Collapse bottom barsurvey

Tagging Reveals Extensive Movement by Dolphin

By Don Hammond, Cooperative Science Services and www.dolphintagging.com

Ideal tag recovery involves direct and timely communication with the anglers or boat captains tagging and recovering the fish. It requires these individuals to record the important information (date, latitude & longitude, length of the fish) along with their own contact information to allow for follow-up questions. This provides the best opportunity to maximize the information gained from each recapture. Unfortunately this does not always happen, which is frustrating.

Such is the case with the latest series of reported tag recoveries in 2012.

Reports for more than 330 tagged fish were received this period. While 229 fish were tagged during August, the other reports involved fish tagged as far back as April. The number of fish tagged during August 2012 is the second largest number for that month in the history of the Dolphin Research Program, and could become the largest number for the month of August when all of the tagging reports are in.

Six recaptures have been reported in the most recent period for 2012. Each did yield useful information to science regarding their movement, but none provided complete information about both the release and the recapture event.

Recovery One

The first recovery involved a fish tagged on June 8, 2012, off Charleston, South Carolina, by Robbie Hooker of Walterboro, South Carolina, during a fishing trip aboard the Summer Girl. This fish was recovered 19 days later off Cape Hatteras, North Carolina, by the charter boat Low Profile. The recovery report was made by Jim Lyons, who runs a fish-cleaning business at Hatteras Harbor Marina and has reported numerous tag recoveries in the past. As a second party to the recapture, he was only able to gather the basic information as to where the fish was caught but did record a precise length and weight. During its liberty the fish had traveled 307 miles northeast of its release site, averaging 16.2 miles per day. At recapture the fish measured 27 inches and weighed 5.85 pounds. The fish had been estimated at 14 inches when released, showing why estimated lengths are not used to gauge growth.

Recovery Two

A dolphin released off Marathon, Florida, in May 2011 was recovered in June 2012 as it was making its second pass along the U.S. Atlantic Coast.

The next recovery produced a new record for time-at-liberty for a tagged common dolphinfish. This fish was tagged by Dave Wamer, from Taylors, South Carolina, while fishing on his boat Wam Jam off Marathon, Florida, on May 24, 2011.
David Player, a port sampler for the South Carolina Department of Natural Resources, reported the recovery following a conversation with a commercial fisherman who had recaptured the fish two to six weeks previously and wanted to remain anonymous. The fisherman was only able to provide a rough location off Georgetown, South Carolina, where he caught the fish, that it was caught during the month of June 2012, and that the fish was nice size, probably around 38 inches in length.

From this information we learn that the fish was at liberty from 373 to 403 days (previous record was 371 days). For purposes of this study, a recapture date of June 15 was assigned, resulting in a liberty 388 days. From this information, we can estimate that the fish was most likely 15 to 16 months old when recaptured.

While the direct distance between Marathon and Georgetown is about 600 miles, the fish was most probably making its second pass through these waters. Since it was tagged in the spring of the previous year, this fish had already completed one full migration up the East Coast and back down to the Caribbean for the winter. It was on its second trip up the U.S. Atlantic coast, having covered a distance of roughly 4,400 miles if it went by way of the Mid-Atlantic Ridge. While the distance may seem astonishing for a fish starting the trip at 14 inches in fork length, it would require the fish to cover only 11.2 miles per day. This is a moderate pace for these open ocean travelers known to be capable of sustained travel of 90 miles per day.

Recovery Three

Another one of Capt. Bouncer Smith’s fish was involved in the third recovery. Tagged off Miami, Florida, on June 14, 2012, the dolphin was recaptured 34 days later off Jacksonville Beach, Florida, by R. Ogden, of Atlantic Beach, Florida. Ogden measured the fish at 19.25 inches, less than the legal minimum, so he re-released it after removing the tag. The fish had traveled 331 miles northward from its release site, resulting in an average daily travel of 9.7 miles per day. This is only the third tag recovery from the Jacksonville area.

Recovery Four

The fourth tag recovery report received also set a program record, that of being the longest time between the fish’s recovery and its report: 11 months. In July 2012 Buddy Gaskins, of Kill Devil Hills, North Carolina, apparently re-encountered the forgotten tag he had removed from a dolphin he caught in 2011. He did report that it was caught off Oregon Inlet, North Carolina, on August 31 and that it was probably about 26 inches in length. The fish had been tagged by Bill Baugh off Ramrod Key, Florida.

Bill, who is normally precise in his record keeping, could not find the card on his boat. Since it has not been received by the DRP, it may have been a victim of the postal service. The one thing we do get from this recapture is another confirming link between the fish off the Florida Keys and those found off the Outer Banks, two areas separated by 900 miles of open water.

Recovery Five

A fish tagged off Cudjoe Key, Florida, on June 7, 2012, by the crew of Don Gates’ boat the Killin Time II was the subject of the fifth recapture. Kevin Beard recaptured the tagged dolphin during a fishing trip off St. Augustine, Florida, on August 3. At liberty for 57 days, the fish had traveled 449 miles north from its release site, moving at an average rate of 7.9 miles per day. The fish measured 18 inches in fork length when angler Darryl Williams released it, so with the eight weeks of growing time the fish would have been in the 22- to 24-inch range, close to the reported recovery size of 24 to 28 inches.

This tagged dolphin is one of only a very few to be recaptured off St. Augustine and the first dolphin reported to have been hooked through the eye socket at time of release to be recovered. Don and his crew go to extra lengths to minimize harm to their fish during tagging and this recovery shows that it pays off.

Recovery Six

The sixth and final recovery reported this period also involved a fish tagged by the crew of the Killin Time II, their sixth fish tagged this year to be reported recaptured. Kelley Allen, one of the Killin Time II’s crew members, tagged this fish on June 9, 2012, off Cudjoe Key. The dolphin was recovered 785 miles north of its release site by Petey DuBose of Morehead City, North Carolina, during a fishing trip off Beaufort Inlet, North Carolina. During its 23 days at liberty, the fish averaged traveling northward 34.1 miles per day. While this speed of travel is high, there have been three fish this year that traveled at rates in excess of 50 miles per day.

Each of these recoveries provided additional insight into the life and movements of dolphin. Even a late report can still provide important information. If you are sitting on a tag recovery for any research program, report it now. Any information that you can provide will be appreciated by the research program involved.