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141.
Nearly 17 years wave records from deep water and shore‐based stations are used to describe the ocean wave characteristics around New Zealand. The wave environment is dominated by west and southwest swell and storm waves generated in the temperate latitude belt of westerly winds. As a result, the west and south coasts are exposed, high energy shores, the east coast is a high energy lee shore, and the northern coast from North Cape to East Cape is a low energy lee shore sheltered from these winds and waves. South of New Zealand, wave energies are extremely high; the prevailing deep water wave is 3.5–4.5 m high and has a 10–12 s period, with a slight increase in wave heights in winter.

The west coast wave environment is mixed, and consists of locally generated westerly and southerly storm waves, and swell waves generated to the south. The prevailing wave is t.0–3.0 m and 6–8 s period. There are no strong seasonal rhythms, only shorter period cycles of wave height (5 day) associated with similar quasi‐rhythmic cycles in the weather.

The east coast also has a mixed wave climate with southerly swells, originating in the westerlies south of New Zealand, and locally generated southerly and northerly storm waves. The prevailing wave is 0.5–2.0 m and 7–11 s period. A short period rhythmic cycle, similar to that on the west coast, is superimposed on a weak seasonal cycle. The seasonal, cycle results from an increase in the frequency of local northerly waves in summer.

The prevailing wave on the north coast is a northeasterly, 0.5–1.5 m high and 5–7 s period. Subtropical disturbances and southward‐moving depressions generate a mixed wave environment and a possible seasonally reflecting a winter increase in. storminess.  相似文献   
142.
音响驯化技术被广泛应用于海洋牧场及淡水水域对鱼类行为的控制,但在采用何种频率和波形声音方面的研究积累尚少。试验室条件下,利用400 Hz矩形波连续音对鲤、草鱼进行了音响驯化试验。结果表明,鲤、草鱼的反应时间和聚集时间均逐日减少。平均反应时间分别为25.4 s和34.6 s,平均聚集时间分别为48.9 s和56.9 s;聚集率则逐日增加.驯化5 d后,鲤、草鱼的聚集率均达到100%,平均聚集率分别为89.7%和94.1%。由此可见.400 Hz矩形波连续音对鲤、草鱼均有明显的驯化作用。  相似文献   
143.
海南岛东海岸海草床生态系统健康评价   总被引:5,自引:2,他引:5  
根据2004~2009年海南岛东海岸长圮港、龙湾、高隆湾、黎安港、新村港等地海草分布区的水质、沉积物、生物质量、栖息地、生物5个指标调查数据,按照《近岸海洋生态健康评价指南》(HY/T087-2005)海草生态系统评价方法,对海南岛东海岸海草床生态系统健康指标进行评价。结果显示,海南岛东海岸海草床水环境与沉积环境均处于健康状态;龙湾海草床生物残毒评价为亚健康,其余站位均处于健康状态;黎安港与长圮港海草床栖息地评价处于不健康状态,其余站位均处于健康状态;黎安港海草床生物评价处于不健康状态,新村港海草床生物评价处于亚健康状态,其他地方栖息地与生物评价均处于健康状态。海草床生态系统健康评价显示,黎安港处于不健康状态,新村港与长圮港处于亚健康状态,龙湾与高隆湾处于健康状态。总体上看,海南岛东海岸分布于珊瑚沿岸海草床生态系统比较健康,分布泻湖沿岸海草床趁于亚健康向不健康方向转变。本文希望通过对海南岛东海岸海草床生态系统的健康评价研究,为海草床生态系统的保护与修复提供理论依据。  相似文献   
144.
为筛选适合添加于草鱼(Ctenopharyngodon idellus)饲料的植物源免疫增强剂,本试验以白芍(Radix paeoniae Alba)、杜仲(Eucommia ulmoides)和知母(Rhizoma anemarrhenae)三种允饲植物配制的复方制剂A、B和C为研究对象,开展其对草鱼非特异性免疫功能的比较研究。试验将二龄草鱼随机分成6个试验组和1个对照组,试验组和对照组按鱼体重量的3%每天分别投喂添加复方制剂的饲料和空白饲料。试验第7、14、21、28天分别采集试验草鱼血液,用于检测血液细胞组分、血清溶菌酶、血清SOD;试验第29天,对各组试验草鱼进行腹腔注射嗜水气单胞菌活菌,记录攻毒后14天内各组草鱼的存活率。结果表明,与对照组相比,试验第14天时,以2%和4%剂量添加的复方制剂A分别显著提高草鱼白细胞吞噬活性128%和143%,分别提高草鱼血清溶菌酶活性69%和85%,分别提高草鱼血清SOD活性61%和55%;连用28天对草鱼的保护率分别达到49%和55%,复方制剂A对草鱼非特异性免疫增强效果优于复方制剂B和C。  相似文献   
145.
定置网具是1种被动过滤性渔具,其渔获效果往往受水流、底质以及季节等因素的影响.为了改进传统的定置网具,本试验参考定置张网、多门网箱簖以及底层鱼诱捕定置网箱等定置网中拦网、八字门的设计参数,结合本次试验条件设计了由拦网、八字门组成的模型网,研究了鲤、草鱼在400 Hz矩形波连续音的刺激下对该模型网的行为反应,探讨了音响驯化技术与定置网具相结合的联合渔法中拦网、八字门的相关参数以及开发新渔具、渔法的可行性.结果表明,鲤、草鱼在声音刺激下能够通过模型网至聚集区内聚集,其平均开始进入拦网时间分别为76.9和89.4 s;平均开始进入八字门时间分别为79.3和71.2 s;平均开始聚集时间分别为120.0和96.0 s;平均聚集时间分别为125.8和87.8 s;平均聚集率为76.5%和84.2%.由此可见,结合音响驯化技术能够提高定置网具的捕捞效率.  相似文献   
146.
Integrating the Red Edge channel in satellite sensors is valuable for plant species discrimination. Sentinel-2 MSI and Rapid Eye are some of the new generation satellite sensors that are characterized by finer spatial and spectral resolution, including the red edge band. The aim of this study was to evaluate the potential of the red edge band of Sentinel-2 and Rapid Eye, for mapping festuca C3 grass using discriminant analysis and maximum likelihood classification algorithms. Spectral bands, vegetation indices and spectral bands plus vegetation indices were analysed. Results show that the integration of the red edge band improved the festuca C3 grass mapping accuracy by 5.95 and 4.76% for Sentinel-2 and Rapid Eye when the red edge bands were included and excluded in the analysis, respectively. The results demonstrate that the use of sensors with strategically positioned red edge bands, could offer information that is critical for the sustainable rangeland management.  相似文献   
147.
陈开宁 《湖泊科学》1996,8(Z1):93-98
通过人工围隔内伊乐藻种植区、无草区和围隔外湖区对照点的水质,底质定期观测,研究了伊乐藻对围栏养鱼环境的影响。结果表明:(1)围栏养鱼残饲和排泄物增加了水中N、P和COD含量,使DO与pH值降低,但伊乐藻对N的净化能力较强,使种植区TN和ION比无草区低14.5%和33.1%;(2)围栏养鱼对底泥的影响,无草区无明显变化,伊乐藻种植区养鱼前期N、P、C含量均低于本底值,养鱼后期有明显的增加趋势;(3)据N、P投入、输出计算,输出和迁移至伊乐藻与鱼体的大于投入的,计算表明,在伊乐藻生长旺季,养鱼与种植面积之比为1:3.58时,不会增加水中N、P含量。(4)养殖水体稀释扩散试验结果,在有草水体中围栏养殖水体对环境影响不大。  相似文献   
148.
草鱼、团头鲂对伊乐藻的消化与利用   总被引:3,自引:2,他引:3  
本文分析了伊乐藻的生化成分和能值,测定了草鱼、团头鲂对伊乐藻生化成分的消化率,草鱼对伊乐藻的最大摄食量、蛋白质利用率和饲料系数。结果表明,伊乐藻含水率为89.8%,干物质中粗蛋白质、粗脂肪、粗纤维素和无氮浸出物含量分别为23.52%、2.88%、26.71%和29.27%,含有17种常见氨基酸,总量为198.04mg/g(干重)。在平均水温20.4℃的室外条件下,草鱼,团头鲂对伊乐藻的干物质消化率分别为56.02%、54.97%,对粗蛋白质消化率分别为79.05%、74.96%,对氨基酸总量的消化率均为77.00%,对粗脂肪消化率分别为73.96%,64.63%,对碳水化合物消化率分别为58.46%、51.36%。在伊乐藻饲养试验中,草鱼每天最大摄食量(Y)与试验鱼体重(X)相关显著,相关系数为0.9154,关系式为Y=3.9449X~(0.8357)。在网箱中饲养草鱼,伊乐藻的粗蛋白质利用率为17.1%,饲料系数为48.2。在小型围栏中饲养草鱼,伊乐藻的粗蛋白质利用率为13.1%,饲料系数为63.4。  相似文献   
149.
满洲里-新巴尔虎右旗地球化学普查找到一批大、中、小型铜-钼-银-铅-锌矿床,区带化探扫面1:5万土壤测量对矿床的发现起到至关重要的作用.文章重点论述:①满洲里~新巴尔虎成矿带——干旱、低山丘陵景观区1:5万区带土壤测量工作方法与技术;②区带与典型矿床地球化学异常特征及找矿效果.  相似文献   
150.
GIMMS(Global Inventory Modeling and Mapping Studies) NDVI(Normalised Difference Vegetation Index) from 1982 to 2006 and MODIS(Moderate Resolution Imaging Spectroradiometer) NDVI from 2001 to 2010 were blended to extract the grass coverage and analyze its spatial pattern. The response of grass coverage to climatic variations at annual and monthly time scales was analyzed. Grass coverage distribution had increased from northwest to southeast across China. During 1982–2010, the mean nationwide grass coverage was 34% but exhibited apparent spatial heterogeneity, being the highest(61.4%) in slope grasslands and the lowest(17.1%) in desert grasslands. There was a slight increase of the grass coverage with a rate of 0.17% per year. Increase in slope grasslands coverage was as high as 0.27% per year, while in the plain grasslands and meadows the grass coverage increase was the lowest(being 0.11% per year and 0.1% per year, respectively). Across China, the grass coverage with extremely significant increase(P0.01) and significant increase(P0.05) accounted for 46.03% and 11% of the total grassland area, respectively, while those with extremely significant and significant decrease accounted for only 4.1% and 3.24%, respectively. At the annual time scale, there are no significant correlations between grass coverage and annual mean temperature and precipitation. However, the grass coverage was somewhat affected by temperature in alpine and sub-alpine grassland, alpine and sub-alpine meadow, slope grassland and meadow, while grass coverage in desert grassland and plain grassland was more affected by precipitation. At the monthly time-scale, there are significant correlations between grass coverage with both temperature and precipitation, indicating that the grass coverage is more affected by seasonal fluctuations of hydrothermal conditions. Additionally, there is one-month time lag-effect between grass coverage and climate factors for each grassland types.  相似文献   
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