Field Study - Indian River Lagoon Dolphins
Through The Years
Dolphin 56's history goes back to August 28, 1979 when he was captured along with five other dolphins near the NASA Causeway in the IRL. We caught five dolphins that day and assigned them the numbers 55, 56, 57, 58 and 59. Dolphin 57 was female, the others were male.
At the time he was captured, Dolphin 56 was 238 cm long and weighed 145 kg. Based on growth layers in one of his teeth, we estimated that he was about 12 years old. After we had weighed and measured him, and taken a blood sample, we branded him with the number "56". We also attached a small RotoTag near the tip of his dorsal fin. This was a small plastic ear tag similar to those used on cattle and sheep. The RotoTag allowed us to identify him before the brand became visible (about 2 weeks later). From our observations we know the RotoTag fell off sometime in 1979.
After the branding, Dolphin 56 was first resighted on September 15, 1979. By the end of 1979, he was seen a total of 18 times. We recaptured dolphin 56 in October 1980 and November 1981 to examine him closely and photograph his brands. During follow-up observations dolphin 56 was reported by the public thirteen times between 1981 and March 1982. Our research team saw dolphin 56 twenty-four times between the fall of 1980 and the spring of 1982 when the contract ended and the study was stopped. All of the sightings were in the IRL and included two sightings in the Banana River.
In the years since 1982 we have regularly received reports of sightings of dolphin 56 in the north end of the IRL and in Mosquito Lagoon. Although it is illegal to feed wild dolphins, people began to feed dolphin 56 fish and he learned to approach boats and "beg" for fish. He became very bold and would often put his snout right on the edge of a boat, which really surprised the boaters! He became a local celebrity in September 1996 when he got his picture in the Orlando Sentinel. I opened up the newspaper and there's dolphin 56.
Feeding Wild Dolphins Is Illegal
While dolphin 56 often "begs" for food, he is perfectly capable of catching fish on his own and, since dolphins are protected by the Marine Mammal Protection Act of 1972, it is illegal for people to feed wild dolphins. For more information, visit www.nmfs.gov.
Then things really started to get interesting. Early in 1997 dolphin 56 was seen just north of the St. John's River in Jacksonville, Florida. Even though we didn't get any pictures, the person making the observation is very reliable. Just what was dolphin 56 doing? From around the world there have been a number of observations of solitary, friendly male dolphins. Was dolphin 56 turning into one of these solitary males? He had always been friendly before. Then things got even more interesting!
Dolphin 56 - The misaligned jaw may be due to an incorrectly
healed broken jaw or uneven tooth wear.
Photo courtesy of Keith Rittmaster.
On April 2, 1997, I got a call from Sally Murphy, who works for the South Carolina Department of Natural Resources. Sally told me that dolphin observers at Hilton Head Island had seen dolphin 56 that morning. Here in Florida, 300 miles away, we couldn't believe that he had moved so far from "home". He kept going north and spent the summer of 1997 in the North Carolina-Virginia area. He "disappeared" in the winter an reappeared in Virginia. He again moved northward as far as Sheepshead Bay, New York, but spent most of the summer in the Virginia, Maryland, Delaware, New Jersey area. As the winter approached he moved southward to North Carolina and again "disappeared" during the winter. He reappeared off Virginia Beach, Virginia, in March 1999. From there he moved southward and spent the summer in North Carolina and northern South Carolina.
So, what do dolphin 56's movements mean? We don't really know. Will he keep going north? Will he return to the Indian River Lagoon? We'll just have to wait and see! It's possible that he's done this before but no one saw or reported him during his journey.
From a scientific viewpoint, the behavior of dolphin 56 points out how important long-term studies of dolphins really are. We can learn some things in a very short time but when you are studying animals with an average life span of 25 years - and a maximum life span of about 50 years - it simply takes a long time to see everything. Dolphin 56 is approximately 30 years old now, and he continues to surprise us.