birding-aus

Climate change does not bode well for picky eaters

To: Ian May <>
Subject: Climate change does not bode well for picky eaters
From: Dave Torr <>
Date: Fri, 23 Jan 2015 10:49:32 +1100
I think increasing krill harvesting by humans will also play a role Ian!

On 23 January 2015 at 10:28, Ian May <> wrote:

> 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 < <mailto:
>>> >> 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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