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Dolphin Watch — Chapter 4

Chapter 4

* Collecting Data
* Dolphin 56
* After the Branding
* The Latest Sightings
* The Future


Meet Dan Odell
Interview With Dan
Well, Mother Nature struck again! It's still spring and the weather is rough. We had small-craft advisories on the east coast of Florida Monday, Tuesday, and Wednesday. We had planned boat trips for Monday and Tuesday. The rest of the week was taken up by meetings. At least I got caught up on some of my paperwork.

Megan and Rachel went to North Carolina to a dolphin conference. I can't wait to hear their report.

I also had a chance to look at some of the digital photographs we took last week. I was really surprised how much detail was present when I enlarged small parts of the images. You'll see some of these images in upcoming reports.

What's up for the coming week? I've scheduled boat trips for Monday and Friday, but it doesn't look good for Monday. Another set of cold fronts are moving into Florida over the weekend. The boat is ready and I hope the weather will be!

In Chapter 2 I told you about the three-year study of bottlenose dolphins in the Indian River Lagoon that began in 1979. The project was run by the Hubbs-Sea World Research Institute, the University of Miami and Sea World of Florida after we obtained a contract from the United States National Marine Fisheries Service.

Collecting Data
The primary objectives of our study were to test freeze-branding methodology and to use freeze branding to determine the home ranges of IRL dolphins. Freeze branding uses a brand dipped in liquid nitrogen to quickly freeze the animal's skin. The skin cells where the brand touches are killed and the end result is a white mark that matches the shape of the branding "iron." When we caught the dolphins to brand them, we were also able to collect data on dolphin blood chemistry, age, size, and reproductive condition.

Dolphin 56From 1979–1980 we marked and recaptured over 100 dolphins during the study and resighted many of the marked dolphins during our field observations. Over the years we have found several of the branded dolphins when they died of natural causes and we have received many sighting reports of marked dolphins.

Dolphin number 56 has been seen the most and, until just this year, he stayed within the Indian River Lagoon.

Dolphin 56 Dolphin 56
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 two weeks later). From our observations we know the RotoTag fell off sometime in 1979.

After the Branding
Dolphin 56 SightingDolphin 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 13 times between 1981 and March 1982. Our research team saw dolphin 56 24 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 was dolphin 56.

The Latest Sightings
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 in Florida

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." And he kept going north another 50 miles! On Friday, April 4, dolphin 56 was sighted about 20 miles south of Charleston, South Carolina.

This past weekend Megan Stolen and Rachel Witcher attended a dolphin conference in Wilmington, North Carolina. They put up posters alerting everyone to be on the look out for dolphin 56 and asking that any sightings be reported to us.

The Future
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.

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