Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A “shark’s eye” view: Witnessing the life of a top predator

28.02.2014

Instruments strapped onto and ingested by sharks are revealing novel insights into how one of the most feared and least understood ocean predators swims, eats and lives.

For the first time, researchers at the University of Hawaii and the University of Tokyo outfitted sharks with sophisticated sensors and video recorders to measure and see where they are going, how they are getting there, and what they are doing once they reach their destinations. (Click here for video).   


A sixgill shark with a combined sensor and video recorder attached to it swims through the ocean. The instruments are giving scientists a “shark’s eye” view of the ocean and revealing new findings about shark behavior, according to research being presented at the Ocean Sciences Meeting.

Credit: Mark Royer/University of Hawaii

Scientists are also piloting a project using instruments ingested by sharks and other top ocean predators, like tuna, to gain new awareness into these animals’ feeding habits. The instruments, which use electrical measurements to track ingestion and digestion of prey, can help researchers understand where, when and how much sharks and other predators are eating, and what they are feasting on. 

The instruments are providing scientists with a “shark’s eye” view of the ocean and greater understanding than ever before of the lives of these fish in their natural environment. 

... more about:
»Biology »Feeding »Hawaii »Marine »Ocean »Sciences »ecosystems

“What we are doing is really trying to fill out the detail of what their role is in the ocean,” said Carl Meyer, an assistant researcher at the Hawaii Institute of Marine Biology at the University of Hawaii at Manoa. “It is all about getting a much deeper understanding of sharks’ ecological role in the ocean, which is important to the health of the ocean and, by extension, to our own well-being.” 

Using the sensors and video recorders, the researchers captured unprecedented images of sharks of different species swimming in schools, interacting with other fish and moving in repetitive loops across the sea bed. They also found that sharks used powered swimming more often than a gliding motion to move through the ocean, contrary to what scientists had previously thought, and that deep-sea sharks swim in slow motion compared to shallow water species. 

“These instrument packages are like flight data recorders for sharks,” Meyer said. “They allow us to quantify a variety of different things that we haven’t been able to quantify before.”

“It has really drawn back the veil on what these animals do and answered some longstanding questions,” he added. 

Meyer and Kim Holland, a researcher also at the Hawaii Institute of Marine Biology, are presenting the new research today at the 2014 Ocean Sciences Meeting co-sponsored by the Association for the Sciences of Limnology and Oceanography, The Oceanography Society and the American Geophysical Union. 

Sharks are at the top of the ocean food chain, Meyer noted, making them an important part of the marine ecosystem, and knowing more about these fish helps scientists better understand the flow of energy through the ocean. Until now, sharks have mainly been observed in captivity, and have been tracked only to see where they traveled. 

These new observations could help shape conservation and resource management efforts, and inform public safety measures, Holland said. The instruments being used by scientists to study feeding habits could also have commercial uses, including for aquaculture, he added. 

Notes for Journalists: 

The researchers on these studies will present oral presentations about their work on Thursday, 27 February 2014 at the Ocean Sciences Meeting. The meeting is taking place from 23 – 28 February at the Hawaii Convention Center in Honolulu. For more information for members of the news media, please go to http://www.sgmeet.com/osm2014/media.asp

Below are abstracts of the presentations. Both presentations are part of Session 091: Advances in approaches to monitoring the occurrence, distribution, and behavior of top predators being held Thursday 27 February from 8 a.m. to 10 a.m. local Hawaii time in room 310 Theater.

 For raw video footage, including caption and credit information, please go to https://www.dropbox.com/sh/7vf90tzva55x1mp/YegWoGRn1_

 Title:

Multi-Instrument Biologging Provides New High Resolution Insight Into Shark Behavior and Biomechanics

Authors:

Meyer, C., Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA;

Nakamura, I., International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan;

Sato, K., International Coastal Research Center, Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwanoha, Kashiwa, Chiba, Japan.

Abstract:

In marine ecosystems, the advent of electronic tags has provided unprecedented new insights into movements of highly mobile sharks. However, until recently we have lacked high-resolution tools capable of revealing fine-scale patterns of behavior and habitat use, or providing empirical insight into swimming biomechanics of free-ranging sharks. Now a combination of high resolution, tri-axial accelerometer-magnetometer data loggers and miniature video loggers is uncovering previously unknown aspects of shark ecology. Recent deployments of these devices on a variety of coastal and deep-sea sharks in Hawaii has revealed complex, three-dimensional movements of these animals over a variety of habitats, provided a clearer understanding of shark swimming biomechanics and yielded a ‘sharks-eye’ view of interactions with other animals.

Title:

Detection and Telemetry of Feeding Events in Free Swimming Sharks and Tuna

Authors:

Holland, K., Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA;

Meyer, C., Hawaii Institute of Marine Biology, University of Hawaii at Manoa, Kaneohe, HI, USA.

Abstract:

An ability to directly measure feeding events in top predators (e.g., tuna, sharks) would represent a major advance in quantifying energy flow through marine ecosystems. An appropriate device must detect these events over prolonged periods and be able to withstand large pressure changes. We hypothesized that physical changes occurring during ingestion and digestion should be quantifiable by measuring Bulk Electrical Impedance across paired electrodes. We successfully demonstrated this using a prototype tag (Wildlife Computers Inc.) to record impedance changes occurring inside the stomachs of free swimming captive sharks over multiple feeding events. Feeding and digestion produced characteristic changes in electrical impedance of the stomach contents identifiable as 5 successive phases: (1) Empty stomach, (2) Ingestion, (3) Chemical ‘lag’ phase, (4) Mechanical ‘chyme’ phase, and (5) Stomach emptying phase. The duration of the chyme phase was positively related to meal size. We recently observed these same phenomena in yellowfin and bluefin tuna. We are now deploying prototype tags in wild animals and adding accelerometry capabilities to assist in interpretation of feeding events. Preliminary results from these recent events will be presented.

Contact information for the researchers:

Carl Meyer, +1 (808) 428-4819, carlm@hawaii.edu

Kim Holland, +1 (808) 220-0112, kholland@hawaii.edu

Itsumi Nakamura, +81-4-7136-6402, itsumi@aori.u-tokyo.ac.jp

Katsufumi Sato, +81-4-7136-6400, katsu@aori.u-tokyo.ac.jp

Mary Catherine Adams | American Geophysical Union
Further information:
http://www.agu.org

Further reports about: Biology Feeding Hawaii Marine Ocean Sciences ecosystems

More articles from Life Sciences:

nachricht More detailed analysis of how cells react to stress
08.02.2016 | Universität Zürich

nachricht A new potential biomarker for cancer imaging
05.02.2016 | Universiti Putra Malaysia (UPM)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: From allergens to anodes: Pollen derived battery electrodes

Pollens, the bane of allergy sufferers, could represent a boon for battery makers: Recent research has suggested their potential use as anodes in lithium-ion batteries.

"Our findings have demonstrated that renewable pollens could produce carbon architectures for anode applications in energy storage devices," said Vilas Pol, an...

Im Focus: Automated driving: Steering without limits

OmniSteer project to increase automobiles’ urban maneuverability begins with a € 3.4 million budget

Automobiles increase the mobility of their users. However, their maneuverability is pushed to the limit by cramped inner city conditions. Those who need to...

Im Focus: Microscopy: Nine at one blow

Advance in biomedical imaging: The University of Würzburg's Biocenter has enhanced fluorescence microscopy to label and visualise up to nine different cell structures simultaneously.

Fluorescence microscopy allows researchers to visualise biomolecules in cells. They label the molecules using fluorescent probes, excite them with light and...

Im Focus: NASA's ICESat-2 equipped with unique 3-D manufactured part

NASA's follow-on to the successful ICESat mission will employ a never-before-flown technique for determining the topography of ice sheets and the thickness of sea ice, but that won't be the only first for this mission.

Slated for launch in 2018, NASA's Ice, Cloud and land Elevation Satellite-2 (ICESat-2) also will carry a 3-D printed part made of polyetherketoneketone (PEKK),...

Im Focus: Sinking islands: Does the rise of sea level endanger the Takuu Atoll in the Pacific?

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister picture is being painted evoking the demise of the island states and their cultures. Are the effects of sea-level rise already noticeable on reef islands? Scientists from the ZMT have now answered this question for the Takuu Atoll, a group of Pacific islands, located northeast of Papua New Guinea.

In the last decades, sea level has been rising continuously – about 3.3 mm per year. For reef islands such as the Maldives or the Marshall Islands a sinister...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

AKL’16: Experience Laser Technology Live in Europe´s Largest Laser Application Center!

02.02.2016 | Event News

From intelligent knee braces to anti-theft backpacks

26.01.2016 | Event News

DATE 2016 Highlighting Automotive and Secure Systems

26.01.2016 | Event News

 
Latest News

Ocean acidification makes coralline algae less robust

08.02.2016 | Earth Sciences

Online shopping might not be as green as we thought

08.02.2016 | Studies and Analyses

Proteomics and precision medicine

08.02.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>