports demonstrated remarkable resilience, continuing to play a pivotal role in the shipping industry. This study categorizes resilience into five key properties (redundancy, flexibility, stability, recoverability, and scalability) using tier-1 and tier-2 indicators to evaluate the resilience performance of 16 ports from 2013 to 2022. To standardize the data, we apply the min-max normalization, followed by entropy weighting to evaluate the performance of various resilience indicators, then construct a DBN model to reflect the state transitions of resilience indicators. The findings reveal strong financial health is crucial for maintaining port resilience. Enhancing financial management and improving profitability provide a robust economic foundation for the sustainable development of ports. Additionally, cargo throughput and import-export trade are highly sensitive to port resilience.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102554"},"PeriodicalIF":2.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.seares.2024.102556
Young-Je Park , Fang Shen , GiHoon Hong , Fang Zuo , Kai Qin , Sophie Hebden
{"title":"Changes in the marine biosphere of the Northwest Pacific and the Central Indo-Pacific observed via Earth Observation data (EO data used for NWP and CIP biosphere)","authors":"Young-Je Park , Fang Shen , GiHoon Hong , Fang Zuo , Kai Qin , Sophie Hebden","doi":"10.1016/j.seares.2024.102556","DOIUrl":"10.1016/j.seares.2024.102556","url":null,"abstract":"","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102556"},"PeriodicalIF":2.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-01DOI: 10.1016/j.seares.2024.102555
Jun Sun , Zhuo Chen , Kuidong Xu , Mao Lin
Global climate changes have had a profound impact on marine biodiversity, prompting marine organisms to adapt rapidly to these changes. Marine biodiversity is a reflection of the stability and variability found within marine ecosystems, upon which they rely. Thirteen articles in this special issue are dedicated to exploring marine biodiversity and its response to global climate changes for a more thoughtful understanding. We are delighted to see that by taking a holistic approach to marine biodiversity and global climate changes, incorporating various disciplines, we can better inform the future restoration of marine ecosystems.
{"title":"Editorial: Marine biodiversity under global climate change","authors":"Jun Sun , Zhuo Chen , Kuidong Xu , Mao Lin","doi":"10.1016/j.seares.2024.102555","DOIUrl":"10.1016/j.seares.2024.102555","url":null,"abstract":"<div><div>Global climate changes have had a profound impact on marine biodiversity, prompting marine organisms to adapt rapidly to these changes. Marine biodiversity is a reflection of the stability and variability found within marine ecosystems, upon which they rely. Thirteen articles in this special issue are dedicated to exploring marine biodiversity and its response to global climate changes for a more thoughtful understanding. We are delighted to see that by taking a holistic approach to marine biodiversity and global climate changes, incorporating various disciplines, we can better inform the future restoration of marine ecosystems.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102555"},"PeriodicalIF":2.1,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143153904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-22DOI: 10.1016/j.seares.2024.102551
Jiayu Bai , Kailei Zhu , Yi Wang , Yingyu Wu
Conservation and sustainable utilization of marine biodiversity in the context of climate change are unavoidable issues for the international community. The BBNJ Agreement, which regulates equity, is being opened for signature as an implementation agreement of UNCLOS after years of international negotiations. The ABMTs, including MPAs, are regulated by the BBNJ Agreement. The role of ABMTs, including MPAs is closely related to climate change response. Its approaches include building ecosystem resilience in response to climate change stress. When interpreting and implementing articles concerning ABMTs, including MPAs, equity should be followed. To what extent do the interpretation and implementation of these articles reflect equity? According to the VCLT, ‘Common action’ and ‘special consideration’ are representative elements of equity. Under the indicators of ‘common action’ and ‘special consideration’, some articles related to the submission of proposals, decision-making, implementation, monitoring, and review processes of ABMTs, including MPAs, are formulated with ambiguous expressions. These ambiguous expressions may not be conducive to the contracting parties fully adhering to equity in the interpretation and implementation of ABMTs, including MPAs. To address these ambiguous expressions, the contracting parties may implement subsequent practices, based on the VCLT. First, the contracting parties may ask the STB to stipulate that the consultation procedure may be concluded after a certain time. Second, the contracting parties may clarify the positioning of particularly affected contracting parties in measuring the efforts exhausted to reach a consensus. Third, the contracting parties may make a declaration. The declaration could indicate that the disproportionate burden in the implementation of the ABMTs, including MPA measures imposed under the objectives, should be considered in supporting developing states.
{"title":"The realization of equity in ABMTs, including MPAs, under the BBNJ agreement for marine ecosystem resilience strength in the climate change context","authors":"Jiayu Bai , Kailei Zhu , Yi Wang , Yingyu Wu","doi":"10.1016/j.seares.2024.102551","DOIUrl":"10.1016/j.seares.2024.102551","url":null,"abstract":"<div><div>Conservation and sustainable utilization of marine biodiversity in the context of climate change are unavoidable issues for the international community. The BBNJ Agreement, which regulates equity, is being opened for signature as an implementation agreement of UNCLOS after years of international negotiations. The ABMTs, including MPAs, are regulated by the BBNJ Agreement. The role of ABMTs, including MPAs is closely related to climate change response. Its approaches include building ecosystem resilience in response to climate change stress. When interpreting and implementing articles concerning ABMTs, including MPAs, equity should be followed. To what extent do the interpretation and implementation of these articles reflect equity? According to the VCLT, ‘Common action’ and ‘special consideration’ are representative elements of equity. Under the indicators of ‘common action’ and ‘special consideration’, some articles related to the submission of proposals, decision-making, implementation, monitoring, and review processes of ABMTs, including MPAs, are formulated with ambiguous expressions. These ambiguous expressions may not be conducive to the contracting parties fully adhering to equity in the interpretation and implementation of ABMTs, including MPAs. To address these ambiguous expressions, the contracting parties may implement subsequent practices, based on the VCLT. First, the contracting parties may ask the STB to stipulate that the consultation procedure may be concluded after a certain time. Second, the contracting parties may clarify the positioning of particularly affected contracting parties in measuring the efforts exhausted to reach a consensus. Third, the contracting parties may make a declaration. The declaration could indicate that the disproportionate burden in the implementation of the ABMTs, including MPA measures imposed under the objectives, should be considered in supporting developing states.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102551"},"PeriodicalIF":2.1,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142719760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-21DOI: 10.1016/j.seares.2024.102553
Jianhui Liu , Fenggui Chen , Lan Xiao
Due to its unique characteristics and positioning, the conservation and management of islands differ from those of mainland and marine environments. As a major maritime nation with over 11,000 islands, China's island policies reflect its comprehensive strategic needs in resource management, ecological protection, and economic development, while also illustrating the profound influence of global climate change and international marine governance on national interests, giving these policies their distinctiveness. Therefore, this study constructs a qualitative content analysis process, focusing on China's island management policies, with the aim of systematically interpreting policy texts to conduct a comprehensive analysis, revealing the evolution and characteristics of China's island management system, as well as identifying new challenges ahead. This approach provides a fresh perspective on integrated island management. Through analysis, we identified three key themes in China's island management: island development, ecological protection, and legal governance. From a longitudinal perspective, China's island management has shifted from an initial focus on development to increasingly emphasizing ecological protection. As island governance policies are gradually introduced, other management measures have also been continuously implemented, including conducting comprehensive national island resource surveys, establishing and developing nature reserves related to islands, undertaking island ecosystem restoration, and incorporating island management into unified national spatial planning. These efforts have progressively advanced China's island management toward greater specialization and legal governance. A horizontal comparison of island management systems reveals that, in China, economic development is often prioritized, especially on islands with significant development potential. This is fundamentally driven by the current stage of economic development and resource demands. Therefore, exploring a path that balances economic development with ecological protection has become a key highlight of China's island management. Over time, new challenges have emerged due to changing environmental conditions, such as sea level rise and increased extreme weather events exacerbating the vulnerability of island ecosystems and disaster risks. Strengthening island climate adaptation requires the establishment of early warning systems for extreme weather and sea level rise, enhancing flood defenses, and restoring natural ecosystems such as mangroves, coral reefs, and wetlands, which serve as protective barriers against climate risks.
{"title":"China's island management system based on qualitative content analysis: The choice between development and conservation","authors":"Jianhui Liu , Fenggui Chen , Lan Xiao","doi":"10.1016/j.seares.2024.102553","DOIUrl":"10.1016/j.seares.2024.102553","url":null,"abstract":"<div><div>Due to its unique characteristics and positioning, the conservation and management of islands differ from those of mainland and marine environments. As a major maritime nation with over 11,000 islands, China's island policies reflect its comprehensive strategic needs in resource management, ecological protection, and economic development, while also illustrating the profound influence of global climate change and international marine governance on national interests, giving these policies their distinctiveness. Therefore, this study constructs a qualitative content analysis process, focusing on China's island management policies, with the aim of systematically interpreting policy texts to conduct a comprehensive analysis, revealing the evolution and characteristics of China's island management system, as well as identifying new challenges ahead. This approach provides a fresh perspective on integrated island management. Through analysis, we identified three key themes in China's island management: island development, ecological protection, and legal governance. From a longitudinal perspective, China's island management has shifted from an initial focus on development to increasingly emphasizing ecological protection. As island governance policies are gradually introduced, other management measures have also been continuously implemented, including conducting comprehensive national island resource surveys, establishing and developing nature reserves related to islands, undertaking island ecosystem restoration, and incorporating island management into unified national spatial planning. These efforts have progressively advanced China's island management toward greater specialization and legal governance. A horizontal comparison of island management systems reveals that, in China, economic development is often prioritized, especially on islands with significant development potential. This is fundamentally driven by the current stage of economic development and resource demands. Therefore, exploring a path that balances economic development with ecological protection has become a key highlight of China's island management. Over time, new challenges have emerged due to changing environmental conditions, such as sea level rise and increased extreme weather events exacerbating the vulnerability of island ecosystems and disaster risks. Strengthening island climate adaptation requires the establishment of early warning systems for extreme weather and sea level rise, enhancing flood defenses, and restoring natural ecosystems such as mangroves, coral reefs, and wetlands, which serve as protective barriers against climate risks.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102553"},"PeriodicalIF":2.1,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.seares.2024.102552
Shipeng Wang , Haiyan Wang , Guoqing Xue , Yang Han , Qi Qin , Leixin Zhang , Xushi Ma
This paper aims to explore the correlations among failure risk factors of automated container port logistics systems from a resilience perspective. Based on the Wuli-Shili-Renli (WSR) theory and a multi-dimensional resilience framework, five key categories of risk factors affecting system resilience are identified: port infrastructure, port logistics operation organization, port personnel, port operational environment, and port emergency response and management. Through expert interviews, system component analysis, and a review of related literature across these five dimensions, 36 specific risk factors were identified to establish an initial set of system failure risk factors. Subsequently, a dual-factor screening method combining grey relational analysis and rank correlation was applied to simplify the initial set, constructing a system failure risk factor index system from a resilience perspective. Finally, a comprehensive model combining the Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL) method and the Total Adversarial Interpretation Structure Model (TAISM) was proposed. This model identifies and quantifies the complex correlations among system failure risk factors from a resilience perspective, revealing their relative importance and their impact on system resilience. The results indicate that system resilience is primarily influenced by internal factors such as the smoothness of collection and distribution operations, infrastructure service capacity, and the stability of technical support systems. External factors, such as the prevention capability for major emergency threats and the improvement of government supervision and coordination feedback mechanisms, also significantly impact system resilience. The complex interactions among key factors have a profound effect on system resilience, underscoring the need to enhance coordination and management measures to strengthen overall system resilience. This study provides a theoretical foundation for developing targeted strategies to enhance the resilience of automated container port logistics systems.
{"title":"Correlation analysis of failure risk factors in automated container port logistics systems from a resilience perspective","authors":"Shipeng Wang , Haiyan Wang , Guoqing Xue , Yang Han , Qi Qin , Leixin Zhang , Xushi Ma","doi":"10.1016/j.seares.2024.102552","DOIUrl":"10.1016/j.seares.2024.102552","url":null,"abstract":"<div><div>This paper aims to explore the correlations among failure risk factors of automated container port logistics systems from a resilience perspective. Based on the Wuli-Shili-Renli (WSR) theory and a multi-dimensional resilience framework, five key categories of risk factors affecting system resilience are identified: port infrastructure, port logistics operation organization, port personnel, port operational environment, and port emergency response and management. Through expert interviews, system component analysis, and a review of related literature across these five dimensions, 36 specific risk factors were identified to establish an initial set of system failure risk factors. Subsequently, a dual-factor screening method combining grey relational analysis and rank correlation was applied to simplify the initial set, constructing a system failure risk factor index system from a resilience perspective. Finally, a comprehensive model combining the Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL) method and the Total Adversarial Interpretation Structure Model (TAISM) was proposed. This model identifies and quantifies the complex correlations among system failure risk factors from a resilience perspective, revealing their relative importance and their impact on system resilience. The results indicate that system resilience is primarily influenced by internal factors such as the smoothness of collection and distribution operations, infrastructure service capacity, and the stability of technical support systems. External factors, such as the prevention capability for major emergency threats and the improvement of government supervision and coordination feedback mechanisms, also significantly impact system resilience. The complex interactions among key factors have a profound effect on system resilience, underscoring the need to enhance coordination and management measures to strengthen overall system resilience. This study provides a theoretical foundation for developing targeted strategies to enhance the resilience of automated container port logistics systems.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102552"},"PeriodicalIF":2.1,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-28DOI: 10.1016/j.seares.2024.102550
Rikke Petri Frandsen , Ludvig Ahm Krag , Bent Herrmann
Common sole (Solea solea) is an economically important species in several European trawl fisheries, yet little is known about the size selective properties of codends used in bottom trawl fisheries targeting sole. This study presents results from a sea trial conducted in the inner Danish waters where common sole is fished in a seasonal trawl fishery using a 90 mm diamond mesh codend with a mandatory large mesh escape panel. To improve understanding of the selectivity in this gear, we in addition tested a plain 90 mm diamond mesh codend without an escape panel. This combination of codend mesh size and large mesh escape panel is part of an ambitious management plan aimed at eliminating bycatch of cod (Gadus morhua) in trawl fisheries in the inner Danish waters. In the fishery for common sole, we found a severe mismatch between gear regulations and minimum conservation reference size of the target species. The outcome is a highly inefficient fishery in which only 22 % (CI: 18–27 %) by weight of the marketable sole is retained in the 90 mm diamond mesh codend. Further, we estimated that 25 % (CI: 16–35 %) of the sole entering the codend would contact the mandatory escape panel and escape, resulting in a total loss of 83 % (CI: 79–87 %) of marketable sole through the mandatory gear. The inefficiency in this fishery demonstrates the need for other means than gear specifications to regulate this type of fishery.
{"title":"The challenge of harvesting common sole (Solea solea) in highly selective trawl fisheries","authors":"Rikke Petri Frandsen , Ludvig Ahm Krag , Bent Herrmann","doi":"10.1016/j.seares.2024.102550","DOIUrl":"10.1016/j.seares.2024.102550","url":null,"abstract":"<div><div>Common sole (<em>Solea solea</em>) is an economically important species in several European trawl fisheries, yet little is known about the size selective properties of codends used in bottom trawl fisheries targeting sole. This study presents results from a sea trial conducted in the inner Danish waters where common sole is fished in a seasonal trawl fishery using a 90 mm diamond mesh codend with a mandatory large mesh escape panel. To improve understanding of the selectivity in this gear, we in addition tested a plain 90 mm diamond mesh codend without an escape panel. This combination of codend mesh size and large mesh escape panel is part of an ambitious management plan aimed at eliminating bycatch of cod (<em>Gadus morhua</em>) in trawl fisheries in the inner Danish waters. In the fishery for common sole, we found a severe mismatch between gear regulations and minimum conservation reference size of the target species. The outcome is a highly inefficient fishery in which only 22 % (CI: 18–27 %) by weight of the marketable sole is retained in the 90 mm diamond mesh codend. Further, we estimated that 25 % (CI: 16–35 %) of the sole entering the codend would contact the mandatory escape panel and escape, resulting in a total loss of 83 % (CI: 79–87 %) of marketable sole through the mandatory gear. The inefficiency in this fishery demonstrates the need for other means than gear specifications to regulate this type of fishery.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102550"},"PeriodicalIF":2.1,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142659854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Silver croaker (Pennahia argentata) is an important economic species in the East China Sea (ECS); however, its population has been declining, and studies on its status are scarce. This study collected biological data, including length, weight, and gonadal maturity of silver croaker from the southern coastal waters of Zhejiang Province between 2015 and 2021, to evaluate its life history and assess stock status. Methods from the TropFishR package were employed to estimate population growth and natural mortality parameters. Two widely used length-based data-limited models, length-based bayesian biomass estimation method (LBB) and length-based spawning potential ratio method (LBSPR), were applied to assess the stock status of silver croaker in the ECS. The results indicated that with a maximum age (Amax) of 4 years, the asymptotic length (Linf) was 23.80 cm, growth rate (K) was 0.74/year, and natural mortality coefficient (M) ranged from 1.068 to 1.376. Under the assumption of Amax = 5 years, Linf was 26.77 cm, K was 0.63/year, and M ranged from 0.818 to 1.193. The LBB and LBSPR models showed that, except for scenarios with L∞ = 23.8 cm, M/K = 1.46, and L∞ = 26.77 cm, M/K = 1.30, 1.38, or 1.48, the selectivity at length parameters and for silver croaker exhibited an increasing trend over the years. In the LBB model, for different years consistently fell below the optimum length (Lc_opt), indicating that most individuals did not reach the size at first sexual maturity or optimal catch length. Moreover, under high fishing pressure, the Spawning Potential Ratio (SPR) and the unfished biomass ratio (B/B0) for silver croaker showed a decreasing trend, despite some stability or recovery in recent years. However, in all scenarios, SPR values were below 0.2, and B/B0 values were below 0.5, suggesting a significant risk of population collapse for silver croaker in the ECS due to intense fishing pressure. Therefore, it is recommended to reduce the current fishing pressure and increase the minimum catch size of this species for effective conservation and management in this region.
{"title":"Stock exploitation status of silver croaker (Pennahia argentata) from the East China Sea","authors":"Shiqing Zhao , Richard Kindong , Chunxia Gao , Njomoue Achille Pandong , Siquan Tian","doi":"10.1016/j.seares.2024.102549","DOIUrl":"10.1016/j.seares.2024.102549","url":null,"abstract":"<div><div>Silver croaker (<em>Pennahia argentata)</em> is an important economic species in the East China Sea (ECS); however, its population has been declining, and studies on its status are scarce. This study collected biological data, including length, weight, and gonadal maturity of silver croaker from the southern coastal waters of Zhejiang Province between 2015 and 2021, to evaluate its life history and assess stock status. Methods from the TropFishR package were employed to estimate population growth and natural mortality parameters. Two widely used length-based data-limited models, length-based bayesian biomass estimation method (LBB) and length-based spawning potential ratio method (LBSPR), were applied to assess the stock status of silver croaker in the ECS. The results indicated that with a maximum age (<em>A</em><sub><em>max</em></sub>) of 4 years, the asymptotic length (<em>L</em><sub><em>inf</em></sub>) was 23.80 cm, growth rate (<em>K</em>) was 0.74/year, and natural mortality coefficient (<em>M</em>) ranged from 1.068 to 1.376. Under the assumption of <em>A</em><sub><em>max</em></sub> = 5 years, <em>L</em><sub><em>inf</em></sub> was 26.77 cm, <em>K</em> was 0.63/year, and <em>M</em> ranged from 0.818 to 1.193. The LBB and LBSPR models showed that, except for scenarios with <em>L</em><sub><em>∞</em></sub> = 23.8 cm, <em>M/K</em> = 1.46, and <em>L</em><sub><em>∞</em></sub> = 26.77 cm, <em>M/K</em> = 1.30, 1.38, or 1.48, the selectivity at length parameters <span><math><msubsup><mi>L</mi><mn>50</mn><mi>S</mi></msubsup><mspace></mspace></math></span>and<span><math><mspace></mspace><msubsup><mi>L</mi><mn>95</mn><mi>S</mi></msubsup></math></span> for silver croaker exhibited an increasing trend over the years. In the LBB model, <span><math><msubsup><mi>L</mi><mn>50</mn><mi>S</mi></msubsup></math></span> for different years consistently fell below the optimum length (<em>L</em><sub><em>c_opt</em></sub>), indicating that most individuals did not reach the size at first sexual maturity or optimal catch length. Moreover, under high fishing pressure, the Spawning Potential Ratio (SPR) and the unfished biomass ratio (<em>B/B</em><sub><em>0</em></sub>) for silver croaker showed a decreasing trend, despite some stability or recovery in recent years. However, in all scenarios, SPR values were below 0.2, and <em>B/B</em><sub><em>0</em></sub> values were below 0.5, suggesting a significant risk of population collapse for silver croaker in the ECS due to intense fishing pressure. Therefore, it is recommended to reduce the current fishing pressure and increase the minimum catch size of this species for effective conservation and management in this region.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102549"},"PeriodicalIF":2.1,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1016/j.seares.2024.102548
Yang Deng , Xiaoguang Xu , Jie Xu , Wenlin Wang , Ruijie Lu , Haihua Zhuo , Yingcai Wang , Yunbing Liu , Xi Liu , Xiaolong Huang
While the spatiotemporal dynamics of phytoplankton community structures in river ecosystems have been extensively studied, their primary driving factors remain elusive, particularly at the watershed scale. This research examined the phytoplankton community structure across three watersheds of an island and concurrently analyzed its response to water level fluctuations (WLFs). The phytoplankton density was notably higher at elevated water levels, registering an increase of 1.29 times in Nandu River, 1.34 times in Changhua River, and 1.28 times in Wanquan River. Notably, the middle reaches of the Changhua River recorded the highest phytoplankton density (4.46 × 108 cells/L). Broadly speaking, Cyanophyta, Chlorophyta, and Bacillariophyta remained the predominant phytoplankton across varied water levels. Dominant phytoplankton species varied with water levels; however, the most prevalent species consistently belonged to the Cyanophyta group, primarily Microcystis or Merismopedia, with dominance ranging between 0.17 to 0.38 (low water level) and 0.18 to 0.32 (high water level). Enhanced phytoplankton diversity and richness were observed at higher water levels, correlating with increased concentrations of NH4+-N, NO3−-N, and PO43− in the river water. Consequently, nutrient fluctuations driven by hydrodynamics significantly influence the phytoplankton community structure in island river ecosystems.
{"title":"Hydrological-driven changes in the phytoplankton community structure under nutrient stress in island river ecosystems","authors":"Yang Deng , Xiaoguang Xu , Jie Xu , Wenlin Wang , Ruijie Lu , Haihua Zhuo , Yingcai Wang , Yunbing Liu , Xi Liu , Xiaolong Huang","doi":"10.1016/j.seares.2024.102548","DOIUrl":"10.1016/j.seares.2024.102548","url":null,"abstract":"<div><div>While the spatiotemporal dynamics of phytoplankton community structures in river ecosystems have been extensively studied, their primary driving factors remain elusive, particularly at the watershed scale. This research examined the phytoplankton community structure across three watersheds of an island and concurrently analyzed its response to water level fluctuations (WLFs). The phytoplankton density was notably higher at elevated water levels, registering an increase of 1.29 times in Nandu River, 1.34 times in Changhua River, and 1.28 times in Wanquan River. Notably, the middle reaches of the Changhua River recorded the highest phytoplankton density (4.46 × 10<sup>8</sup> cells/L). Broadly speaking, Cyanophyta, Chlorophyta, and Bacillariophyta remained the predominant phytoplankton across varied water levels. Dominant phytoplankton species varied with water levels; however, the most prevalent species consistently belonged to the Cyanophyta group, primarily Microcystis or Merismopedia, with dominance ranging between 0.17 to 0.38 (low water level) and 0.18 to 0.32 (high water level). Enhanced phytoplankton diversity and richness were observed at higher water levels, correlating with increased concentrations of NH<sub>4</sub><sup>+</sup>-N, NO<sub>3</sub><sup>−</sup>-N, and PO<sub>4</sub><sup>3−</sup> in the river water. Consequently, nutrient fluctuations driven by hydrodynamics significantly influence the phytoplankton community structure in island river ecosystems.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102548"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-28DOI: 10.1016/j.seares.2024.102547
Guozhen Zha , Zhongbiao Chen , Zhijia Lin , Lin Peng , Jie Zhang , Weiye He
Nautical X-band radars are used to continuously monitor large ocean surface areas with high temporal and spatial resolution. The signatures of ocean surface waves in nautical X-band radar images are typically present as straight or curved stripes with distinct directional and frequency characteristics. Curvelet transform (CT) is a multi-resolution technique with the capability of locational and directional resolving. This study presents a new method for enhancing the signatures of ocean surface waves in nautical X-band radar images. A radar image is decomposed at different scales, directions, and locations using forward CT. The surface wave signals are distributed in the curvelet coefficient (CC) of certain directions and scales. The signals of surface waves are extracted by retaining the CCs in specific directions and scales, whereas the CCs in other directions and scales are all set to zero. Wave signatures are enhanced by adding the extracted signals back to the original image. The proposed method is also feasible for enhancing signatures of surface waves in synthetic aperture radar or optical remote sensing images.
航海 X 波段雷达用于以较高的时间和空间分辨率连续监测大面积海面。在航海 X 波段雷达图像中，海洋表面波的特征通常表现为具有明显方向和频率特性的直线或曲线条纹。小曲线变换（CT）是一种多分辨率技术，具有定位和方向分辨能力。本研究提出了一种增强航海 X 波段雷达图像中海洋表面波特征的新方法。使用前向 CT 对雷达图像进行不同尺度、方向和位置的分解。面波信号分布在特定方向和尺度的小曲线系数（CC）中。通过保留特定方向和尺度上的小曲线系数，提取面波信号，而其他方向和尺度上的小曲线系数则全部置零。通过将提取的信号添加回原始图像来增强波浪特征。所提出的方法也适用于增强合成孔径雷达或光学遥感图像中的表面波特征。
{"title":"A new method for enhancing signatures of ocean surface waves in nautical X-band radar images","authors":"Guozhen Zha , Zhongbiao Chen , Zhijia Lin , Lin Peng , Jie Zhang , Weiye He","doi":"10.1016/j.seares.2024.102547","DOIUrl":"10.1016/j.seares.2024.102547","url":null,"abstract":"<div><div>Nautical X-band radars are used to continuously monitor large ocean surface areas with high temporal and spatial resolution. The signatures of ocean surface waves in nautical X-band radar images are typically present as straight or curved stripes with distinct directional and frequency characteristics. Curvelet transform (CT) is a multi-resolution technique with the capability of locational and directional resolving. This study presents a new method for enhancing the signatures of ocean surface waves in nautical X-band radar images. A radar image is decomposed at different scales, directions, and locations using forward CT. The surface wave signals are distributed in the curvelet coefficient (CC) of certain directions and scales. The signals of surface waves are extracted by retaining the CCs in specific directions and scales, whereas the CCs in other directions and scales are all set to zero. Wave signatures are enhanced by adding the extracted signals back to the original image. The proposed method is also feasible for enhancing signatures of surface waves in synthetic aperture radar or optical remote sensing images.</div></div>","PeriodicalId":50056,"journal":{"name":"Journal of Sea Research","volume":"202 ","pages":"Article 102547"},"PeriodicalIF":2.1,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142427633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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