Featured Research

from universities, journals, and other organizations

Fishy physics: Adaptation lets silvery fish reflect light without polarization, may help them evade predators

Date:
October 21, 2012
Source:
University of Bristol
Summary:
Silvery fish such as herring, sardine and sprat have evolved special skin that gets around a basic law of physics, according to new research. Reflective surfaces polarize light, a phenomenon that fishermen or photographers overcome by using polarizing sunglasses or polarizing filters to cut our reflective glare. However, researchers found that these silvery fish have overcome this basic law of reflection -- an adaptation that may help them evade predators.

Herring. The skin of sardines and herring contain not one but two types of guanine crystal -- each with different optical properties. By mixing these two types, the fish's skin doesn't polarize the reflected light and maintains its high reflectivity.
Credit: dbvirago / Fotolia

Silvery fish such as herring, sardine and sprat have evolved special skin that gets around a basic law of physics, according to new research from the University of Bristol published Oct. 21 in Nature Photonics.

Related Articles


Reflective surfaces polarize light, a phenomenon that fishermen or photographers overcome by using polarizing sunglasses or polarizing filters to cut our reflective glare. However, PhD student Tom Jordan and his supervisors Professor Julian Partridge and Dr Nicholas Roberts in Bristol's School of Biological Sciences found that these silvery fish have overcome this basic law of reflection -- an adaptation that may help them evade predators.

Previously, it was thought that the fish's skin -- which contains "multilayer" arrangements of reflective guanine crystals -- would fully polarize light when reflected. As the light becomes polarized, there should be a drop in reflectivity.

The Bristol researchers found that the skin of sardines and herring contain not one but two types of guanine crystal -- each with different optical properties. By mixing these two types, the fish's skin doesn't polarize the reflected light and maintains its high reflectivity.

Dr Roberts said: "We believe these species of fish have evolved this particular multilayer structure to help conceal them from predators, such as dolphin and tuna. These fish have found a way to maximize their reflectivity over all angles they are viewed from. This helps the fish best match the light environment of the open ocean, making them less likely to be seen."

As a result of this ability, the skin of silvery fish could hold the key to better optical devices. Tom Jordan said: "Many modern day optical devices such as LED lights and low loss optical fibres use these non-polarizing types of reflectors to improve efficiency. However, these human-made reflectors currently require the use of materials with specific optical properties that are not always ideal. The mechanism that has evolved in fish overcomes this current design limitation and provides a new way to manufacture these non-polarizing reflectors."


Story Source:

The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. M. Jordan, J. C. Partridge, N. W. Roberts. Non-polarizing broadband multilayer reflectors in fish. Nature Photonics, 2012; DOI: 10.1038/nphoton.2012.260

Cite This Page:

University of Bristol. "Fishy physics: Adaptation lets silvery fish reflect light without polarization, may help them evade predators." ScienceDaily. ScienceDaily, 21 October 2012. <www.sciencedaily.com/releases/2012/10/121021133911.htm>.
University of Bristol. (2012, October 21). Fishy physics: Adaptation lets silvery fish reflect light without polarization, may help them evade predators. ScienceDaily. Retrieved February 28, 2015 from www.sciencedaily.com/releases/2012/10/121021133911.htm
University of Bristol. "Fishy physics: Adaptation lets silvery fish reflect light without polarization, may help them evade predators." ScienceDaily. www.sciencedaily.com/releases/2012/10/121021133911.htm (accessed February 28, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Saturday, February 28, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Whale-Watching Scientists Spot Baby Orca

Whale-Watching Scientists Spot Baby Orca

AP (Feb. 28, 2015) Researchers following endangered killer whales spotted a baby orca off the coast of Washington state, the third birth documented this winter but still leaving the population dangerously low. (Feb. 28) Video provided by AP
Powered by NewsLook.com
The Best Drinks for Your Health

The Best Drinks for Your Health

Buzz60 (Feb. 27, 2015) When it comes to health and fitness, there&apos;s lots of talk about what foods to eat, but there are a few liquids that can promote good nutrition. Krystin Goodwin (@krystingoodwin) has the healthiest drinks to boost your health! Video provided by Buzz60
Powered by NewsLook.com
Cherries, Snap Peas and More Tasty Spring Produce

Cherries, Snap Peas and More Tasty Spring Produce

Buzz60 (Feb. 27, 2015) From sweet cherries to sugar snap peas, spring is the peak season for some of the tastiest and healthiest produce. Krystin Goodwin (@Krystingoodwin) has the best seasonal fruits and veggies to spring in to good health! Video provided by Buzz60
Powered by NewsLook.com
The Best Foods to Battle Stress

The Best Foods to Battle Stress

Buzz60 (Feb. 26, 2015) If you&apos;re dealing with anxiety, there are a few foods that can help. Krystin Goodwin (@krystingoodwin) has the best foods to tame stress. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins