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

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 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

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.

Sex-related growth of European eel, Anguilla anguilla, with focus on median silver eel age

1997 ◽  
Vol 54 (12) ◽  
pp. 2775-2781 ◽  
Author(s):  
K Holmgren ◽  
H Wickström ◽  
P Clevestam
Keyword(s):  
Growth Rate ◽  
Anguilla Anguilla ◽  
Growing Season ◽  
European Eel ◽  
Silver Eel ◽  
Glass Eel ◽  
Growing Seasons ◽  
Length Increase ◽  
Silver Eels

Silver eels, Anguilla anguilla, migrating downstream were monitored for 15 years since being stocked in 1980 as cultured fingerlings in a Swedish lake. Females were larger than males in each separate year, but mean growth rate was higher in males than in females. This discrepancy was due to different age distributions, with 64.5% of the males migrating after four or five growing seasons, while 86.3% of the females grew for 10-15 seasons before migration. Otolith length in the glass eel stage was independent of sex, and it was not correlated with year of migration. With focus on median year of migration, otolith lengths after one, two, and three growing seasons were significantly larger in males than in females. This was mainly due to a higher otolith length increase during the first growing season, i.e., before the eels were stocked in the lake. These results are inconsistent with the view that female eels generally grow faster than males.

Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  
Keyword(s):  
Brackish Water ◽  
Parasite Species ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Health State ◽  
Component Community ◽  
Metazoan Parasites ◽  
Parasite Communities ◽  
High Dominance ◽  
Argulus Foliaceus

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

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