Over-fishing, pollution, river development, global climate changes, etc. are threatening a large number of migratory fish. Among the endangered species, one can cite the European eel whose numbers have been divided by 10 over the two last decades. To save the species, the priority is better management of the populations subjected to the pressures of the environment.
However, this first assumes better knowledge of the species’ biology and ecology. The exercise is complex, because the European eel’s life cycle is still not fully understood. The species has long been considered a migratory fish that reproduces at sea and grows in rivers. Yet studies conducted over the last 10 years have shown that certain individuals do not spend their growth period in freshwaters. Migratory divergences may exist at the elver stage. At Bordeaux and Saint-Pée-sur-Nivelle, in doctoral work co-supervised by Cemagref and the INRA, Sarah Bureau du Colombier has been studying the source of these different migratory patterns in European eel elvers.Sorting migrant fish and sedentary fish
All of these data were then used to feed an estuarial migration model that will eventually be used to simulate the migratory behaviour of elvers according to different parameters, some of which are related to global climate changes.Contacts:
Agnès Bardonnet, firstname.lastname@example.org (INRA, Saint-Pée-sur-Nivelle)
A complex life cycle
The European eel reproduces near the North American coast in the Sargasso Sea. The young larvae, called leptocephalus, cross the Atlantic Ocean on the ocean currents. Near the European and North African coasts, they metamorphose into elvers (young yellow eels). These individuals then settle in coastal zones or in estuaries, or swim up rivers. After they have metamorphosed into silver eels, the adults embark on their migration and reproduction in the Sargasso Sea.
Marie Signoret | alfa
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At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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