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.

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 April 19, 2014 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 April 19, 2014).

Share This



More Plants & Animals News

Saturday, April 19, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Vermont Goat Meat Gives Refugees Taste of Home

Vermont Goat Meat Gives Refugees Taste of Home

AP (Apr. 18, 2014) Dairy farmers and ethnic groups in Vermont are both benefiting from a unique collaborative effort that's feeding a growing need for fresh and affordable goat meat. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Little Progress Made In Fighting Food Poisoning, CDC Says

Little Progress Made In Fighting Food Poisoning, CDC Says

Newsy (Apr. 18, 2014) A new report shows rates of two foodborne infections increased in the U.S. in recent years, while salmonella actually dropped 9 percent. Video provided by Newsy
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:
from the past week

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