Hello
I would like to announce the recent publication of the following 3 papers in NAMMCO Scientific Publications Volume 7, North Atlantic Sightings Surveys: Counting whales in the North Atlantic, 1987-2001. The volume is available at www.nammco.no, and pdf reprints are available from me at kinguq@gmail.com.
Regards,
Daniel Pike.
Pike, D.G., Víkingsson, G.A.,
Gunnlaugsson, Th. and Řien, N. 2009. A note on the distribution and
abundance of blue whales (Balaenoptera musculus) in the Central and
Northeast North Atlantic. NAMMCO Sci. Publ. 7:19-29.
The
distribution and abundance of blue whales (Balaenoptera
musculus) was assessed from ship surveys conducted in the Central and Northeast Atlantic in 1987, 1989, 1995 and 2001. Blue
whales were most commonly sighted off western Iceland,
and to a lesser extent northeast of Iceland. They were very rare or absent
in the Northeast Atlantic. Sightings were
combined over all surveys to estimate the detection function using standard
line transect methodology, with the addition of a covariate to account for
differences between surveys. Total abundance was highest in 1995 (979, 95% CI 137-2,542) and lowest in 1987 (222, 95% CI 115-440).
Uncertainty in species identity had little effect on estimates of abundance.
There was a significant positive trend in abundance northeast of Iceland and in
the total survey area.
Pike,
D.G., Gunnlaugsson, Th., Víkingsson, G.A., Desportes, G. and Bloch, D.
2009. Estimates of the abundance of minke whales (Balaenoptera
acutorostrata) from Faroese and Icelandic NASS shipboard surveys.
NAMMCO Sci. Publ. 7:81-93.
North Atlantic Sightings Surveys for cetaceans were carried out
Northeast and Central Atlantic in 1987, 1989, 1995 and 2001. Here we
provide estimates of density and abundance for minke whales from the
Faroese and Icelandic ship surveys. The estimates are not corrected for
availability or perception biases. Double platform data collected in
2001 indicates that perception bias is likely considerable for this
species. However comparison of corrected estimates of density from
aerial surveys with a ship survey estimate from the same area suggests
that ship surveys can be nearly unbiased under optimal survey
conditions with high searching effort. There were some regional changes
in density over the period but no overall changes in density and
abundance. Given the recent catch history for minke whales in this
area, we would not expect to see changes in abundance due to
exploitation that would be detectable with these surveys.
Pike, D.G., Paxton, C.G.M., Gunnlaugsson, Th. and Víkingsson, G.A.
2009. Trends in the distribution and abundance of cetaceans from aerial
surveys in Icelandic coastal waters, 1986-2001. NAMMCO Sci. Publ.
7:117-142.
Aerial surveys were carried out in coastal Icelandic waters 4 times
between 1986 and 2001 as part of the North Atlantic Sightings Surveys.
The surveys had nearly identical designs in 3 of the 4 years. The
target species was the minke whale (Balaenoptera acutorostrata) but all
species encountered were recorded. Sighting rate and density from line
transect analysis were used as indices of relative abundance to monitor
trends over the period, and abundance estimates corrected for
perception biases
were calculated for some species from the 2001 survey. More than 11
species were sighted, of which the most common were the minke whale,
humpback whale (Megaptera novaeangliae), dolphins of genus
Lagenorhychus, and the harbour porpoise (Phocoena phocoena). Minke
whales and dolphins showed little change in distribution or abundance
over the period. There were an estimated 31,653 (cv 0.30) dolphins in
the survey area in 2001. Humpback whales increased rapidly at a rate of
about 12%, with much of the increase occurring off eastern and
northeastern Iceland. In 2001 there were an estimated 4,928 (cv 0.463)
humpback whales in the survey area. The relative abundance of harbour
porpoises decreased over the period, but estimates for this species
were compromised by uncorrected perception biases and poor coverage.
The ecological and historical significance of these findings with
respect to previous whaling activities and present-day fisheries is
discussed.