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Wednesday, February 27, 2008

Say Goodbye to Butterflyfish, Sharks, and Antarctic Marine Life

I haven't done a "Goodbye to" post for a while, it is a truly depressing activity. Anyway, no good news this time. The Butterflyfish, nine species of shark (including the hammerhead), and the Antarctic marine ecology are all on the way out, most likely within our lifetimes. The cause, as usual, is us.

The Butterflyfish is out because we are destroying its food supply:

The case of the Chevroned Butterflyfish is a stark example of how human pressure on the world’s coral reefs is confronting certain species with ‘blind alleys’ from which they may be unable to escape, says Dr Morgan Pratchett of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

In a study published in the journal Behavioural Ecology and Sociobiology Dr Pratchett and Dr Michael Berumen of Woods Hole Oceanographic Institution (USA) warn that the highly specialized nature of the feeding habits of this particular butterflyfish – the distinctively patterned Chaetodon trifascialis - make it an extinction risk as the world’s coral reefs continue to degrade due to human over-exploitation, pollution and climate change.

“The irony is that these butterflyfish are widespread around the world, and you’d have thought their chances of survival were pretty good,” Dr Pratchett said.


Sharks are out due to bycatch and the love of shark fin soup:

Nine more species of shark are to be added to the endangered list as scientists warn that oceans are being emptied of the fish by overfishing and finning.

The scalloped hammerhead shark, which has declined by 99% over the past 30 years in some parts of the world, is particularly vulnerable and will be declared globally endangered on the World Conservation Union (IUCN) list.

"Sharks are definitely at the top of the list for marine fishes that could go extinct in our lifetimes," said Julia Baum of the Scripps Institution of Oceanography in California and a member of IUCN shark specialist group. "If we carry on the way that we are, we're looking at a really high risk of extinction for some of these shark species within the next few decades."

At the American Association for the Advancement of Science annual meeting in Boston yesterday, Baum said that in addition to the scalloped hammerhead, other shark species that will be added to the revised IUCN endangered list later this year are the smooth hammerhead, shortfin mako, common thresher, big-eye thresher, silky, tiger, bull and dusky. There are already 126 species of shark on the IUCN's list.


The sharks demise is happening in African waters:

"While the shark net catches have impacted on some species more heavily than others, most of the species that are caught in the shark nets are wide-ranging, with the tropical species inhabiting Mozambican and Tanzanian waters, where exploitation levels may be very high."

For example, their data showed that the great hammerhead shark not one of the nine had undergone a significant decline in catch rates in the nets, Cliff said.

"Between 1978 and 1993 we caught an annual average of 13 great hammers. Since 2000 we have only caught two per annum, with none since 2004.

"This species, very much a tropical one, has either changed its dispersal habits and is no longer visiting our waters, or it has been heavily fished to the north of us."

The local nursery ground of the scalloped hammerhead included the Tugela Banks, where the prawn trawlers had caught large numbers of neo-nates (baby sharks), he added.


Global warming is heating up Antarctic seas, allowing predatory crabs and fish to move in on a marine system unprepared for such an assault.

Predatory crabs and fish are poised to return to warming Antarctic waters for the first time in millions of years, threatening the shallow marine ecosystems surrounding Antarctica. Antarctic marine communities resemble the primeval waters of millions years ago because modern predators - crabs and fish - are missing.

...Antarctic marine communities are functionally Paleozoic - typical of around 250 million years ago,' says paleobiologist Rich Aronson. 'If the crabs' invasion succeeds, they will devastate Antarctica's spectacular Paleozoic-type fauna and fundamentally alter its ecological relationships.'

In January 2007 Dr Sven Thatje and a group of ocean biologists from NOCS and BAS discovered crabs massing in deeper slightly warmer waters, ready to move into the Antarctic shallows should they warm up sufficiently.


Oh fuck.



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