Accumulation of Persistent Pollutants in Normal and Dwarfed Arctic Char (Salvelinus alpinus sp. complex)

1993 ◽  
Vol 50 (12) ◽  
pp. 2574-2580 ◽  
Author(s):  
Johan Hammar ◽  
Per Larsson ◽  
Maris Klavins

Two extreme growth fractions of introgressed sympatric populations of the Arctic char (Salvelinus alpinus) species complex from Lake Blåsjön, northern Sweden, were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of SPCB (sum of PCB congeners found) and p,p-DDE (dominating DDT-compound) than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates (introduced Mysis relicta and Pallasea quadrispinosa) are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass "dilution" of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish.

2007 ◽  
Vol 64 (4) ◽  
pp. 665-671 ◽  
Author(s):  
Mika VM Laakkonen ◽  
Heikki Hirvonen

Previous studies have shown that the antipredator responsiveness of fish degenerates through generations in captive breeding. However, detailed knowledge of the underlying mechanism is still largely lacking. We tested the hypothesis that hatchery fish supposedly selected for faster growth in the hatchery environment are bolder towards predators than their slower-growing conspecifics. This was examined by comparing the antipredator behavior of predator- naïve fast- and slow-growing individuals of a captive-bred Arctic char (Salvelinus alpinus) population to chemical cues from natural predators burbot (Lota lota) and pikeperch (Sander lucioperca). As behavioral responses depended on char body size, we compared boldness towards predators of size-matched fast- and slow-growing char. We found no differences in four behavioral antipredator traits between size-matched groups of fast- and slow-growing char. According to these results, boldness to predator cues is not related to individual growth rate in captive-bred Arctic char.


Author(s):  
Véronique Dubos ◽  
André St-Hilaire ◽  
Normand E Bergeron

Arctic char is a fish species known to occupy diverse habitats within the Arctic region. However, summer habitat use during the juvenile stage of the anadromous form is largely unknown. The present study aims to characterize fry and parr summer habitat preferences. Surveys were conducted by electrofishing, associated with physical habitat characterization on several rivers of the Ungava Bay, Nunavik, Canada. At the microhabitat and station scales, fry showed significant habitat preferences for shallow water and slow velocity. At the mesohabitat scale, fry showed a significant habitat selectivity for riffles. This habitat selectivity implies that habitat models can be built to evaluate the potential of habitat suitability for Arctic char fry. However, no significant habitat selectivity was found for parr. Parr size was nonetheless positively correlated with velocity, which was found to be a limitative factor for juvenile habitat use. This first attempt at modeling juvenile anadromous Arctic char habitat in rivers emphasizes the importance of selecting an appropriate spatial scale and reiterates the fact that parr showed relatively high plasticity in stream habitat selection.


1973 ◽  
Vol 3 (2) ◽  
pp. 315-318 ◽  
Author(s):  
D. J. Ursino

Young trees from seedlots representing single tree progeny of white spruce and assessed as either fast- or slow-growing on the basis of shoot height, were allowed to photoassimilate 14CO2 and either 24 or 48 h later, the magnitude and distribution of 14C were determined. In comparison to the slow-growing plants 48 h after 14CO2 photoassimilation, the fast-growing spruce retained a higher percentage of the assimilated 14C and translocated less to the root. Differences in growth rate between the seedlots did not affect the partitioning of 14C between the 80% ethanol-soluble and -insoluble fractions.


2006 ◽  
Vol 84 (7) ◽  
pp. 1019-1024 ◽  
Author(s):  
Jonathan Vaz Serrano ◽  
Ivar Folstad ◽  
Geir Rudolfsen ◽  
Lars Figenschou

Theoretical models predict that subordinate males should have higher sperm velocity to compensate for their disadvantaged mating role and because they experience sperm competition more frequently than dominant males. Differences in mean velocity between sperm of dominants and subordinates in the predicted direction are also documented for a few species, including the Arctic char, Salvelinus alpinus (L., 1758). Yet, this difference in mean velocity does not imply that the fastest sperm within an ejaculate, which are those most likely to fertilize eggs, swim faster in subordinates than in dominants. We studied the 5% and 10% fastest sperm cells in ejaculates of dominant and subordinate Arctic char. Before individuals attained their status, there were no differences in velocity between the fastest sperm of males that later became dominant or subordinate. Yet, after establishment of social position, subordinates showed significantly higher sperm swimming speed of the fastest cells in the first 30 s post activation (i.e., at 15, 20, and 30 s post activation). Males that became subordinates showed no change in sperm speed of the fast cells compared with those at pre-trial levels, whereas males that became dominant reduced the speed of their sperm (15 s post activation) compared with those at pre-trial levels. Our results suggest that males which attain social dominance are unable to maintain high sperm velocity, even among the small fraction of the fastest cells.


1999 ◽  
Vol 56 (8) ◽  
pp. 1370-1375
Author(s):  
Even H Jørgensen ◽  
Johannes Wolkers

In this study, the time-dependent P450 response to oral benzo[a]pyrene exposure at 1 and 10°C was investigated in winter- and summer-acclimated Arctic char (Salvelinus alpinus). In both seasons, a strong induction of CYP1A activities and protein levels (measured only in the winter experiment) were seen at both 1 and 10°C. At 1°C, the responses were delayed and more long-lasting than at 10°C. No within-season difference between 1 and 10°C in the magnitude of the induction response was found, but due to elevated baseline CYP1A activities, the induction response was seven times lower in winter- as compared with the response in summer-acclimated Arctic char. The results show that the CYP1A enzymes of the Arctic char respond to temperature changes in a compensatory way, and they are promising with respect to the applicability of the P450 enzyme system of the Arctic char as a biomarker for monitoring polycyclic aromatic hydrocarbon contamination in high-latitude environments. More studies are needed, however, to reveal seasonal differences in the biomarker response to pollutants.


1989 ◽  
Vol 35 (5) ◽  
pp. 578-582 ◽  
Author(s):  
James L. Sinclair ◽  
Martin Alexander

The survival of six bacterial species that had different growth rates was tested in raw sewage and sewage that was rendered free of protozoa. When test bacteria were added to protozoa-free sewage at densities of approximately 105 to 106 cells/mL, five of the six species did not decline below 105 cells/mL. If protozoa were present, the population sizes of all test species were markedly reduced, but bacterial species able to grow faster in artificial media had the larger number of survivors. When the same bacteria were inoculated into protozoa-free sewage at densities of less than 103 cells/mL, only the three species able to grow quickly in artificial media increased in abundance. When the six species were inoculated at the same densities into sewage containing protozoa, the three slow-growing species were rapidly eliminated, and two of the three fast-growing species survived in detectable numbers. We suggest that in environments with intense protozoan predation, protozoa may alter the composition of the bacterial community by eliminating slow-growing bacteria.Key words: growth rate, predation, protozoa, sewage.


2018 ◽  
Author(s):  
Sarah J. Salisbury ◽  
Gregory R. McCracken ◽  
Donald Keefe ◽  
Robert Perry ◽  
Daniel E. Ruzzante

ABSTRACTWe sequenced a portion of the D-loop region in over 1000 Arctic char (Salvelinus alpinus) samples from 67 locations across Newfoundland and Labrador to assess the extent of secondary contact among the Arctic, Atlantic, and Acadian glacial lineages in Newfoundland and Labrador. Within Labrador, the Arctic and Atlantic lineages were widespread. Two locations (one landlocked and one with access to the sea) also contained individuals of the Acadian lineage, constituting the first record of this lineage in Labrador. Atlantic and Acadian lineage individuals were found in both eastern and western Newfoundland. Multiple sampling locations in Newfoundland and Labrador contained fish of two or more different glacial lineages, implying their introgression. Glacial lineage did not appear to dictate contemporary genetic divergence between the pale and dark morph of char present in Gander Lake, Newfoundland. Both were predominately of the Atlantic lineage, suggesting the potential for their divergence in sympatry. This study reveals Newfoundland and Labrador to be a unique junction of three glacial lineages which have likely hybridized extensively in this region.


2017 ◽  
Vol 60 (4) ◽  
pp. 427-437 ◽  
Author(s):  
Philipp C. Muth ◽  
Anne Valle Zárate

Abstract. The effects of the increase of body weight of contemporary broilers during growth on functional meat quality and color characteristics of the chicken breast muscle are controversially debated. Therefore, male chickens (n = 264) of a fast-growing commercial broiler (Ross 308) and two slow-growing experimental meat-type chicken lines were compared at equal age and at similar body weight in order to investigate the effect of growth rate on selected functional breast meat traits and meat color. Additionally, the breast meat characteristics of birds with different growth profiles were compared within lines. When the body weight of commercial broilers reached about 40 to 60 % of their growth potential, they exhibited particularly high ultimate pH values compared with slow-growing lines. The ability of the meat of fast-growing broilers to retain water during cooking was impaired (5 to 16 percentage points increased cooking loss compared to slow-growing lines), which, in contrast to pH, was only marginally affected by body weight and/or age at slaughter. No unfavorable correlations of breast meat quality traits with the growth profile, represented by growth curve parameters derived from the Gompertz–Laird equation, were detected within any of the investigated chicken lines. It is noteworthy that the associations of ultimate pH and cooking loss with maximum growth speed indicate a non-linear relationship. Thus, some of the functional characteristics of breast meat of the fast-growing broiler resembled the white-striping defect described for poultry meat, but the hypothesis that selection on increased growth rates is detrimental for meat quality per se could not be confirmed. In fact, an elevated growth potential in particular, i.e., body weight at maturity, could have some beneficial effects for the water-holding capacity of breast meat, regardless of the genotypic growth rate.


Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 402 ◽  
Author(s):  
Li Zhang ◽  
Li Liu ◽  
Han Zhao ◽  
Zaimin Jiang ◽  
Jing Cai

Carbon starvation and hydraulic failure are considered important factors in determining the mechanisms associated with tree mortality. In this study, iso/anisohydric classification was used to assess drought resistance and mortality mechanisms in two contrasting poplar species, as it is generally believed that isohydric species are more susceptible to carbon starvation, while anisohydric species are more susceptible to hydraulic failure. However, these assumptions are rarely tested in poplar genotypes with contrasting growth strategies. Thus, we subjected potted poplar genotypes (I-101 (Populus alba L.) × 84K (Populus alba L. × Populus glandulosa Uyeki)) with fast and slow growth rates to drought–rehydration treatments. The slow-growing genotype maintained higher stomatal conductance and lower predawn leaf water potential than the fast-growing genotype, thus exhibiting a near-anisohydric stomatal behavior throughout the treatment period. The nonstructural carbohydrate (NSC) content indicated that the two genotypes had the same trend of carbon change (e.g., the NSC content in the leaves increased with drought and then decreased). However, when NSC content data were combined with the growth and photosynthetic data, it was observed that the slow-growing genotype mobilized carbon to maintain hydraulic safety, while the NSC content of the fast-growing genotype among tissues was static. The percent loss of hydraulic conductivity in the branches during treatments indicated that the fast-growing genotype could recover more quickly from xylem embolism than the slow-growing genotype. The slow-growing genotype with a slow growth recovery after rehydration showed a significant increase in carbon consumption, combined with a significant increase in the hydraulic safety threshold value, indicating that there may be drought tolerance. In comparison, the fast-growing genotype showed a faster hydraulic recovery ability that had no effect on the NSC content in the leaves and roots. Our findings demonstrate intraspecific isohydric behavior in poplar; however, the trade-off between carbon distribution and stomatal regulation should be considered separately within genotypes of the same species. In addition, NSC plays an important role in water–carbon balance in the drought–rehydration cycle.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Pratima Chapagain ◽  
Brock Arivett ◽  
Beth M. Cleveland ◽  
Donald M. Walker ◽  
Mohamed Salem

Abstract Background Diverse microbial communities colonizing the intestine of fish contribute to their growth, digestion, nutrition, and immune function. We hypothesized that fecal samples representing the gut microbiota of rainbow trout could be associated with differential growth rates observed in fish breeding programs. If true, harnessing the functionality of this microbiota can improve the profitability of aquaculture. The first objective of this study was to test this hypothesis if gut microbiota is associated with fish growth rate (body weight). Four full-sibling families were stocked in the same tank and fed an identical diet. Two fast-growing and two slow-growing fish were selected from each family for 16S rRNA microbiota profiling. Microbiota diversity varies with different DNA extraction methods. The second objective of this study was to compare the effects of five commonly used DNA extraction methods on the microbiota profiling and to determine the most appropriate extraction method for this study. These methods were Promega-Maxwell, Phenol-chloroform, MO-BIO, Qiagen-Blood/Tissue, and Qiagen-Stool. Methods were compared according to DNA integrity, cost, feasibility and inter-sample variation based on non-metric multidimensional scaling ordination (nMDS) clusters. Results Differences in DNA extraction methods resulted in significant variation in the identification of bacteria that compose the gut microbiota. Promega-Maxwell had the lowest inter-sample variation and was therefore used for the subsequent analyses. Beta diversity of the bacterial communities showed significant variation between breeding families but not between the fast- and slow-growing fish. However, an indicator analysis determined that cellulose, amylose degrading and amino acid fermenting bacteria (Clostridium, Leptotrichia, and Peptostreptococcus) are indicator taxa of the fast-growing fish. In contrary, pathogenic bacteria (Corynebacterium and Paeniclostridium) were identified as indicator taxa for the slow-growing fish. Conclusion DNA extraction methodology should be carefully considered for accurate profiling of the gut microbiota. Although the microbiota was not significantly different between the fast- and slow-growing fish groups, some bacterial taxa with functional implications were indicative of fish growth rate. Further studies are warranted to explore how bacteria are transmitted and potential usage of the indicator bacteria of fast-growing fish for development of probiotics that may improve fish health and growth.


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