Fishery-independent surveys can provide high-quality data and support fishery assessment and management.Optimization of sampling design is crucial to increase the quality of fishery surveys.Crab pots are important fis...Fishery-independent surveys can provide high-quality data and support fishery assessment and management.Optimization of sampling design is crucial to increase the quality of fishery surveys.Crab pots are important fishing gears used to catch crabs.We analyzed the impacts of sampling design of crab pots on the abundance of Portunus trituberculatus in the Changjiang(Yangtze)River estuary to the Hangzhou Bay and its adjacent waters in East China Sea.The crab pots were cylindrical,240 mm in height and 600 mm in diameter of the iron ring.Our sampling designs(including fixed-station sampling,simple random sampling,stratified fixed-station sampling,and stratified random sampling),three number of stations(9,16,and 24),and three numbers of crab pots(500,1000,and 3000)were simulated and compared with the“true”abundance that obtained from bottom trawl surveys in the study area in 2007.The scenarios with 16 stations were set in stratification as a control group for comparison with unstratified designs.Results show that simple random sampling can obtain more stable results than fixed-station sampling in the abundance estimation of P.trituberculatus.In addition,stratified sampling resulted in more accurate abundance than unstratified sampling.The accuracy of the simulated results improved with the increase of the number of stations.No remarkable differences in the results were found among the scenarios of different number of crab pots at each station.However,resource-intensive areas exerted great impacts on simulation results.Thus,prior information or pre-survey results about resource abundance and density distribution are necessary.This study may serve as a reference for future sampling designs of crab pots of P.trituberculatus and other species.展开更多
The effects of bark on komatsuna (Japanese spinach) and tomato were investigated by changing the nitrogen content of chemical fertilizers and bark mixing ratio. Mixing 25 and 50% of bark with soil improved komatsuna g...The effects of bark on komatsuna (Japanese spinach) and tomato were investigated by changing the nitrogen content of chemical fertilizers and bark mixing ratio. Mixing 25 and 50% of bark with soil improved komatsuna growth, and also exceeded the growth rates obtained by using chemical fertilizers. However, komatsuna could not grow in 100% bark alone, with excessive amounts of bark majorly inhibiting komatsuna growth. The aeration of bark also did not enhance komatsuna growth. The nitrogen content and bark-mixing ratio had a much lower impact on tomato growth compared to komatsuna. In comparison, aerated bark was more effective in enhancing tomato growth compared to komatsuna growth.展开更多
ChoflgqRgls iOURt8R Cty rt th6southwestern China,is fsmous for its peppery hotpot dishes．Spiciness of hot pot fills every cornerof the city,and引Ivisitors to Chongqingaretempted to taste this delicacy．Of all the hot...ChoflgqRgls iOURt8R Cty rt th6southwestern China,is fsmous for its peppery hotpot dishes．Spiciness of hot pot fills every cornerof the city,and引Ivisitors to Chongqingaretempted to taste this delicacy．Of all the hot potF6St8UFSRtS tri ChOOgqiDgl th6 bFSRd’Litt旧 SWSR’is th6 iOSt W6II krtOWrt．展开更多
基金Supported by the National Key Research and Development Program of China(No.2019YFD0901304)the Science and Technology Project of Zhoushan(No.2017C41012)。
文摘Fishery-independent surveys can provide high-quality data and support fishery assessment and management.Optimization of sampling design is crucial to increase the quality of fishery surveys.Crab pots are important fishing gears used to catch crabs.We analyzed the impacts of sampling design of crab pots on the abundance of Portunus trituberculatus in the Changjiang(Yangtze)River estuary to the Hangzhou Bay and its adjacent waters in East China Sea.The crab pots were cylindrical,240 mm in height and 600 mm in diameter of the iron ring.Our sampling designs(including fixed-station sampling,simple random sampling,stratified fixed-station sampling,and stratified random sampling),three number of stations(9,16,and 24),and three numbers of crab pots(500,1000,and 3000)were simulated and compared with the“true”abundance that obtained from bottom trawl surveys in the study area in 2007.The scenarios with 16 stations were set in stratification as a control group for comparison with unstratified designs.Results show that simple random sampling can obtain more stable results than fixed-station sampling in the abundance estimation of P.trituberculatus.In addition,stratified sampling resulted in more accurate abundance than unstratified sampling.The accuracy of the simulated results improved with the increase of the number of stations.No remarkable differences in the results were found among the scenarios of different number of crab pots at each station.However,resource-intensive areas exerted great impacts on simulation results.Thus,prior information or pre-survey results about resource abundance and density distribution are necessary.This study may serve as a reference for future sampling designs of crab pots of P.trituberculatus and other species.
文摘The effects of bark on komatsuna (Japanese spinach) and tomato were investigated by changing the nitrogen content of chemical fertilizers and bark mixing ratio. Mixing 25 and 50% of bark with soil improved komatsuna growth, and also exceeded the growth rates obtained by using chemical fertilizers. However, komatsuna could not grow in 100% bark alone, with excessive amounts of bark majorly inhibiting komatsuna growth. The aeration of bark also did not enhance komatsuna growth. The nitrogen content and bark-mixing ratio had a much lower impact on tomato growth compared to komatsuna. In comparison, aerated bark was more effective in enhancing tomato growth compared to komatsuna growth.
文摘ChoflgqRgls iOURt8R Cty rt th6southwestern China,is fsmous for its peppery hotpot dishes．Spiciness of hot pot fills every cornerof the city,and引Ivisitors to Chongqingaretempted to taste this delicacy．Of all the hot potF6St8UFSRtS tri ChOOgqiDgl th6 bFSRd’Litt旧 SWSR’is th6 iOSt W6II krtOWrt．
