Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Track Atlantic bluefin tuna to learn migration, habitat secrets

23.05.2012
New fish-tagging studies of young bluefin tuna in Atlantic waters off New England by researchers at the University of Massachusetts Amherst are offering the first fishery-independent, year-round data on dispersal patterns and habitat use for the popular game fish. The availability of miniaturized pop-up satellite tags suitable for smaller (two- to five-year-old) fish helped make the research possible.

Fisheries oceanographer Molly Lutcavage and lead author Benjamin Galuardi say the work shows that scientists now have tools to directly observe bluefin tuna annual migration patterns and vertical habitat use (depth) in the Atlantic and Mediterranean oceans in detail not possible in earlier studies. This new information should lead to better understanding of bluefin tuna ecology, catch patterns and management of wild stocks that provide a multi-million dollar sport fishery from Maine to North Carolina.

Lutcavage, director of UMass Amherst's Marine Research Station and the Large Pelagics Research Center (LPRC) in Gloucester, says, "Our tagging data are important because for the first time we've got direct measurements of bluefin tuna movements and habitat associations. In other words, their travel routes, depth and temperature patterns, and where they intersect with recreational fisheries."

Galuardi, an LPRC scientist and doctoral candidate in the Graduate School of Marine Science at UMass Dartmouth, led the analysis of data returned from pop-up satellite tags used in this study, as well as oceanographic conditions across bluefin migration paths. Details are reported in today's issue of the Public Library of Science One (PLoS) journal.

"Knowing the dispersal patterns of these young fish after they leave their nursery grounds and learning their year-round habitat needs are important goals for the commercial fishery of adult bluefin tuna, as well," she adds. For example, these tunas' winter and spring movements and behavior of juveniles have largely been unknown until now.

For this study, Lutcavage, Galuardi and fishermen partners deployed 58 miniature pop-up satellite archival tags (PSAT) and 132 implanted archival tags on juvenile Atlantic bluefin tuna between 2005 and 2009. Because only one archival tag was retrieved, data reported are mainly from 26 PSATs.

To deploy the PSATs, fish were caught by hook and line and brought aboard the boat to attach a miniaturized PSAT to the fish's fin by a tether and dart anchored at the base of the fin. These were programmed to record external temperature, depth and daily position based on light sensor readings every 15 minutes and to release after 12 months. Later models also recorded light level. Once at the surface, the PSAT tags transmitted the collected data to receivers on earth-orbiting satellites. The data were then transmitted to the researchers, allowing scientists to trace the fish's journeys and habitat over the previous year.

The authors report that all tagged bluefin tuna remained in the northwest Atlantic for the duration observed, and, in summer months they stayed in coastal waters from Maryland to Cape Cod out to the continental shelf. In the winter, they wandered more widely, exiting the Gulf of Maine and ranging south to the South Atlantic Bight (North Carolina to Florida), the northern Bahamas and the Gulf Stream edge.

Lutcavage and Galuardi found that vertical habitat patterns showed juvenile bluefin primarily occupied shallow depths, averaging about 16 to 40 feet (5 to 12 meters) and relatively warm water, averaging 64 to 70 degrees F (about 18 to 21 degrees C). In winter, they frequented deeper water and showed more variable depth patterns.

"These findings are the first long-term view into a year in the life of a juvenile bluefin tuna in the western Atlantic," Lutcavage notes. "The geographic and vertical concentration of summer habitat had been suspected due to patterns in the recreational fishery, but was not confirmed until this study. In addition, little information existed on what these fish did in winter months when the fishery does not operate. This information provides a window into what areas and conditions are important for growth and survival of juvenile bluefin tuna."

The authors add, "Our tagging results reveal annual dispersal patterns, behavior and oceanographic associations of juvenile Atlantic bluefin tuna that were only surmised in earlier studies. Fishery independent profiling from electronic tagging also provides spatially and temporally explicit information for evaluating dispersal rates, population structure and fisheries catch patterns and supports development of direct assessments."

Janet Lathrop | EurekAlert!
Further information:
http://www.umass.edu

More articles from Ecology, The Environment and Conservation:

nachricht Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University

nachricht Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Corporate coworking as a driver of innovation

22.11.2017 | Business and Finance

PPPL scientists deliver new high-resolution diagnostic to national laser facility

22.11.2017 | Physics and Astronomy

Quantum optics allows us to abandon expensive lasers in spectroscopy

22.11.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>