scholarly journals Genetic variation in the eel II. Transferrins, haemoglobins and esterases in the eastern North Atlantic. Possible interpretations of phenotypic frequency differences

1970 ◽  
Vol 16 (3) ◽  
pp. 277-284 ◽  
Author(s):  
E. M. Pantelouris ◽  
A. Arnason ◽  
F. W. Tesch
Keyword(s):  
Genetic Variation ◽  
North Atlantic ◽  
Regional Differences ◽  
Anguilla Anguilla ◽  
Gene Frequencies ◽  
Eastern North Atlantic ◽  
American Eels

SUMMARYComparison, by electrophoretic methods, of eel samples from Iceland, Scotland and Germany confirmed previous reports of uniformity in haemoglobin types. When liver esterases were examined, significant differences in the frequencies of phenotypes in the ‘fast’ zone of the electropherogram were found between samples from Germany and samples from Iceland and Scotland. The frequencies of transferrin phenotypes in Icelandic and Scottish eels differed significantly from those of French and American eels.It follows that regional differences in gene frequencies probably exist within the species Anguilla anguilla. The implications for the ‘atlantic eel problem’ are briefly discussed.

scholarly journals Notes on Eel Larvae (Anguilla Anguilla Linnaeus, 1758) from the Central and Eastern North Atlantic and on Glass Eels from the European Continental Shelf

1985 ◽  
Vol 55 (2) ◽  
pp. 249-262 ◽  
Author(s):  
W.L. van Utrecht ◽  
M.A. Holleboom
Keyword(s):  
Continental Shelf ◽  
Fresh Water ◽  
Continental Slope ◽  
North Atlantic ◽  
Anguilla Anguilla ◽  
Portuguese Coast ◽  
Glass Eels ◽  
Eastern North Atlantic

Eel larvae caught in the mid North Atlantic and along the continental slope off the Portuguese coast are studied together with samples of glass eels caught just before entering fresh water along the Dutch and French coasts.

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.

Temperature, Salinity and Plankton in the Eastern North Atlantic and Coastal Waters of Britain, 1957.: I. The Characterisation and Distribution of Surface Waters

1963 ◽  
Vol 20 (3) ◽  
pp. 789-826 ◽  
Author(s):  
B. McK. Bary
Keyword(s):  
North Sea ◽  
North Atlantic ◽  
Coastal Waters ◽  
Water Bodies ◽  
English Channel ◽  
Oceanic Water ◽  
Climatic Fluctuations ◽  
The North ◽  
The North Sea ◽  
Eastern North Atlantic

Monthly temperature-salinity diagrams for 1957 have demonstrated that three surface oceanic "water bodies" were consistently present in the eastern North Atlantic; two are regarded as modified North Atlantic Central water which give rise to the third by mixing. As well in the oceanic areas, large and small, high or low salinity patches of water were common. Effects of seasonal climatic fluctuations differed in the several oceanic water bodies. In coastal waters, differences in properties and in seasonal and annual cycles of the properties distinguish the waters from the North Sea, English Channel and the western entrance to the Channel.The geographic distributions of the oceanic waters are consistent with "northern" and "southern" water bodies mixing to form a "transitional" water. Within this distribution there are short-term changes in boundaries and long-term (seasonal) changes in size of the water bodies.Water in the western approaches to the English Channel appeared to be influenced chiefly by the mixed, oceanic transitional water; oceanic influences in the North Sea appear to have been from northern and transitional waters.

A longitudinal study of humpback whales in Irish waters

2015 ◽  
Vol 96 (4) ◽  
pp. 877-883 ◽  
Author(s):  
Conor Ryan ◽  
Pádraig Whooley ◽  
Simon D. Berrow ◽  
Colin Barnes ◽  
Nick Massett ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
North Atlantic ◽  
Spatial Scales ◽  
Humpback Whales ◽  
Migratory Species ◽  
The Public ◽  
Photo Identification ◽  
The North ◽  
Breeding Grounds ◽  
Eastern North Atlantic

Knowledge on the ecology of humpback whales in the eastern North Atlantic is lacking by comparison with most other ocean basins. Humpback whales were historically over-exploited in the region and are still found in low relative abundances. This, coupled with their large range makes them difficult to study. With the aim of informing more effective conservation measures in Ireland, the Irish Whale and Dolphin Group began recording sightings and images suitable for photo-identification of humpback whales from Irish waters in 1999. Validated records submitted by members of the public and data from dedicated surveys were analysed to form a longitudinal study of individually recognizable humpback whales. The distribution, relative abundance and seasonality of humpback whale sighting records are presented, revealing discrete important areas for humpback whales in Irish coastal waters. An annual easterly movement of humpback whales along the southern coast of Ireland is documented, mirroring that of their preferred prey: herring and sprat. Photo-identification images were compared with others collected throughout the North Atlantic (N = 8016), resulting in matches of two individuals between Ireland and Iceland, Norway and the Netherlands but no matches to known breeding grounds (Cape Verde and West Indies). This study demonstrates that combining public records with dedicated survey data is an effective approach to studying low-density, threatened migratory species over temporal and spatial scales that are relevant to conservation and management.

scholarly journals Crassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean

2017 ◽  
Vol 3 ◽  
Author(s):  
LAETITIA LEMPEREUR ◽  
MORGAN DELOBELLE ◽  
MARJAN DOOM ◽  
JAN HAELTERS ◽  
ETIENNE LEVY ◽  
...  
Keyword(s):  
North Atlantic ◽  
18S Rrna ◽  
North Atlantic Ocean ◽  
18S Rrna Gene ◽  
The Body ◽  
Rrna Gene ◽  
Balaenoptera Physalus ◽  
Fin Whale ◽  
Eastern North Atlantic ◽  
The Right

SUMMARY On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage.

Observed and modeled pathways of the Iceland Scotland Overflow Water in the eastern North Atlantic

2017 ◽  
Vol 159 ◽  
pp. 211-222 ◽  
Author(s):  
Sijia Zou ◽  
Susan Lozier ◽  
Walter Zenk ◽  
Amy Bower ◽  
William Johns
Keyword(s):  
North Atlantic ◽  
Eastern North Atlantic
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