Following sharks into the deephttps://indianexpress.com/article/news-archive/print/following-sharks-into-the-deep/

Following sharks into the deep

For days,crew members scanned the sea from their converted crabbing vessel,the Ocearch,anchored in the waters three miles off the Cape.

Beachgoers on Cape Cod may have spotted several sharks this summer,but when Chris Fischer and his crew went looking for the great whites here this month,there were none.

For days,crew members scanned the sea from their converted crabbing vessel,the Ocearch,anchored in the waters three miles off the Cape. Then,nine days later,a giant shark that would become known as Genie reared her her fin,and burst into oceanographic history. Hooked in the corner of her mouth,she became what Fischer said was the first great white—all 2,292 pounds of her—to be captured live off Cape Cod,the home waters of Jaws.

The Ocearch crew held her for 15 minutes in a cradle off the side of the boat. A team of scientists attached a GPS tag to her dorsal fin and took blood and tissue samples before releasing her back into the deep. Now the researchers,and anyone with an Internet connection,can follow her movements in real time online on the “shark tracker” on ocearch.org.

Catching sharks is something that Fischer,the founding chairman of Ocearch,a nonprofit organisation that facilitates research on oceans and fish,and his crew have done scores of times. The purpose of their mission,said Fischer,44,is to crack the code of these fascinating animals. He and the scientists travelling with him hope to understand their migratory patterns and breeding habits.

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For some environmentalists,the mission is not so benign,or even necessary. They see the live capture of sharks as more invasive than other methods of tagging.

Fischer chafes at the criticism; that one reason for inviting the media was to open the process to the public. For example,he said,tags implanted on sharks through harpooning are less reliable than those attached to the fin because they can fall off after six months. By contrast,he said,when sharks are captured,the GPS tags can be attached securely with a drill.

Dr. Greg Skomal,a shark expert working for the state of Massachusetts,was on the Cape Cod expedition. He has tagged sharks through harpooning,but this was the first time he had his hands on a live one. “Any time you capture a fish by any methodology,you’re going to expose it to some level of stress. But we try to minimise that”,he said.

But through an instrument called an accelerometer he could follow their behaviour after they were released and see if they were lying on the ocean bottom,how fast they were swimming and the beats of their tails. This was the first time accelerometers have been attached to sharks.

Genie is now pinging her location to satellites and creating a Hansel-and-Gretel-like online trail of where she has traveled since she was tagged.