(A small group of scientists are getting
DNA samples, following the whales' movements and reproductive habits-and they
think there's hope.)
still promiscuous, North Atlantic right whales have largely given up the
singles bar scene, instead making their way to the more homey surroundings of
the Bay of Fundy.
There are two established right whale
conservation zones in the Maritimes - one off Grand Manan in the Bay of Fundy
and another off the southern tip of Nova Scotia. Because mothers and their
young were often in the Bay of Fundy area, it was dubbed "the nursery" by
scientists. Meanwhile, the area off Nova Scotia was called "the singles bar"
because it attracted predominantly males, who would engage in group sex with
females in what scientists have termed "surface active groups."
However, the number of whales frequenting the singles bar
has fallen off recently while the number in the Bay of Fundy has more than
doubled, to 180 or more a year (almost two-thirds of the entire right whale
population) from about 70 whales five years ago. Now surface active groups take
place in the Bay of Fundy. It isn't known where the other 120 or so right
whales are during this period.
At the same time, the
whales are staying for a longer period of time in the bay, first appearing in
June and staying until December, whereas they used to arrive in July and have
in November to head down south.
Scientists aren't sure
what has caused the whales to move to the Bay of Fundy and lengthen their stay.
One thing that corresponds with the change is a drop in the sea surface
temperature of the Scotian shelf so that the water there is now colder than the
Bay of Fundy. The food supply in the two areas could also be a factor, though
it hasn't been measured.
"It's sort of intuitive that
if the whales are here instead of there, they are in the northern portion of
their range this time of year to eat," says Moira Brown, a senior scientist
with the New England Aquarium's field research station in Lubec, Me.
"It makes sense that there must be a pretty good food supply
in the Bay of Fundy to support that number of animals. Of course, the
alternative theory is that there isn't enough food out there and they're having
to stay longer to achieve the same weight gain. That's an alternative theory
that we cannot disprove."
BROWN, from Montreal
originally, brings a Canadian component to the field research station in Lubec,
which operates during August and September - the peak period of whale activity
in the bay - with seven scientists, an intern and two volunteers trying to
learn all they can about the whales, mapping their movements through satellite
tagging, photographing them for identification purposes and obtaining skin
samples for DNA testing.
The field research is being
carried out this year on a budget of $85,000, with funding cobbled together
from a variety of sources, such as private foundations in the U.S. and abroad,
and the Department of Fisheries and Oceans in Canada. The $40,000 contribution
from DFO, through Brown's East Coast Ecosystems of Nova Scotia, is the first
such offering by the federal department. It allows for aerial surveys for
whales to be carried out from June through December and pays for the hiring of
The research project was started in 1980 and
Brown joined in 1985. In 1988 she started a genetic sampling program by using a
modified crossbow to obtain plugs of skin about the size of a licorice Nib,
from which DNA samples can be extracted.
hits and bounces off the whale very easily. It's sort of like a dart and a
rubber tire," she says. "The whales don't react to it. The occasional one will
twitch its skin like a horse will twitch to get rid of a fly."
By obtaining skin samples from about 70 per cent of the
population, the sex ration of males to females has been determined at about
50-50. "That's a healthy sex ratio for a wild population," says Brown.
The samples are also being used to chart the female family
lines in the whales, through the mitochondrial DNA pattern which remains
constant as it passes from a mother to her offspring.
Initially, it was thought that all the right whales alive today were from three
unrelated families,but more detailed analysis has broadened that finding. "It
looks like there are probably five unrelated families of right whales in this
population," says Brown. "That's not huge, but it's better than what we thought
we had, which were only three.
"It's not great, but
it's better than one."
In comparing the DNA of North
Atlantic right whales to their south Atlantic cousins - a similar but separate
species numbering about 2,000 to 3,000 - it was determined that the level of
inbreeding in the North Atlantic species wasn't as great as might have been
"There's some level of inbreeding avoidance
in this population," says Brown, "The end result is there are not conceptions
resulting from matings between closely related individuals.
"In other words, if a brother and sister mate, the level of
DNA variation right now indicates that they are not successful in having an
offspring. The level of success having an offspring rests at about an uncle and
The next step in the genetic mapping work
being carried out by Dr. Bradley White at McMaster University in Hamilton is to
establish a pedigree for the entire population.
look at one female right whale, are all of her offspring full siblings or half
siblings. In other words, do any of them have a father in common? We don't know
the answer to that, but we will be able to figure that out.
"The second part of that is if you look at all of the
offspring born in a given year, they all have different mothers. Do any of them
have the same father?
"These sort of questions have
implications on the mating system for this species."
While scientists see sexual activity during the summer stay in the Bay of
Fundy, that isn't when conception takes place, as the gestation period is one
year long and right whales give birth in December and January off the coast of
Florida. Only mothers and calves are seen off Florida during that time and the
whereabouts of the rest of the population at that time is unknown.
"Even though we see mating groups going on at all different
times of the year, the real thing may be happening in a very different way
somewhere else in December or in January," says Brown.
There is a three-year calving interval for right whales. They are pregnant for
a year, nurse for a year, then need a year to rest. However, scientists have
detected that the calving interval has increased, on average, to a little more
than four years.
"That's cause for alarm," says Brown.
"We're seeing more animals, that are waiting four, six
or seven years. Why, we haven't been able to answer yet. "Food is always a
theory. Are these animals getting, enough to eat so that they're capable of
The future of the species is hanging
in the balance at present, says Brown. "Just think about it in terms of if for
you lose 10 more animals a year than are born [annually] then this population
is wiped out in less than 30 years."
On the other hand,
if the present rate of increase of 2.5 percent annually can he maintained, the
population of 300 would double in 35 years. If the rate of increase could
somehow be increased to 7 per cent, the population would double in 15 years.
I'd be real happy to get this population up around
l,000 animals," says Brown. "It's going to take a long time.
Even 500 animals would make me feel a whole lot better.
She believes there's hope.
are no indications at this point that there's not the genetic potential there
for this population to survive," she says.
been other species of animals that have recovered from even smaller
"lf I thought we were monitoring the
demise of these animals, I wouldn't do it"
to reduce human related mortality. There is always going to be some natural
mortality. Animals get old and die, that's fine," she says. "But let's
especially try and protect those reproductive females and allow them to get on
The New Brunswick Reader/Sept. 20,