The original purpose of Vessel Monitoring System(VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to im...The original purpose of Vessel Monitoring System(VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to improve the accuracy of fisheries stock assessment. In this paper, we simulated the trawl trajectory under different time intervals using the cubic Hermite spline(c Hs) interpolation method based on the VMS data of 8 single otter trawl vessels(totally 36000 data items) fishing in Zhoushan fishing ground from September 2012 to December 2012, and selected the appropriate time interval. We then determined vessels' activities(fishing or non-fishing) by comparing VMS speed data with the corresponding speeds from logbooks. The results showed that the error of simulated trajectory greatly increased with the increase of time intervals of VMS data when they were longer than 30 minutes. Comparing the speeds from VMS with those from the corresponding logbooks, we found that the vessels' speeds were between 2.5 kn and 5.0 kn in fishing. The c Hs interpolation method is a new choice for improving the accuracy of estimation of sailing trajectory, and the VMS can be used to determine the vessels' activities with the analysis of their trajectories and speeds. Therefore, when the fishery information is limited, VMS can be one of the important data sources for fisheries stock assessment, and more attention should be paid to its construction and application to fisheries stock assessment and management.展开更多
The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues liver, kidney and muscles offish C. batrachus at varying intervals and exposures. Alterations in 5...The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues liver, kidney and muscles offish C. batrachus at varying intervals and exposures. Alterations in 5'-Nuclcotidase activity of body organs gave an idea of the toxicity caused by the fertilizer. Thus the enzyme 5'-Nucleotidase can be used to monitor the pollution in aquatic ecosystem.展开更多
Fishing activities result in a depletion of fish resources and an increase in bycatch probability of non-target species,which are thought to be the cause of the recent demographic change experienced by coastal cetacea...Fishing activities result in a depletion of fish resources and an increase in bycatch probability of non-target species,which are thought to be the cause of the recent demographic change experienced by coastal cetaceans in waters off Guangdong province,China.However,fishing intensity and its spatiotemporal pattern remain poorly examined in this region.Here,random daily tracks from 100 fishing vessels were used to estimate fishing operations in the coastal waters off Guangdong province.The performance of two methods was tested with Automatic Identification System(AIS)data collected in the Pearl River Delta region(PRD).This assessment found that the Density-Based Spatial Clustering of Applications with Noise(DBSCAN)could falsely identify port regions as fishing grounds,while the speed-based method provided a more accurate estimate of fishing grounds with less computational effort.Subsequently,the spatiotemporal pattern of fishing intensity in the coastal waters off the entire Guangdong province was examined with the speed-based method.Our results showed that 87.75%of the coastal fishing activities occurred in waters<40 m in depth.The method detected two spatially heterogeneous fishing grounds extending from the PRD to either the west or east sides of Guangdong province.In the west fishing ground,43.4%of fishing vessels operated in the waters off Yangjiang city;while in the east fishing ground,fishing activities were more evenly distributed.The present study suggests that the AIS is able to provide high-resolution data to monitor the development of fishing activities,which may be useful for informing marine resource management and spatial planning.展开更多
基金supported by the National Natural Science Foundation (No. 40801225)the Natural Science Foundation of Zhejiang Province (No. LY13D 010005)Young academic leader climbing program of Zhejiang Province (grant number pd 2013222)
文摘The original purpose of Vessel Monitoring System(VMS) is for enforcement and control of vessel sailing. With the application of VMS in fishing vessels, more and more population dynamic studies have used VMS data to improve the accuracy of fisheries stock assessment. In this paper, we simulated the trawl trajectory under different time intervals using the cubic Hermite spline(c Hs) interpolation method based on the VMS data of 8 single otter trawl vessels(totally 36000 data items) fishing in Zhoushan fishing ground from September 2012 to December 2012, and selected the appropriate time interval. We then determined vessels' activities(fishing or non-fishing) by comparing VMS speed data with the corresponding speeds from logbooks. The results showed that the error of simulated trajectory greatly increased with the increase of time intervals of VMS data when they were longer than 30 minutes. Comparing the speeds from VMS with those from the corresponding logbooks, we found that the vessels' speeds were between 2.5 kn and 5.0 kn in fishing. The c Hs interpolation method is a new choice for improving the accuracy of estimation of sailing trajectory, and the VMS can be used to determine the vessels' activities with the analysis of their trajectories and speeds. Therefore, when the fishery information is limited, VMS can be one of the important data sources for fisheries stock assessment, and more attention should be paid to its construction and application to fisheries stock assessment and management.
文摘The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues liver, kidney and muscles offish C. batrachus at varying intervals and exposures. Alterations in 5'-Nuclcotidase activity of body organs gave an idea of the toxicity caused by the fertilizer. Thus the enzyme 5'-Nucleotidase can be used to monitor the pollution in aquatic ecosystem.
基金funded by the Natural Science Foundation of Guangdong province in China[Grant number 2018A030313870]the Ocean Park Conservation Foundation Hong Kong[Grant number MM01.1920],Alashan Society of Entrepreneurs and Ecology(SEE)+1 种基金the Shenzhen Zhilan Foundation[Grant number 2019040231B]the“One Belt One Road”Science and Technology Cooperation Special Program of the International Partnership Program of Chinese Academy of Sciences[Grant number 183446KYSB20200016].
文摘Fishing activities result in a depletion of fish resources and an increase in bycatch probability of non-target species,which are thought to be the cause of the recent demographic change experienced by coastal cetaceans in waters off Guangdong province,China.However,fishing intensity and its spatiotemporal pattern remain poorly examined in this region.Here,random daily tracks from 100 fishing vessels were used to estimate fishing operations in the coastal waters off Guangdong province.The performance of two methods was tested with Automatic Identification System(AIS)data collected in the Pearl River Delta region(PRD).This assessment found that the Density-Based Spatial Clustering of Applications with Noise(DBSCAN)could falsely identify port regions as fishing grounds,while the speed-based method provided a more accurate estimate of fishing grounds with less computational effort.Subsequently,the spatiotemporal pattern of fishing intensity in the coastal waters off the entire Guangdong province was examined with the speed-based method.Our results showed that 87.75%of the coastal fishing activities occurred in waters<40 m in depth.The method detected two spatially heterogeneous fishing grounds extending from the PRD to either the west or east sides of Guangdong province.In the west fishing ground,43.4%of fishing vessels operated in the waters off Yangjiang city;while in the east fishing ground,fishing activities were more evenly distributed.The present study suggests that the AIS is able to provide high-resolution data to monitor the development of fishing activities,which may be useful for informing marine resource management and spatial planning.
