Welcome to FIS   Sponsored By
United States
Subscribe to FIS | Register with FIS | Advertise with FIS | Newsletter | About FIS | Contact us
   


Wide-ranging acoustic images could help researchers identify populations on the brink of collapse.(Photo: news.mit.edu)

Oceanographers manage to image entire cod shoals

Click on the flag for more information about United States UNITED STATES
Thursday, November 08, 2018, 02:50 (GMT + 9)

A team of researchers has been able to image multiple cod shoals, the largest spanning 50 kilometres (about 30 miles), which let them estimate that the average cod shoal consists of about 10 million individual fish.

These scientists, led by Nicholas Makris, professor of mechanical engineering and director of the Centre for Ocean Engineering and Olav Rune Godø from the Norwegian Institute of Marine Research, also found that when the total population of cod dropped below the average shoal size, the species remained in decline for decades.

To image cod and herring shoals, the team made use of the Ocean Acoutic Waveguide Remote Sensing (OAWRS system), an imaging technique developed at the Massachusetts Institute of Technology (MIT) by Makris and co-author Purnima Ratilal, which emits low-frequency sound waves that can travel over a much wider range than high-frequency sonar.

 

  Spatial population distributions of entire Atlantic cod spawning groups of the Northeast Arctic obtained by instantaneous imaging. The image above on the left shows, in red circles, areas where researchers imaged spawning grounds of Atlantic cod in Lofoten, Norway. The image on the right depicts a 40-kilometre-wide stable cod group containing about 40 million specimens. The image at the bottom on the left shows a 20-kilometre-scale cod group of about 1 million specimens near Andenes, Norway. (Photo: Courtesy of the researchers / mit.edu)

The sound waves are essentially tuned to bounce off fish, in particular, off their swim bladder — a gas-filled organ that reflects sound waves — like echoes off a tiny drum. As these echoes return to the ship, researchers can aggregate them to produce an instant picture of millions of fish over vast areas.

In February and March of 2014, Makris and a team of students towed OAWRS aboard the Knorr, a US Navy research vessel that is operated by the Woods Hole Oceanographic Institution. The ship left Woods Hole and crossed the Atlantic over two weeks, during which time the crew continuously battled storms and choppy winter seas.

The RV Knorr, in Norway’s Alesund harbour in February 2014, as the crew prepare to begin their Nordic Seas Experiment. (Image: Michael Collins, U.S. Naval Research Laboratory / mit.edu)

When they finally arrived at the southern coast of Norway, they spent the next three weeks imaging herring, cod, and capelin along the entire Norwegian coast, from the town of Alesund, north to the Russian border.

As they moved up the Norwegian coast, the researchers towed a 0.5-kilometre-long array of passive underwater microphones and a device that emitted low-frequency sound waves. After imaging herring shoals in southern Norway, the team moved north to Lofoten, which remains a primary spawning ground for cod, and there, Makris’ team was able to produce the first-ever images of an entire cod shoal, spanning 50 kilometres.

Toward the end of their journey, the researchers planned to image one last cod region, just as a hurricane was projected to hit. The team realized there would be only two windows of relatively calm winds in which to operate their imaging equipment.

Back on dry land, the researchers analyzed their images and estimated that an average shoal size consists of about 10 million fish. 

The team also imaged shoals of herring and found a similar trend through history: When the total population dropped below the level of an average herring spawning shoal, it took decades for the fish to recover.

Makris and Godø hope that the team’s results will serve as a measuring stick of sorts, to help researchers keep track of fish stocks and recognize when a species is on the brink.

This research findings were published in the journal Fish and Fisheries


editorial@fis.com
www.fis.com


 Print


Click to know how to advertise in FIS
MORE NEWS
Chile
Dec 15, 03:00 (GMT + 9):
Industrial fishing unions protest about Fisheries Act amendment agreement
European Union
Dec 15, 02:50 (GMT + 9):
Council of Ministers to set TACs for the Atlantic, North Sea and Black Sea
New Zealand
Dec 15, 02:10 (GMT + 9):
Govt. announces investments in Eastern Bay of Plenty aquaculture initiatives
European Union
Dec 15, 01:20 (GMT + 9):
Europêche rejects quota increase of fish imports with zero tariff
United States
Dec 15, 01:20 (GMT + 9):
Fisheries landings grow in volume and in value in 2017
Japan
Dec 15, 00:00 (GMT + 9):
Shrimp fishing season called off in Suruga Bay to protect the resource
Argentina
Dec 14, 23:30 (GMT + 9):
Hake maximum capture set for 2019
Peru
Dec 14, 23:00 (GMT + 9):
Singapore-based technology firm to help boost trout farming using AI
United States
Dec 14, 22:40 (GMT + 9):
Pacific Islands countries call for high sea tuna transshipment measures
Chile
Dec 14, 21:10 (GMT + 9):
Artisanal organizations from Valparaíso granted funds for value aggregation projects
United Kingdom
Dec 14, 20:50 (GMT + 9):
IN BRIEF - Brexit: MPs 'disappointed' with response to inquiry into future of fishing in NI
Uganda
Dec 14, 20:30 (GMT + 9):
IN BRIEF - Makerere unveils fat research deal to improve fish farming
United States
Dec 14, 20:30 (GMT + 9):
IN BRIEF - Warmer Arctic temperatures are killing cod and the effects are being felt in Oregon
United Kingdom
Dec 14, 20:00 (GMT + 9):
IN BRIEF - Ship transporting live fish breaks down off Ardnamurchan
United Kingdom
Dec 14, 20:00 (GMT + 9):
IN BRIEF - Why the wrasse is the UK's most expensive fish



Lenguaje
FEATURED EVENTS
  
TOP STORIES
Jealsa becomes a new IPNLF member
Spain Galicia’s Jealsa Rianxeira Group has become the latest Member of the International Pole & Line Foundation.
SONAPESCA files suit against SUBPESCA for fishery auctions
Chile The National Fishing Society filed a new lawsuit with the Free Competition Court against the tenders of six fisheries initiated by the Undersecretariat of Fisheries and Aquaculture in November.
WWF urges EU Member states to meet CFP deadlines
European Union The conservation organisation WWF indicates that Member States are still lagging behind and are likely to miss important 2020 deadlines on biodiversity conservation and sustainable fisheries management.
EU Council of Ministers agrees on autonomous EU tariff quotas for 2019-2020
European Union The European Union Council of Ministers have adopted a regulation that will allow the EU fish processing industry to continue to import raw material for further processing from non-EU countries at reduced rates or duty free.
 
Maruha Nichiro Corporation
Nichirei Corporation - Headquarters
Pesquera El Golfo S.A.
Ventisqueros - Productos del Mar Ventisqueros S.A
Wärtsilä Corporation -Wartsila Group Headquarter-
ITOCHU Corporation -Headquarter-
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.
Blue Continent Products (Pty) Ltd - (Oceana Group Limited)
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
Hamburg Süd Group - (Headquearters)
Armadora Pereira S.A. - Group Headquarters
NOAA - National Oceanic and Atmospheric Administration (Headquarters)
Omega Protein Corporation
Marona S.A.
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
Mitsubishi Corporation Marine Products Depts. D.Team
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
AKBM - Aker BioMarine ASA
Seafood Choices Alliance -Headquarter-
Austevoll Seafood ASA
Walmart / Wal-Mart Stores, Inc. (Supermarket) -Headquarter-
New Japan Radio Co.Ltd (JRC) -Head Office-
Gulfstream JSC
INVE Group - Head Office
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
Morpol ASA - Group Headquarters
SeaChoice
National Geographic Society
AmazonFresh, LLC - AmazonFresh

Copyright 1995 - 2018 Fish Info & Services Co.Ltd| All Rights Reserved.   DISCLAIMER