Thanks for your reply David.
Yes I think "prior to ma's assault on whales and other cetaceans" the
available food balance was probably of little concern regarding
population survival, but the problem as I see it, is that now is a time
when overall seabird numbers are artificially increased due to the
absence of significant feeding competition from Cetaceans, and because
of this, the entire seabird population is now at much greater risk of a
crash from starvation if impacts on the same available food source are
suddenly increased, as must be the case now, not from Climate Change,
but from Cetacean feeding competition.
Most people with an agricultural background will be aware of what
happens to animals, both wildlife and domestic when severe drought
descends on the country. If my memory of J curve is correct, when a
population exceeds the carrying capacity of its food source, there "will
be" a significant population crash. After this occurs, for species that
have evolved to adapt to a boom bust cycle, most of these populations
will recover, but as you would be aware, boom bust ecology is not how it
is with seabirds and a major crash may well go beyond the tipping point
for many of them.
regards
Ian May
PO Box 110
St Helens, TAS 7216
------------------------------------------------------------------------
David Bishop wrote:
Dear Ian,
This sort of connectivity fascinates me. I cannot help but ponder your
question as it makes one wonder, if you are correct, what were penguin
numbers like prior to ma's assault on whales and other cetaceans?
Perhaps the krill population was commensurately larger in those far
off times?
David Bishop
P. O. Box 1234, Armidale, NSW 2350, Australia
M +61 412 737 297 Office +61 2 6771 5580
On 23 Jan 2015, at 9:10 am, Ian May <
<>> wrote:
H
Hello Laurie
Not wanting to upset "the believers", I cannot help but wonder if
these researchers ever considered that a decline of Antarctic Krill
could be caused by the exponential increase of Cetaceans that has
occurred over the past two decades. Is it true that a current
population estimate of just one species, the humpback whale has now
reached 80,000 individuals? About five years ago, the population
estimate at that time had increased to 35,000 animals?
See
http://en.wikipedia.org/wiki/List_of_cetaceans#Global_Population_Estimates
or http://whaleone.com.au/whale-facts/
As a part time researcher from a time nearing the end of the
commercial whaling era when it was rare to sight a large whale in
Australian waters, I occasionally pondered the effects on the pelagic
world from competition on the basic marine food source impacted by
the presence or absence of Cetaceans.
My conclusion was that you cannot have your krill and eat it too.
regards
Ian May
PO Box 110
St Helens, 7216
------------------------------------------------------------------------
Laurie Knight wrote:
The following study contrasts the fortunes of Chinstrap and Gentoo
Penguins
see http://www.sciencedaily.com/releases/2015/01/150120121304.htm
Original study: MJ Polito, WZ Trivelpiece, WP Patterson, NJ
Karnovsky, CS Reiss, SD Emslie. Contrasting specialist and
generalist patterns facilitate foraging niche partitioning in
sympatric populations of Pygoscelis penguins. Marine Ecology
Progress Series, 2015; 519: 221 DOI: 10.3354/meps11095
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