Spawning salmon increase brook trout movements in a Lake Michigan tributary

Abstract – Salmon and trout have been introduced to many ecosystems worldwide, yet the ecological impacts of salmonid introductions remain poorly understood. We investigated the effects of introduced Pacific salmon on stream‐resident fish in the Great Lakes basin by monitoring the movements of passive integrative transponder (PIT)‐tagged brook trout in a Lake Michigan tributary receiving a salmon spawning run and in a nearby stream not receiving salmon. Coincident with the September arrival of salmon, an estimated 52% of resident brook trout moved >200 m, while no such movements were detected in the nonsalmon stream. After 3–4 days, however, brook trout movement patterns became similar in the two streams, suggesting that salmon effects on brook trout movements were short‐lived. Movements in the salmon stream were predominantly upstream in direction, with 50% of the tagged brook trout travelling from below to above the stationary PIT tag readers during the study. Declining water temperatures with the onset of fall coincided with low levels of brook trout movement at both sites, likely due to relocation for spawning. Increased brook trout movements coincident with the arrival of salmon spawners could be driven by a combination of interference competition and egg consumption. Using a bioenergetics model, we estimated that the energy lost to movement was likely compensated by the energy obtained from consuming salmon eggs. We conclude that salmon spawners can substantially increase brook trout movement, but in our study, these effects were short‐lived and likely negligible from a bioenergetics perspective.     

Comparisons of growth and condition of fluvial and resident brook trout within partially migratory populations

Abstract  In partially migratory salmonid populations, growth and condition of migratory fish may be different than that of residents. To ascertain if a similar phenomenon exists in fluvial brook trout, Salvelinus fontinalis (Mitchell), populations, the growth and condition of fluvial and resident brook trout was measured in four Appalachian stream networks. Sites were sampled during summer, cohorts separated via scale analysis and differences in length and condition were investigated. Age-1 and -2 fluvial fish were significantly longer ( P  <   0.001) than residents of the same cohort. Additionally, age-2 fluvial fish had significantly greater condition ( P  <   0.005) than resident fish of the same cohort. This suggests that the use of spatially segregated resources can result in growth and condition advantages. However, potentially greater rates of mortality as suggested by low abundance in main stem sites may limit the fitness advantages of this energetically profitable, but ultimately risky, behaviour.     

Divergence of Salvelinus species from northeastern Asia based on mitochondrial DNA

Abstract –  Phylogenetic analysis of charrs of the genus Salvelinus was performed using PCR-RFLP analysis of mitochondrial DNA (mtDNA). Three fragments of mtDNA (ND1/ND2, ND5/ND6 and Cyt b /D-loop) were amplified by PCR and examined for restriction site variation using 13 restriction endonucleases. Analysis of 313 sites of over 7672 bp of charr mtDNA was conducted. Six phylogenetic lineages of the mtDNA were revealed, corresponding to six separate charr taxa: Salvelinus leucomaenis Pallas; Salvelinus levanidovi Chereshnev, Skopetz & Gudkov; Salvelinus taranetzi Kaganovsky; Salvelinus malma krascheninnikovi Taranetz; Salvelinus malma malma Walbaum and Salvelinus alpinus alpinus . The Levanidov ( S. levanidovi ) and white-spotted ( S. leucomaenis ) charrs represented the most divergent lineages. These are probably closest to a common ancestor of the genus. Salvelinus taranetzi was the next divergent lineage. Salvelinus malma krascheninnikovi was placed between S. leucomaenis and S. taranetzi . Salvelinus malma malma and S. a. alpinus were sister taxa, and were on the last branch to diverge. The divergence between S. m. malma and S. a. alpinus inferred from mtDNA nucleotide sequences was 1.1%; between S. m. malma and S. taranetzi 2.8%; between S. m. malma and S. m. krascheninnikovi 4%; between S. taranetzi , S. m. krascheninnikovi and S. a. alpinus 2.8%. Salvelinus levanidovi and S. leucomaenis were almost equally remote from the other charrs by some 9% and 7%, respectively. The extent of genetic differences between the northern S. m. malma populations and the European S. a. alpinus populations indicates that they diverged recently. The existence of many putative charr species with different divergence times in northeastern Asia suggests that this region may be one of the centres of speciation of the genus Salvelinus .     

Pharmacokinetics of Ivermectin in Salvelinus leucomaenis Following Two Ways of Administration

[目的]研究伊维菌素在白点鲑体内的药动学。[方法]对白点鲑以0．3mg／kg的剂量分别单次口灌和腹腔注射伊维菌素,采用高效液相色谱-紫外检测法（HPLC—UV）于给药后不同时间点连续进行采样检测,通过3p97软件分析药动学参数。[结果]在2种给药方式下,伊维菌素在血浆、肌肉、肝和肾中的药时关系均符合一级吸收一室开放模型。口灌给药方式下,血浆中药动学参数为Tmax=4．503h、Cmax=0．252mg／L、t1/2ka=0．476h、t1/2ka=331．160h、AUC=121．524（mrdL）·h;腹腔注射给药方式下,血浆中药动学参数为Tmax=2．751h、Cmax=0．230mg／L、t1/2ka=0．306h、t1/2ka=153．868h、AUC=51．689（mg／L）·h。[结论]两种给药方式下伊维菌素在白点鲑体内的药动学存在差异,腹腔注射给药比口灌给药吸收快。     

Offspring or ornaments? Is carotenoid‐based ornamentation in female Arctic charr,Salvelinus alpinus (L.), condition‐dependent and traded off against offspring?

Abstract –  In several carotenoids-based ornamented species, females invest carotenoids also into their gametes to increase the quality of the rapidly growing zygote. The extra carotenoids demand may cause females to trade-off valuable carotenoids between ornament and eggs. This may be one reason why females are less showy ornamented than males. In our study-population of Arctic charr, individuals of both sexes vary in degree of conspicuousness of their red abdomen and fins. None of the two carotenoids-based ornaments was significantly associated with either (i) the amount of carotenoids in the egg, although being negative and close to significance, or (ii) potential condition-dependent parameters like relative density of leucocytes, condition-factor and parasitism. This study does not support the 'direct selection hypothesis' to explain the existence of female ornaments, and gives equivocal support for the hypothesis of asymmetrical investment of carotenoids into gametes to explain the less showy ornaments in females when compared with males.     

高地省藤种苗培育的影响因子研究

采用正交试验设计法研究了种植密度、复合肥、N肥、透光率对1年生高地省藤苗木生长的影响。结果显示,4种因素对苗木生长均有极显著影响,其中种植密度是最关键因素,其次为复合肥,影响因素最小的为透光率;筛选出的最佳处理组合为植株密度15 cm×15 cm、透光率50%、不施N肥和复合肥时藤苗生长效果最佳。     

野生与养殖花羔红点鲑肌肉营养成分的比较分析

分别对野生与养殖花羔红点鲑Salvelinus malma肌肉中营养成分进行了比较分析.结果表明:(1)野生与养殖花羔红点鲑肌肉的一般营养成分的含量存在差异.野生群体肌肉中水分的含量显著低于养殖群体(P0.05),而粗蛋白质的含量和粗脂肪的含量则显著高于养殖群体(P0.05),野生群体肌肉中粗灰分的含量高于养殖群体,差异不显著(P0.05),野生群体肌肉中无氮浸出物的含量低于养殖群体,差异显著(P0.05).(2)野生与养殖花羔红点鲑肌肉中氨基酸总量(w)分别为(18.01±0.29)%和(16.46±0.15)%.野生群体肌肉中各种氨基酸的含量均高于或等于养殖群体,其中,谷氨酸含量最高.(3)野生与养殖花羔红点鲑肌肉中脂肪酸组成均以油酸(C18∶1)含量最高,硬脂酸(C18∶0)含量最低.亚油酸(C18∶2)、EPA(C20∶5)、二十二碳五烯酸(C22∶5)、DHA(C22∶6)的含量野生群体低于养殖群体,差异显著(P0.05).(4)野生和养殖花羔红点鲑的化学评分分别为0.90和0.87,氨基酸评分分别为0.67和0.64,第一限制性氨基酸都为蛋氨酸.     

利用虹鳟微卫星标记评价白斑红点鲑养殖群体的遗传结构

本实验筛选出30个虹鳟Oncorhynchus mykiss微卫星标记在白斑红点鲑Salvelinus leucomaenis养殖群体中表现出多态性,并利用这30个标记来评价白斑红点鲑养殖群体的遗传结构。在随机采样的32个个体中共检测到143个等位基因,片段大小为106~454bp,标记的等位基因数(No)为2~11个,有效等位基因数(Ne)为1.135~7.161个,观测杂合度(Ho)为0.094~1.000,期望杂合度(He)为0.121~0.874,多态信息含量(PIC)为0.116~0.846。群体的5项遗传多样性参数平均值分别为4.767、3.006、0.423、0.568,及0.524。统计结果显示:白斑红点鲑养殖群体处于高度多态水平(PIC=0.524≥0.5)。经χ~2检验估计Hardy-Weinberg平衡,结果表明白斑红点鲑群体处于平衡状态,仅11个微卫星标记显著偏离了遗传平衡,其中OMM1112、OMM1130和OMM1231等6个标记表现为杂合子显著缺失(P0.05),而OMM3006、OMM3044和OMM3144等5个标记表现为杂合子显著过剩(P0.05)。本实验从近缘种中鉴定可用于白斑红点鲑遗传分析的共显性标记,评估白斑红点鲑种质的遗传多样性,为该引进种种质的保护和持续利用提供参考。