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Satellite Tag to Reveal Adventures of Giant Bluefin Tuna


Atlantic bluefin tuna, Thunnus thynnus, pictured above. Three species of bluefin tuna are found around the world—Northern (or Atlantic), Southern, and Pacific.

Popup Satellite Archival Tag (PSAT) used to tag and track large highly migratory species.

Kyle Sanders (NOAA Corps, part of the Jersey team) retrieves the tag south of Long Island, New York.  


NOAA researchers Daniel Wieczorek (left) and DeMond Timmons (right), part of the Jersey recovery team, back at the Sandy Hook Lab with the tag.

The map shows the drift of the bluefin tuna tag that the Jersey team recovered and where they grabbed the tag and brought it back to Sandy Hook, N.J.

 

August 8, 2012

Where, Oh Where, Did That Huge Tuna Go?

To take a bite out of the Big Apple, of course.

Three basic things you should know about bluefin tuna—they’re big, they’re fast, and they like to travel. So, when scientists from NOAA’s Southeast Fisheries Science Center actually tagged and released an 8-foot-long, 400-pound bluefin tuna in the Gulf of Mexico in April, they anxiously awaited to discover…where did that huge tuna go? They’ll have the answer soon thanks to a team from NOAA’s Northeast Fisheries Science Center that went offshore in late July to retrieve the satellite tag once attached to the giant fish. The kicker is that the tag was floating like a cork in the ocean—atop four- to six-foot seas—near Long Island, New York.

This story of dedication, luck, and sharp eyes started on April 24, 2012, when a longline vessel in the Gulf of Mexico hooked a bluefin tuna as part of a cooperative research project to evaluate gear modifications led by the Southeast Fisheries Science Center. Once caught, scientists quickly attached a special electronic satellite tag called a Popup Satellite Archival Tag (PSAT) and released the tuna. The tag records depth, temperature, and light levels every 10 seconds, which allows scientists to monitor fish movements, behavior, location, and habitat preferences.

A full ninety days later, on July 23, the tag popped off the tuna, bobbed to the surface, and began transmitting its location via satellite, just as it was designed to do. Based on that locator signal, the NOAA researchers in Miami, Florida, calculated its approximate location giving the NOAA team from the Sandy Hook Lab in New Jersey the information it needed to physically recover the tag from the ocean.  However, the Jersey team was up against the clock.

Tick Tock

The holy grail of these satellite tags is the detailed, high-resolution data they contain. But, researchers can only access that level of information if they get the tag back. So it was critical that the team try to physically retrieve the tag from the ocean while it was still transmitting its location. Once a tag pops up to the surface it starts an immediate data dump, transmitting information to satellites overhead in summary form only. Unless scientists physically retrieve the tag, they will never be able to access the rich data set it contains. While the summary data is still valuable, it’s incomplete because the battery might die before all the data is transmitted. The scientists at the Fisheries’ lab in Florida knew that the clock was ticking on the satellite tag battery so, once they received the signal the tag had surfaced, they sprang into action to retrieve it. 

Find Tiny Tag in Big Ocean—Mission Impossible?

The Florida scientists immediately circulated information on the tag’s location to local fishermen in New York and New Jersey who were eager to help if they could, but rough weather was keeping many in port. The scientists also contacted their colleagues at NOAA's Sandy Hook Lab in New Jersey, who were given the green light to help retrieve the tag. To assist in the search, the Florida scientists sent a directional scanner to the Jersey team so they could track the tag from their boat. Even with this special scanner, sharp eyes were still required to find the small tag once scientists got close to its location.

The Jersey team left the dock on July 27, at 10:45 am, and motored 43 nautical miles east. The Florida team stayed in contact with them, providing frequent updates on the tag’s location. The Jersey team located the signal on the directional scanner as they got closer, but the four- to six-foot seas made it difficult to spot the small tag in the big ocean. Because of the distance to and from port, the search crew only had a two-hour window to find the tag. With only two minutes remaining before it was time to pack up and call it day, the team spotted the tag off of Long Island and brought it aboard. Mission accomplished. And none too soon—the satellite tag battery only had 12 hours of power left.

Stay Tuned

The Jersey team quickly brought the tag back to shore and sent it to their NOAA colleagues in Florida. The tag’s next stop will be to the manufacturer for data downloading, refurbishment, and reuse. A new tag costs approximately $3,500. The same tag can be refurbished for $750. Soon, researchers will have detailed information and insight about the adventures of this big tuna, plus a refurbished tag to pop on another tuna. Stay tuned for the rest of the story.  

Recovering Tuna Tags Is Rewarding in More Ways Than One

During the course of NOAA Fisheries’ ongoing bluefin and yellowfin tuna tagging projects, beachcombers have returned 10 Popup Satellite Archival Tags, also called PSATs, to the NOAA Southeast Fisheries Science Center and received a $500 reward for each tag return. NOAA personnel, sometimes in collaboration with the public, have recovered five additional tags—twice by NOAA personnel using directional scanners, twice by fisherman who were guided to the tags by text messages or emails sent from NOAA Fisheries scientists, and once by a scientist on a beach in the Bahamas directed there by NOAA scientists.


Captain Bart Sherwood of Miami, Florida showing off the yellowfin tuna tag that he retrieved while it was drifting off Bimini, Bahamas.  He and his crew reacted quickly after getting an email from the SEFSC scientists (left). Tag recovered on the beach, Eleuthera Bahamas. Annabelle Brooks, Research Manager at the Cape Eleuthera Institute (right).