首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
通过对千岛湖网箱养殖区内外水域的四季水质调查,分析得出网箱养殖对千岛湖局部水域会产生明显的影响。造成养殖区水域的DO、pH下降,TN升高,不同季节和不同的水层影响存在差别。冬季对浅层的DO、pH产生明显下降,影响区域小;春季对表层的DO、pH产生明显下降,影响区域大;夏季受水温分层,影响不明显;秋季造成各层水体DO、pH下降,TN上升,影响区域大。千岛湖网箱养殖在春季和秋季对养殖区局部水域影响明显,但分散的网箱养殖对水域影响范围较小,对千岛湖水体短期内影响不明显。  相似文献   

2.
2008年至2011年在丰水期和枯水期对鄱阳湖区都昌县蚌类养殖水体进行调查,探究理化环境参数的变化特征,运用SPSS 16.0进行环境因子与营养盐的相关性分析。结果表明,水温、pH和DO随季节性变化明显,丰水期和枯水期平均水温为29.4℃和8.6℃,pH为7.43和7.22,DO均值为7.11 mg/L和10.84 mg/L,符合国家渔业水质标准;环境因子的年际变化趋势不一,水温升高趋势明显,DO经历缓慢下降的过程,pH有升高的趋势;环境因子之间相关性不明显,营养盐与环境因子相关性中,TP与水温极显著负相关,相关系数最大(r=-0.7102)。  相似文献   

3.
水库运行导致河流水文条件发生改变,对鱼类洄游及其性腺发育产生显著负面影响。为了探究丹江口水库运行对汉江草鱼(Ctenopharyngodon idella)洄游的影响,利用三维水动力模型EFDC模拟水库不同运行情景下的库区和下泄口水动力条件,建立带有外源输入的非线性自回归神经网络(NARX)模型预测下游水动力条件;通过室内试验获取草鱼洄游与水文条件响应关系,并建立草鱼洄游适宜度计算公式,评价丹江口水库上游、库区和下游的洄游适宜性。结果表明,时间上,由于4月水温升温较慢,且流速较低,草鱼洄游状况劣于5-7月;空间上,无论是水库下游还是库区,鱼类洄游状况都劣于未受丹江口水库影响的上游区域。库区极低的流速是影响草鱼上溯的限制因素,而下游降低的流速和水温对草鱼上溯和性腺发育都造成了阻碍。在鱼类洄游期间,降低库区水位、增大下泄量有利于提升库区及下游的流速和水温,改善洄游的外部环境条件。根据已有水库下泄方案(初始水位153 m),如果初始水位降至142 m、下泄增大20%,库区平均洄游适宜度可提高6.5%,下游可提高22.0%。  相似文献   

4.
2008年至2011年丰枯水期对都昌县水域蚌类养殖水体调查取样,通过水化学环境参数的分析得出变化特征,运用SPSS软件做环境因子与营养盐的相关性探究,揭示鄱阳湖区典型蚌类养殖区水化学参数的基本规律。结果显示,水温、pH和DO随季节性变化明显,丰、枯水期平均水温为28.39℃和7.86℃,pH、DO均值分别为7.43、7.22mg/L和7.11、10.84mg/L,符合国家渔业水质标准;环境因子年际间变化趋势不一,水温升高趋势明显,DO经历缓慢下降的过程,pH有升高趋势;环境因子之间相关性不明显,营养盐与环境因子相关性中TP与水温极显著负相关,相关系数最大(r=-0.7102)。  相似文献   

5.
分别于2006年9月、2006年12月、2007年3月和2007年7月调查了分布在江苏省苏州市、浙江省杭州市和绍兴市、湖北省荆州市、江西省九江市的10个三角帆蚌(Hyriopsis cumingii)养殖水体的理化环境。结果表明调查期间上述水体水温为6.5~34.0℃,Ca2+为17.89~66.54 mg/L,总硬度为61.02~217.78 mg CaCO3/L,总碱度为43.30~218.24 mg CaCO3/L,总氮(TN)为0.46~2.78 mg/L,总磷(TP)为0.01~0.35 mg/L,高锰酸盐指数(COD Mn)为4.36~17.98 mg/L。从地点上看:苏州、杭州、绍兴的水体水温和透明度高于九江和荆州的水体,但表层溶氧(DO)、pH和总碱度低于后者;苏州的水体盐度、Ca2+和总硬度高于九江、荆州、杭州和绍兴的水体;杭州、绍兴的水体TN和TP高于九江、荆州和苏州的水体;荆州的水体COD Mn高于杭州、绍兴、九江和苏州的水体。从时间上看:7月和9月水温、TP和COD Mn高于3月和12月,而表层DO、pH、Ca2+、总硬度和TN低于后者;透明度、盐度和总碱度季节变化趋势不明显。所调查的水体DO、COD Mn与水温相关,TN、TP与DO相关,表明DO、COD Mn、TN、TP随水温变化而变化。  相似文献   

6.
为了探究上覆水类型及流速对养殖池塘底泥耗氧速率(SOD)的影响,在实验室进行6组水池平行实验,实验期为2 d,采用6个装置相同的玻璃缸进行对照实验,分别选取自来水和池塘原水作为上覆水体,在实验过程中利用水泵对上覆水进行循环流动,调节水泵循环流量以得到不同的上覆水流速,并采用2台溶氧仪测定不同实验条件下的上覆水水温和DO浓度,记录每次测量的对应时间点,测量间隔约为30 min。结果表明,当上覆水体为自来水和池塘原水时,在不同的循环流速下,SOD的范围为0.042~0.426 g/(m~2·d)。实验第2天各水池的SOD值较第1天均有一定下降,说明SOD随着水体中DO降低也相应减小,表明SOD与DO浓度有显著相关性。当上覆水处于静止状态时,其类型对SOD值有较大的影响,池塘原水在第1天和第2天的SOD值分别为0.426 g/(m~2·d)和0.297 g/(m~2·d),而自来水在第1天和第2天的SOD值均为0.258 g/(m~2·d),与上覆水体为自来水相比,有机物质含量高的池塘原水在第1天和第2天的SOD值分别高出65.12%和15.12%;当上覆水处于流动状态时,池塘原水的SOD为0.042~0.237 g/(m~2·d),自来水的SOD为0.045~0.252 g/(m~2·d),增幅仅为5.9%~15.0%,表明在此条件下上覆水体类型对实验水池的SOD值影响不显著。SOD与上覆水流速存在一定的相关性,对应最小的SOD值有一个流速较低值。  相似文献   

7.
2018年7月12日采样分析江苏省泗阳县9处青虾(Macrobrachium nipponense)养殖中期水体的理化环境、浮游植物种类组成和密度,并比较不同养殖模式对养殖环境的影响。结果显示:青虾养殖水体中,溶氧(DO)8.44 mg/L、pH 7.91~9.26、总氮(TN)1.030~1.571 mg/L、总磷(TP)0.174~0.421 mg/L、高锰酸钾指数(COD_(Mn))4.39~8.16 mg/L,说明青虾养殖水体具有DO和pH较高,N、P及有机质较低的特点。养殖水体内共观察到浮游植物64属/种,以蓝藻和绿藻为主,浮游植物多样性指数较高,群落结构较稳定;浮游植物密度为0.06×10~8~3.06×10~8个/L。RDA分析显示,水温、亚硝酸盐氮(NO_2~--N)和COD_(Mn)是影响青虾养殖水体中优势浮游植物密度的主要环境因子。不同混养种类对青虾养殖水体理化指标和浮游植物具有一定的影响,但管理模式对环境因子的影响更显著。鉴于所调查的青虾养殖水体内pH和Ca~(2+)质量浓度低于青虾生长最适值及TP和COD_(Mn)质量浓度升高会增加蓝藻水华暴发的风险,建议适当施加生石灰来提高养殖水体中的pH和Ca~(2+)质量浓度,并通过建立构建生态沟渠、生态塘等生态工程化设施控制养殖水体中TP和COD_(Mn)的增加。  相似文献   

8.
为了解瓦氏雅罗鱼对盐碱水体的适应性,在吉林西部盐碱水体三王湖中移入瓦氏雅罗鱼(Leuciscus waleckii),通过对其生长、食性和生态位的研究,分析其对三王湖的适应情况,并与吉林东部老龙口水库的瓦氏雅罗鱼野生群体相比较。结果显示,两个水体中瓦氏雅罗鱼的生长均属于非等速生长类型中的正异速增长,肥满度指数没有显著性差异(P≥0.05)。瓦氏雅罗鱼在三王湖处于中等营养生态位,为偏动物食性的杂食性鱼类。三王湖瓦氏雅罗鱼的相对多度与pH值、盐度、电导率、TDS、TN、TP、非离子氨、CODMn、BOD5、碱度和浮游植物密度呈负相关,与DO和浮游动物密度呈正相关,但相关性不显著(P≥0.05)。说明瓦氏雅罗鱼对吉林省西部盐碱水体适应性良好,对水环境的耐受度极高,在适宜的鱼类区系组成情况下能很快形成优势种群。  相似文献   

9.
为研究大型海藻龙须菜(Gracilaria lemaneiformis)规模栽培对水质和浮游植物的影响,于2016年3―6月在南澳深澳湾选择龙须菜栽培区(G)、鱼类养殖区(F)和对照区(C)3个采样区域,每个采样区域3个采样点,进行每月1次的采样调查。对海水温度(WT)、盐度(salinity)、pH、溶氧(DO)、总氮(TN)、总磷(TP)、无机氮(DIN)、无机磷(DIP)、叶绿素a(Chl a)和浮游植物密度进行测试分析。结果表明:(1)在龙须菜栽培期和收获期(3―5月),龙须菜栽培区的pH和DO均显著高于其余区域(P0.05),收获后各区域无显著性差异(P0.05);(2)在龙须菜栽培期(3―4月),栽培区的TN、TP、DIN和DIP含量均显著低于对照区和鱼类养殖区(P0.05);(3)龙须菜栽培期间和收获期(3―5月)栽培区浮游植物密度显著低于其他区域(P0.05),龙须菜收获后(6月),3个采样区域浮游植物的密度大幅上升;(4)2016年南澳海域共收获龙须菜49729 t,据估算,龙须菜规模栽培从海水中移除了2212 t N、174 t P和13300 t C,至少释放了34700tO_2。研究表明,龙须菜规模栽培能有效去除N、P营养盐,防治海洋富营养化;提高栽培区域的pH和DO,有利于防治海洋酸化和低氧问题;降低浮游植物密度,抑制有害藻华的发生。  相似文献   

10.
根据澜沧江下游一级支流补远江2006年鱼类洄游季节3~6月的采样数据,分析了该流域鱼类多样性,并结合同期水文、水质数据,应用人工神经网络分析环境因子与鱼类多样性的关联。结果表明,2006年3~6月共采集补远江鱼类34种,隶属于3目8科22属,其中有8种洄游鱼类。3月份多样性指数最高,各月均匀度指数无差异,4、6月优势度指数高,主要是优势种马口鱼、月斑长臀鲃造成。4、5月鱼类组成相似性最高。最低水位对鱼类数量影响最大,其次是平均流速和平均水温;最高水温对鱼类体重影响最大,其次是总磷和溶解氧。人工神经网络下模拟值与实测值相关性高,具较好的适用性。  相似文献   

11.
Hydroacoustic surveys were conducted to understand the relationship between fish density, spatial distribution, and behavior upstream and downstream of the Changzhou Dam on the Pearl River, China, and the condition (open/closed) of the spillways. When the spillways were open on 24 June 2010, numerous fish were observed to be densely distributed in the forebay upstream of the dam, with an average fish density was 0.22 fish m−3. When the spillways were closed on 25 June 2010, the fish upstream of the dam dispersed, and the average fish density decreased to 0.007 fish m−3. Prior to operating the spillways on 24 May 2010, the average fish density downstream of the dam was 0.28 fish m−3; in comparison, on 26 June, immediately following closure of the spillways, the average fish density downstream of the dam was 0.08 fish m−3. Fish were more active on June 24 than on 25 June: they swam faster and their positions in the water column varied greatly. On 26 June, fish did not to swim as freely in the water column as those measured on 24 May. Based on these observations, we conclude that a large number of fish are able to swim to the upstream side of the dam while the spillways are open.  相似文献   

12.
2009年1月2日—2月10日,沿长江从上往下选取云南水富码头、四川泸州市合江弥陀镇、重庆江津航道处、宜昌葛洲坝下磨基山四个江段进行了6次不同天气下的水下光照度的测量。水富码头、弥陀镇以及江津航道处三个江段的4次测量,无论天气是阴雨天、阴天、大雾还是晴天,其水下照度在水面下0~1.5 m急剧衰减,在1.5 m处衰减率达到99.5%以上,以后光照度随着水深呈缓慢衰减之势,1.5 m以下至江底的照度基本维持在1.2~8.9 lx。而葛洲坝下磨基山江段的水下照度无论是大雾还是晴天,都呈逐步衰减的态势,在20 m的水底光度衰减率才达到99.9%,维持在9~20 lx。根据调查的数据,从鱼类行为生态学研究与野生鱼类驯养、中华鲟保护及四大家鱼等产漂流性卵鱼类的保护三个方面进行了生态学意义探讨。  相似文献   

13.
池塘养殖水体不同水层水质变化研究   总被引:1,自引:0,他引:1  
为探讨池塘养殖水体时间和空间上的变化特征,在上海市标准化养殖池塘里进行了水质参数监测和分析,研究了池塘上层、中层、下层不同水层的水质变化情况。结果表明:一年中池塘水质呈季节性变化,氨氮均值在9—11月最高,在5月份最低;溶氧均值在9—11月最低,在12月至次年3月最高;pH无明显季节性变化。不同水质参数日变化研究发现,一天中氨氮值在6:00左右最高,在17:00左右最低;溶氧最高值出现在15:00—17:00,最低值在5:00左右;pH在1:00最低,14:00左右最高。养鱼池塘水体有较明显的分层现象,上层、中层、下层不同水层的氨氮、溶氧、pH均有差异。一天中氨氮与溶氧总体呈负相关性(t<0.05),溶氧值升高时氨氮值下降。  相似文献   

14.
The increased demand for juvenile tambaqui Colossoma macropomum for grow-out ponds and stocking programs in the Amazon state of Brazil has increased the transportation of this species. This study was designed to determine the optimum density of juvenile tambaqui during transportation in closed containers. Fish (51.9 ± 3.3 g and 14.9 ± 0.4 cm) were packed in sealed plastic bags and transported for 10 h at four densities: 78, 156, 234, and 312 kg/m3. After transportation, fish from each density were kept in separate 500-L tanks for 96 h. Mortality, 96-h cumulative mortality, water quality, and blood parameters (hematocrit, plasma cortisol, and glucose) were monitored. Fish mortality after transportation was significantly lower at densities of 78 and 156 kg/m3 than at 234 and 312 kg/m3. Cumulative mortality was significantly lower at a density of 78 kg/m3. Dissolved oxygen after 10 h of transportation remained high at a density of 78 kg/m3, but reached critically low values at all other densities. Ammonia concentration was highest at the lowest density and was lower at higher densities. Carbon dioxide concentration was lowest at the density of 78 kg/m3 but higher in the other treatments. Plasma glucose and cortisol increased significantly immediately after transportation at densities of 156, 234, and 312 kg/m3, returning to control values by 24 h. The best density for juvenile tambaqui during a 10-h transportation haul in a closed container was 78 kg/m3. At this density there was no fish mortality, water quality was kept within acceptable values, and fish were not stressed.  相似文献   

15.
16.
Concentration of dissolved oxygen (DO) was measured in non-fouling tanks with sea bass and in fouling tanks without fish. The rate of oxygen production and respiration of fouling organisms and the rate of oxygen consumption by sea bass were calculated from the changes of DO. It was possible to approximate diurnal changes of these rates as periodical functions of time. A mathematical model was used to study the effects of fouling, density of fish and water flow on DO during the day (0–24 h). During the sunlight the fouling increases DO in the tank, while during the night it does not affect DO significantly. Water detention time significantly affects the minimum values of DO, and relatively little the maximum ones during the day.  相似文献   

17.
Effects of daily feeding frequency, water temperature, and stocking density on the growth of tiger puffer, Takifugu rubripes, fry were examined to develop effective techniques to produce tiger puffer in a closed recirculation system. Fish of 4, 14, and 180 g in initial body weight were fed commercial pellet diets once to five times a day to apparent satiation each by hand for 8 or 12 wk at 20 C. Daily feeding frequency did not affect the growth of 14‐ and 180‐g‐size fish. However, the daily feed consumption and weight gain of the 4‐g‐size fish fed three and five times daily were significantly higher than those of fish fed once daily (P < 0.05). Fish of 4 and 50 g in initial body weight were reared with the pellet diet at 15–30 C for 8 wk. The weight gain of fish increased with increasing water temperature up to 25 C and decreased drastically at 30 C for both sizes. Similar trends were observed for feed efficiency, although 4‐g fish had highest efficiency at 20 C. Effects of stocking density on growth were examined with fish of 8, 13, and 100 g in initial body weight. Fish were reared with the pellet diet for 8 or 16 wk at 20 C. Fish were placed in floating net cages in the culture tank, and the stocking density was determined based on the total weight of fish and volume of the net cage. Fish of 8 g in body weight grew up to 35–36 g during the 8‐wk rearing period independent of the stocking density of 8, 15, and 31 kg/m3 at the end of rearing. Final biomass per cage reached 32, 60, and 115 kg/m3 for 13‐g‐size fish, and 10, 18, and 35 kg/m3 for 100‐g‐size fish, and the growth of the fish tended to decrease with increasing stocking density for both sizes.  相似文献   

18.
ABSTRACT:   A microscopic bubble generating system (MBGS) has been developed to control dissolved oxygen (DO) levels suitable for fish farming. The MBGS has been tested to confirm its capability in net pens. Water conditions in a fish farm were monitored every two hours from June to October 2004 by setting an online vertical profiling system (OVPS) close to the net pen. DO in the net pen water decreased to physiologically stressful levels for the fish during the night (4.84–5.51 mg/L), while the DO was kept in saturated conditions during the day, due to oxygen supply from phytoplankton. The MBGS was operated from the evening to the morning of the next day for 16 h, to successfully create DO-saturated conditions in the net pen water at night. By using microscopic bubbles during the warm seasons, DO levels in the net pen water could be improved to a level suitable for fish farming. However, the low DO levels (<5.0 mg/L) of the bottom water occasionally extended to the net pen layers, despite the supply of microscopic bubbles to the water. To maintain the DO of the net pen water at levels suitable for fish farming, DO supply to the net pen water and the bottom water needs to be increased, and the organically enriched sediment just below the net pens needs to be treated.  相似文献   

19.
2013年9月15日至2014年2月22日,在自然状态下观察江豚在皖河口活动作为对照组。2014年3月2、11、17、20日购买2龄鲢(Hypophthalmichthys molitrix)等冬片鱼种692 kg,在投食状态下观察江豚在皖河口活动作为试验组。每次在白天整点时刻,采用瞬间扫描法记录10 min内江豚的出水次数和出水位置,作为1个样本。皖河汇流区设置304个网格(50 m×50 m),每头江豚出水1次,在相应网格位置以黑点标注。皖河入口端线中点为圆心,以半径500 m半圆面积为有效观察窗,根据江豚平均游动速度(4.3 km/h),窗内群体之间的时间间隔超过7 min,视为2个独立的群体。结果表明,自然状态下,江豚在皖河口觅食活动主要在支流区和滞留区,9:00、12:00和14:00出现3个活动高峰期;集群规模在1~8头,平均为3.67头。投放活体幼鱼后,江豚在分离区和急流区平均出水次数增多,而滞留区减少;出水次数骤然升高,以后逐渐降低;集群规模在2~10头,均值为5.80头,可见投放鱼饵后江豚集群规模明显增大(P<0.05)。在皖河18次调查的144个样本中,有效观察时间为1400 min,共记录江豚活动87次,累计记录309头(含重复数),分为156个亚群类型,以夫妻型居多(37.10%),家庭型最少(14.67%)。自然状态下,每天观察到江豚约15头,投放鱼苗时观察到约24头,两者差异不明显(P>0.05),但出水平均次数明显增多(P<0.05)。所以在其经常出没的汇流水域投放鱼苗可以减缓施工对江豚捕食的负面影响。  相似文献   

20.
华元渝  陈佩薰 《水产学报》1992,16(4):322-329
长江中游宜昌-城陵矶河段,受葛洲坝枢纽和下荆江系统裁弯工程的影响,水流速增大、河床下切、床面粗化,洲滩渚汊并流,破坏和恶化了白鱀豚赖以生存的生态环境,引起白鱀豚分布区向下游退缩。1986年作者调查时,白鱀豚分布区上限尚在离葛洲坝下50公里处的宜都河段;而1991年已下移至距坝下160公里处的沙市河段。同时,藕池口-城陵矶河段(158公里)内白鱀豚分布密度逐年变稀,已从 1986年时的 3.67公里/头锐减到 1991年的10.36公里/头。白鱀豚种群规模小,虽已被列为国家保护动物,但人类活动仍严重危及该物种的生存。随着人们进一步开发利用长江,新的水利工程还将兴建,亟待来取相应保护对策。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号