Whalewatcher 1987 - vol 21 no 4

The past fifteen years have seen a major change in the nature of whale research. While most research was conducted using the carcasses of dead whales before the 1970s, attention is now primarily dedicated to non-lethal studies of population biology, ecology, behavior, social structure, and other related topics. Several of these have been the focus of articles in recent issues of Whalewatcher, and continue to generate much interest.

Since 1980, I have been fortunate enough to be a part of a long-term study of humpback whales. As director of the Cetacean Research Unit, I have been part of a detailed study on a population of 420 identified humpbacks. Our group has reported on these studies in numerous articles (including two in this journal), and several scientific presentations and papers. In most of these we present analyzed data and remove ourselves and our conclusions from any personal feelings we have towards the animals we study in order to remain scientifically objective. While this sounds cold, it is a necessary part of the process, to ensure that we do not bias our findings.

While we do maintain scientific objectivity in data analyses and conclusions, it is difficult not to become attached to the animals with which we spend so much of our lives. These feelings surfaced, recently, when one of our well-known animals, Beltane, washed ashore dead. I offer this article to let you, the reader, know something about what can be learned from following a single animal and, moreover, to show a humane aspect of what is often viewed as insensitive, objective science.

I first saw Beltane in July, 1980. It was the first year I was collecting data for the Cetacean Research Unit, and there were reports of a whale in our area missing her right tail fluke. This was Silver, a whale photographed in our study area (off the Massachusetts coast) the previous year. However, we were surprised to learn that she had a calf with her in 1980.

When first sighted, the calf was some 20 feet long, and would have been some 10-12 feet at birth. We saw this mother/ calf pair six times during July and August. Thankfully, Silver's calf had a distinctive dorsal fin, since obtaining a good photograph of its flukes had not been easy. All we had was a distant photograph of a breach so high we could see almost all of the fluke pattern out of the water. We had an opportunity for a better photograph in early August, when the youngster brought its tail up perfectly within 100 feet of our boat. Of course, I was changing film at the time, and could only look on, helplessly.

The shape of this calf's dorsal fin allowed us to recognize her when she reappeared in the middle of 1981. We saw her often that year, as she stayed in the center of our study site. She was seen almost daily from early August to early October, and endeared herself to us through spectacular breaching, lobtailing, and flipper-slapping displays. Obtaining photos of her fluke pattern was easy (fluking is a behavior that usually develops through the first year of life), and we were then able to give her a study name based on that pattern. The name Beltane was chosen for a mark on her right fluke that looked like an eye and eyelash, so she was named for the "eye of Bel" (the celtic god of the sun), or Beltane.

Like most young animals, Beltane continued to return to the study area, and continued to grow. She became one of our "residents,"--animals often sighted both within and between years. While she spent most of her time with young animals, she was spending more time with adults when she was four years old. In 1983 we found that she was a female, based on a small lobe behind the genital wall that is characteristic of that gender.

In 1985 Beltane became unique: she was the first humpback anywhere in the world that had been followed from birth until she had her first calf. The age of sexual maturity had been estimated from whaling data over many years, but never did we have such concrete evidence of age at sexual maturity and first reproduction. Since humpbacks are pregnant for 11 1/2 months, Beltane had been sexually mature at four, and first gave birth at five. She and her calf, named Cat Eyes, stayed together for the typical one year period.

Beltane's movements were now those of an adult. She spent most of 1986 in an offshore area called the Great South Channel, where many adults located considerable amounts of food. She spent the first part of 1987 in the same area, then moved to Jeffreys Ledge (along the New Hampshire coast) for August and September, where she was last seen on September 24. In all, Beltane was sighted over 400 times since first seen as a calf.

The death of Beltane was the first of a minimum of 14 deaths (as of the first week in January). Thanks to the response of a unified task force set up by the National Marine Fisheries Service, the deaths were quickly tied to the presence of a biotoxin present in the liver, viscera, and gonads of mackerel. The results led to a state-wide warning on human consumption of mackerel.

Beltane: July 27, 1981

In Death

On November 28, 1987 members of the stranding team of the New England Aquarium received a call that there was a dead humpback on the beach in Eastham, on Cape Cod. They went to the site, took external measurements and did a quick internal examination. While this was going on, Phil Clapham and Lisa Baraff of the Center for Coastal Studies-another group engaged in the long-term monitoring of New England humpbacks-heard of the stranding and went down to the beach, camera in hand. They commented on the superficial resemblance of the dead animal's flukes to Beltane, but the size of the 45 foot female seemed much larger than the agreed-upon estimate of Beltane based on live sightings.

While the carcass was being towed off the beach, Phil and Lisa went back to their lab. Looking at a photo of Beltane, they realized there was more than a superficial resemblance. They developed the photos of the humpback carcass, and realized that it was Beltane dead on the beach.

The opportunity to do a thorough examination of a mature female of known age was another first. Here was a chance to test the methods used with whaling data to estimate age and age at maturity, as well as learning more about Beltane's reproductive biology through an examination of her reproductive tract. Thanks to the non-stop, round-the-clock efforts of Phil Clapham, arrangements were made to re-beach the carcass on November 30.

Through the combined forces of the New England Aquarium, Center for Coastal Studies, and the Cetacean Research Unit, a thorough necropsy took place on that day. What we found was surprising: Beltane had been in excellent health, and large, undigested pieces of mackerel found in a very full stomach showed she had been feeding immediately before she died. There was no evidence that she had become entangled in fishing gear or was hit by a boat, both increasing problems for whales. As Greg Early of the Aquarium stated, "It looked like she was feeding, then rolled over and died!" He felt that the immediate cause of death may have been drowning. But what caused her to drown? Was she being held underwater by something? Was she unconscious?

Although we do not know how long humpbacks live in the wild, we do know this was an abnormal death. Estimates of humpback life span range from 30-70 years, and we have several animals that were producing calves when first photographed (1979-1980) that are still actively calving in 1987. We do not know why she died.

Reflections

When I arrived on the beach to help with Beltane's necropsy, the animal I had known for so long was reduced to a large mass of blubber, muscle, tendons, organs, and bone on the beach. I have helped with necropsies of other large and small cetaceans, but never one that I had known so well in life. Surprisingly, I felt little sorrow during the necropsy; the idea that the object below my knife blade was the same animal I had watched breaching and feeding and living her humpback life seemed truly unreal.

That remained the case for much of the day, but towards the end of the day feelings became stronger. Although she was now cut into pieces, I had still been able to be close to her; I was learning more about her life. When we were finished, however, it was very hard to turn my back and walk away, knowing I would never have the chance to see my friend Beltane again.

Beltane will continue to live in an abstract way. She will be a data point on many graphs and in numerous tables, and a scientific article about her age at maturity has already been published. The data gathered from her necropsy may lead to at least one more paper, and we learned from her that mackerel are a prey for this humpback population (something we had not previously known). Yet writing "Deceased 11/87" on the front of her file had an unexpected impact of finality.

Thank you, Beltane. We learned more from you than you could ever know. Your calf remains behind as your legacy, and we can never look at Silver again without thinking of you. You remain in our data base and, more importantly, in our hearts. Goodbye, Beltane.

Beltane: November 30, 1987