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111.
Effects of stocking of piscivorous brown trout, Salmo trutta L., on stunted Arctic charr, Salvelinus alpinus (L.) 总被引:1,自引:0,他引:1
To study the effects on a stunted freshwater population of Arctic charr, Salvelinus alpinus (L.), two groups of large (26–45 cm) individually tagged brown trout, Salmo trutta L., were released and recaptured with gillnets after 1, 7, 11 and 63 weeks. One group of trout was trained on a fish diet before release, and the other, reared on commercial dry pellets, served as a control. Specific growth rates in both groups were negative 1 week after release and approached zero after 63 weeks. Condition factor and internal fat content decreased during the experiment. Although only 11% of the trout stomachs examined contained fish prey, charr represented 79% of the total stomach weight content. Gillnet samples of charr before and 63 weeks after the release of trout indicated a decreasing population size of charr. Individual growth and mean length of charr increased after release of trout, especially for charr at age 4 years. After the release of trout, 35% of the charr were longer than 20 cm as compared with 6% before the release. 相似文献
112.
Creation of artificial upwelling areas for brown trout, Salmo trutta, spawning in still water bodies
Abstract Brown trout, Salmo trutta L., spawning sites were constructed by creating areas of artificial upwelling water, 252 ± 37 mL m−2 min−1 (95% CL), through appropriately sized spawning gravel substrate in 3 m2 vessels buried in the bottom of a 150-m2 pond. Natural spawning occurred in the vessels during autumn 2001–2004, with hatching and alevin swim up the following spring. In areas of upwelling, egg survival was 85–95%, while no live eggs were observed in areas without upwelling. In areas with upwelling, the maximum density of live eggs at the eyed stage was 570–1510 eggs m−2 . In spring 2004 and 2005, the density of alevins was estimated at 322 (±187) m−2 and 567 (±217) m−2 , respectively, in areas with upwelling water, compared with 35.2 ± 25.4 m−2 in areas without upwelling water in 2004. 相似文献
113.
Effects of predation and intraspecific interactions on habitat use and foraging by brown trout in artificial streams 总被引:3,自引:0,他引:3
Abstract— We studied habitat use, foraging rates and behavior of 10 cm and 12 cm long brown trout, Salmo trutta , at two densities, 1.5 and 3.0 fish. m−2 , in artificial streams that contained either the amphipod, Gammarus pulex , alone or G. pulex together with the piscivore, northern pike, Esox lucius. Gammarus were stocked in and largely restricted to the pools at a density of 128 Gammurus. m−2 . pool−1 Large trout (12 cm) used pools more and riffles less when small trout (10 cm) were present than when small trout were absent. Small trout consumed fewer Gammarus when together with large trout than when alone, but showed no difference in habitat use in the presence and abscnce of large trout. Habitat use and number of Gammarus consumed per trout were not affected by trout density for either size-class when alone. For both size-classes of trout, use of pools and foraging rates were higher in the absence than in the presence of pike, and pike primarily resided in the pools. The number of aggressive interactions by both size-classes of trout decreased when pike was present. Our results indicate that for habitats that differ in food resources and predation risk, size structure may affect habitat use and foraging by brown trout. 相似文献
114.
Yoshimasa Sugiura Yoshirou Takeuchi Makoto Kakinuma Hideomi Amano 《Fisheries Science》2006,72(6):1286-1291
ABSTRACT: The effects of 80% methanol extracts from frozen samples of 41 macroalgae and one sea grass collected in the Ise-Shima region of Japan were investigated on histamine release from rat basophile leukemia cells (RBL-2H3) sensitized with antidinitrophenyl (DNP) IgE and stimulated with DNP-BSA. Of the 21 brown algae, five green and 15 red algae, and one sea grass tested, only extracts from seven brown algae suppressed histamine release from RBL cells, as determined by high-performance liquid chromatography (HPLC) analysis. When the cytotoxic effects of the seven brown algal extracts were investigated by Trypan blue staining, only Eisenia arborea and Sargassum thunbergii did not show cytotoxic effects. Therefore, we conclude that E. arborea and S. thunbergii may contain compounds that have antiallergic effects without inducing cell death. 相似文献
115.
Francisco Javier Estay Rodrigo Noriega Jose Pedro Ureta Werner Martín & Nelson Colihueque 《Aquaculture Research》2004,35(5):447-452
Data on reproductive traits in a cultured population of brown trout (Salmo trutta L.) in southern Chile were collected over three consecutive reproductive seasons: 1999, 2000 and 2001, corresponding to the first (at 3 years), second and third spawnings in females. Data were collected from individual females (n=238, 273 and 169 respectively). The reproductive season lasted mainly from June to August. The peak (July) tended to increase with each season (55.46%, 62.27% and 80.81% of total spawning fish respectively). Female body weight (470.8±102.5, 735.0±150 and 1263.9±263.4 g), total fecundity (1182±344, 1904±595 and 2744±605) and egg diameter (4.64±0.11, 4.67±0.27 and 5.24±0.12 mm) increased significantly (P<0.01) over successive reproductive seasons, particularly between the second and third spawnings. Relative fecundity, on the other hand, decreased significantly with each season (3577±471, 2591±900 and 2181±360). Following analysis of the variables over the three seasons, the correlation pattern of female body weight with total fecundity (r=0.91, n=458; P<0.001) and relative fecundity (r=?034, n=451; P<0.001) proved similar to that described in other salmonid females. Fertilization rate and survival to the eyed egg stage were also positively correlated (r=0.73, n=453; P<0.001). The systematically high values obtained for these latter variables over the seasons evaluated (consistently above 90%) are clearly greater than those we registered in other species of salmonids bred in Chile under similar conditions and suggest highly efficient biological variables that determine the gamete fertilization of this species. The brown trout is, therefore, an interesting potential aquaculture resource in Chile. 相似文献
116.
Yukihiro Kitade Michiko Nakamura Hirotoshi Endo Satoru Fukuda Kazuyoshi Kuwano Naotsune Saga 《Fisheries Science》2006,72(3):639-645
ABSTRACT: A cDNA ( PyARP4 ) containing an open reading frame for a protein of 573 amino acids was identified in the marine red alga Porphyra yezoensis . The conceptual PyARP4 protein exhibits significant similarity to actin-related protein (ARP) 4 in the terrestrial plant Arabidopsis . Comparison of the deduced amino acid sequence showed moderate sequence identity (30%) to a conventional actin in P. yezoensis , as seen in comparisons between ARP and conventional actins of other organisms. A putative bipartite nuclear localization signal and an actin motif were found within the PyARP4 amino acid sequence. In a phylogenetic analysis, the PyARP4 was found to cluster with the ARP4 of other organisms. The expression level of PyARP4 did not change significantly among four developmental stages of life cycle and was lower than that of a conventional actin. This cDNA therefore may serve as a useful internal standard in gene expression analyses of differentially expressed genes in P. yezoensis . 相似文献
117.
Laura de Andrade Moura Ana Carolina Marqui de Almeida Thaisa Francielle Souza Domingos Fredy Ortiz-Ramirez Diana Negr?o Cavalcanti Valéria Laneuville Teixeira André Lopes Fuly 《Marine drugs》2014,12(5):2471-2484
Cardiovascular diseases represent a major cause of disability and death worldwide. Therapeutics are available, but they often have unsatisfactory results and may produce side effects. Alternative treatments based on the use of natural products have been extensively investigated, because of their low toxicity and side effects. Marine organisms are prime candidates for such products, as they are sources of numerous and complex substances with ecological and pharmacological effects. In this work, we investigated, through in vitro experiments, the effects of three diterpenes (pachydictyol A, isopachydictyol A and dichotomanol) from the Brazilian marine alga, Dictyota menstrualis, on platelet aggregation and plasma coagulation. Results showed that dichotomanol inhibited ADP- or collagen-induced aggregation of platelet-rich plasma (PRP), but failed to inhibit washed platelets (WP). In contrast, pachydictyol A and isopachydictyol A failed to inhibit the aggregation of PRP, but inhibited WP aggregation induced by collagen or thrombin. These diterpenes also inhibited coagulation analyzed by the prothrombin time and activated partial thromboplastin time and on commercial fibrinogen. Moreover, diterpenes inhibited the catalytic activity of thrombin. Theoretical studies using the Osiris Property Explorer software showed that diterpenes have low theoretical toxicity profiles and a drug-score similar to commercial anticoagulant drugs. In conclusion, these diterpenes are promising candidates for use in anticoagulant therapy, and this study also highlights the biotechnological potential of oceans and the importance of bioprospecting to develop medicines. 相似文献
118.
为研究光照对香菇菌丝后熟转色过程中活性氧代谢的影响,通过设置自然光照条件与黑暗条件下香菇菌丝后熟转色对比试验,分析其活性氧含量、丙二醛(MDA)含量、还原型烟酰胺腺嘌呤二核苷酸磷酸(NADPH)氧化酶活性、抗氧化酶活性及自噬的差异。结果表明,自然光照条件下香菇菌丝正常后熟转色,黑暗条件下香菇菌丝不转色。自然光照条件下香菇菌丝活性氧含量、MDA含量、NADPH氧化酶活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性均显著高于黑暗条件,超氧化物歧化酶(SOD)活性变化则与之相反。同时,香菇菌丝细胞自噬的透射电镜分析及实时荧光定量PCR(qRT-PCR)对自噬基因Atg8的表达水平分析结果表明,在自然光照条件下香菇菌丝细胞的自噬特征明显。本研究结果为优化香菇栽培的环境条件提供了一定的理论依据,也为后续对光照环境下香菇体内氧化平衡的作用机理研究提供了有效参考。 相似文献
119.
120.
[目的]研究烟草赤星病发病规律及防治技术.[方法]比较不同品种、不同施肥量、不同移栽期、不同药剂对赤星病的抗病、发病关系以及防治效果.[结果]中烟103抗性最强,中烟100、K326次之,云烟87、CF205最差.N、P、K比例以1.0∶1.2∶3.0或1.0∶1.5∶3.0为宜,氮肥用量一般施纯氮67.5~90.0 kg/hm2为宜.5月5~20日移栽是最适宜的种植时期.防治赤星病效果最好为40%菌核净可湿性粉剂,防效为53.44%.[结论]为烟草赤星病的防治提供参考. 相似文献