游离氨基酸对褐鳟和金鳟精子活力的影响     

程琳  徐革锋  黄天晴  谷伟  史秀兰  刘晨斌  王炳谦 《东北农业大学学报》2019,50(10)

为探究体外储存条件下游离氨基酸(FAA)对鳟鱼精子活力的影响,分析褐鳟(Salmo trutta)和金鳟(Oncorhynchus mykiss)精液中FAA组成,通过向人工精液保存液(ASP)中添加不同种类氨基酸孵育褐鳟和金鳟精子,孵育1、24、48、72和96 h后,研究FAA对精子活力的影响(定义为孵育后可激活活力)。结果表明,褐鳟精浆FAA主要为缬氨酸、亮氨酸、精氨酸、异亮氨酸、赖氨酸、丝氨酸及甲硫氨酸,其精子FAA主要为天冬氨酸、精氨酸、谷氨酸及丝氨酸。金鳟精浆和精子中主要FAA为精氨酸。当精子与精浆孵育48 h后,两种鱼的氨基酸含量与组成模式均发生变化,发生新陈代谢。丝氨酸、异亮氨酸及甲硫氨酸+异亮氨酸对两种鱼的精子活力有积极影响,在一定时间内能够通过添加可FAA延续精子活力,解决鳟鱼雌雄成熟不同步问题,提高受精效果,对鳟鱼苗种繁育及养殖具有重要意义。  相似文献   

Fecundity and water flow influence the dynamics of Atlantic salmon          下载免费PDF全文

Bror Jonsson  Nina Jonsson 《Ecology of Freshwater Fish》2017,26(3):497-502

Populations are retained at reduced levels by resource competition and environmental stochasticity. In the Norwegian River Imsa, the relationship between fecundity of Atlantic salmon (Salmo salar) spawners and number of smolts per unit river area was investigated for cohorts spawned from 1976 to 2011. Annual number of smolts produced per unit area was best described by a multiplicative model and increased with the fecundity of the females as proxy for number of eggs deposited and the minimum water flow in August towards the end of the first growth season. Mean monthly water temperature, or water flow in any other month during the first year, had no significant effect on number of smolts produced. At sea, there was an almost linear relationship between number of emigrating smolts and returning adults, possibly because population abundance of Atlantic salmon is low relative to the carrying capacity in the ocean. Thus, both number of eggs spawned and minimum water flow in late summer influenced population abundance in the present river.  相似文献   

Factors influencing the success of salmonid egg development in river substratum     

Katharina Sternecker  David E. Cowley  Juergen Geist 《Ecology of Freshwater Fish》2013,22(2):322-333

Interstitial water conditions in the hyporheic zone of the stream bed are determinants of salmonid egg hatching success. We used standardised egg exposures to develop and validate discriminant analysis and generalised linear model models linking the hatching success of brown trout (Salmo trutta) with physicochemical factors of the interstitial zone (e.g., oxygen, specific conductance, nitrate, nitrite, ammonium, pH and redox potential). Interstitial water quality was identified as a limiting factor for egg development (median of relative hatching rates = 0.23). Hatching success was unimodal in hatchery and field references incubated in free‐flowing water, but bimodal (very high or very low hatching success) in natural sediment exposures. The effects of physicochemical factors on the hatching success of Salmo trutta strongly depended on both the time and spatial scale analysed. The variables retained in the models differed between the macroscale (over all rivers), the river‐specific scale (within a river) and the microscale (at different sediment depths). Egg hatching success decreased with increased substratum depth (decrease of 26% in 150 mm compared with 50 mm). Increasingly more variable interstitial water conditions (e.g., oxygen) throughout the egg incubation period suggest progressive degradation rates in the stream substratum during the incubation period at the microscale level. Consequently, consideration of different spatial and temporal scales is necessary for the evaluation of habitat quality in salmonid conservation and catchment management plans.  相似文献   

Foreign brown trout in protected landscapes as a consequence of connectivity     

J. L. HORREO  E. GARCIA‐VAZQUEZ 《Fisheries Management and Ecology》2011,18(5):431-436

Abstract To preserve the local genetic patrimony of wild aquatic species, population enhancement should be limited to supportive breeding of native lineages and controlled releases in target areas with depleted population size. This is the case of brown trout, Salmo trutta L., in northern Iberia, a species of high economic and cultural value in the region. Employing a combination of conserved and hypervariable genetic markers, illegal stocking of domestic brown trout in protected areas (National Park, Natural Reserve) within the Cantabric chain was detected. The most likely origin of the domestic individuals was determined by assignment tests to hatchery stocks as a result of past releases conducted downstream and out of the protected areas. Where connectivity exists along a water course, the entire drainage should be considered as a single management unit to preserve the native genetic diversity of upstream protected areas.  相似文献   

Genetic basis of phenotypic differences between transplanted stocks of brown trout     

S. Palm  N. Ryman 《Ecology of Freshwater Fish》1999,8(3):169-180

Abstract– We present results from an experiment testing for the existence of genetically based phenotypic differences among populations of brown trout ( Salmo trutta L.) born and raised under entirely natural environmental conditions. Genetically tagged individuals from two stocks (A and B) were introduced into a drainage system in Sweden previously void of brown trout, and the first generation (F₁) progeny were sampled from two lakes during nine consecutive years. Phenotypic differences among groups of progeny (A, B, and the AB hybrid) are expected to reflect genetically determined dissimilarities between the introduced stocks. Phenotypic differences among progeny groups were observed for age at maturity and for migratory and reproductive behavior, and these characters are apparently determined by genetic factors to an extent that permit their detection even in the presence of confounding and naturally occurring sources of variation such as lake, age, cohort and year of sampling. There was also significant variation among offspring groups with respect to body size (length), but only a small proportion of the total variation in size could be attributed to stock differences. These genetically based stock characteristics may represent local adaptations, and the fishery management implications of these findings are discussed.  相似文献   

Comparison of food availability and performances of first-feeding alevins through spring with the occurrence of a flood     

Elorri Arevalo  Aitor Larrañaga  Agnès Bardonnet 《Ecology of Freshwater Fish》2020,29(4):693-704

Climate change will increase the temperature of rivers and will lead to more extreme events, such as floods. Temperature increases and floods will likely alter the phenology of freshwater species differently and have the potential to significantly disturb prey–predator interactions. In spring, an increase in temperature triggers an increase in primary production and controls the timing of the emergence in brown trout (Salmo trutta L.). Hydrology regulates the abundance of invertebrates, which are the main food source for newborn alevins. As such, climate change may desynchronise the relationship between fish emergence and invertebrate production, resulting in a negative impact on the performance of newly emerged alevins. In the present study, we quantified the abundance of invertebrates and the performance (survival and growth) of newborn alevins in early spring (March) compared to late spring (April/May) in 8 enclosures in a semi-natural channel. In addition, we simulated a flood in 4 enclosures in late spring. Our results revealed that survival and growth of alevins in early spring were limited due to low invertebrate abundance. In late spring, there was a decrease in the survival of alevins placed in the flooded enclosures, likely due to the reduction of food availability. However, the growth of survivors increased, probably because of the increase in the abundance of Chironomidae after the flood and a reduced competition between congeners. Our results demonstrate that when emergence and flooding happen simultaneously, they can limit resources which will impact the survival and growth of young salmonids in running waters.  相似文献   

Swimming performance of brown trout and grayling show species‐specific responses to changes in temperature     

Annette Taugbl  Kjetil Olstad  Kim Magnus Brum  Jon Museth 《Ecology of Freshwater Fish》2019,28(2):241-246

Fishways have historically been constructed to restore and preserve the ecological connectivity for fish in fragmented rivers. However, the fishways are often selective on species due to different size and swimming capacity. As the proportion of dammed rivers is still increasing, there is a growing need for more information on wild fish and their migration potential. In this study, we compared the swimming capacity of wild caught brown trout (Salmo trutta) and European grayling (Thymallus thymallus) until the fish were exhausted in a critical swimming speed (U_crit) test, under three different naturally occurring stream temperatures in Norway: 1.7, 5.5 and 10°C. The results indicated that trout swim better at the warmer temperatures than at colder temperatures. The grayling showed consistent swimming patterns with little variation across all tested temperatures. The results therefore signify the need to have operational fishways already early in the spring when the grayling migration starts and highlight the need for more studies on fish migration abilities across a wider range of species and seasons.  相似文献   

The effects of ration size on migration by hatchery‐raised Atlantic salmon (Salmo salar) and brown trout (Salmo trutta)     

Linnea Lans  Larry A. Greenberg  Jens Karlsson  Olle Calles  Monika Schmitz  Eva Bergman 《Ecology of Freshwater Fish》2011,20(4):548-557

Abstract – The possibility to increase the proportion of migrating hatchery‐reared smolts by reducing their food ration was studied. Lake‐migrating, hatchery‐reared salmon (Salmo salar) and trout (Salmo trutta) smolts were either fed normal rations, based on recommendations from the fish‐farming industry, or reduced (15–20%) rations. They were released into the River Klarälven, western Sweden, and followed as they swam downstream to Lake Vänern, a distance of around 25 km. For both Atlantic salmon and brown trout, smolts fed a reduced ration migrated faster than fish fed a normal ration. Furthermore, a higher proportion of salmon smolts fed reduced rations migrated to the lake than fish fed normal rations in 2007 but not in 2006. This difference between years corresponded to greater treatment differences in size and smolt status in 2007 than in 2006. For trout, the proportion of migrating individuals and smolt development did not differ with ration size. Trout migrants fed a normal ration had a higher standard metabolic rate (SMR) than nonmigrants, whereas there was no difference in SMR between migrating and nonmigrating salmon. These results show that it is possible to use a reduced food ration to increase the migration speed of both Atlantic salmon and brown trout and to increase the proportion of migrating Atlantic salmon.  相似文献   

β-葡聚糖对亚东鲑幼鱼存活及生长的影响     

王万良  牟振波  周建设  王且鲁  陈美群  张驰 《水产科学》2021,(2):273-278

在水温13~14 ℃下,将平均体质量(1.07±0.3) g的亚东鲑幼鱼养在100 cm×100 cm×60 cm圆形玻璃缸循环水系统中,密度为159尾/m^( 3) ,水深约40 cm,投喂添加0%、0.1%、0.2%、0.5%、 1.0% 、1.5%和2.0%β-葡聚糖的饲料饲养60 d,研究β-葡聚糖对亚东鲑幼鱼存活及生长的影响。试验结果显示,不同含量β-葡聚糖对亚东鲑幼鱼存活率差异不显著,均为100%;平均质量增长率0.5%试验组最大,显著高于其他各组( P <0.05),平均体长增长率0.5%试验组最大,与0.2%、0.5%、1.5%试验组之间差异不显著,显著高于其他各组( P <0.05),0%试验组平均体长增长率最小;特定生长率0.5%试验组最高,显著高于其他各组( P <0.05),0%试验组最低;肝体指数依次递减,0%试验组最大,与 0.1% 、 0.2% 和0.5%试验组之间差异不显著,但显著高于其他各组( P <0.05);肥满度0.1%、0.2%、 0.5% 、 1.0% 试验组之间差异不显著,显著高于其他各组( P <0.05),0%试验组最小;摄食率0.1%试验组最高,随着β-葡聚糖添加量增加依次递减,但各试验组之间差异不显著;食物转化率0.5%试验组最高,与1.0%、 1.5% 、2.0%之间差异不显著,显著高于其他各组( P <0.05),0%试验组最低。肠道脂肪酶、胰蛋白酶和淀粉酶活性均随β-葡聚糖含量增加呈先增后减变化趋势,说明β-葡聚糖能够提升肠道消化酶活性。综上所述,饲料中添加0.5%β-葡聚糖对亚东鲑存活与生长效果较好。  相似文献   

Evaluation of sodium percarbonate as a bath treatment for amoebic gill disease in Atlantic salmon     

Richard S. Taylor  Joel Slinger  Paula Camargo Lima  Chloe J. English  Ben T. Maynard  Francisca Samsing  Russell McCulloch  Petra R. Quezada‐Rodriguez  James W. Wynne 《Aquaculture Research》2021,52(1):117-129

Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a major health challenge for Atlantic salmon aquaculture globally. While freshwater bathing for 2 hr is effective in reducing infection severity, there is need for more rapid and lower cost alternatives. To this end, a combination of sodium percarbonate (SPC) in freshwater was examined for its treatment efficacy. Initial in vitro studies showed a reduction in amoeba viability when exposed for 30 min to freshwater containing >500 mg/L SPC. Subsequently, AGD‐affected salmon were bathed for 30 min in 16°C freshwater containing 100, 500 or 1,000 mg/L SPC, or for 2 hr in 16°C freshwater to mimic industry practice. Treatment at the highest SPC concentration caused extensive gill damage and substantial mortality. Neither occurred to a significant extent at lower SPC concentrations. Gill pathology of surviving fish 10 days post‐treatment (dpt) was comparable to or more severe than pre‐treatment, and significantly (p < .001) more severe than in 2 hr freshwater bathed fish. N. perurans DNA was confirmed by qPCR in all treatment groups at 10 dpt. The data indicate that a 30‐min exposure to SPC in freshwater is not a suitable alternative to existing freshwater treatment of AGD.  相似文献