Low larval abundance in the Sargasso Sea: new evidence about reduced recruitment of the Atlantic eels

2014 ◽  
Vol 101 (12) ◽  
pp. 1041-1054 ◽  
Author(s):  
Reinhold Hanel ◽  
Daniel Stepputtis ◽  
Sylvain Bonhommeau ◽  
Martin Castonguay ◽  
Matthias Schaber ◽  
...  
Keyword(s):  
Larval Abundance ◽  
Sargasso Sea ◽  
New Evidence ◽  
Atlantic Eels

scholarly journals New clues on the Atlantic eels spawning behavior and area: the Mid-Atlantic Ridge hypothesis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu-Lin K. Chang ◽  
Eric Feunteun ◽  
Yasumasa Miyazawa ◽  
Katsumi Tsukamoto
Keyword(s):  
Ocean Circulation ◽  
Specific Area ◽  
Migration Behavior ◽  
Sargasso Sea ◽  
Distribution Fitting ◽  
Particle Tracking Method ◽  
Spawning Area ◽  
Mid Atlantic Ridge ◽  
And Migration ◽  
Atlantic Eels

Abstract The Sargasso Sea has long been considered as the only spawning area for Atlantic eels, despite the absence of direct observations. The present study raises a novel scenario, deviating from Schmidt’s dogma, begins with a review of historical and recent observations that were combined to build up a global theory on spawning ecology and migration behavior of Atlantic eels. From this, it is argued that a favorable spawning area could be located eastward of Sargasso Sea at the intersection between the Mid-Atlantic Ridge and the oceanic fronts. Ocean circulation models combined with 3D particle-tracking method confirmed that spawning at this specific area would result in larval distribution fitting the field observation. This study explores the hypothesis that leptocephali are able to swim and orientate to reach their specific growth areas. It proposes a novel framework about spawning ecology, based on orientation, navigation and meeting cues of silver eels to the spawning area. Together this framework may serve as a stepping-stone for solving the long-lasting mystery of eel reproduction which first came out 2,400 years ago and promotes the understanding of oceanic migration and reproduction of marine organisms.

Hatching time and larval growth of Atlantic eels in the Sargasso Sea

2017 ◽  
Vol 164 (5) ◽  
Author(s):  
Mari Kuroki ◽  
Lasse Marohn ◽  
Klaus Wysujack ◽  
Michael J. Miller ◽  
Katsumi Tsukamoto ◽  
...  
Keyword(s):  
Larval Growth ◽  
Sargasso Sea ◽  
Hatching Time ◽  
Atlantic Eels

scholarly journals Oceanic fronts in the Sargasso Sea control the early life and drift of Atlantic eels

2010 ◽  
Vol 277 (1700) ◽  
pp. 3593-3599 ◽  
Author(s):  
Peter Munk ◽  
Michael M. Hansen ◽  
Gregory E. Maes ◽  
Torkel G. Nielsen ◽  
Martin Castonguay ◽  
...  
Keyword(s):  
Life Cycle ◽  
Life Histories ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Sargasso Sea ◽  
American Eel ◽  
Wide Range ◽  
Frontal Processes ◽  
Glass Eels ◽  
Atlantic Eels

Anguillid freshwater eels show remarkable life histories. In the Atlantic, the European eel ( Anguilla anguilla ) and American eel ( Anguilla rostrata ) undertake extensive migrations to spawn in the oceanic Sargasso Sea, and subsequently the offspring drift to foraging areas in Europe and North America, first as leaf-like leptocephali larvae that later metamorphose into glass eels. Since recruitment of European and American glass eels has declined drastically during past decades, there is a strong demand for further understanding of the early, oceanic phase of their life cycle. Consequently, during a field expedition to the eel spawning sites in the Sargasso Sea, we carried out a wide range of dedicated bio-physical studies across areas of eel larval distribution. Our findings suggest a key role of oceanic frontal processes, retaining eel larvae within a zone of enhanced feeding conditions and steering their drift. The majority of the more westerly distributed American eel larvae are likely to follow a westerly/northerly drift route entrained in the Antilles/Florida Currents. European eel larvae are generally believed to initially follow the same route, but their more easterly distribution close to the eastward flowing Subtropical Counter Current indicates that these larvae could follow a shorter, eastward route towards the Azores and Europe. The findings emphasize the significance of oceanic physical–biological linkages in the life-cycle completion of Atlantic eels.

Systematic effects in observed parallaxes

1978 ◽  
Vol 48 ◽  
pp. 31-35
Author(s):  
R. B. Hanson
Keyword(s):  
Error Estimates ◽  
Zero Point ◽  
Absolute Zero ◽  
Apparent Magnitude ◽  
Coherent System ◽  
Preliminary Results ◽  
General Catalogue ◽  
Systematic Effects ◽  
New Evidence ◽  
Right Ascension

Several outstanding problems affecting the existing parallaxes should be resolved to form a coherent system for the new General Catalogue proposed by van Altena, as well as to improve luminosity calibrations and other parallax applications. Lutz has reviewed several of these problems, such as: (A) systematic differences between observatories, (B) external error estimates, (C) the absolute zero point, and (D) systematic observational effects (in right ascension, declination, apparent magnitude, etc.). Here we explore the use of cluster and spectroscopic parallaxes, and the distributions of observed parallaxes, to bring new evidence to bear on these classic problems. Several preliminary results have been obtained.

MERLIN Finds New Evidence of Ranolazine Safety

2007 ◽  
Vol 40 (9) ◽  
pp. 36
Author(s):  
BRUCE JANCIN
Keyword(s):  
New Evidence

Vaccination for travellers – new evidence and recommendations

2001 ◽  
Vol 58 (6) ◽  
pp. 362-366 ◽  
Author(s):  
Matius P. Stürchler ◽  
R. P. Steffen
Keyword(s):  
Hepatitis B ◽  
Hepatitis A ◽  
New Evidence

Impfungen sind einfache und effektive Maßnahmen zur Verhinderung von Reisekrankheiten. Compliance-Probleme sind gering, da alle Impfungen noch vor Abreise verabreicht werden und bei manchen Impfungen nur eine Dosis für den zuverlässigen Schutz nötig ist. Für jeden Reisenden sind die Hepatitis A- und die Diphtherie-Tetanus-Impfung empfohlen, für Asien und Afrika auch die Polioimpfung. Bei Reisen >30 Tagen, jüngeren Personen und Reisenden mit Risikoverhalten sollte immer auch eine Hepatitis B-Impfung, eventuell als Kombination mit Hepatitis A in Betracht gezogen werden. Je nach Reisestil, -destination und -dauer können auch weitere Impfungen wie z.B. die Typhus-, Tollwut-, Zeckenenzephalitis-, Grippe-, Masern-Mumps-Röteln-, Gelbfieber-, Meningokokkenmeningitis- und die Japanische Enzephalitis-Impfung in Frage kommen. Mehrere Impfungen können gleichzeitig verabreicht werden – eine Staffelung ist nicht nötig. i BAG Supplementum VI, Stand Juli 2000 «Impfungen für Auslandreisende»; http://www.admin.ch/bag/infekt/prev/reisemed/index.htm; Safetravel http://www.safetravel.ch; Tropimed

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