Subject: Belugas:1995 Survey, St Lawrence belugas (fwd)

Michael Williamson (
Thu, 13 Feb 1997 09:30:47 -0500 (EST)

J. Michael Williamson
   Principal Investigator-WhaleNet <>
   Associate Professor-Science
   Wheelock College, 200 The Riverway, Boston, MA 02215
voice: 617.734.5200, ext. 256
fax:    617.734.8666, or 617.566.7369

---------- Forwarded message ----------
Date: Wed, 12 Feb 1997 12:44:34 -0800
From: MARMAM Editors <marmamed@UVic.CA>
Reply-To: Marine Mammals Research and Conservation Discussion
To: Multiple recipients of list MARMAM <MARMAM@UVVM.BITNET>
Subject: 1995 Survey, St Lawrence belugas (fwd)


On 21 Jan. 1997, the Canadian Department of Fisheries and Oceans released
the following:


'QUIBEC - The condition of the St Lawrence beluga population is improving,
according to the latest data published by Fisheries and Oceans Canada. The
results of an aerial survey carried out in 1995 show that the population
index estimate for belugas of the St Lawrence and the Saguenay is 705,
compared with 525 in 1992, which confirms that the population is not

'Moreover, Fisheries and Oceans Canada scientists are now considering the
possibility that the St Lawrence beluga population could be increasing:
other information on the dynamics of the population, such as the high age
at death of adults, the apparently normal birth rate, and the rarity of
juvenile mortalities, are encouraging.

'The 1995 survey, carried out under the programme -St Lawrence Vision
2000-, is the latest in a 15-year series of aerial surveys by which
Fisheries and Oceans Canada has monitored the numbers and trend of the St
Lawrence population of belugas.  The next survey will be carried out in
the summer of 1997.

'For the 1995 survey, two aircraft equipped with mapping cameras flew at
4000 feet over the estuary between Nle aux Coudres and Nle du Bic, taking
continuous bands of photography which covered 50% of the area.  While
these aircraft were shooting their 1092 frames, a visual observer surveyed
the length of the Saguenay Fjord aboard another aircraft.

'The report -Population Index Estimate for the Belugas of the St Lawrence
in 1995- is available at Fisheries and Oceans Canada's Communications
Branch in Quebec City (418-648-7747) and Mont-Joli (418-775-0526).'

The abstract of the Technical Report on the survey is as follows:

'Kingsley, M.C.S.  1996.  Population index estimate for the belugas of the
St Lawrence in 1995.  Can. Tech. Rep. Fish. Aquat. Sci. 2117.  vi + 38 p.

'On 25 August 1995 a survey flight was carried out to estimate a
population index for the St Lawrence population of belugas (Delphinapterus
leucas).  Two aircraft, each equipped with a metric mapping camera
shooting 9" x 9"  frames through a 6"  lens, flew at 4000 feet over a
systematic grid of transects, aligned from northwest to southeast, that
stretched from Nle aux Coudres to Nle du Bic.  The transects were spaced 2
nautical miles apart, giving a 50% coverage of the estuary.  One thousand
and ninety-two frames were shot on colour positive aerial survey film.  At
the same time, another aircraft surveyed the length of the Saguenay Fjord
with a single visual observer.

'The wind was light over the whole survey area and the sky was clear, so
good- quality photography was obtained.  The film was analysed on a light
table using low-power microscopy.  A total of 377 belugas were counted on
86 frames.  Ninety-three were judged to be duplicates of belugas also seen
on the adjacent frame, so the net count was 284.  Fifty of 197 (25%)
appeared from their small size to be juveniles.  The resulting estimate of
visible belugas was 568 (sampling S.E. 94.0).  A 15% visibility correction
gave an estimated index for the St Lawrence of 653.2 (S.E. 108.1).  The
counts were not corrected for sun glare reflected from the water surface
and appearing on the photo frames.  On the simultaneous visual survey of
the Saguenay Fjord, 51 more belugas were seen at baie Ste-Marguerite and
one further upstream; these counts were not corrected for visibility.  The
final total estimated population index, including the Saguenay, was 705.2.

'This index estimate is 34% bigger than the value of 525 obtained on a
windier day in 1992 using the same methods, and a 16% increase over the
1990 estimate.'

Copies of the Technical Report are available.

M.C.S. Kingsley

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