Right Whale Biopsy

New England Aquarium

Southeast
Surveys For Right Whales

NEA Reports
and
Research Logs



(Page sponsored and maintained by WhaleNet)
Research Log
Entries
By
Joe Roman

Jan. 10, 1998

Jan. 12/13, 1998

Jan. 22, 1998

Jan. 30, 1998

Mar. 26, 1998


How to Take
a Biopsy Sample

Sighting
Finding The Whales

Collect Sample
Collecting the Sample

Biopsy Sample
Preparing the Sample

Prepared Sample
Prepared Sample


BACKGROUND: A VERY SMALL PIECE OF SKIN

Chris Slay


Take a biopsy

Dr. Moira Brown (known affectionately to us as Moe) set out to take a small piece of skin from as many North Atlantic right whales as she could manage to dart, wielding her crossbow like some high-tech Diana, ancient goddess of the hunt. Moe was pretty good with that bow but her appetite for skin was insatiable so she recruited me to help. Having grown up rooting for the Indians in the Westerns, I became an experienced archer at an early age and I was glad to help Moe with darting duties.

Initially, the aim of this effort was to determine the sex of the animals we were photo identifying without having to wait on an animal to roll over and expose its belly (the most obvious clue being the presence of mammary slits on females). To understand a population, it is important to know the ratio of females to males, and genetic analysis of the skin samples has allowed Moe to determine the sex of an animal without other clues. Additional analyses of the samples have helped Moe and her colleagues, Dr. Cathy Schaeff and Ruth Waldick, to explore more complex genetic questions concerning inbreeding and "families" within the population. It's amazing what can be learned from a piece of skin the size of a pencil eraser.

Often a small piece of blubber comes away with the skin and this certainly doesn't go to waste. From these tiny pieces of fatty tissue, scientists at Woods Hole Oceanographic Institute can glean information about the presence manmade of toxins in whales and how these toxins might affect the success of a population. My colleague Joe Roman will explain some these things in more detail later. Joe will accompany me on darting excursions this winter and write accounts of these trips so that you can follow our progress.

As for the mechanics of darting, it's really simple. At the end of the arrow shaft is a buoyant hard foam collar that stops the arrow when it hits a whale's skin. In front of the collar is a small steel cylinder about an inch long and smaller in diameter than a pencil. This little cylinder essentially takes a core sample of a whale's skin. Rarely do the whales seem to notice the dart, though they sometimes begin swimming away from us as our vessel approaches. Occasionally, their skin will twitch as a horse's does when it's harassed by a horsefly. Usually the whale goes about its business as if nothing had happened.

After plucking our arrow from the water we remove the tissue from the cylinder and put the skin in a preservative. The blubber is sliced into two tiny bits, one is preserved in formalin, the other is frozen. Hopefully, the photos will make this more clear. We will update the site with new photos as often as possible. Thanks for your interest.


DARTING: WHAT IT'S ALL ABOUT

Joe Roman

Skin Biopsies

Once Chris and I have successfully retrieved a skin sample, we send it up to Dr. Brad White's lab at McMaster University in Canada, where Moe Brown, Ruth Waldick, and Cathy Schaeff have been investigating the genetics of the North Atlantic right whale.

Biopsy sample

Since Moe started the project in 1988, skin samples have been taken from nearly two hundred right whales for genetic analysis. The trouble is most of these samples come from whales darted in the Bay of Fundy in the summertime. But there's an entire group of whales that we don't see up there in Canada. "These elusive animals, twenty-three of which are reproductive females, all go to some unknown location in the summer," says Moe. "Since the females do show up every three or four years to give birth to a calf, the Southeast calving ground may be our only chance to get samples from these rarely seen females and their calves."

But why do we need these samples anyway?

Back at the lab, DNA is isolated from the skin samples using chemical detergents. By analyzing these fine white strands of genetic material, we can detect patterns specific to each individual whale and learn things that photos taken from a plane can't reveal. DNA allows us to determine the sex of an animal as well as its family history. Since females stay with their calves for nine to twelve months, we can easily photo identify a calf's mother, but who's the father? Because males aren't present when the females give birth and play no known role in rearing calves, this is a difficult question to answer.

Mothers usually calve every three to five years. Are these calves sired by the same male or do they have different fathers? And what about the calves born this year--do some of them share the same father, or do they all come from different males? Answering these questions can help us determine the size of the breeding population.

"The importance of knowing the fathers in this population cannot be overemphasized," says Ruth. If only a few males are responsible for all the successful fertilizations, it may be that inbreeding depression--a loss of genetic diversity due to the mating of closely related partners--is reducing the number of successful impregnations or breeding events. This problem has been suspected in the Florida panther, which was reduced to a population of about thirty and displayed physical ailments associated with inbreeding. In that case, Texas cougars were introduced to offset the effects of inbreeding. That decision was controversial, and certainly no one's considering introducing southern right whales into our population. But even if inbreeding is not a factor, if there are only a few parents out there, it will take the population a long time to recover.

Of course, this work involves more than biopsy darting and test tubes. Math plays an important role as well. By looking at the number of males who are siring offspring, we can determine the effective population size of the North Atlantic right whale. This number reflects how many whales in the population are actively breeding. Although it is generally agreed that there are about three hundred whales in the North Atlantic, we have no idea how many of these are producing offspring. Through photo identification, we can estimate the number of females who have reared calves. By combining this visual analysis with genetics to determine the number of reproductive males, we can get an estimate of the total number of breeding individuals in the population. Some scientists suggest that a small effective population faces a strong likelihood of extinction. How endangered are these whales? And what can we do to protect them further?

Well, the most important step is to protect all the right whales. Dead right Whale on beach. So, we need to learn more about that unknown group of females that Moe mentioned earlier. By getting skin samples in the Southeast (and without even locating their summer feeding grounds) we can get an idea of what this unknown population is like. DNA will enable us to determine if the same males are fathering calves in both groups, or if there are other males associated with these females. Then we can compare reproductive rates and scarring to see if whales from this unlocated area are in greater danger than those we see in the Bay. If their reproductive rates are lower, or if they are more vulnerable to entanglements, it will be very important to find--and protect--their summer feeding grounds.

Once all the whales are sampled, we can establish relationships and family trees for the entire population. Using both genetic and photo IDs, we can see where different family members go and if some are more exposed to threats such as ship strikes, fishing-gear entanglements, or pollution. The more we know about these whales, the more power we'll have to convince legislators and policy makers that certain areas or groups need greater protection.

Just as importantly, these samples allow us to know individual whales much better. Each sample we get can act as a genetic ID card. It tells us parentage, genetic history, and can serve for later identification. During the first few months of a whale's life, the characteristic callosity pattern, wartlike patches of skin covered by whale lice, is not yet formed. This crest gives older whales the distinctive white pattern on the head we use to identify them. DNA samples will allow us to identify a calf before it develops this visual clue and to follow it into adulthood, thus getting a more complete picture of its life. As Moe says, "We are trying to save this population . . . one animal at a time."


Blubber Biopsies

When possible, Chris tries to get a small piece of blubber along with the skin sample when he darts a whale. About the size of a pencil eraser, this blubber sample is used for chemical analysis, partly to determine if pollutants are affecting the right whales in our area. Michael Moore from the Biology Department of the Woods Hole Oceanographic Institute in Massachusetts writes:

Biopsy Sample
"Since 1993, Carolyn Miller, John Stegeman, and I have been looking at blubber biopsies collected by the New England Aquarium's North Atlantic Right Whale Research Project to see if there are any clues about the importance of chemicals in the ability of northern right whales to raise calves. Our interest came from the observation that right whales in the northern hemisphere have fewer calves than their cousins in the southern hemisphere. Most studies of chemicals in whales focus on estimating the amounts of particular compounds in the blubber. This assumes that the concentration of these chemicals predicts their effects in sensitive parts of the body, such as the liver, brain, and kidney. However, some important chemicals are not accumulated in the body, so we have been using a measure of chemical exposure that is not dependent on actual accumulation of these chemicals.

"We now have biopsies from seven different parts of the world, including the North Atlantic, South Atlantic, Antarctica, and south of New Zealand. We have shown low levels of accumulated chemicals at all sites but have found increased chemical throughput in right whales feeding off New England. One of the sites that we need a larger number of samples from is the animals that are currently being biopsied off the coasts of Georgia and Florida. Thus the work that Chris Slay and his friends are currently doing will be very important for us."

Because the skin and blubber samples come from the same whales, the two studies can be compared. Ruth notes that through genetic analysis, "links can be made between the susceptibility of right whales to pollutants and their genetic composition. Perhaps there is a vulnerability to pollutants that is genetically inherited." By working together, researchers--and all of those interested in whales--can make connections between the right whale's biology and their environment. And the more we learn, the more we can all do to protect these endangered whales.

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