This study aims to assess ecological effects of the construction of marine ranching in the eastern Guangdong waters. Variations in sea surface temperature (SST), chlorophyll a concentration (Chl-a), catch per unit eff...This study aims to assess ecological effects of the construction of marine ranching in the eastern Guangdong waters. Variations in sea surface temperature (SST), chlorophyll a concentration (Chl-a), catch per unit effort (CPUE), biodiversity, biomass and density of benthos were compared during the pre- (August in 2011) and post- (August in 2013) marine ranching. These were based on satellite remote sensing and survey data. Results showed that the ratio of Nitrogen (N): Phosphorus (P) was closed to 16, Chl-a increased from 7.5 - 12.3 mg·m-3 to 10.4 - 16.2 mg·m-3, and CPUE increased from 2.1 - 5.5 kg·h-1 to 5.8 - 14.5 kg·h-1. The species number of fish, crustaceans, cephalopods and shellfish increased by 25, 3, 2 and 3 respectively. Shannon-Wiener biodiversity index of fish, crustaceans, cephalopods and shellfish increased by 0.5, 0.4, 0.1 and 1.0 respectively. Both biomass and density of benthos increased also. The construction of marine ranching in the eastern Guangdong had restored the habitat to some extent, and played positive effects in the conservation and proliferation of fishery resources in local area.展开更多
GPS-based surface drifters were used to investigate the surface currents in Daya Bay and along the eastern Guangdong coast in China.Surface current vectors were measured based on the GPS location and corresponding tim...GPS-based surface drifters were used to investigate the surface currents in Daya Bay and along the eastern Guangdong coast in China.Surface current vectors were measured based on the GPS location and corresponding time information sent by drifters through the mobile phone network.The analysis of data from 120 drifters,deployed in late spring 2018 in the case-study region,shows that the drifters are generally capable of capturing the surface(tidal and residual)currents.The drifter trajectories suggest an anticlockwise surface current inside Daya Bay and a north-eastward current along the eastern Guangdong coast,where the coastal current along the eastern Guangdong coast is faster than that inside Daya Bay.The surface currents in the investigated region follow an irregular semidiurnal cycle due to the influence of the tidal current,while the currents inside Daya Bay are strongly affected by the topography.According to the harmonic analysis,an irregular semidiurnal type of tidal current is evident at a study grid inside Daya Bay,with an Eulerian residual current speed of 9.0 cm/s and a direction of 276°.The Lagrangian residual current outside Daya Bay moves north-eastward with a mean speed of 22 cm/s along the eastern Guangdong coast,while the current inside Daya Bay moves northward to the bay head with a mean speed of about 8.0 cm/s,which agrees well with the one reported in other literatures.展开更多
文摘This study aims to assess ecological effects of the construction of marine ranching in the eastern Guangdong waters. Variations in sea surface temperature (SST), chlorophyll a concentration (Chl-a), catch per unit effort (CPUE), biodiversity, biomass and density of benthos were compared during the pre- (August in 2011) and post- (August in 2013) marine ranching. These were based on satellite remote sensing and survey data. Results showed that the ratio of Nitrogen (N): Phosphorus (P) was closed to 16, Chl-a increased from 7.5 - 12.3 mg·m-3 to 10.4 - 16.2 mg·m-3, and CPUE increased from 2.1 - 5.5 kg·h-1 to 5.8 - 14.5 kg·h-1. The species number of fish, crustaceans, cephalopods and shellfish increased by 25, 3, 2 and 3 respectively. Shannon-Wiener biodiversity index of fish, crustaceans, cephalopods and shellfish increased by 0.5, 0.4, 0.1 and 1.0 respectively. Both biomass and density of benthos increased also. The construction of marine ranching in the eastern Guangdong had restored the habitat to some extent, and played positive effects in the conservation and proliferation of fishery resources in local area.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.91958203,41776027,and 41606009)the Xiamen University Fundamental Research Funds for the Central Universities(Nos.20720180103,20720180099)+1 种基金the Laboratory for Regional Oceanography and Numerical Modeling,Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2017A02)the municipal project of Huizhou City(No.F2017-01-1)
文摘GPS-based surface drifters were used to investigate the surface currents in Daya Bay and along the eastern Guangdong coast in China.Surface current vectors were measured based on the GPS location and corresponding time information sent by drifters through the mobile phone network.The analysis of data from 120 drifters,deployed in late spring 2018 in the case-study region,shows that the drifters are generally capable of capturing the surface(tidal and residual)currents.The drifter trajectories suggest an anticlockwise surface current inside Daya Bay and a north-eastward current along the eastern Guangdong coast,where the coastal current along the eastern Guangdong coast is faster than that inside Daya Bay.The surface currents in the investigated region follow an irregular semidiurnal cycle due to the influence of the tidal current,while the currents inside Daya Bay are strongly affected by the topography.According to the harmonic analysis,an irregular semidiurnal type of tidal current is evident at a study grid inside Daya Bay,with an Eulerian residual current speed of 9.0 cm/s and a direction of 276°.The Lagrangian residual current outside Daya Bay moves north-eastward with a mean speed of 22 cm/s along the eastern Guangdong coast,while the current inside Daya Bay moves northward to the bay head with a mean speed of about 8.0 cm/s,which agrees well with the one reported in other literatures.
