Welcome   Sponsored By
Subscribe | Register | Advertise | Newsletter | About us | Contact us
   


Simulated view of how fish camouflage in the sea. (Photo: Cummings lab.)

Scientists reveal ocean fish camouflage secrets

Click on the flag for more information about United States UNITED STATES
Tuesday, November 24, 2015, 01:50 (GMT + 9)

A team of scientists from the University of Texas, Austin, has found out that certain fish use microscopic structures called platelets in their skin cells to reflect polarized light, which allows the fish to seemingly disappear from their predators.

The discovery of this method, known as ocean camouflage, could help materials scientists and military technologists create more effective methods of ocean camouflage.

According to the report describing the discovery results, published in the journal Science, polarized light is made up of light waves all traveling in the same plane, such as the bright glare you sometimes see when sunlight reflects off the surface of water.

Under the surface of the water, light tends to be polarized. Many fish—and sophisticated modern satellites—have the ability to detect variations in such polarized light.

“Fish have evolved the means to detect polarized light,” said Molly Cummings, professor of integrative biology in the College of Natural Sciences. “Given that, we suggested they’ve probably evolved the means to hide in polarized light. If we can identify that process, then we can improve upon our own camouflage technology for that environment.”

Whether it’s a predator pursuing a fish or a satellite seeking an adversary, light patterns help with detection of targets in the the open ocean in three ways: through brightness contrast, color contrast and polarization contrast. Of the three, polarization contrast is considered most effective for detection in the open ocean.

The US Navy has sought for many years to learn how to hide in open water and supported the work of Cummings and her colleagues exploring how fish avoid detection in the open ocean.

In a previous study, the researchers demonstrated in the lab that a fish called the lookdown was able to manipulate polarized light to its advantage. The new study—conducted in the actual ocean, not just in test environments—shows lookdowns and other fish that live in the open ocean camouflage themselves this way.

For his part, Parrish Brady, a collaborator with Cummings and lead author on the new study, built a video polarimeter that can record polarized light in real time, allowing the researchers to essentially see polarized light as fish do.

Brady and Cummings worked with scientists from City College of New York, Texas A&M University and other institutions to build an automated rotating platform that would hold the fish in place in the water while Brady’s polarimeter took constant measurements.

On the platform, a fish is held in place on a mirror, while an adjustable arm holds the video polarimeter a meter away. Once started, the platform takes three minutes to spin 360 degrees, with the polarimeter recording the whole time.

After every revolution researchers would make an adjustment, such as moving the polarimeter to a slightly different angle or adjusting how much the fish was tilted, and then start the apparatus on another rotation.

More than 1,500 different angular configurations were recorded in this way for each fish, taking into account camera location, angle of the sun overhead and position of the fish. Recordings were conducted in the Florida Keys and Curaçao for five species of fish.

The results showed that the two fish from the open ocean, the lookdown and the bigeye scad, had much better camouflage in polarized light than a mirror had. They also blended in better than two reef-dwelling fish and one surface-skimming fish, all of which live in environments where polarized light is not as important.

Notably, the open ocean fish were most camouflaged in what are called “chase angles,” which extend out 45 degrees in all directions from the tail or head. These are the directions from which a predator would chase the fish, or from which the fish would pursue its own prey.

As to how the fish accomplish this concealment, the Cummings lab found that the fish’s ability to camouflage in polarized light is due to the structure of platelets within the skin cells, which scatter polarized light differently depending on the angle. The researchers will next look into whether the fish can actively manipulate this ability, maybe by changing the angle at which they swim or somehow adjusting the platelets within their skin.

“I think it’s a great example of how human applications can take advantage of evolutionary solutions and the value of evolutionary biology,” said Cummings. “It's important for people to recognize that we take advantage of evolutionary processes and solutions all the time and that even our military does.”

Many fish that live in the open ocean are silvery, which allows them to reflect light as a mirror does. For many years, experts assumed this was the main means of camouflage among such fish, but this camouflage approach works well only if the surrounding water appears uniform, as it does to human eyes. Polarized light turns out to be an important component of the underwater light field, and it is not uniform but instead highly variable. Using mirrors for camouflage in such an environment can actually backfire and make it easier to stand out in the open ocean.


editorial@seafood.media
www.seafood.media


 Print


Click to know how to advertise in FIS
MORE NEWS
Japan
Mar 29, 03:00 (GMT + 9):
Driftnet fishing for salmon and trout starts early. Agreement with Russia
Russian Federation
Mar 29, 01:00 (GMT + 9):
Will the Russian Far East be the country with the most snow crabs in 2025?
Viet Nam
Mar 29, 01:00 (GMT + 9):
Shrimp exports from Ecuador are facing many challenges
Australia
Mar 28, 21:10 (GMT + 9):
IN BRIEF - At WTO, Australia seeks details on India's fisheries plan
Croatia
Mar 28, 21:00 (GMT + 9):
IN BRIEF - Cromaris business results in 2023
United States
Mar 28, 07:20 (GMT + 9):
AQUA Cultured Foods Partners with Ginkgo Bioworks to Optimize Alt-Seafood Production
United States
Mar 28, 07:00 (GMT + 9):
Seafood Expo Global Announced Finalists of the 2024 Seafood Excellence Global Awards
Norway
Mar 28, 07:00 (GMT + 9):
Borealis and AKVA group launch groundbreaking Polarcirkel™ workboat hull crafted from renewable feedstock-based plastic
Viet Nam
Mar 28, 07:00 (GMT + 9):
China & HK imported 75 million USD of Vietnamese pangasius
Japan
Mar 28, 07:00 (GMT + 9):
The first fly meal-based food in Japan developed by Nichimo
United States
Mar 28, 06:50 (GMT + 9):
Southern Shrimp Alliance Praises Congressional Representatives for Demanding Action on Indian Shrimp
Norway
Mar 28, 06:50 (GMT + 9):
Fish Pool Salmon Price Status Report for week 13
Norway
Mar 28, 06:40 (GMT + 9):
Statistics │ Export by destination │ Atlantic salmon: semi-dress/fillet fresh │ by country │ 2022-23-24
Papua New Guinea
Mar 28, 04:00 (GMT + 9):
IN BRIEF - Thrilling progress in PNG fisheries sector
Norway
Mar 28, 01:00 (GMT + 9):
IN BRIEF - Marine protected areas safeguard more than ecology – they bring economic benefits to fisheries and tourism



Lenguaje
FEATURED EVENTS
  
TOP STORIES
Clipfish challenges in Brazil: Port bureaucracy stops millions worth
Brazil More and more clipfish containers are being stopped in Brazilian ports. - Complicated regulations make market access challenging, to say the least, say Norwegian exporters who risk large losses. Bra...
Catches in the Sea of Okhotsk and Bering Sea
Russia Fed. Situational update as of 03/24/2024 Source: Stockfile FIS Sea of Okhotsk (pollock) According to OSM data in the Sea of Okhotsk, pollock catch (industrial and coastal fisheries) as of March 24, 20...
Productive Development of the Fishing Activity
Peru Fishing Sector Bulletin - January 2024 The landing of hydrobiological resources registered a negative interannual variation of 62.7%, as a result of the lower landing of fishing resources for indirec...
NGO Sues UK Government Over International Fishing Quotas
United Kingdom Blue Marine Foundation, a charity dedicated to restoring the ocean to health, has launched legal proceedings over the government’s decision to set fishing opportunities, for more than half UK st...
 

Maruha Nichiro Corporation
Nichirei Corporation - Headquarters
Pesquera El Golfo S.A.
Ventisqueros - Productos del Mar Ventisqueros S.A
Wärtsilä Corporation - Wartsila Group Headquarters
ITOCHU Corporation - Headquarters
BAADER - Nordischer Maschinenbau Rud. Baader GmbH+Co.KG (Head Office)
Inmarsat plc - Global Headquarters
Marks & Spencer
Tesco PLC (Supermarket) - Headquarters
Sea Harvest Corporation (PTY) Ltd. - Group Headquarters
I&J - Irvin & Johnson Holding Company (Pty) Ltd.
AquaChile S.A. - Group Headquarters
Pesquera San Jose S.A.
Nutreco N.V. - Head Office
CNFC China National Fisheries Corporation - Group Headquarters
W. van der Zwan & Zn. B.V.
SMMI - Sunderland Marine Mutual Insurance Co., Ltd. - Headquarters
Icicle Seafoods, Inc
Starkist Seafood Co. - Headquearters
Trident Seafoods Corp.
American Seafoods Group LLC - Head Office
Marel - Group Headquarters
SalMar ASA - Group Headquarters
Sajo Industries Co., Ltd
Hansung Enterprise Co.,Ltd.
BIM - Irish Sea Fisheries Board (An Bord Iascaigh Mhara)
CEFAS - Centre for Environment, Fisheries & Aquaculture Science
COPEINCA ASA - Corporacion Pesquera Inca S.A.C.
Chun Cheng Fishery Enterprise Pte Ltd.
VASEP - Vietnam Association of Seafood Exporters & Producers
Gomes da Costa
Furuno Electric Co., Ltd. (Headquarters)
NISSUI - Nippon Suisan Kaisha, Ltd. - Group Headquarters
FAO - Food and Agriculture Organization - Fisheries and Aquaculture Department (Headquarter)
Hagoromo Foods Co., Ltd.
Koden Electronics Co., Ltd. (Headquarters)
A.P. Møller - Maersk A/S - Headquarters
BVQI - Bureau Veritas Quality International (Head Office)
UPS - United Parcel Service, Inc. - Headquarters
Brim ehf (formerly HB Grandi Ltd) - Headquarters
Hamburg Süd Group - (Headquearters)
Armadora Pereira S.A. - Grupo Pereira Headquarters
Costa Meeresspezialitäten GmbH & Co. KG
NOAA - National Oceanic and Atmospheric Administration (Headquarters)
Mowi ASA (formerly Marine Harvest ASA) - Headquarters
Marubeni Europe Plc -UK-
Findus Ltd
Icom Inc. (Headquarter)
WWF Centroamerica
Oceana Group Limited
The David and Lucile Packard Foundation
Ajinomoto Co., Inc. - Headquarters
Friosur S.A. - Headquarters
Cargill, Incorporated - Global Headquarters
Benihana Inc.
Leardini Pescados Ltda
CJ Corporation  - Group Headquarters
Greenpeace International - The Netherlands | Headquarters
David Suzuki Foundation
Fisheries and Oceans Canada -Communications Branch-
Mitsui & Co.,Ltd - Headquarters
NOREBO Group (former Ocean Trawlers Group)
Natori Co., Ltd.
Carrefour Supermarket - Headquarters
FedEx Corporation - Headquarters
Cooke Inc. - Group Headquarters
AKBM - Aker BioMarine ASA
Seafood Choices Alliance -Headquarter-
Austevoll Seafood ASA
Walmart | Wal-Mart Stores, Inc. (Supermarket) - Headquarters
New Japan Radio Co.Ltd (JRC) -Head Office-
Gulfstream JSC
Marine Stewardship Council - MSC Worldwide Headquarters
Royal Dutch Shell plc (Headquarter)
Genki Sushi Co.,Ltd -Headquarter-
Iceland Pelagic ehf
AXA Assistance Argentina S.A.
Caterpillar Inc. - Headquarters
Tiger Brands Limited
SeaChoice
National Geographic Society
AmazonFresh, LLC - AmazonFresh

Copyright 1995 - 2024 Seafood Media Group Ltd.| All Rights Reserved.   DISCLAIMER