Dolphin Tagging Recaptures Exploding!

Dolphin Tagging Recaptures Exploding!

The Dolphin Research Program managed by Don Hammond of Cooperative Science Services reports that Dolphin or otherwise known as Mahi-Mahi, tagging activity and tag recoveries have exploded during June and July. Anglers tagged more than 800 dolphins during the month of June. A total of 28 boats have tagged ten or more fish with the top boat honors going to Don Gates’ “Killing Time II” with an impressive 249 tagged fish. June is typically the highest number of tag recoveries with a total of 22 recorded recoveries for 2014.

During the 30 days of June there were 21 reported recoveries, but the primary reason was the tagging of more than 800 dolphin by recreational anglers with the vast majority being released off South Florida and the Keys. This placed an extraordinary number of tagged dolphin at the migratory starting point of their route up the East Coast, which exposed them to the most fishermen and greatest potential for recovery that they would face during their migration route.

The crew of one boat provided the fish that were involved in 10 of the tag recoveries. It did not hurt that they tagged 249 dolphin off Cudjoe Key, Florida, during the first two weeks of June. Their fish were recaptured following liberties of zero to five days exhibiting a wide variation in travel speeds ranging from 9 to 75 miles per day. A fisherman recaptured a fish off Marathon, Florida, the same day that it was tagged but 27 miles from where it had been released. Another fisherman recovered a fish off Cudjoe Key, two days and 38 miles away from its release site, while another was recovered off Islamorada, Florida, 47 miles from where it was released. At liberty for three days, one fish traveled only 27 miles to Marathon, where it was caught, while another fish was able to make it 214 miles to Boynton Beach, Florida, where it was caught.

Four fish were recovered after they had been at liberty for four days. The first fish was recovered off Miami, Florida, 98 miles from its release site. Another fish was caught off Port Everglades, Florida, 158 miles from its release site. The third fish was caught off Jupiter Inlet, Florida, 241 miles from where it was released. The Killin Time II’s final recovery in this group was at liberty for five days, traveling 93 miles from its point of release before being recaptured off Key Largo, Florida.

No group of fish showed a wider variation in the speed at which they travel as the 13 recoveries of dolphin tagged off south Florida and the Keys and recovered off Florida the same year. Their rates of travel ranged from four miles per day up to 104 miles per day and averaged 40.3. This group of fish was the fastest travelers during this period. They clearly felt the need to be farther north. The second-fastest travel rates belong to two fish tagged off south Florida and the Keys that escaped Florida only to end their travels in Georgia and South Carolina. These fish averaged 25.4 miles per day. Comparison of the travel speeds of the fish tagged off South Carolina (10.1 miles per day) and North Carolina (12.9 miles per day) showed them to be starkly slower than the rates observed for Florida fish. Everything is relative and the speed of the fish off the Carolinas is a sizzling rate when it is compared to the movements of the two dolphin in Exuma Sound, Bahamas, which averaged 0.5 miles per day. This body of water has very weak currents similar to the Tongue of the Ocean sound between New Providence and Andros Islands, and fish in both areas commonly exhibit very little movement even over longer periods of time.

It is hard to assign a specific travel speed to fish making a return visit to the U.S. East Coast when their liberty period spans the winter. The two recoveries this period that exhibited this type of movement had very similar speeds of 1.5 and 1.6 miles per day, if you only look at the distance between their release and recovery sites. Hundreds of previous tag recoveries of fish traveling through the same areas, like other recaptures this period, clearly show a far more rapid pace. This indicates that these fish did not linger in this area but left the area and returned. The frequent fall to early spring recovery off Caribbean islands of fish tagged on the East Coast suggests that this is the region East Coast dolphin pass through during the colder periods. With these facts considered, it is likely that these fish could have traveled as much as 3,000 to 4,000 miles during their liberties!

Learn more about the Dolphin Research Program at