Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How do fishes perceive their environment?

03.05.2017

Fishes perceive changes in water currents caused by prey, conspecifics and predators using their lateral line. The tiny sensors of this organ also allow them to navigate reliably. However, with increasing current velocities, the background signal also increases. Scientists at the University of Bonn have now created a realistic, three-dimensional model of a fish for the first time and have simulated the precise current conditions. The virtual calculations show that particular anatomical adaptations minimize background noise. The results are now being presented in The Journal of the Royal Society Interface.

The ide (Leuciscus idus) is a fish that inhabits the lower stretches of slow-flowing rivers. Like most fishes, it can perceive the current using its lateral line. The mechanoreceptors of this organ are distributed over the surface of the entire body, which is why the organ provides a three-dimensional image of the hydrodynamic conditions.


In this image generated using micro-computed tomography, the blue dyed lateral lines of the ide (Leuciscus idus) are clear to see.

Source: Dr. Hendrik Herzog


Dr. Hendrik Herzog (left) and Dr. Alexander Ziegler from University of Bonn.

Photo: Dr. Andreas Kroh

Fishes can thus also find their way around themselves in the dark and identify prey, conspecifics, or predators. The recently retired zoologist Prof. Horst Bleckmann from the University of Bonn has spent many years researching the sensitive organ and has used it as inspiration for technical flow sensors in order to, for instance, identify leakages in water pipes.

First realistic three-dimensional computer model

The scientists Dr. Hendrik Herzog from the Institute of Zoology and Dr. Alexander Ziegler from the Institute of Evolutionary Biology and Ecology at the University of Bonn have now entered a new dimension of research into the lateral line in fish: they created the first realistic, three-dimensional computer model of the lateral line system, which they used to calculate the precise flow conditions of the surrounding water.

“We concentrated on the head of the ide, because the lateral line of the fish has a particularly complex form there,” reports Dr. Herzog.

This organ has two different types of sensors. Some protrude like small bumps from the surface of the fish’s skin and the water flows directly over them. Others sit in canals that are submerged into the cranial bone and are connected to the water via small pores. “If prey, such as a freshwater shrimp, is close by, the local water current and pressure conditions change,” explains Dr. Ziegler. The fish registers this with its many sensors. “However, until now, the actual function of such different types of current measurement had not been clarified conclusively.”

Both researchers received active support from Birgit Klein from the Westphalian University of Applied Sciences. In her bachelor thesis at the Institute of Zoology, the current master student compared various methods of 3D reconstruction. She took around 350 photos of the head of the ide from various angles and used them to produce a 3D model of the fish surface. She had dyed the channels and sensors of the lateral line beforehand, which is why the structures in the model can be clearly identified. She then optimized the dataset by digitizing the fish head using a much higher-resolution laser scanning procedure.

This created a realistic image of the fish surface, but the inside of the animal was not recorded in this way. This is why the researchers used a micro-computed tomography scanner as the third method. A contrast agent allowed the soft tissue to be shown even when using this X-ray technique. At the end, data from all three techniques flowed into the realistic model of the lateral line. The zoologists thus simulated various current conditions and calculated the hydrodynamic signals to the various sensors.

A strong current is a challenge for the fish, as the background noise for the sensors is particularly great. Nevertheless, the fish can precisely perceive its environment even with high water speeds. As the researchers show with their calculations, depressions ensure that the current is significantly reduced for the bump-like sensors that sit on the surface of the skin. “The relative signal strength of, for instance, prey organisms thus becomes greater,” explains Dr. Herzog. For the sensors in the channels, it was shown that certain sections of the lateral line are particularly sensitive to the respective current strength due to different channel diameters.

Bio-inspired application: improved navigation of underwater robots

“Using our methodical approach, comparative anatomical studies between different fish species with an especially high level of detail will be possible in the future,” reports Dr. Ziegler. His colleague sees bio-inspired applications in the foreground: "The knowledge from such 3D models of fish may also make it possible to significantly improve the autonomous navigation of underwater robots using flow sensors,” suggests Dr. Herzog.

Publication: Form and function of the teleost lateral line revealed using three-dimensional imaging and computational fluid dynamics, The Journal of the Royal Society Interface

Media contact:

Dr. Hendrik Herzog
Institute of Zoology
University of Bonn
Tel. +49 (0)228/735490
E-mail: hendrik.herzog@uni-bonn.de

Dr. Alexander Ziegler
Institute of Evolutionary Biology and Ecology
University of Bonn
Tel. +49 (0)228/735758
E-mail: aziegler@evolution.uni-bonn.de

Weitere Informationen:

http://dx.doi.org/10.1098/rsif.2016.0898 Publication

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de/

More articles from Life Sciences:

nachricht Flavins keep a handy helper in their pocket
25.04.2018 | University of Freiburg

nachricht Complete skin regeneration system of fish unraveled
24.04.2018 | Tokyo Institute of Technology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Getting electrons to move in a semiconductor

25.04.2018 | Physics and Astronomy

Reconstructing what makes us tick

25.04.2018 | Physics and Astronomy

Cheap 3-D printer can produce self-folding materials

25.04.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>