Since the concept of ＂fishing down marine food webs＂ was first proposed in 1998, mean trophic level of fisheries landings（MTL） has become one of the most widely used indicators to assess the impacts of fishing on ...Since the concept of ＂fishing down marine food webs＂ was first proposed in 1998, mean trophic level of fisheries landings（MTL） has become one of the most widely used indicators to assess the impacts of fishing on the integrity of marine ecosystem and guide the policy development by many management agencies. Recent studies suggest that understanding underlying causes for changes in MTL is vital for an appropriate use of MTL as an indicator of fishery sustainability. Based on the landing data compiled by Food and Agriculture Organization（FAO） and trophic information of relevant species in Fishbase, we evaluated MTL trends in 14 FAO fishing areas and analyzed catches of upper and lower trophic level groups under different trends of MTL and found that both the cases of a recovered MTL trend and a generally increasing MTL trend could be accompanied by decreasing catches of lower trophic level species. Further, community structure and exploitation history should be considered in using MTL after excluding species with trophic levels lower than 3.25 to distinguish ＂fishingthrough＂ from ＂fishing-down＂. We conclude that MTL used as an indicator to measure fishery sustainability can benefit from a full consideration of both upper and lower trophic level species and masking effects of community structure and exploitation history.展开更多
This article is written to celebrate the 95th anniversary of Laboratory of Water Management Research, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Czech Republic. Short ...This article is written to celebrate the 95th anniversary of Laboratory of Water Management Research, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Czech Republic. Short trip to the history, a few words about the founder Prof. Smrcek and the laboratory works - education, projects, physical and mathematical modelling today.展开更多
In the last two to three decades or so, the spatial pattern of mineral occurrences of a deposit-type has been studied to derive insights to mineralization controls and assist mineral exploration. In the Skellefte dist...In the last two to three decades or so, the spatial pattern of mineral occurrences of a deposit-type has been studied to derive insights to mineralization controls and assist mineral exploration. In the Skellefte district, Fry plots of volcanogenic massive sulfide （VMS） mines/ prospects reveal patterns that are likely due to post- mineralization deformation events. The fractal dimensions of the spatial patterns of the present-day VMS mines/ prospects and that of the ＇original＇ VMS deposits support the concept that spatial patterns of mineral deposits are spatially-invariant. Therefore, analysis of the spatial pattern of mineral deposits is useful not only in research about pre- and syn-mineralization geological settings but also post-mineralization geological settings.展开更多
基金The National Natural Science Foundation of China under contract Nos NSFC41306127 and NSFC41276156the Funding Program for Outstanding Dissertations in Shanghai Ocean University+1 种基金the Funding Scheme for Training Young Teachers in Shanghai Colleges and Shanghai Leading Academic Discipline Project(Fisheries Discipline)the involvement of Y.Chen was supported by SHOU International Center for Marine Studies and Shanghai 1000 Talent Program
文摘Since the concept of ＂fishing down marine food webs＂ was first proposed in 1998, mean trophic level of fisheries landings（MTL） has become one of the most widely used indicators to assess the impacts of fishing on the integrity of marine ecosystem and guide the policy development by many management agencies. Recent studies suggest that understanding underlying causes for changes in MTL is vital for an appropriate use of MTL as an indicator of fishery sustainability. Based on the landing data compiled by Food and Agriculture Organization（FAO） and trophic information of relevant species in Fishbase, we evaluated MTL trends in 14 FAO fishing areas and analyzed catches of upper and lower trophic level groups under different trends of MTL and found that both the cases of a recovered MTL trend and a generally increasing MTL trend could be accompanied by decreasing catches of lower trophic level species. Further, community structure and exploitation history should be considered in using MTL after excluding species with trophic levels lower than 3.25 to distinguish ＂fishingthrough＂ from ＂fishing-down＂. We conclude that MTL used as an indicator to measure fishery sustainability can benefit from a full consideration of both upper and lower trophic level species and masking effects of community structure and exploitation history.
文摘This article is written to celebrate the 95th anniversary of Laboratory of Water Management Research, Department of Water Structures, Faculty of Civil Engineering, Brno University of Technology, Czech Republic. Short trip to the history, a few words about the founder Prof. Smrcek and the laboratory works - education, projects, physical and mathematical modelling today.
文摘In the last two to three decades or so, the spatial pattern of mineral occurrences of a deposit-type has been studied to derive insights to mineralization controls and assist mineral exploration. In the Skellefte district, Fry plots of volcanogenic massive sulfide （VMS） mines/ prospects reveal patterns that are likely due to post- mineralization deformation events. The fractal dimensions of the spatial patterns of the present-day VMS mines/ prospects and that of the ＇original＇ VMS deposits support the concept that spatial patterns of mineral deposits are spatially-invariant. Therefore, analysis of the spatial pattern of mineral deposits is useful not only in research about pre- and syn-mineralization geological settings but also post-mineralization geological settings.
