Environmental stress and life-stage dependence on the detection of heterozygosity–fitness correlations in the European eel, Anguilla anguilla

Genome ◽  
2006 ◽  
Vol 49 (11) ◽  
pp. 1428-1437 ◽  
Author(s):  
J.M. Pujolar ◽  
G.E. Maes ◽  
C. Vancoillie ◽  
F.A.M. Volckaert
Keyword(s):  
Growth Rate ◽  
Genetic Variability ◽  
Life Stage ◽  
Temporal Stability ◽  
Anguilla Anguilla ◽  
Differential Mortality ◽  
European Eel ◽  
Handling Stress ◽  
Growth And Survival ◽  
Mass Increase

Heterozygosity–fitness correlations (HFCs) have been reported in populations of many species, although HFCs can clearly vary across species, conspecific populations, temporal samples, and sexes. We studied (i) the temporal stability of the association between genetic variation and growth rate (length and mass increase) and (ii) the influence of genetic variability on survival in the European eel ( Anguilla anguilla L). HFCs were assessed using genotypes from 10 allozyme and 6 microsatellite markers in 22-month-old experimental individuals. The results were compared with those of a previous study carried out in 12-month-old individuals, in which more heterozygous individuals showed a significantly faster growth rate. In contrast, 22-month-old individuals showed no evidence that genetic variability was correlated with growth rate. Additionally, heterozygous individuals did not show a higher survival rate compared with more homozygous individuals after either handling stress or parasite infection. The decrease in HFCs over time is consistent with the general prediction that differences in growth and survival among individuals are maximal early in life and in our case most likely due to the relaxation of environmental conditions related to population-density effects. Alternatively, the decline in HFCs could be attributed to either ontogenetic variance in gene activity between 12- and 22-month-old individuals or differential mortality leaving only the largest individuals.

scholarly journals Growth potential can affect timing of maturity in a long-lived semelparous fish

2018 ◽  
Vol 14 (7) ◽  
pp. 20180269 ◽  
Author(s):  
Kazuki Yokouchi ◽  
Françoise Daverat ◽  
Michael J. Miller ◽  
Nobuto Fukuda ◽  
Ryusuke Sudo ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Growth Conditions ◽  
Growth Potential ◽  
Individual Growth ◽  
Growth Trajectories ◽  
Female Size ◽  
European Eel ◽  
Growth And Survival ◽  
Silver Eels ◽  
Reproduction Cost

Many diadromous fishes such as salmon and eels that move between freshwater and the ocean have evolved semelparous reproductive strategies, but both groups display considerable plasticity in characteristics. Factors such as population density and growth, predation risk or reproduction cost have been found to influence timing of maturation. We investigated the relationship between female size at maturity and individual growth trajectories of the long-lived semelparous European eel, Anguilla anguilla . A Bayesian model was applied to 338 individual growth trajectories of maturing migration-stage female silver eels from France, Ireland, the Netherlands and Hungary. The results clearly showed that when growth rates declined, the onset of maturation was triggered, and the eels left their growth habitats and migrated to the spawning area. Therefore, female eels tended to attain larger body size when the growth conditions were good enough to risk spending extra time in their growth habitats. This flexible maturation strategy is likely related to the ability to use diverse habitats with widely ranging growth and survival potentials in the catadromous life-history across its wide species range.

scholarly journals Age, growth, and condition of European eel (Anguilla anguilla) from six lakes in the River Havel system (Germany)

2007 ◽  
Vol 64 (7) ◽  
pp. 1414-1422 ◽  
Author(s):  
Janek Simon
Keyword(s):  
Growth Rate ◽  
Condition Factor ◽  
Energy Content ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Annual Increment ◽  
Otolith Increments ◽  
Gross Energy ◽  
Glass Eels ◽  
Mean Annual Increment

Abstract Simon, J. 2007. Age, growth, and condition of European eel (Anguilla anguilla) from six lakes in the River Havel system (Germany). – ICES Journal of Marine Science, 64: 1414–1422. A total of 199 female yellow European eels (Anguilla anguilla), 21.6–66.2 cm long and 3–14 years old, was collected by electro-fishing from six lakes in the River Havel system (Germany) in spring 2001. The condition and the growth rate, estimated by otolith increments, varied between eels within single lakes and between lakes. Fulton's condition factor ranged from 0.10 to 0.24 and the gross energy content varied between 4.3 and 15.3 MJ kg−1. There were no significant differences in mean condition factor (0.16–0.18) or gross energy content (6.5–9.3 MJ kg−1) between lakes. Fastest growth was in Lake Blankensee (mean 5.3 cm year−1), and the slowest in Lake Sacrow (mean 4.0 cm year−1). For all lakes combined, the overall mean annual increment was estimated to be 4.5 cm year−1. The biggest annual increment on the otoliths was generally laid down during the first and second years in fresh water, when the growth rate was 6.1–8.5 cm year−1. Then, in the subsequent 12 years, the annual increment remained almost constant or decreased slightly (with lake-dependent values of between 1.6 and 6.8 cm year−1). In the River Havel system, the time between stocking of the lakes with glass eels and the recapture of eels at 45 cm body length was 7–10 years. The physiologically possible maximum length (L∞ values) of eels lay in the range 50–130 cm. In comparison with previous investigations (between the 1950s and the 1970s), the only difference observed was a trend towards slower growth.

scholarly journals Rethinking swimming performance tests for bottom-dwelling fish: the case of European glass eel (Anguilla anguilla)

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
P. Vezza ◽  
F. Libardoni ◽  
C. Manes ◽  
T. Tsuzaki ◽  
W. Bertoldi ◽  
...  
Keyword(s):  
Water Temperature ◽  
Swimming Performance ◽  
Life Stage ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Fish Swimming ◽  
Glass Eel ◽  
Swimming Time ◽  
Swimming Mode ◽  
Active Swimming

Abstract Systematic experiments on European eel (Anguilla anguilla) in their juvenile, early life stage (glass eel), were conducted to provide new insights on the fish swimming performance and propose a framework of analysis to design swimming-performance experiments for bottom-dwelling fish. In particular, we coupled experimental and computational fluid dynamics techniques to: (i) accommodate glass eel burst-and-coast swimming mode and estimate the active swimming time (tac), not considering coast and drift periods, (ii) estimate near-bottom velocities (Ub) experienced by the fish, rather than using bulk averages (U), (iii) investigate water temperature (T) influence on swimming ability, and (iv) identify a functional relation between Ub, tac and T. Results showed that burst-and-coast swimming mode was increasingly adopted by glass eel, especially when U was higher than 0.3 ms-1. Using U rather than Ub led to an overestimation of the fish swimming performance from 18 to 32%, on average. Under the range of temperatures analyzed (from 8 to 18 °C), tac was strongly influenced and positively related to T. As a final result, we propose a general formula to link near-bottom velocity, water temperature and active swimming time which can be useful in ecological engineering applications and reads as $${\rm{U}}_{\rm{b}}=0.174\cdot \left({{\rm{t}}_{\rm{ac}}}^{-0.36}\cdot {\rm{T}}^{0.77}\right)$$ U b = 0.174 · t ac - 0.36 · T 0.77 .

scholarly journals Elemental composition of otoliths as a discriminator of life stage and growth habitat of the European eel, Anguilla anguilla

2005 ◽  
Vol 56 (5) ◽  
pp. 629 ◽  
Author(s):  
W. N. Tzeng ◽  
K. P. Severin ◽  
C. H. Wang ◽  
H. Wickström
Keyword(s):  
Elemental Composition ◽  
Environmental History ◽  
Life Stage ◽  
Anguilla Anguilla ◽  
Primary Component ◽  
European Eel ◽  
Yellow Eel ◽  
Minor Elements ◽  
Electron Probe Microanalyser ◽  
History Of

The hypothesis that elemental composition of otoliths of the eel (Anguilla spp.) changes with life stage and growth habitat was tested in the present study. The minor elements Cl, Na, K, Mg, Ca, Sr and P in otoliths of European eels (Anguilla anguilla) were examined by using an Electron Probe Microanalyser (EPMA) equipped with wavelength dispersive spectrometers (Cameca SX-50). Yellow-stage eels were collected from coastal waters and lakes of Sweden in 1987, 1988, 1991, and 1994, with ages ranging from 5 to 18 years old. Strontium maps and profiles of Sr : Ca ratio, as well as the elver check in otoliths, were used to classify life history stages of the eels as leptocephalus, and freshwater- and seawater-resident yellow eels. Canonical score plots of the otolith elemental compositions of the freshwater-resident yellow eel were completely separated from those of leptocephalus and seawater-resident yellow eel, but the latter two partially overlapped. Strontium is the primary component in determining the discrimination, but the nutrient-related (S and P), and the physiologically controlled elements (Na and Cl), may also play an important role in the discrimination. These results indicate that multiple-elemental information can provide additional insight into the migratory environmental history of diadromous fishes.

scholarly journals Genetic variability is unrelated to growth and parasite infestation in natural populations of the European eel (Anguilla anguilla)

2009 ◽  
Vol 18 (22) ◽  
pp. 4604-4616 ◽  
Author(s):  
J. M. PUJOLAR ◽  
D. BEVACQUA ◽  
F. CAPOCCIONI ◽  
E. CICCOTTI ◽  
G. A. DE LEO ◽  
...  
Keyword(s):  
Genetic Variability ◽  
Natural Populations ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Parasite Infestation

scholarly journals Panmixia in the European eel: a matter of time…

2005 ◽  
Vol 272 (1568) ◽  
pp. 1129-1137 ◽  
Author(s):  
Johan Dannewitz ◽  
Gregory E Maes ◽  
Leif Johansson ◽  
Håkan Wickström ◽  
Filip A.M Volckaert ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Structure ◽  
North Atlantic ◽  
Isolation By Distance ◽  
Temporal Stability ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Sargasso Sea ◽  
The North ◽  
Temporal Genetic Variation

The European eel ( Anguilla anguilla L.) has been a prime example of the panmixia paradigm because of its extraordinary adaptation to the North Atlantic gyral system, semelparous spawning in the Sargasso Sea and long trans-oceanic migration. Recently, this view was challenged by the suggestion of a genetic structure characterized by an isolation-by-distance (IBD) pattern. This is only likely if spawning subpopulations are spatially and/or temporally separated, followed by non-random larval dispersal. A limitation of previous genetic work on eels is the lack of replication over time to test for temporal stability of genetic structure. Here, we hypothesize that temporal genetic variation plays a significant role in explaining the spatial structure reported earlier for this species. We tested this by increasing the texture of geographical sampling and by including temporal replicates. Overall genetic differentiation among samples was low, highly significant and comparable with earlier studies ( F ST =0.0014; p <0.01). On the other hand, and in sharp contrast with current understandings, hierarchical analyses revealed no significant inter-location genetic heterogeneity and hence no IBD. Instead, genetic variation among temporal samples within sites clearly exceeded the geographical component. Our results provide support for the panmixia hypothesis and emphasize the importance of temporal replication when assessing population structure of marine fish species.

scholarly journals GROWTH RATE CORRELATES TO INDIVIDUAL HETEROZYGOSITY IN THE EUROPEAN EEL, ANGUILLA ANGUILLA L.

Evolution ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 189-199 ◽  
Author(s):  
J. M. Pujolar ◽  
G. E. Maes ◽  
C. Vancoillie ◽  
F. A. M. Volckaert
Keyword(s):  
Growth Rate ◽  
Anguilla Anguilla ◽  
European Eel

scholarly journals GROWTH RATE CORRELATES TO INDIVIDUAL HETEROZYGOSITY IN THE EUROPEAN EEL, ANGUILLA ANGUILLA L

Evolution ◽  
2005 ◽  
Vol 59 (1) ◽  
pp. 189 ◽  
Author(s):  
J. M. Pujolar ◽  
G. E. Maes ◽  
C. Vancoillie ◽  
F. A. M. Volckaert
Keyword(s):  
Growth Rate ◽  
Anguilla Anguilla ◽  
European Eel
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