Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study of Bigeye Tuna in Northwest Atlantic Uses New Tracking Methods

01.08.2014

A first-of-its-kind study of bigeye tuna movements in the northwestern Atlantic Ocean led by Molly Lutcavage, director of the Large Pelagics Research Center at the University of Massachusetts Amherst, found among other things that these fish cover a wide geographical range with pronounced north-south movements from Georges Bank to the Brazilian shelf, and they favor a high-use area off Cape Hatteras southwest of Bermuda for foraging.

This NOAA-funded research, which used a new approach to study one of the most important commercial tuna species in the Atlantic, provides the longest available fishery-independent record of bigeye tuna movements to date. Data should help researchers to further characterize habitat use and assess the need for more monitoring in high-catch areas.


Pelagic longline vessel Captain Scott Drabinowicz and crew preparing to deploy a tag from the deck of the FV Eagle Eye II.

Results appear this week in an early online edition of the Canadian Journal of Fisheries and Aquatic Science.

Fisheries oceanographer Lutcavage says, “Although Atlantic bigeye tuna are delivering high prices to the U.S. commercial fleet and are highly sought by recreational fishermen and fishing tournaments, there’s been a surprising lack of scientific research on this species.

And in contrast to the Pacific, where tuna fisheries programs have deployed over 400,000 tags over 25 years, the Atlantic lacks the fisheries infrastructure that would increase the odds of recovering tags. We have to rely on popup satellite tags that are fishery independent to make sure we get information back from the tuna.”

Two earlier electronic tagging studies by others yielded relatively short tracking data, 113 days or fewer, and did not allow for seasonal analysis of movement or exploration of an alternate stock composition hypotheses, Lutcavage and colleagues note. Bigeye are currently managed as a single Atlantic stock, she explains, and the greater resolution of habitat use and migratory behavior revealed in this study are important first steps towards determining whether or not a more complex management approach may be warranted.

Working with pelagic longline vessel captains Scott Drabinowicz and John Caldwell of the FV Eagle Eye II out of Fairhaven, Mass., Lutcavage, with LPRC colleagues Tim Lam and doctoral candidate Ben Galuardi, deployed 21 pop-up satellite archival tags (PSAT) on adult bigeye tuna between 2008 and 2010 in the northwest Atlantic.

The sea captains fit tags on fish in good condition and return them to the sea. The PSATs were programmed to record relative light level, temperature and pressure (depth) every two minutes for eight or 12 months.

Lutcavage, Lam and Galuardi were able to collect full-resolution time series data from a total of nine tags, providing data ranging from one to 292 days. The team also downloaded remote sensing and climatological information from the NOAA to characterize possible associations between bigeye tuna movement and behavior and environmental factors. 

Among variables they analyzed were the bigeyes’ use of the deep scattering layer for foraging. That is an ocean layer of marine life that rises and falls in relation to diurnal vertical migration. The researchers also looked at lunar influences on swimming depth, horizontal movements, plus vertical activity and factors influencing it such as temperature.

Lam explains, “Bigeye tuna dive deeply, like clockwork, at dusk and dawn, making it hard to use light-based geolocation methods to estimate their daily locations. Here, we showcase a new positioning technique to get around the problem of low light levels at depth by using temperature and the bigeyes’ spatial ecology and movements in the western Atlantic. But there’s much more to learn.”

The authors hope their results will inform the International Commission for the Conservation of Atlantic Tuna’s upcoming tagging effort and assist ICCAT scientists as they plan new research to better understand the population.

Alain Fonteneau, an emeritus scientist at France’s Institut de Recherches pour le Développement and a recognized expert member of scientific panels that manage regional tuna fisheries worldwide, called this work “fantastic.” He says, “Although we don’t see major unexpected surprises in these results, as we often see with Atlantic bluefin tuna results, this paper is the first one in the scientific literature to provide very new and very interesting results on bigeye vertical and geographical movements in the western Atlantic,” he points out.

Fonteneau adds, “Although these real observations are based on a small number of PSAT tags, they are much more comprehensive than the traditional catch-and-effort fishery data, at one time the only type available to ICCAT tuna scientists. It would clearly be of major scientific interest to develop this type of work at the scale of the entire Atlantic Ocean.”

Link

Janet Lathrop | Eurek Alert!
Further information:
http://www.umass.edu/newsoffice/article/umass-amherst-study-bigeye-tuna-northwest

Further reports about: Amherst Fisheries PSAT Tracking depth movement movements satellite species temperature tuna

More articles from Studies and Analyses:

nachricht High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg

nachricht Brain connectivity reveals hidden motives
04.03.2016 | Universität Zürich

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Computational high-throughput screening finds hard magnets containing less rare earth elements

Permanent magnets are very important for technologies of the future like electromobility and renewable energy, and rare earth elements (REE) are necessary for their manufacture. The Fraunhofer Institute for Mechanics of Materials IWM in Freiburg, Germany, has now succeeded in identifying promising approaches and materials for new permanent magnets through use of an in-house simulation process based on high-throughput screening (HTS). The team was able to improve magnetic properties this way and at the same time replaced REE with elements that are less expensive and readily available. The results were published in the online technical journal “Scientific Reports”.

The starting point for IWM researchers Wolfgang Körner, Georg Krugel, and Christian Elsässer was a neodymium-iron-nitrogen compound based on a type of...

Im Focus: Atomic precision: technologies for the next-but-one generation of microchips

In the Beyond EUV project, the Fraunhofer Institutes for Laser Technology ILT in Aachen and for Applied Optics and Precision Engineering IOF in Jena are developing key technologies for the manufacture of a new generation of microchips using EUV radiation at a wavelength of 6.7 nm. The resulting structures are barely thicker than single atoms, and they make it possible to produce extremely integrated circuits for such items as wearables or mind-controlled prosthetic limbs.

In 1965 Gordon Moore formulated the law that came to be named after him, which states that the complexity of integrated circuits doubles every one to two...

Im Focus: Researchers demonstrate size quantization of Dirac fermions in graphene

Characterization of high-quality material reveals important details relevant to next generation nanoelectronic devices

Quantum mechanics is the field of physics governing the behavior of things on atomic scales, where things work very differently from our everyday world.

Im Focus: Graphene: A quantum of current

When current comes in discrete packages: Viennese scientists unravel the quantum properties of the carbon material graphene

In 2010 the Nobel Prize in physics was awarded for the discovery of the exceptional material graphene, which consists of a single layer of carbon atoms...

Im Focus: Transparent - Flexible - Printable: Key technologies for tomorrow’s displays

The trend-forward world of display technology relies on innovative materials and novel approaches to steadily advance the visual experience, for example through higher pixel densities, better contrast, larger formats or user-friendler design. Fraunhofer ISC’s newly developed materials for optics and electronics now broaden the application potential of next generation displays. Learn about lower cost-effective wet-chemical printing procedures and the new materials at the Fraunhofer ISC booth # 1021 in North Hall D during the SID International Symposium on Information Display held from 22 to 27 May 2016 at San Francisco’s Moscone Center.

Economical processing

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Networking 4.0: International Laser Technology Congress AKL’16 Shows New Ways of Cooperations

24.05.2016 | Event News

Challenges of rural labor markets

20.05.2016 | Event News

International expert meeting “Health Business Connect” in France

19.05.2016 | Event News

 
Latest News

LZH shows the potential of the laser for industrial manufacturing at the LASYS 2016

25.05.2016 | Trade Fair News

Great apes communicate cooperatively

25.05.2016 | Life Sciences

Thermo-Optical Measuring method (TOM) could save several million tons of CO2 in coal-fired plants

25.05.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>