18-07-2004, 07:52 AM
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Interesting wee discussion that you're having here!
What wasn't mentioned in the article is that the 'loft' is also full of things like stomach contents of stranded cetaceans, the likes of the sperm whale (Physeter macrocephalus) and pygmy sperm whale (Kogia breviceps); ~ 15 samples of the former and 26 of the latter.
Toothed whales generally consume vast quantities of cephalopods - Physeter supposed to take 800-1000 per day just to sustain its bulk. There are only a few locations hwre they are known to dine on fish, and historically New Zealand wasn't considered to be one of them. The importance of the 1967 paper wherein 37% by wet weight commercial fish species was recorded from stomach contents of sperm whales harpooned in Cook Strait (the body of water that separates North from South Island's of New Zealand), hasn't really been recognised; but it is a fact, if we are to believe the earlier data (and I see no reason not to). It is also a fact that the diet of the whale in regional waters is nowadays exclusively squid. Many of these squid are now being seriously impacted by deep-sea trawl activity, bottom and mid water, adults and egg masses. Consequently what we expect to find is a change in either the size-class composition of squid in the diet of these whales (all stomach contents recovered from stranded [dead] whales over the past few decades), or a change in the relative abundances of certain species, or actual diversity of squid present in the stomach contents of these specimens [a consequence of changes in the abundance and diversity of squid species out there].
The majority of squid eaten by the whale are quite small, sometimes even less than that of earlier prey items (orange roughy), most definitely smaller than fish like ling. For every 1 giant squid that these whales eat they will eat several thousand considerably smaller squid (the giant squid, Architeuthis dux, is relatively important in the diet of the sperm whale in terms of biomass, but certainly not in numerical representation).
Nice to see I wasn't being criticised online; there have been a number of critical statements made about this press release.
Steve :geek
Interesting wee discussion that you're having here!
What wasn't mentioned in the article is that the 'loft' is also full of things like stomach contents of stranded cetaceans, the likes of the sperm whale (Physeter macrocephalus) and pygmy sperm whale (Kogia breviceps); ~ 15 samples of the former and 26 of the latter.
Toothed whales generally consume vast quantities of cephalopods - Physeter supposed to take 800-1000 per day just to sustain its bulk. There are only a few locations hwre they are known to dine on fish, and historically New Zealand wasn't considered to be one of them. The importance of the 1967 paper wherein 37% by wet weight commercial fish species was recorded from stomach contents of sperm whales harpooned in Cook Strait (the body of water that separates North from South Island's of New Zealand), hasn't really been recognised; but it is a fact, if we are to believe the earlier data (and I see no reason not to). It is also a fact that the diet of the whale in regional waters is nowadays exclusively squid. Many of these squid are now being seriously impacted by deep-sea trawl activity, bottom and mid water, adults and egg masses. Consequently what we expect to find is a change in either the size-class composition of squid in the diet of these whales (all stomach contents recovered from stranded [dead] whales over the past few decades), or a change in the relative abundances of certain species, or actual diversity of squid present in the stomach contents of these specimens [a consequence of changes in the abundance and diversity of squid species out there].
The majority of squid eaten by the whale are quite small, sometimes even less than that of earlier prey items (orange roughy), most definitely smaller than fish like ling. For every 1 giant squid that these whales eat they will eat several thousand considerably smaller squid (the giant squid, Architeuthis dux, is relatively important in the diet of the sperm whale in terms of biomass, but certainly not in numerical representation).
Nice to see I wasn't being criticised online; there have been a number of critical statements made about this press release.
Steve :geek