共查询到20条相似文献,搜索用时 0 毫秒
1.
The host specificity of Gyrodaclylus Solaris is examined experimentally with respect to its ability to infect the brook trout, Salvelinus fontinalis . The parasite readily attached to and reproduced on parr of this host and infections grew for c. 20 days from first monitoring (c. 30 days from first infection) before declining. Parasites could persist on this host for up to 70 days before finally disappearing. The pattern of infection resembled that seen in many other gyrodactylid species on their normal hosts, and suggested the action of a host response, In this respect infections of G. salaris on parr of S. fontinalis , anadromous Salvelinus alpinus, Oncorhynchus mykiss, Thymallus thymallus and Baltic Salmo salar follow a normal pattern, while infections of Norwegian S. salar are unusual in a continued unchecked growth, until the host dies, under pooled laboratory conditions. 相似文献
2.
引进美洲红点鲑群体遗传多样性微卫星的分析 总被引:1,自引:0,他引:1
为了解引进种美洲红点鲑种群遗传结构和种质资源现状,本研究利用15个微卫星标记对其养殖群体遗传多样性进行了分析。结果表明:在30个个体中,15对微卫星引物除1对扩增产物为单态外,其余14对在美洲红点鲑群体内扩增均出现了多态,14个多态性位点等位基因数目为3~7不等,共检测到等位基因数为69个,平均有效等位基因数为3.03;期望杂合度在0.540~0.809之间,平均期望杂合度为0.664;多态信息含量在0.360~0.719之间,平均多态信息含量为0.578,表明引进的美洲红点鲑遗传多样性水平较高,具有良好的选育潜力,可以作为良好的育种材料。 相似文献
3.
W. A. Spoor 《Journal of fish biology》1990,36(3):363-373
A self-recording linear gradient tank and procedures are described in which individual brook trout fingerlings unstressed by recent transfer, unaccustomed surroundings or the presence of an observer could move freely in 16 oxygen concentration gradients within the limits of 1 and 8.9 mg O2 1−1 . They avoided oxygen concentrations below 4 mg 1−1 most of the time and preferred 5 mg 1−1 or higher more than half the time, which supports the field-derived belief that fish avoid oxygen concentrations below 5 mg l−1 in the natural environment if they can. 相似文献
4.
The olfactory systems of brook and brown trout were equally sensitive to prostaglandin F2a and its derivatives, suggesting that these species have similar sex pheromone systems. This may explain partially hybridization behaviour observed between these species. 相似文献
5.
6.
In the field, juvenile brook charr Salvelinus fontinalis inhabiting high-velocity water were found to have larger caudal fins and more slender bodies than those inhabiting low-velocity water. Young-of-the-year S. fontinalis were reared in either a high- or low-velocity treatment for 16 weeks and their morphology was measured bi-weekly. From the second to fourth weeks of the experiment onwards, fish reared in the high-velocity treatment had larger maximum caudal fin heights and deeper caudal peduncles than fish reared in the low-velocity treatment. This study demonstrated that the morphological variation in caudal area exhibited by wild juvenile brook charr from microhabitats differing in water velocity could be a consequence of phenotypic plasticity in response to hydrological conditions. 相似文献
7.
Seawater acclimation of diploid (FF) and triploid (F2F) brook charr Salvelinus fontinalis , diploid (AA) Arctic charr Salvelinus alpinus , and diploid (FA) and triploid (F2A) hybrids between female brook charr and male Arctic charr was investigated. Triploidization of brook charr and the hybrid did not have any effect on the acclimation. Seawater acclimation of the hybrid was achieved during the experimental period and was comparable to that observed in brook charr. Acclimation could not be ascertained in Arctic charr since the level of cortisol, a stress indicator, was still high at the end of the experiment. No relationship between either length or condition factors and plasma osmolality was observed. Elevated plasma cortisol concentrations in Arctic charr and in diploid or triploid hybrids, both in fresh water and sea water, indicate more favourable rearing conditions for brook charr. 相似文献
8.
B. Angers L. Bernatchez † A. Angers ‡ L. Desgroseillers ‡ 《Journal of fish biology》1995,47(SA):177-185
We have isolated specific microsatellite loci from a partial genomic library of brook charr Salvelinus fontinalis. Their usefulness was investigated by measuring intra- and inter-population genetic diversity at four loci among 20 individuals from each of five lakes located 3 to 22 km apart in La Mauricie national park (Canada). These markers were moderately to highly polymorphic. A total of five, six, 16 and 18 alleles per locus were detected, and their overall expected heterozygosity was 0.53, 0.58, 0.86 and 0.87. Strong inter-population diversity was detected. Highly significant differences in allelic frequencies were found in all but two pairwise χ2 permutation tests between populations at all loci. Numerous population unique alleles were observed in all five lakes. Consequently, a highly significant component of total genetic diversity was due to interpopulation variance, as exemplified by G ST values of 0.33, 0.42, 0.47 and 0.84 for each individual locus. Altogether, the results indicated that these loci should be valuable in addressing fine scale population genetics questions in brook charr. To our knowledge, they also represent the first available microsatellites developed in the genus Salvelinus. 相似文献
9.
Stream-dwelling fish populations have long served as important models of animal movement. Populations of adult stream-dwelling fishes are generally composed of a mix of relatively sedentary and mobile individuals. However, we do not know whether this pattern that we typically observe among adults is indicative of patterns of movement that occur throughout the life cycle. Therefore, we do not know whether we can apply these patterns to understanding or predicting processes such as migration and thus the potential for the evolution of genetic differences among populations. We test the general hypothesis that patterns of movement throughout the life cycle are consistent with patterns of movement inferred by indirect genetic methods and, more specifically, that the characteristics of the mobile fraction of the population are consistent with patterns of genetic differentiation. We used parentage analyses to infer the movements of alevin brook charr (Salvelinus fontinalis) in Freshwater River, Newfoundland, Canada, and a capture-recapture study of one cohort in this population to infer movement throughout the rest of the life cycle. We found that alevins move large distances shortly after emergence, primarily in the downstream direction, and that the population is composed of a mix of relatively sedentary and mobile individuals throughout all other intervals of the life cycle. In contrast, when we considered movements of individuals first captured as juveniles and eventually recovered as reproductively mature adults, we found relatively large and uniform distributions of net movement distance. Thus, heterogeneity in individual movement of adults is not representative of patterns of movement throughout the life cycle and therefore may provide only limited inference of population-level processes such as gene flow. 相似文献
10.
Despite the abundance of studies of genetic diversity in freshwater fishes, few have specifically addressed the role of habitat structure in partitioning genetic variance within and among populations. In this study, we analysed the variability of six microsatellite loci among 24 brook charr population samples in order to correlate hydrographic structure with genetic organization. These populations originated from three Canadian National parks (Kouchibouguac, Fundy and Forillon) that showed distinct hydrographic structure. Considering the general characteristics of these habitats, we formulated specific hypotheses in regard to genetic structure, which were principally based on the potential for gene flow and population size associated with each habitat. The hierarchical analysis of molecular variance and the genetic distances computed among populations revealed that habitat structure analyses constitute an important, but insufficient, predictor of genetic structure. We discuss the importance of habitat complexity on genetic structure in the context of management and conservation. 相似文献
11.
Early growth of wild, anadromous and non-anadromous (resident) brook charr Salvelinus fontinalis was compared under controlled laboratory conditions. Offspring were collected as they emerged from natural redds in the Miramichi River, New Brunswick, Canada. Anadromous offspring were initially longer and heavier than residents. Anadromous offspring had lower specific growth rates during their first 2 months post-emergence, but surpassed residents by the third month. Consequently, anadromous offspring remained larger at the end of 3 months and it is concluded that they had a predetermined, maternal and genetic advantage related to body size, rather than an environmentally determined advantage during their first summer of growth. Other studies hypothesize that juvenile development affects life-history strategy adopted as adults, which suggests anadromy in this population may be, at least in part, predetermined by maternal and genetic effects. 相似文献
12.
We determined the amount and temporal stability of genetic differentiation among brook cham sampled from five rivers on Cape Race, Newfoundland, with an electrophoretic analysis of 42 protein coding loci. Fish from four of these rivers were analysed for restriction fragment length polymorphisms in mitochondrial DNA (mtDNA). A single mtDNA clone was observed in all rivers sampled, except one, where 47% offish were from a different and relatively divergent clone (0.31 % sequence divergence). In contrast, Cape Race brook charr show large amounts of genetic differentiation at six enzyme coding loci; Nei's genetic distance ranged between 0,020 and 0.048. This differentiation is relatively stable as no significant differences in allele frequencies were detected between fish sampled from two rivers over two consecutive years. The most divergent population based on protein polymorphism is not that with two mtDNA clonal lineages. In contrast to the commonly held view, mtDNA analyses do not necessarily provide greater resolution of population structure than allozyme analyses. 相似文献
13.
A primary toxic action of manganese to brook charr, Sulvelinusjonfinalis, at concentrations near or above the 96 h LC50 was the disruption of sodium regulation. Body and plasma sodium concentrations of brook charr declined by 52 and 40%, respectively, during exposure to 10.9 mM manganese (in 250 PM CaCI), and all fish died within 36 h. Sodium balance was less severely affected by 2.7 and 5.5 mM manganese. An increase in the external calcium concentration from 0.05 to 1.0 mM raised the LC50 for manganese from 4.9 to 5.8 mM, and a further increase to 2.5 mM calcium almost doubled it to 10.2 mM. An examination of stable manganese uptake by the gills revealed that accumulation was inversely correlated with body sodium concentration (r =−0.77). Radioactive J4Mn entered the bloodstream in low levels and accumulated in the liver. Thus manganese may have systemic effects as well as those attributable to surface binding on the gill. Studies of the mechanism ofdissolved iron toxicity were less conclusive, but it did not appear to involve extensive disruption of sodium balance. There was about a 15% drop in body sodium concentration when the trout were exposed for 48 h to the 96 h LC50 level of iron, but plasma sodium was unaffected. Also, an iron concentration at twice the LC50 did not escalate the loss of body sodium, and increasing the water calcium concentration did not raise the LC50 . 相似文献
14.
1. We surveyed 62 Canadian Shield lakes (<50 ha) to determine the relationship between factors related to isolation and extinction and the occurrence of brook trout (BT) (Salvelinus fontinalis), for which local extinctions have been documented over the last century in half of the lakes. 2. Logistic regression and information–theoretic model selection were used to determine the importance for the occupancy of BT of (i) isolation factors (degree of lake connectivity and the proximity of source populations of BT in neighbouring bodies of water) and (ii) extinction factors (lake morphometry and trophic status, as proxies of the risk of lake anoxia; predation and competition; and flooding caused by beaver (Castor canadensis) dams, which could potentially increase the risk of anoxia). 3. Isolation factors were the best predictors of the absence of BT in these lakes. Among extinction factors, only the impact of beaver dams (as measured by an index of increased water level and mortality of shrubs and trees in the littoral zone) improved model fits. Beaver dams were present at the outlets of all study lakes, but extensive mortality of riparian trees and shrubs was more common in lakes where BT populations were extinct. 4. Taken together, these results suggest that recolonization is a major factor determining the occurrence of BT while flooding caused by beaver dams might contribute to BT extinction by increasing the likelihood of winterkill in these small lakes. 相似文献
15.
GUY M. L. PERRY TIM L. KING JR
ME ST.‐CYR MANON VALCOURT LOUIS BERNATCHEZ 《Molecular ecology resources》2005,5(2):346-351
The brook charr (Salvelinus fontinalis; Osteichthyes: Salmonidae) is a phenotypically diverse fish species inhabiting much of North America. But relatively few genetic diagnostic resources are available for this fish species. We isolated 41 microsatellites from S. fontinalis polymorphic in one or more species of salmonid fish. Thirty‐seven were polymorphic in brook charr, 15 in the congener Arctic charr (Salvelinus alpinus) and 14 in the lake charr (Salvelinus namaycush). Polymorphism was also relatively high in Oncorhynchus, where 21 loci were polymorphic in rainbow trout (Oncorhynchus mykiss) and 16 in cutthroat trout (Oncorhynchus clarkii) but only seven and four microsatellite loci were polymorphic in the more distantly related lake whitefish (Coregonus clupeaformis) and Atlantic salmon (Salmo salar), respectively. One duplicated locus (Sfo228Lav) was polymorphic at both duplicates in S. fontinalis. 相似文献
16.
Synopsis The age structures of brook charr (Salvelinus fontinalis) and ouananiche (Salmo salar) stocks inhabiting a large rapid the river Méo, tributary to the Caniapiscau River were used to compare population stability and production of these species in north central Quebec. The brook chart stock was stable whereas ouananiche showed considerable variation in year class strength. Stock estimates were not significantly different for the two species although the brook charr estimate was 1.5 that of the ouananiche. Production estimates differed by a greater margin because of different growth patterns. Brook chair production was estimated at 19.4 kg ha−1 yr−1. Above age 2+ it was 11.4 kg ha−1 yr−1 which compares with 4.8 kg ha−1 yr−1 for the same age groups of ouananiche. 相似文献
17.
The intensity and duration of the period of osmotic disturbance during introduction of brook charr into sea water were decreased by introducing the fish according to a gradient of salinity over a period of 6 days. Survival in summer increased from 25 to 90% with the use of a salinity gradient. However, kinetics and levels of activation of the gill Na+ , K+ -ATPase were not affected by the mode used for introducing brook charr into sea water. Neither was its level of activity modified by the use of a salted diet when the fish were in fresh water. The addition of 8 and 12% of salt to the diet prevented the plasma electrolyte surge of concentrations during the first days in sea water. In very cold water, survival rate was also drastically improved by giving an 8% salted diet during the 6 weeks preceding the introduction into sea water. These results show that both salty diets and exposure to brackish water during 6 days help brook charr face osmotic stress and improve their survival rate when introduced into full-strength sea water. The combined use of these preconditioning strategies might facilitate rearing this species in sea cages or silos. 相似文献
18.
Shannon L. White Benjamen C. Kline Nathaniel P. Hitt Tyler Wagner 《Journal of fish biology》2019,95(4):1061-1071
Individual aggression and thermal refuge use were monitored in brook trout Salvelinus fontinalis in a controlled laboratory to determine how fish size and personality influence time spent in forage and thermal habitat patches during periods of thermal stress. On average, larger and more exploratory fish initiated more aggressive interactions and across all fish there was decreased aggression at warmer temperatures. Individual personality did not explain changes in aggression or habitat use with increased temperature; however, larger individuals initiated comparatively fewer aggressive interactions at warmer temperatures. Occupancy of forage patches generally declined as ambient stream temperatures approached critical maximum and fish increased thermal refuge use, with a steeper decline in forage patch occupancy observed in larger fish. These findings suggest that larger individuals may be more vulnerable to stream temperature rise. Importantly, even at thermally stressful temperatures, all fish periodically left the thermal refuge to forage. This indicates that the success of refugia at increasing population survival during periods of stream temperature rise may depend on the location of thermal refugia relative to forage locations within the larger habitat mosaic. These results provide insights into the potential for thermal refugia to improve population survival and can be used to inform predictions of population vulnerability to climate change. 相似文献
19.
1. Movements between a stream reach and two adjacent lentic macrohabitats, a beaver pond and a lake, were followed for the Appalachian crayfish and two fish species, brook charr and brown bullhead, over an 85‐d period from early June to late August, and were analysed in relation to water level, maximum water temperature, photoperiod length, lunar luminosity, and age, by use of time‐series regressions. 2. Brook charr showed strong net immigration to the stream reach for underyearling (age class 0+) fish but net emigration for 1+ fish. Both immigration and emigration were positively related to water level and temperature; migratory responses to temperature were age‐specific. 3. Brown bullhead used the stream primarily as a corridor for downstream migration from the beaver pond to the lake. As with brook charr, water level and temperature had a positive effect on movement and responses were stronger in younger individuals. 4. Crayfish emigrated from the stream during the summer. Movements were positively related to increases in water level and temperature, with responses of 1+ crayfish much stronger than those of older individuals. 5. The results indicate that the stream tributary played different roles for brook charr (nursery), brown bullhead (dispersal corridor) and Appalachian crayfish (early summer refuge), and suggest that variation in water level or temperature resulting from climatic change or local anthropogenic activities might modify connectivity between macrohabitats, particularly for younger individuals. 相似文献
20.
To examine constraints on evolution of larger body size in two stunted populations of brook charr (Salvelinus fontinalis) from a single river in Cape Race, Newfoundland, Canada, we measured viability selection acting on length-at-age traits, and estimated quantitative genetic parameters in situ (following reconstruction of pedigree information from microsatellite data). Furthermore we tested for phenotypic differentiation between the populations, and for association of high juvenile growth with early maturity that is predicted by life history theory. Within each population, selection differentials and estimates of heritabilities for length-at-age traits suggested that evolution of larger size is prevented by both selective and genetic constraints. Between the populations, phenotypic differentiation was found in length-at-age and age of maturation traits, whereas early maturation was associated with increased juvenile growth (relative to adult growth) both within and between populations. The results suggest an adaptive plastic response in age of maturation to juvenile growth rates that have a largely environmental basis of determination. 相似文献