Subject: North Atlantic blue whales

S. Jones (betej@u.washington.edu)
Mon, 9 Nov 1998 16:50:48 -0800 (PST)

On Sun, 8 Nov 1998 IMarks3519@aol.com wrote:

> From Wheelock's research in the Gulf of St. Lawrence, how many blue whales do
> you estimate for the North Atlantic? For the entire world? Are the populations
> growing - if so, at what rate?
> 
Hello,

The information I have obtained came from the U.S. Atlantic and Gulf of
Mexico Stock Assessments - 1996 and the Recovery Plan for the Blue Whale
prepared by Reeves et.al.

I do not know the estimate of the North Atlantic population of blue whales
from Wheelock's research.  However, according to the stock assessment
report, "little is known about the population size of blue whales except
for in the Gulf of St. Lawrence area.  Here, 308 individuals have been
catelogued (Sears et al. 1987).  Mitchell (1974) estimated that the blue
whale population in the western North Atlantic may number only in the low
hundreds.  R. Sears (pers. comm.) suggests that no present evidence exists
to refute this estimate".  There are insufficient data to determine
population growth rates for this species.  Off west and southwest Iceland,
an increasing trend of 4.9% a year was reported for the period 1969-1988
(Sigurjonsson and Gunnlaugsson  1990).

As far as world populations are concerned, there is no definitive
estimate.  352 individuals were photo-identified in the Gulf of St.
Lawrence from 1979 to 1997 in eastern Canada and New England.  Sighting
data from whaling vessels operating off the west and southwest coasts of
Iceland have been interpreted as demonstrating a trend of increase, at
about 5% per year, in the number of blue whales since the late 1960s.
This increasing trend is considered to apply specifically to the whale
population in these waters, not in the North Atlantic as a whole.  There
is no current estimate for the number of blue whales in eastern North
Atlantic waters.  In the North Pacific, the estimated number of blue
whales is 3,500.  This figure does not include all of the whales that feed
in summer off Alaska and British Columbia.  The best guess is the total
worldwide population of blue whales is between 4,000-5,000 individuals.

I hope this information helps you.

Bete