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

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.

2006 ◽  
Vol 73 (23) ◽  
Author(s):  
Yuta Sato ◽  
Takashi Yumura ◽  
Kazu Suenaga ◽  
Koki Urita ◽  
Hiromichi Kataura ◽  
...  

2021 ◽  
Vol 1 (4) ◽  
pp. 20-32
Author(s):  
Anastasia Sokolova ◽  
Olga Kalachikova

The aim of this article is to investigate the connection between behavioral economy and migration processes. Behavioral economics is a relatively new phenomenon in science and the fact that some research in this area has earned the Nobel Prize makes its contribution significant in the consideration of economic processes. The analysis of sources shows that in the field of Russian studies there is practically no mention of the fact that migration behavior can be explained by the behavioral economics theses. In this article, we explore several key ideas in this area: nudge theory, prospect theory, evolutionary game theory, cognitive distortion, and hedonistic adaptation. In this article, we put forward a hypothesis that migration processes can not only be explained from the standpoint of behavioral economics but can also be regulated using the tools of this direction. Behavioral economics can be the key for discovering the dynamics and true motives of migration. The analysis of information in this area shows, that a person makes decisions mainly based not on the laws of logic and rationalism. Paradoxes such as cognitive biases, etc. reduce the effectiveness of an individual's actions and provide an incentive for the scientific community to expand the number of empirical studies of migration processes within the framework of behavioral economics theories.


2021 ◽  
Author(s):  
Stephen Kelly ◽  
Ekaterina Popova ◽  
Zoe Jacobs

<p>Marine circulation connectivity describes the pathways and timescales over which spatially separated parts of the ocean are connected by oceanic currents. In the Western Indian Ocean (WIO), these pathways and associated timescales are characterised by pronounced seasonal and interannual variability, including monsoon-driven reversal of surface currents in the northern part of the basin.</p><p>Understanding the connectivity timescales in the WIO – and their variability – is important for a multitude of reasons. Ecological connectivity between coral reefs is necessary to maintain their biodiversity, understanding downstream connectivity from marine resource exploitation sites is important to understand which areas are likely to be affected, and circulation connectivity is a key concern when designing marine conservation measures. For example, establishing an effective network of marine protected areas (MPAs) requires that they are connected on ecologically relevant timescales (e.g. the duration of species’ pelagic larval stages), but gaps in the existing MPA network mean that decisions need to be undertaken about which areas to prioritise for future protection. Therefore, knowledge of the advective pathways connecting the WIO over these timescales is essential for effective management of the region.</p><p>Here, a Lagrangian particle tracking method is used in conjunction with a 1/12° resolution ocean model to elucidate the advective pathways mediated by major surface currents in the WIO. Model experiments are performed with virtual particles released into several major WIO currents and tracked for 100 days, and the resulting trajectories are analysed. Significant variability was found, with advective pathways and timescales sensitive to both season and year of release. The main differences are associated with the different monsoon regimes driving changes in connectivity timescales, and reversing direction of advective pathways in the north of the WIO. In addition to this seasonal variability, interannual changes are explored. Case studies of anomalous connectivity pathways / timescales are presented and discussed in the context of extremes in forcing and larger scale variability, including the Indian Ocean Dipole.  </p>


2022 ◽  
Vol 276 ◽  
pp. 125334
Author(s):  
Z.A.Y. Abdalla ◽  
E.G. Njoroge ◽  
M. Mlambo ◽  
S.V. Motloung ◽  
J.B. Malherbe ◽  
...  

IUBMB Life ◽  
2019 ◽  
Vol 71 (12) ◽  
pp. 1929-1936
Author(s):  
Sadaf Ghanaatgar‐Kasbi ◽  
Forouzan Amerizadeh ◽  
Farzad Rahmani ◽  
Seyed Mahdi Hassanian ◽  
Majid Khazaei ◽  
...  

2012 ◽  
Vol 198 (5) ◽  
pp. 941-952 ◽  
Author(s):  
Stephanie Woo ◽  
Michael P. Housley ◽  
Orion D. Weiner ◽  
Didier Y.R. Stainier

Embryo morphogenesis is driven by dynamic cell behaviors, including migration, that are coordinated with fate specification and differentiation, but how such coordination is achieved remains poorly understood. During zebrafish gastrulation, endodermal cells sequentially exhibit first random, nonpersistent migration followed by oriented, persistent migration and finally collective migration. Using a novel transgenic line that labels the endodermal actin cytoskeleton, we found that these stage-dependent changes in migratory behavior correlated with changes in actin dynamics. The dynamic actin and random motility exhibited during early gastrulation were dependent on both Nodal and Rac1 signaling. We further identified the Rac-specific guanine nucleotide exchange factor Prex1 as a Nodal target and showed that it mediated Nodal-dependent random motility. Reducing Rac1 activity in endodermal cells caused them to bypass the random migration phase and aberrantly contribute to mesodermal tissues. Together, our results reveal a novel role for Nodal signaling in regulating actin dynamics and migration behavior, which are crucial for endodermal morphogenesis and cell fate decisions.


2014 ◽  
Vol 783-786 ◽  
pp. 1634-1639
Author(s):  
Dmitri A. Molodov ◽  
Jann Erik Brandenburg ◽  
Luis Antonio Barrales-Mora ◽  
Günter Gottstein

The faceting and migration behavior of low angle <100> grain boundaries in high purity aluminum bicrystals was investigated. In-situ technique based on orientation contrast imaging was applied. In contrast to the pure tilt boundaries, which remained straight/flat and immobile during annealing at elevated temperatures, mixed tilt-twist boundaries readily assumed a curved shape and steadily moved under the capillary force. Computational analysis revealed that this behavior is due to the inclinational anisotropy of grain boundary energy, which in turn depends on boundary geometry – the energy of pure tilt low angle <100> boundaries is anisotropic, whereas that of mixed tilt-twist boundaries isotropic with respect to boundary inclination.


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