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QIN Chuanxin DONG Shuanglin TAN Fuyi TIAN Xiangli WANG Fang DONG Yunwei GAO Qinfeng 《青岛海洋大学学报(英文版)》2009,(3):296-302
Optimal stocking densities were investigated for the sea cucumber Apostichopusjaponicus Selenka under feed-supplement and non-feed-supplement regimes in net enclosures for 333 d. Substantial weight loss occurred during the aestivation phase （AE）. Decreased growth rates were also observed during the winter phase （WT）. In contrast, sea cucumbers showed rapid growth during the spring （SP） and autumn （AU） phases. Feeding regimes considerably influenced the growtb performance, i.e., sea cucumbers grew faster under feed-supplement regime than under non-feed-supplement regime （P 〈 0.05）. The average survival rates of sea cucumbers under feed-supplement regime were higher than those under non-feed-supplement regime for both the autumn phase and spring phase, but the differences were only significant for the latter phase （P〈 0.05）. The fitted B-N curves showed that the optimal stocking densities, in terms of net production, were 22.3 ind. m^-2 for feed-supplement regime and 14.1 ind. m^-2 for non-feed-supplement regime. 相似文献
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基于县域单元的陕西苹果越冬冻害风险分布 总被引：2，自引：1，他引：1
为了有效利用气候资源、趋利避害、合理规划和发展陕西苹果产业,促进县域苹果种植布局优化,实现健康、可持续生产,依据3个苹果种植代表县县站与其境内区域站越冬期气温的关系,进行概率移植,借助各代表县县站1971—2011年越冬期气温数据,计算获得各代表县县站及其境内区域站苹果不同等级越冬期冻害的发生概率。根据对30多个苹果越冬冻害历史个例的分析结果,分别赋予苹果越冬期轻度、中度、重度等级冻害0.3、0.5和0.7的灾损系数。依据气候致灾风险的基本原理和模型,计算获得各代表县县站及其境内区域站的越冬期冻害风险指数,并基于GIS系统制作了各代表县的降尺度苹果越冬期冻害风险分布图。 相似文献
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陕西苹果干旱指数研究及基于县域单元的苹果干旱风险分布 总被引：2，自引：0，他引：2
为了有效利用气候资源,趋利避害,合理规划和发展陕西苹果产业,促进县域苹果种植布局优化和健康、可持续生产,结合陕西省苹果种植区地理、气候的实际特征,计算和分析了代表不同气候类型的4个代表县的苹果各生育期的干旱指数;并对4个代表县进行了分生育期的苹果干旱风险分布分析。结果显示:萌芽—幼果期是陕西苹果全生育期旱情最重时段,其次是果实膨大期和着色—成熟期,再次是越冬期;延安果区苹果全生育期的旱情在整个陕西果区最为严重,其次是渭北东部果区,再次是渭北西部果区,关中果区苹果全生育期旱情相对最轻。研究成果可为陕西苹果不同生育期、不同果区的防旱抗灾工作开展和县域单元内苹果产业防灾减灾决策提供参考。 相似文献
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Three color variants of the sea cucumber,Apostichopus japonicus are recognized,the red one is highly valued in the market. When the red variant is cultured in ponds in China,its body color changes from red to celadon in 3–6 months. The effects of water depth and substrate color on the growth and body color of this animal were investigated. Juveniles of red A. japonicus were cultured in cages suspended at a range of water depths(20,50,100,150 and 200 cm). The specific growth rate of red sea cucumbers was significantly higher in animals cultured at deeper water layers compared with those grown at shallowers. Body weights were greatest for sea cucumbers cultured at a depth of 150 cm and their survival rates were highest at a depth of 200 cm. A scale to evaluate the color of red sea cucumbers(R value) was developed using a Pantone standard color card. All stocked animals in the 9-month trial retained a red color,however the red body color was much more intense in sea cucumbers cultured at shallower depths,while animals suspended in deeper layers became pale. In a separate trial,A. japonicus were cultured in suspended cages with seven different colored substrates. Substrate color had a significant effect on the growth and body-color of red A. japonicus. The yield were greatest for A. japonicus cultured on a yellow substrate,followed by green white orange red black and blue. All sea cucumbers in the 7-month trial retained a red color,although the red was most intense(highest R value) in animals cultured on a blue substrate and pale(lowest R value) for animals cultured on a green substrate. 相似文献
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以陕西苹果花期为研究对象,针对4个机理性物候模型——顺序模型（SM）、平行模型（PM）、深度休息模型（DRM）和热时模型（TTM）,基于各果区代表站的花期数据及同期气象数据订正模型参数,利用内部检验和交叉验证（留一验证）方法,评价模型在模拟花期上的适用性。结果表明:内部检验时各站点的最适模型不同,总体上,SM和TTM均方根误差略低（3.30 d）;交叉验证时模型表现相当,各模型平均的均方根误差为4.52 d,略优于内部检验。使用单站外推和求平均后外推将TTM参数应用至果区内其他站,这两种方法的均方根误差均优于国外同类研究（10.0 d）,其中单站外推的均方根误差（5.90 d）又高于求平均后外推（7.21 d）。综合考虑模型的复杂性与模拟精度,推荐使用TTM并分果区模拟陕西苹果花期。 相似文献
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The present study was conducted to determine the change of digestive physiology in sea cucumber Apostichopus japonicus(Selenka) induced by corn kernels meal and soybean meal in diets. Four experimental diets were tested, in which Sargassum thunbergii was proportionally replaced by the mixture of corn kernels meal and soybean meal. The growth performance, body composition and intestinal digestive enzyme activities in A. japonicus fed these 4 diets were examined. Results showed that the sea cucumber exhibited the maximum growth rate when 20% of S. thunbergii in the diet was replaced by corn kernels meal and soybean meal, while 40% of S. thunbergii in the diet can be replaced by the mixture of corn kernels meal and soybean meal without adversely affecting growth performance of A. japonicus. The activities of intestinal trypsin and amylase in A. japonicus can be significantly altered by corn kernels meal and soybean meal in diets. Trypsin activity in the intestine of A. japonicus significantly increased in the treatment groups compared to the control, suggesting that the supplement of corn kernels meal and soybean meal in the diets might increase the intestinal trypsin activity of A. japonicus. However, amylase activity in the intestine of A. japonicus remarkably decreased with the increasing replacement level of S. thunbergii by the mixture of corn kernels meal and soybean meal, suggesting that supplement of corn kernels meal and soybean meal in the diets might decrease the intestinal amylase activity of A. japonicus. 相似文献
17.
Zhongming Zheng Shuanglin Dong Xiangli Tian Fang Wang Qinfeng Gao Peifeng Bai 《洁净——土壤、空气、水》2009,37(3):218-224
Sediment samples were collected from three seawater aquaculture ponds, and soil characteristics, sediment oxygen consumption (SOC), dissolved organic carbon (DOC) and nutrient fluxes were measured using chamber incubations at laboratory. The three ponds were each representing a specific monoculture or polyculture model of sea cucumber. Total organic carbon (TOC) and total nitrogen (TN) contents in the dry sediment ranged from 0.14 to 0.26% and 0.022 to 0.037%, respectively. Total phosphorus (TP) contents in the sediment were more spatially and temporally variable. SOC ranged from 15.29 to 45.86 mmol m–2 d–1 and showed significant differences among the three ponds (p < 0.05). TOC, total carbon (TC) contents, and SOC of the sediment in the pond polycultured with jellyfish increased with culture time, indicating that jellyfish farming enhanced the accumulation of organic matter in the sediments to some extent. Sediment showed net nitrate and ammonium uptake in most ponds and months, and significant differences were found among months (p < 0.05). Dissolved inorganic phosphate (DIP) was released from the sediments in all ponds with low flux rates. DOC was released from the sediment in all ponds and ranged from 0.67 to 1.74 g DOC m–2 d–1. The results suggested that non‐artificial‐feeding sea cucumber culture ponds could not only yield valuable seafood products, but also effectively remove nutrients from the aquaculture systems and consequently alleviate nutrient loadings of the nearby coast. 相似文献
18.
利用上下解构造辅助方程,结合Leray-Schauder度理论研究二阶p-Laplacian方程多点边值问题正解的存在性,并用单调迭代技巧与拟线性化方法讨论了正解迭代序列的收敛性. 相似文献
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Using net enclosures in an earthen pond, we established three culture treatments with the sea cucumber Apostichopus japonicus and the Chinese white shrimp Fenneropenaeus chinensis: monoculture of sea cucumbers (C), monoculture of shrimp (S), and co-culture of the two species (CS). We measured levels of suspended particulate matter in the water column; total organic matter, total organic carbon, total nitrogen, and carbon/nitrogen ratios in both settling particles and the sediment; and chlorophyll a levels in the sediment. We then compared these variables between the three treatments. We also examined growth, survival, and yield of the two species in the different treatments. From June to September, the mean monthly suspended particulate matter sedimentation rates in the CS and S treatments were significantly (P<0.05) greater than those in the C treatment. From August to November, the mean monthly total organic matter, total organic carbon, total nitrogen, and chlorophyll a contents in the sediment in the CS and S treatments were significantly ( P <0.05) greater than those in the C treatment. Final wet weight, specific growth rate, survival rate, and total yield of sea cucumbers in co-culture were all significantly greater than those of sea cucumbers in monoculture. There were no significant differences among any of these variables for shrimp reared in the two systems. The bioturbation of the sediment and fecal production of the shrimp likely supplied natural food for the sea cucumbers. Co-culture of the two species is a viable option for increasing yield per unit area, maximizing use of the water body, and diversifying crop production. 相似文献