Ecological plasticity of the European eel Anguilla anguilla in a tidal Atlantic lake system in Ireland

2019 ◽  
Vol 99 (5) ◽  
pp. 1189-1195 ◽  
Author(s):  
Takaomi Arai ◽  
Aya Kotake ◽  
Chris Harrod ◽  
Michelle Morrissey ◽  
T. Kieran McCarthy
Keyword(s):  
Fresh Water ◽  
Growth Phase ◽  
Brackish Water ◽  
Habitat Preference ◽  
Salinity Gradient ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Ecological Plasticity ◽  
Lake System ◽  
Freshwater Habitats

AbstractRecent studies have shown that anguillid eel populations in habitats spanning the marine–freshwater ecotone can display extreme plasticity in the range of catadromy expressed by individual fish. The apparent use of marine and freshwater habitats by the European eel Anguilla anguilla was examined by analysing the strontium (Sr) and calcium (Ca) concentrations in otoliths of eels collected from a tidal Atlantic lake system in Ireland. Variations of the Sr:Ca ratio in the otoliths indicated that a variety of environmental salinities had been experienced in the habitats that were occupied during the growth phase of these individuals in the tidal Atlantic lake system. The otolith microchemistry of these eels indicated that most of the eels had entered each salinity environment (freshwater (FW); brackish water (BW); marine-dominated water (MW) and full seawater (SW)) from fresh water to full seawater just after recruitment and had stayed in each environment until maturation without movement to other salinity environments. Only 2 of 93 (2%) eels had shifted their habitat once in their lives. This result suggests that each individual might have an environmental habitat preference, although each individual could move along a short (<2 km) salinity gradient.

scholarly journals Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany

2008 ◽  
Vol 66 (2) ◽  
pp. 358-366 ◽  
Author(s):  
Eva Jakob ◽  
Reinhold Hanel ◽  
Sven Klimpel ◽  
Karsten Zumholz
Keyword(s):  
Fresh Water ◽  
Brackish Water ◽  
Parasite Species ◽  
Diversity Index ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Northern Germany ◽  
Parasite Communities ◽  
Helminth Communities ◽  
Parasite Infestation

Abstract Jakob, E., Hanel, R., Klimpel, S., and Zumholz, K. 2009. Salinity dependence of parasite infestation in the European eel Anguilla anguilla in northern Germany. – ICES Journal of Marine Science, 66: 358–366. The aim of the study was to examine metazoan parasite communities of European eels (Anguilla anguilla) in fresh-water, brackish water and marine localities in northern Germany. In all, 29 parasite species/taxa were found in 170 eels: eight digeneans, one monogenean, five cestodes, ten nematodes, two acanthocephalans, and three crustaceans. Measures of diversity characteristics of the helminth communities included species richness, Shannon's diversity index and its evenness, and the Berger–Parker dominance index. The highest species diversity and lowest dominance values were calculated for the helminth communities of eels from the two Baltic Sea localities. Parasite communities of European eels clearly exhibit the habitat preferences of their hosts, salinity-dependent specificities, and a clustering into fresh-water, brackish, and marine groups. The highly pathogenic parasite species Anguillicola crassus and Pseudodactylogyrus spp. were found at all sampling sites in fresh water and brackish water, with high prevalence. Basic information is provided on the risks of restocking programmes solely focusing on fresh-water sites.

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.

Kinetics of Water and Chloride Exchanges During Adaptation of the European Eel to Sea Water

1973 ◽  
Vol 58 (1) ◽  
pp. 105-121
Author(s):  
R. KIRSCH ◽  
N. MAYER-GOSTAN
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Maximum Level ◽  
Progressive Increase ◽  
Plasma Sodium ◽  
European Eel ◽  
Drinking Rate ◽  
The One ◽  
Kinetics Of

Using isotopic procedures, the drinking rate and chloride exchanges were studied in the eel Anguilla anguilla during transfer from fresh water to sea water. 1. Following transfer to sea water there is a threefold increase of the drinking rate (lasting about 1 h). Then it falls to a minimum after 12-16 h and rises again to a maximum level about the seventh day after the transfer. Then a gradual reduction leads to a steady value which is not significantly different from the one observed in fresh water. 2. The changes with time of the plasma sodium and chloride concentrations are given. Their kinetics are not completely alike. 3. The chloride outflux increases 40-fold on transfer of the eel to sea water, but even so it is very low. After the sixth hour in sea water there is a progressive increase in the flux, so that on the fourth day it is higher (500 µ-equiv. h-1.100 g-1) than in the seawater-adapted animals (230 µ-equiv.h-1.100 g-1). 4. Drinking rate values in adapted animals are discussed in relation to the external medium. The kinetics of the drinking rate together with variations in body weights after freshwater-seawater transfer are discussed in relation to the possible stimulus of the drinking reflex. 5. Chloride fluxes (outflux, net flux, digestive entry) are compared and lead one to assume that in seawater-adapted fish one-third of the chloride influx enters via the gut and two-thirds via the gills.

RENAL FUNCTION IN THE EUROPEAN EEL (ANGUILLA ANGUILLA L.): CHANGES IN BLOOD PRESSURE AND RENAL FUNCTION OF THE FRESHWATER EEL TRANSFERRED TO SEA-WATER

1969 ◽  
Vol 43 (1) ◽  
pp. 9-19 ◽  
Author(s):  
I. CHESTER JONES ◽  
D. K. O. CHAN ◽  
J. C. RANKIN
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Fresh Water ◽  
Inorganic Phosphate ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Urine Flow ◽  
Inulin Clearance ◽  
European Eel ◽  
Clearance Rates

SUMMARY A method for the study of renal function and measurement of mean ventral and dorsal aortic blood pressure for the freshwater and seawater-adapted eel, and during transfer of the animal from fresh water to sea-water, is described. Freshwater eels have higher resting blood pressure, p-aminohippuric acid (PAH) and inulin clearance rates and urine flow than seawater eels. Urine from freshwater animals has low Na, K, Ca, Mg and Cl concentrations, while the clearance rate of inorganic phosphate exceeded that of inulin. Urine from seawater animals has high Na, Ca, Mg and Cl concentrations while that of inorganic phosphate was low. Clearance rates for Ca and Mg greatly exceeded those of inulin. During transfer from fresh water to sea-water there was an initial fluctuation in blood pressure, urine flow and PAH and inulin clearance rates which lasted about 2 hr. Thereafter these gradually declined to values observed for the seawater-adapted animal. The significance of PAH and inulin clearance rates in the study of renal function in the eel and in teleosts in general is discussed.

scholarly journals The relationship between the moon cycle and the orientation of glass eels ( Anguilla anguilla ) at sea

2019 ◽  
Vol 6 (10) ◽  
pp. 190812 ◽  
Author(s):  
Alessandro Cresci ◽  
Caroline M. Durif ◽  
Claire B. Paris ◽  
Cameron R. S. Thompson ◽  
Steven Shema ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Lunar Cycle ◽  
Global Scale ◽  
European Eel ◽  
Sargasso Sea ◽  
The Moon ◽  
Detection Mechanism ◽  
Freshwater Habitats ◽  
Glass Eels ◽  
Open Question

Links between the lunar cycle and the life cycle (migration patterns, locomotor activity, pulses in recruitment) of the European eel ( Anguilla anguilla ) are well documented. In this study, we hypothesized that the orientation of glass eels at sea is related to the lunar cycle. The European eel hatches in the Sargasso Sea and migrates across the Atlantic Ocean towards Europe. Upon reaching the continental shelf, the larvae metamorphose into glass eels and migrate up the estuaries, where some individuals colonize freshwater habitats. How glass eels navigate pelagic waters is still an open question. We tested the orientation of 203 glass eels in a transparent circular arena that was drifting in situ during the daytime, in the coastal Norwegian North Sea, during different lunar phases. The glass eels swimming at sea oriented towards the azimuth of the moon at new moon, when the moon rose above the horizon and was invisible but not during the other moon phases. These results suggest that glass eels could use the moon position for orientation at sea and that the detection mechanism involved is not visual. We hypothesize a possible detection mechanism based on global-scale lunar disturbances in electrical fields and discuss the implications of lunar-related orientation for the recruitment of glass eels to estuaries. This behaviour could help glass eels to reach the European coasts during their marine migration.

Colonisation of freshwater habitats by the European eel Anguilla anguilla

2002 ◽  
Vol 47 (9) ◽  
pp. 1696-1706 ◽  
Author(s):  
Anton Ibbotson ◽  
Jim Smith ◽  
Peter Scarlett ◽  
Miran Aprhamian
Keyword(s):  
Anguilla Anguilla ◽  
European Eel ◽  
Freshwater Habitats

PITUITARY AND ADRENOCORTICAL FACTORS IN THE CONTROL OF THE WATER AND ELECTROLYTE COMPOSITION OF THE FRESHWATER EUROPEAN EEL (ANGUILLA ANGUILLA L.)

1968 ◽  
Vol 42 (1) ◽  
pp. 91-98 ◽  
Author(s):  
D. K. O. CHAN ◽  
I. CHESTER JONES ◽  
W. MOSLEY
Keyword(s):  
Body Weight ◽  
Water Content ◽  
Fresh Water ◽  
Normal Values ◽  
Anguilla Anguilla ◽  
Electrolyte Composition ◽  
Electrolyte Balance ◽  
European Eel ◽  
Marked Decline ◽  
K Concentration

SUMMARY The hypophysectomized eel (Anguilla anguilla L.) in fresh water showed a marked decline in serum Na and Ca concentrations whilst serum K concentration was elevated compared with sham-operated controls. Muscle was hyperhydrated with decline in Na, K and Mg concentrations. The total amount of Na and K/kg. fat-free dried muscle was decreased. The ratio serum [Na]:[K] was lowered. Injection of mammalian prolactin rendered water content normal but not the electrolyte values. Injections of corticotrophin or cortisol brought electrolyte levels towards normal values though muscle hyperhydration was still evident. Injection of prolactin (2 mg./100g. body weight/day) plus cortisol (20 μg./100 g. body weight/day) rendered the values for water and electrolyte composition similar to those for intact and sham-operated controls. The results are discussed in terms of the equivalence of mammalian prolactin to the fish hormone, paralactin, and of cortisol as a prime agent in controlling electrolyte balance in the Teleostei.

scholarly journals Detection of Prochlorothrix in Brackish Waters by Specific Amplification of pcb Genes

2003 ◽  
Vol 69 (10) ◽  
pp. 6243-6249 ◽  
Author(s):  
Ulrike Geiß ◽  
Ingo Bergmann ◽  
Miriam Blank ◽  
Rhena Schumann ◽  
Martin Hagemann ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Brackish Water ◽  
Salinity Gradient ◽  
Water Environment ◽  
Sensitive Species ◽  
Gene Detection ◽  
Freshwater Habitats ◽  
Specific Amplification ◽  
Brackish Water Environment ◽  
Estuarine Phytoplankton

ABSTRACT Prochlorothrix hollandica is the only filamentous chlorophyll b (Chlb)-containing oxyphotobacterium that has been found in freshwater habitats to date. Chlb serves as a light-harvesting pigment which is bound to special binding proteins (Pcb). Even though Prochlorothrix was initially characterized as a highly salt-sensitive species, we detected it in a brackish water environment that is characterized by salinities of up to 12 practical salinity units. Using PCR and reverse transcription, we amplified pcb gene fragments of phytoplankton samples taken along a salinity gradient in the eutrophic Darss-Zingst estuary (southern Baltic Sea). After sequencing, high levels of homology to the pcbB and pcbC genes of P. hollandica were found. Furthermore, autofluorescence of Prochlorothrix-like filaments that indicated that Chlb was present was detected in enrichment cultures prepared from the estuarine phytoplankton. The detection of Chlb-containing filaments, as well as the pcb and 16S ribosomal DNA sequences, suggests that Prochlorothrix is an indigenous genus in the Darss-Zingst estuary and may also inhabit many other brackish water environments. The potential of using pcb gene detection to differentiate Prochlorothrix from morphologically indistinguishable species belonging to the genera Pseudanabaena and Planktothrix (Oscillatoria) in phytoplankton analyses is discussed.

Plasma Chloride and Sodium, and Chloride Space in the European Eel, Anguilla Anguilla L

1972 ◽  
Vol 57 (1) ◽  
pp. 113-131
Author(s):  
R. KIRSCH
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Chloride Concentration ◽  
Anguilla Anguilla ◽  
The Body ◽  
European Eel ◽  
Plasma Chloride ◽  
Sea Water Adaptation ◽  
Sodium Regulation ◽  
High Degree

1. New intra-vascular cannulation techniques are described, and also an extra-corporal blood circuit containing an artificial heart and a counting cell. This makes possible a continuous study of the radioactivity of the blood. 2. Plasma chloride concentration varies greatly in fresh-water eels despite good sodium regulation. 3. The fresh-water to sea-water adaptation of eels is frequently accompanied by a temporary hypermineralization of the internal medium. This necessitates a high degree of cellular euryhalinity. 4. The sea-water-adapted eel maintains strict homeostasis of its plasma chloride and sodium. 5. The chloride distribution space decreases by 10% when eels are transferred from fresh water to sea water. The internal distribution of chloride is also modified and its fluxes between the ion compartments of the body are considerably increased.

scholarly journals Checklist of the parasites of European eel Anguilla anguilla (Linnaeus, 1758) (Anguillidae) in Poland

2020 ◽  
Vol 8 ◽  
Author(s):  
Joanna Dzido ◽  
Leszek Rolbiecki ◽  
Joanna Izdebska ◽  
Rafał Bednarek
Keyword(s):  
Parasite Species ◽  
Developmental Stages ◽  
Anguilla Anguilla ◽  
European Eel ◽  
New Host ◽  
Freshwater Habitats ◽  
Acanthocephalus Lucii ◽  
Infection Parameters ◽  
New Host Records ◽  
Raphidascaris Acus

The present paper lists all parasite species of the European eel Anguilla anguilla (Linnaeus, 1758), recorded in Poland, in both its saltwater and freshwater habitats. The list has been drawn up, based on data acquired since 1844. The majority of included parasite species are presented with fish infection parameters together with data on their developmental stages and occupied microhabitats, localities and dates of collection of the eels themselves. The database includes 62 parasite taxa (including 50 species, nine identified to the genus level and three to higher taxa), representing at least 47 genera and 39 families. The most frequently-noted parasites of the European eel are the cestode Bothriocephalus claviceps, the nematodes Anguillicoloides crassus, Camallanus lacustris and Raphidascaris acus and the acanthocephalan Acanthocephalus lucii. Four alien species have been noted from this host: A. crassus, the monogeneans Pseudodactylogyrus anguillae and Pseudodactylogyrus bini and the acanthocephalan Paratenuisentis ambiguus. The present list includes both new host records and earlier records not included in previous lists of parasites of eels.

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