Hello all
There’s no suggestion from me that we cull whales to protect seabirds so some of you, please settle down, its OK. Nevertheless, it is a fact that seabirds that eat Krill have enjoyed much less food competition during the past whale-harvesting century than is now the case.
Moreover, it is probable that the more food (Krill) available during that period, helped raise some seabird populations above a typical level, in a manner more recognised as the good times in a boom/bust cycle. Changing Krill predator feeding dynamics will have ecological consequences and this includes a potentially negative impact on krill eating Seabirds.
As others have suggested, the decline of Krill is likely to be caused by various factors. The claim of 80% decline of Krill due to climate change is nonsense and is totally alarmist. If it is true, the optimist should rejoice because the surviving 20% are clearly immune to climate change and will breed.
Ian May
St Helens, Tasmania
Tim Jones wrote: > All, > > I was lucky enough to travel to the Antarctic this January. There were > lectures on board ship regarding everything from explorers to geology to > wildlife, and there was a very informative one about krill. The decline > in krill probably has nothing whatsoever to do with predators. I am no > scientist, but my understanding is that it is likely due to: > > – decrease in ice in key areas due to climate change, although large > areas of the Antarctic may be getting colder, with some increasing in > temperature > – the invasion of Salp – an animal which is numerous like krill and is > gradually displacing it but has no known role in the upward food chain > – ocean acidifcation due to fossil fuel absorbtion – even immediate > cessation would take time to reverse the acidification > – possible overharvesting by humans. Certain countries have signed on to > a convention which limits krill harvesting to a very sustainable level > but there is much which goes on illicitly. However, krill is difficult > to process after harvest, so it is not hugely economically attractive > and the amount of trade which goes on may not be sufficient to be having > a serious effect. > > These things may be right or wrong but certainly a fair bit seemed > empirically and scientifically based. > > I doubt those nasty whales have much to do with it given that there were > a thousand times as many in the Antarctic a hundred years ago…. > > The seabird declines are also probably much more due to increasing human > pressures (including the loss of krill) while we are carefully > protecting whales (at least most countries are). > > When all is said and done, whatever nature’s imbalances and competition > for resources are, it all comes down to one species – homo sapiens. > > Cheers > > Tim > > > > > Date: Wed, 13 Apr 2011 06:32:52 -0700 > > From: nhaass@yahoo..com > > To: birding@ozemail.com.au; l.knight@optusnet.com.au > > CC: birding-aus@vicnet.net.au > > Subject: Re: [Birding-Aus] Antarctic penguins losing to climate > change through 80% krill decline > > > > Any details? Which “pelagic sea birds”? Which “whales”? Species? > Numbers? Rather than a terribly superficial statement? > > > > —————- > > Nikolas Haass > > nhaass@yahoo.com > > Sydney, NSW > > > > > > ________________________________ > > From: Ian May
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