草鱼不同养殖模式底泥间隙水与上覆水营养盐的分布特征     

郭永坚  王芳  刘红彩  张振东  董双林  高勤峰  张美昭 《中国海洋大学学报(自然科学版)》2012,(Z2):82-89

于2009年6～10月采集草鱼(Ctenopharyngodon idellus)不同养殖模式围隔底泥的样品,对上覆水和间隙水中营养盐形态与含量进行分析,探讨间隙水和上覆水中营养盐浓度间的相关关系。结果表明:草鱼不同养殖模式围隔大部分间隙水中营养盐浓度要高于上覆水,上覆水与间隙水中PO43--P浓度呈极显著的正相关性(P<0.01)。上覆水和间隙水中的NO2--N和NO3--N浓度垂直分布特征随月变化规律较一致。养殖期间,间隙水溶解态无机氮(DIN)中NH4+-N比例最高,占95%以上。间隙水中NH4+-N浓度随深度增加而逐渐升高(0～10cm),而NO2--N和NO3--N浓度则随深度增加而减小(0～4cm)。表层底泥在0→1cm方向PO43--P浓度明显增加,从2～3cm层后多数养殖模式下浓度缓慢下降,而4→10cm方向上浓度会随深度增加而明显下降。总体而言,三元混养组中(GSL2)上覆水中营养盐的浓度一般要低于GSL1组和GSL3组,且养殖期间该组底层水DO浓度要高于GSL1组和GSL3组,初步认为是一种较为优化的草鱼混养模式。  相似文献   

丁香油和乙醇混合液对福瑞鲤的麻醉效果     

张宁  马庆男  苏胜彦  董在杰  袁新华  朱文斌  刘伟 《广东海洋大学学报》2012,(1):92-96

将丁香油溶与乙醇混合进行对福瑞鲤麻醉,结果表明:丁香油与70%乙醇按1︰1.5得到的混合液与丁香油相比,使用3min时对福瑞鲤具有更好的麻醉效果;混合液的半致死浓度为0.2233mL/L,0.1 mL/L混合液在鱼密度达到1尾/L时的麻醉率最高;将处理过的样品血清进行生化指标检测,丁香油处理样品的CREA比对照显著高,而混合液处理样品所有血清指标与对照差异都不显著。  相似文献   

Some effects of eutrophication and the removal of aquatic plants by grass carp (Ctenopharyngodon idella) on rainbow trout (Salmo gairdnerii) in Lake Parkinson,New Zealand     

D. K. Rowe 《新西兰海洋与淡水研究杂志》2013,47(2):115-127

Temporary removal of aquatic plants in Lake Parkinson, a small, eutrophic dune lake, resulted in a number of changes to the population of stocked rainbow trout (Salmo gairdnerii). During each summer the lake stratified and low oxygen levels limited the distribution of trout to shallow (0–4 m) surface waters. In the first summer following weed removal the numbers of black shags (Phallacrocorax carbo) counted at the lake increased, and their predation resulted in a decline in trout density. However, the growth rate and condition of the trout population then exceeded that of trout present before weed removal. During the second summer after weed removal a cladoceran bloom was followed by low phytoplankton levels and high ammonia concentrations. A prolonged calm compounded this situation with the result that oxygen levels in bottom and surface waters dropped below 2 ppm. These low oxygen levels eliminated the trout population, but other fish species present survived. Elimination of aquatic plants affected the population dynamics of other fish species in the lake with potential implications for the trout. The experiment demonstrated the importance of weed beds in maintaining a stable fish community in lakes such as Lake Parkinson.  相似文献   

Deep scattering layers resolved by narrow‐beam echo sounder along 35°s in the south pacific     

Dale C. Krause 《新西兰海洋与淡水研究杂志》2013,47(2):219-232

The narrow‐beam echo sounder (3.5° half angle, 20 kHz) is capable of resolving the configuration of deep scattering layers to 750 m and was used to study the ecology and population density of organisms that make up the layers. Several layers to 1,000 m depth were identified in the South Pacific Ocean, and the population densities calculated. Swimming speeds of possible predators are estimated at 0.2–0.3 m.sec‐¹. Among organisms calculated to range in length from 0.01 m to 0.07 m, the larger were interpreted as grazing on smaller organisms, after comparing results from two echo sounders of 12 kHz and 20 kHz frequencies respectively.  相似文献   

Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp:Phosphorus dynamics     

《国际泥沙研究》2016,(2):173-180

This is the third paper of the series about “Dynamics of algae growth and nutrients in experimental enclosures culturing bighead carp and common carp”. In this paper, phosphorus dynamics were inves-tigated under the condition of culturing bighead carp and common carp with added fish food (nitrogen dynamics is discussed in the second paper because their behaviors are so different from each other). Nearly fifty days’ observation results indicated that the reservoir water was typical of “phosphorus limited” water, and soluble reactive phosphorus (SRP) was the main constituent of measured total phosphorus (TP). The presence of fish food resulted in significantly higher SRP, dissolved total phos-phorus (DTP) and TP concentrations in contrast with the reservoir water. Moreover, continuous supply of fish food led to the decline of total nitrogen to total phosphorus (TN:TP) from more than 100 to less than 5. Variations in the ratio of TN to TP favored the growth of blue-green algae. Fish species affected phosphorus concentrations, and culturing bait-eating common carp contributed more to reducing the SRP, DTP and TP concentrations than culturing planktivorous bighead carp. 0.5%, 4.1%and 3.1%TP can be removed in enclosures with culturing bighead carp, common carp and mixed bighead carp and common carp, respectively. Abundant phosphorus in the fish culturing activities may be present as the uneaten food, algae cells, and within the water column and sediment, which should be taken into serious con-sideration for the target of future water eutrophication prevention and safety of the drinking water supply.  相似文献   

Fatty Acid Composition of Plankton and Bighead Carp (Aristichthys nobilis) in Freshwater Ponds     

Ganlin Guo  Shuanglin Dong  Wen Zhao  Wei Chen 《洁净——土壤、空气、水》2008,36(2):209-215

The community structure and fatty acid composition of plankton in broodstock ponds were studied at the Bishui Fisheries Company in the Liaoning Province, northeast China, between May and December 2002 and in March 2003. The Fatty acid analysis of bighead carp larvae and plankton in the fry pond occurred during June, July, and September 2002. The fatty acid composition of the plankton varied with seasonal changes in the community structure. When blue‐green algae dominated the broodstock ponds in spring and summer, the percentage of saturated fatty acids (SFA) (especially 16:0) was high. When diatoms and cryptophytes dominated in autumn and winter, the percentage of polyunsaturated fatty acids (PUFAs) (mainly n–3 PUFA) was high. Similarly, a high content of docosahexaenoic acid (DHA) occurred in autumn and winter when DHA‐rich copepods became an important group of zooplankton. In addition, environmental factors, especially water temperature, influenced the fatty acid composition of plankton. 16:0, DHA, and 18:1n–9 were dominant fatty acids of bighead carp larvae during ontogeny. 16:0, C18 unsaturated fatty acids, and eicosapentaenoic acid (EPA) were major fatty acids of plankton in the fry pond. Analysis of the relationship between the fatty acids of the larvae and those of plankton showed that the fatty acid profiles of the larvae did not always agree with those of plankton.  相似文献   

鲢鱼幼鱼对盐、碱耐受性的研究     

章征忠  张兆琪  董双林 《中国海洋大学学报(自然科学版)》1999,(3)

利用盐碱地区氯化物型地下水进行了鲢鱼幼鱼（Ｌ＝５．４～８．２ｃｍ）对盐度（ｐＨ＝８．６０±０．１８）、碱度（ｐＨ＝８．７４±０．３４）及盐碱混合的急性毒性试验。研究结果表明：鲢鱼幼鱼对盐度的２４、４８、７２和９６ｈ的半致死浓度（ＬＣ５０）分别为：１１．２,９．０,８．６和８．２ｇ·Ｌ－１;对碱度的相应ＬＣ５０值分别为５１．４、２７．１、２３．７和１５．７ｍｍｏｌ·Ｌ－１。盐碱混合的正交试验表明盐度和碱度在致毒过程中作用显著;２４ｈＬＣ５０碱度（Ａｌｋ,ｍｍｏｌ·Ｌ－１）及盐度（Ｓ,ｇ·Ｌ－１）的关系为：Ａｌｋ＝３４．１７－１．７８Ｓ。  相似文献