During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of...During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of Tuna el-Gabal, El-Minia-Upper Egypt. It’s going back to 2nd century AD and involves different sites of Ptolemaic and Roman chapels;some are in the immaculate established style while others are a blend of Pharaonic-Greek style and both are secured with mural painting. Deterioration problems observed on the wall paintings of the funerary house are, loss of plaster layers, disintegration of plaster layers, loss of paint layers (blistering and peeling), discoloration and severely damaged owing to a lot of deterioration factors as weakness of mud brick support, deterioration of surface treatments and to the widespread presence of different salts. The materials used in the painting, preparation layers and the state of conservation of the mural painting at funerary house were investigated by integrated physio-chemical measurements, particularly micro-Raman spectroscopy (µRaman), light optical microscopy (LOM), scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). In addition, the morphology of multilayer plaster from wall painting was investigated using atomic force microscopy (AFM). A wide color palette utilized as a part of the necropolis has been identified with mineral pigments and pigment mixtures. It is found that, the paints were based on an organic binder and traditional pigments (azurite, hematite, ochre, vegetable black) were used as colorants on plaster. The examination demonstrated that the preparatory layer is verging on made of pure lime while the plaster layer based mainly of lime and gypsum with variable amounts of quartz. The obtained results provided information about the painting technique, chemical composition, crystal structure in addition to the stratigraphy of the paint layers and the state of preservation and on the causes of the painting deterioration. Furthermore, the obtained results can be used in the conservation and restoration interventions of these sites.展开更多
This study focused on the preparation of docosahexaenoic acid(DHA) and eicosapentaenoic acid(EPA)enriched-triacylglycerols by enzymatic interesterification using tuna oil and capric acid. The content of DHA+EPA is 26....This study focused on the preparation of docosahexaenoic acid(DHA) and eicosapentaenoic acid(EPA)enriched-triacylglycerols by enzymatic interesterification using tuna oil and capric acid. The content of DHA+EPA is 26.86% in the tuna oil used in this study. A response surface methodology(RSM) was used to optimize the reaction parameters(reaction temperature, substrate molar ratio, enzyme amount and reaction time), and the optimized conditions were determined to be: reaction temperature 58℃, substrate molar ratio(capric acid : tuna oil) 4:1, enzyme amount 4%, and reaction time 7.5 h. Under the optimized conditions, the content of DHA+EPA in the glycerides was 40.03%, which is 13.17% higher than that in raw tuna oil. In addition,the MLM-type structured lipids containing medium chain fatty acids(capric acid) at positions sn-1,3 and a long chain fatty acid(DHA/EPA) at the position sn-2 may have many health benefits for humans.展开更多
In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zon...In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zonal distribution of skipjack tuna(Katsuwonus pelamis).Although causality has been suggested by researchers using physical-biological interaction models,cumulative evidence needs to be obtained and the tenability of assertion needs to be tested from an ecological habitat perspective,based on fisheries data.For purse seine fishery,the use of catch per unit effort(CPUE)as an indication of the abundance is confusing because of technical improvements over the whole exploitation history and unbalanced individual fishing characteristic of vessels.It is particularly interesting to discriminate between habitat characteristics in comparative scenarios of CPUE application.This study identified habitat traits based on a series of oceanographic factors from a global ocean reanalysis model.A comparison was conducted between two habitat models based on unprocessed purse seine CPUE and standardized CPUE considering fishing characteristics.The results suggest that standardized CPUE could model the regular zonal shift of habitat compatible with the observed fishing efforts transfer,and achieved better prediction capacity than unprocessed CPUE.Furthermore,the habitat of skipjack tuna was also characterized and linked with surface and subsurface thermal environment,ocean current,dissolved oxygen,biotic environment,and ENSO variability.The monthly-averaged habitat suitable index,derived from the optimal habitat model prediction,showed a significant linear relationship with the southern oscillation index,which suggested that El Ni?o episodes eventually provide more preferable habitat for skipjack tuna under ENSO variability.展开更多
The modern fishery stock assessment could be conducted by various models,such as Stock Synthesis model with high data requirement and complicated model structure,and the basic surplus production model,which fails to i...The modern fishery stock assessment could be conducted by various models,such as Stock Synthesis model with high data requirement and complicated model structure,and the basic surplus production model,which fails to incorporate individual growth,maturity,and fishery selectivity,etc.In this study,the Just Another Bayesian Biomass Assessment(JABBA)Select which is relatively balanced between complex and simple models,was used to conduct stock assessment for yellowfin tuna(Thunnus albacares)in the Atlantic Ocean.Its population dynamics was evaluated,considering the influence of selectivity patterns and different catch per unit effort(CPUE)indices on the stock assessment results.The model with three joint longline standardized CPUE indices and logistic selectivity pattern performed well,without significant retrospective pattern.The results indicated that the stock is not overfished and not subject to overfishing in 2018.Sensitivity analyses indicated that stock assessment results are robust to natural mortality but sensitive to steepness of the stock-recruitment relationship and fishing selectivity.High steepness was revealed to be more appropriate for this stock,while the fishing selectivity has greater influence to the assessment results than life history parameters.Overall,JABBA-Select is suitable for the stock assessment of Atlantic yellowfin tuna with different selectivity patterns,and the assumptions of natural mortality and selectivity pattern should be improved to reduce uncertainties.展开更多
In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) and Villa Putzu (...In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) and Villa Putzu (South East Sardinia, Italy) in order to assess the current levels of these two contaminants in fish muscle and the consequent risk to humans consuming said fish. Values of polychlorobiphenyls in bluefin tuna muscle vary between 0.155 and 1.403 mg/kg f.w.;the average of PCBs in tuna muscle is 0.732 mg/kg f.w. With regard to PCBs the presence of more elevated concentrations is confirmed in larger fish. The results regarding mercury in muscle show an average of 0.660 mg/kg f.w. and mercury values vary between 0.140 f.w. and 2.211 mg/kg f.w.;for mercury as well, the highest concentrations were found in the largest bluefin tuna. Six samples, 26% of total, contained more than 1 mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for this species. Mercury, in particular methylmercury, poses a risk to public health, therefore, taking into account the important nutritional contribution that tuna fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children strictly limit their consumption of tuna from this area of the Mediterranean.展开更多
Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the facto...Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the factors which affect its time series pattern. Our research was aimed at elucidating the climatic factors which affected the trajectory of the yellowfin tuna stock in the Eastern and Western South Pacific Ocean. We utilized various climatic factors for the years t - n with n = 0, 1, ..., 8 and investigated their statistical relationship with the catch per unit effort (CPUE) of yellowfin tuna stock from 1957-2008 for three South Pacific zones ranging from the East to the West Pacific Ocean within the coverage area of the Western and Central Pacific Convention Area. Results showed that the climatic conditions of: (i) the global mean land and ocean temperature index (LOTI), (ii) the Pacific warm pool index (PWI) and (iii) Southern Oscillation Index (SOI) had significant relationship with the CPUE of yellowfin tuna in all three zones. LOTI, PWI and SOI were used as independent variables and fitted through modeling to replicate the CPUE trajectory of the yellowfin tuna in Zone 1, Zone 2 and Zone 3. Model selection was based on significant parameter estimates (p < 0.05), Akaikes Information Criterion (AIC) and R2 values. Models selected for all three zones had LOTI, PWI and SOI as the independent variables. This study shows that LOTI, PWI and SOI are climatic conditions which have significant impact on the fluctuation pattern of the yellowfin tuna CPUE in the Eastern and Western South Pacific Ocean. From the findings of this study it can be recommended that when management decisions are made for yellowfin tuna fishery conservation and sustainability in the Eastern and Western South Pacific, it is imperative to take the effect of climatic factors into account.展开更多
Pacific bluefin tuna (Thunnus orientalis) is one of the most economically important species in the Percomorpha group of teleost fishes. Their migrations are extensive and depend upon continuous swimming at a high rate...Pacific bluefin tuna (Thunnus orientalis) is one of the most economically important species in the Percomorpha group of teleost fishes. Their migrations are extensive and depend upon continuous swimming at a high rate of speed throughout their life. The draft genome sequence of this species has been reported but remains highly fragmented. We constructed a Pacific bluefin tuna genetic linkage map using microsatellite markers developed on each of the scaffolds from the draft genome sequence to link these genome fragments and understand the genomic structure of species in Percomorpha. Of the 606 polymerase chain reaction microsatellite primer pairs tested, 473 were polymorphic in the mapping populations for the linkage analysis. We constructed sex-specific maps for 24 linkage groups consisting of 470 markers, which allowed us to place scaffolds that cumulatively represented 20.8% (153.8 Mb) of the sequenced genome onto the linkage groups. The distribution of orthologous genes on the chromosomes of tuna and four other teleost fish species suggested that the constitution of tuna chromosomes is closest to that of medaka. Both species have the 24 chromosomes of the ancestral teleost, including several chromosomal inversions. The integrated map developed in this study will be useful to construct a complete physical map to conduct comparative teleost genomics and genetic studies on economically useful traits in Pacific bluefin tuna.展开更多
文摘During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of Tuna el-Gabal, El-Minia-Upper Egypt. It’s going back to 2nd century AD and involves different sites of Ptolemaic and Roman chapels;some are in the immaculate established style while others are a blend of Pharaonic-Greek style and both are secured with mural painting. Deterioration problems observed on the wall paintings of the funerary house are, loss of plaster layers, disintegration of plaster layers, loss of paint layers (blistering and peeling), discoloration and severely damaged owing to a lot of deterioration factors as weakness of mud brick support, deterioration of surface treatments and to the widespread presence of different salts. The materials used in the painting, preparation layers and the state of conservation of the mural painting at funerary house were investigated by integrated physio-chemical measurements, particularly micro-Raman spectroscopy (µRaman), light optical microscopy (LOM), scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). In addition, the morphology of multilayer plaster from wall painting was investigated using atomic force microscopy (AFM). A wide color palette utilized as a part of the necropolis has been identified with mineral pigments and pigment mixtures. It is found that, the paints were based on an organic binder and traditional pigments (azurite, hematite, ochre, vegetable black) were used as colorants on plaster. The examination demonstrated that the preparatory layer is verging on made of pure lime while the plaster layer based mainly of lime and gypsum with variable amounts of quartz. The obtained results provided information about the painting technique, chemical composition, crystal structure in addition to the stratigraphy of the paint layers and the state of preservation and on the causes of the painting deterioration. Furthermore, the obtained results can be used in the conservation and restoration interventions of these sites.
文摘This study focused on the preparation of docosahexaenoic acid(DHA) and eicosapentaenoic acid(EPA)enriched-triacylglycerols by enzymatic interesterification using tuna oil and capric acid. The content of DHA+EPA is 26.86% in the tuna oil used in this study. A response surface methodology(RSM) was used to optimize the reaction parameters(reaction temperature, substrate molar ratio, enzyme amount and reaction time), and the optimized conditions were determined to be: reaction temperature 58℃, substrate molar ratio(capric acid : tuna oil) 4:1, enzyme amount 4%, and reaction time 7.5 h. Under the optimized conditions, the content of DHA+EPA in the glycerides was 40.03%, which is 13.17% higher than that in raw tuna oil. In addition,the MLM-type structured lipids containing medium chain fatty acids(capric acid) at positions sn-1,3 and a long chain fatty acid(DHA/EPA) at the position sn-2 may have many health benefits for humans.
基金The National Key R&D Program of China under contract Nos 2020YFD0901202 and 2019YFD0901502the National Natural Science Foundation of China under contract Nos 41806110,41506151 and 31902426。
文摘In the western and central Pacific Ocean,upper strata waters exhibit highly dynamic oceanographic features under ENSO variability.This has been proved to be responsible for the dynamic change of both abundance and zonal distribution of skipjack tuna(Katsuwonus pelamis).Although causality has been suggested by researchers using physical-biological interaction models,cumulative evidence needs to be obtained and the tenability of assertion needs to be tested from an ecological habitat perspective,based on fisheries data.For purse seine fishery,the use of catch per unit effort(CPUE)as an indication of the abundance is confusing because of technical improvements over the whole exploitation history and unbalanced individual fishing characteristic of vessels.It is particularly interesting to discriminate between habitat characteristics in comparative scenarios of CPUE application.This study identified habitat traits based on a series of oceanographic factors from a global ocean reanalysis model.A comparison was conducted between two habitat models based on unprocessed purse seine CPUE and standardized CPUE considering fishing characteristics.The results suggest that standardized CPUE could model the regular zonal shift of habitat compatible with the observed fishing efforts transfer,and achieved better prediction capacity than unprocessed CPUE.Furthermore,the habitat of skipjack tuna was also characterized and linked with surface and subsurface thermal environment,ocean current,dissolved oxygen,biotic environment,and ENSO variability.The monthly-averaged habitat suitable index,derived from the optimal habitat model prediction,showed a significant linear relationship with the southern oscillation index,which suggested that El Ni?o episodes eventually provide more preferable habitat for skipjack tuna under ENSO variability.
基金The Fund of National Key R&D Programs of China under contract No.2019YFD0901404the China Postdoctoral Science Foundation under contract No.2019M651475。
文摘The modern fishery stock assessment could be conducted by various models,such as Stock Synthesis model with high data requirement and complicated model structure,and the basic surplus production model,which fails to incorporate individual growth,maturity,and fishery selectivity,etc.In this study,the Just Another Bayesian Biomass Assessment(JABBA)Select which is relatively balanced between complex and simple models,was used to conduct stock assessment for yellowfin tuna(Thunnus albacares)in the Atlantic Ocean.Its population dynamics was evaluated,considering the influence of selectivity patterns and different catch per unit effort(CPUE)indices on the stock assessment results.The model with three joint longline standardized CPUE indices and logistic selectivity pattern performed well,without significant retrospective pattern.The results indicated that the stock is not overfished and not subject to overfishing in 2018.Sensitivity analyses indicated that stock assessment results are robust to natural mortality but sensitive to steepness of the stock-recruitment relationship and fishing selectivity.High steepness was revealed to be more appropriate for this stock,while the fishing selectivity has greater influence to the assessment results than life history parameters.Overall,JABBA-Select is suitable for the stock assessment of Atlantic yellowfin tuna with different selectivity patterns,and the assumptions of natural mortality and selectivity pattern should be improved to reduce uncertainties.
文摘In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in 23 bluefin tuna samples collected in the spring of 2012 in Porto Scuso (South West Sardinia, Italy) and Villa Putzu (South East Sardinia, Italy) in order to assess the current levels of these two contaminants in fish muscle and the consequent risk to humans consuming said fish. Values of polychlorobiphenyls in bluefin tuna muscle vary between 0.155 and 1.403 mg/kg f.w.;the average of PCBs in tuna muscle is 0.732 mg/kg f.w. With regard to PCBs the presence of more elevated concentrations is confirmed in larger fish. The results regarding mercury in muscle show an average of 0.660 mg/kg f.w. and mercury values vary between 0.140 f.w. and 2.211 mg/kg f.w.;for mercury as well, the highest concentrations were found in the largest bluefin tuna. Six samples, 26% of total, contained more than 1 mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for this species. Mercury, in particular methylmercury, poses a risk to public health, therefore, taking into account the important nutritional contribution that tuna fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children strictly limit their consumption of tuna from this area of the Mediterranean.
文摘Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the factors which affect its time series pattern. Our research was aimed at elucidating the climatic factors which affected the trajectory of the yellowfin tuna stock in the Eastern and Western South Pacific Ocean. We utilized various climatic factors for the years t - n with n = 0, 1, ..., 8 and investigated their statistical relationship with the catch per unit effort (CPUE) of yellowfin tuna stock from 1957-2008 for three South Pacific zones ranging from the East to the West Pacific Ocean within the coverage area of the Western and Central Pacific Convention Area. Results showed that the climatic conditions of: (i) the global mean land and ocean temperature index (LOTI), (ii) the Pacific warm pool index (PWI) and (iii) Southern Oscillation Index (SOI) had significant relationship with the CPUE of yellowfin tuna in all three zones. LOTI, PWI and SOI were used as independent variables and fitted through modeling to replicate the CPUE trajectory of the yellowfin tuna in Zone 1, Zone 2 and Zone 3. Model selection was based on significant parameter estimates (p < 0.05), Akaikes Information Criterion (AIC) and R2 values. Models selected for all three zones had LOTI, PWI and SOI as the independent variables. This study shows that LOTI, PWI and SOI are climatic conditions which have significant impact on the fluctuation pattern of the yellowfin tuna CPUE in the Eastern and Western South Pacific Ocean. From the findings of this study it can be recommended that when management decisions are made for yellowfin tuna fishery conservation and sustainability in the Eastern and Western South Pacific, it is imperative to take the effect of climatic factors into account.
文摘Pacific bluefin tuna (Thunnus orientalis) is one of the most economically important species in the Percomorpha group of teleost fishes. Their migrations are extensive and depend upon continuous swimming at a high rate of speed throughout their life. The draft genome sequence of this species has been reported but remains highly fragmented. We constructed a Pacific bluefin tuna genetic linkage map using microsatellite markers developed on each of the scaffolds from the draft genome sequence to link these genome fragments and understand the genomic structure of species in Percomorpha. Of the 606 polymerase chain reaction microsatellite primer pairs tested, 473 were polymorphic in the mapping populations for the linkage analysis. We constructed sex-specific maps for 24 linkage groups consisting of 470 markers, which allowed us to place scaffolds that cumulatively represented 20.8% (153.8 Mb) of the sequenced genome onto the linkage groups. The distribution of orthologous genes on the chromosomes of tuna and four other teleost fish species suggested that the constitution of tuna chromosomes is closest to that of medaka. Both species have the 24 chromosomes of the ancestral teleost, including several chromosomal inversions. The integrated map developed in this study will be useful to construct a complete physical map to conduct comparative teleost genomics and genetic studies on economically useful traits in Pacific bluefin tuna.
