Instrument Packages Help Researchers Get A Better Understanding Of Sharks

April Flowers for – Your Universe Online
Researchers from the University of Hawaii and the University of Tokyo are gaining novel insights into how one of the most feared and least understood ocean predators swims, eats and lives — all courtesy of instruments strapped onto and ingested by sharks.
The sharks were outfitted with sophisticated sensors and video recorders to measure and see where they are going, how they are getting there, and what they do once they reach their destinations.
Using instruments ingested by sharks and other top predators, like tuna, a new project is gaining an awareness into these animals’ feeding habits. The instruments use electrical measurements to track ingestion and digestion of prey. These measurements help scientists understand where, when and how much sharks and other predators are eating, as well as what they are eating.
The ‘shark’s eye view’ of the ocean is providing the researchers with a greater understanding than ever before of the lives of these fish in their natural environment.
“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.”
The team used the sensors and video recorders to capture unprecedented images of sharks of different species swimming in schools. They were also able to capture the shark species interacting with other fish and moving in repetitive loops across the sea bed. Contrary to what researchers had previously thought, the sharks used powered swimming more often than a gliding motion to move through the water. They also found 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 collaborated with Kim Holland, also a researcher at the Hawaii Institute of Marine Biology. The two presented their research 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.
Meyer notes that sharks are at the top of the ocean food chain, making them an important part of the marine ecosystem. Gaining more knowledge of these fish will help researchers better understand the flow of energy through the ocean. Prior to this study, most shark studies have observed the fish in captivity, and they were only tracked to see where they traveled.
The findings could help shape future conservation and resource management efforts, as well as inform public safety measures. Holland added that the instruments being used to study the feeding habits of sharks could have commercial uses, including some for aquaculture.
Image 2 (below): 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