Fish 'starving to death'

[fishingjew]

Fish 'starving to death'
By Vincent Morello
December 27, 2006

FISH species on the Great Barrier Reef are starving to death because climate change is killing off their food source, an environmental study has found.
Rising sea temperatures have bleached more than 30 per cent of the world's coral reefs, a five-year study by the ARC Centre of Excellence for Coral Reef Studies (CoECRS) has found.

As a result, smaller fish which would normally feed on live coral are dying off, which could throw the fish food chain out of balance, and consequently hinder local fishing and tourism operations.

The coral damage is predicted to double by 2030 if sea temperatures continue their warming patterns, CoECRS senior researcher Morgan Pratchett said.

The starving fish fail to breed and fail to migrate to thriving reefs.

"Fish can be very territorial and it may be hard for refugee fish, which have lost their reef, to relocate elsewhere because the locals will try to keep them out," Dr Pratchett said.

CoECRS was set up in 2005 in Townsville, Queensland, to study coral reefs over a five-year period.

It is a partnership between three Queensland universities and two marine research organisations.
Dr Pratchett and his colleagues spent five years charting the collapse of coral-feeding butterfly fish on the reef following severe bleaching between 2000 and 2002.

Bleaching causes the corals to shed their natural bacteria and die.

"Ours and other studies indicate that when coral bleaching occurs, affecting up to 10 per cent of the reef, it affects the abundance of nearly two-thirds of the fish species on that reef.

"As the damage rises to 20 per cent and above, there is a marked decline in the richness of fish species on the reef and the losses can last for years."

But coral-feeding fish will return if the corals recover, Dr Pratchett said.

http://freepage.twoday.net/stories/3110280/


Seems like you blokes up there are really having a bad time with the Ongoing collapse of coral reef shark populations the GBRMPA green zones and fines and now this must be hard trying to get a fish

[billfisher]

Theres more to come on the 'Ongoing collapse of coral reef shark populations' study - in the form of a scientific review. I'll put it up when its available.

I have seen the 'Great Barrier Reef fish are starving to death because of climate change study' reported widely in the media. Not suprising given the eco-sensationalist style (very similar in this respect to reef shark collapse study). I won't comment till I get some more info. I don't want to give Chaz and PJW an excuse to quibble.

[billfisher]

Here are some notes from Dr Walter Starck on global warming (GW) and coral reef bleaching:

.....that after a strong bleaching event there is a shift in the fish fauna of affected areas. Not surprisingly there is a decrease in coral feeders and an increase in algal grazers with the previous balance being recovered after a few years as coral repopulates. In the meantime normal numbers of coral feeders tend to remain along the deeper slopes of the same reefs below the shallow areas affected by bleaching.
In today's atmosphere of climate change alarmism the finding of totally unremarkable natural fluctuations can readily gain widespread attention and an appearance of importance by simply suggesting a connection with GW.

Bleaching events result from extended periods of calm weather during which mixing from wave action ceases and surface water becomes exceptionally warm. Such warming is especially marked in very shallow water such as on reef flats. At the same time the absence of waves also eliminates the wave driven currents that normally flush the reef top. Bleaching conditions require at least a week or more of calm weather to develop and this may happen every few years, only once in a century, or never, depending on geographic location. On the outer GBR it is uncommon due to ocean swell and currents even in calm weather. In the mid-shelf and inshore areas it is much more common due to the absence of swell and reduced currents.

Characteristic bleaching scars and isotope temperature records from coral cores commonly show evidence of past bleaching events going back thousands of years. There is no evidence for a recent increase in frequency and/or severity of bleaching events and nothing to link extended periods of calm winds with global warming.

In past geologic periods when global climate was warmer than at present corals enjoyed greater latitudinal distribution. The most likely effect of a warming climate on reefs would seem to be an expansion of their geographic distribution and there is some evidence this is already happening. In Florida recent growth of coral has occurred farther north than it did a few decades ago and in the same areas sub-fossil corals indicate previous such advances in the recent geologic past.

Hoegh-Guldberg has found an attractive GW niche in the well established guild of GBR doomscryers. It has provided notoriety, acclaim and generous research support. Whether his prophesies will stand up to the reality test remains to be seen. Based on the track record of science based doomscrying his odds don't look too good. In fact sheep's entrails and tea leaves seem to produce better results, probably because they at least incorporate some element of intuitive judgment."

The same coral species that have bleached on the GBR thrive elsewhere at considerably higher temperatures and in some bleaching locations subsequent events have shown less effect even at higher temperatures. The reason is believed to lie in differing clades of algal symbionts adapted to different temperatures. How far such adaptation can go is not known but species distributions of corals and associated water temperatures indicate that the temperatures associated with bleaching events on the GBR are several degrees below what the same coral species routinely survive elsewhere.

Combined with the AGW climate predictions of less warming at lower latitudes and past distributions of reefs in much warmer geologic periods a hollowing out in the middle seems unlikely. In any event it is wind (or rather lack of it) plus local geography and currents, not air temperature that is the key factor in bleaching events. On the GBR they are more likely to occur at the southern end of the reef than at the top where the strong currents of Torres Strait assures mixing and the flushing of reef tops even in calm weather.
Posted by: Walter Starck at April 12, 2006 03:36 PM
-----------
Indeed storms do prevent bleaching. The recent storm up here (Cyclone Larry) has already been accredited with saving the reef from this years bleaching that had been predicted by OH-G. However we were already past the time of highest temperatures and calmest weather and temperatures were falling but, any storm in a punt.
Posted by: Walter Starck at April 12, 2006 03:46 PM
-------------
*The 0.7 C. increase in temperature over the past century and a half coming out of the LIA is comparable to the rate of decrease entering into it.
* Corals can and do change their algal clades from one bleaching event to the next. They even do so seasonally without apparent bleaching.
*In a number of areas healthy corals tolerate seasonal temperature ranges of as much as 15 C. and at the high end this may regularly be 3-4 C higher than those on the GBR.
* Although bleaching does result in a temporary growth hiatus in corals the increased water temperatures over the past century has been associated with substantially increased growth and calcification.
* Intense tropical cyclones do immense damage to reefs but they are a natural element in many reef areas. Whether they will increase in frequency and intensity due to GW is unclear. Proponents of AGW claim they have. Storm experts say they there is no evidence for this. A storm like the recent one hitting the coast every few years would be far more devastating to humans than to the reef.

[choppa]

food for thought,,,,,,,,,,i was reading an edition of the National Geographic re global warming and the effects on sealife as we know it,,at a recent visit to the wesley hospital

the article covered the GBR in detail, and gave forecasts/predictions on the effects and the results of current studies and various other stuff,,,all of which i must add was and is relevant

global warming is real,,,and even though there are a few sceptics amongst us judging on replies that have been posted in various threads,,, its effecting everyone worldwide

the National Geographic that i was reading,, was donated along with about 10-12 other editions,,,

all were dated 1992

[PinHead]

food for thought,,,,,,,,,,i was reading an edition of the National Geographic re global warming and the effects on sealife as we know it,,at a recent visit to the wesley hospital

the article covered the GBR in detail, and gave forecasts/predictions on the effects and the results of current studies and various other stuff,,,all of which i must add was and is relevant

global warming is real,,,and even though there are a few sceptics amongst us judging on replies that have been posted in various threads,,, its effecting everyone worldwide

the National Geographic that i was reading,, was donated along with about 10-12 other editions,,,

all were dated 1992

this summer sure isn't warmer than last year..lol

[FNQCairns]

It was good to read about the recent CSIRO report that states the current drought is a direct result of natural variation (and in my words) cannot in anyway be linked to sensationalised global warming predictions.

Strangely this report didn't get a very thourough run through the media outlets-wonder why?!!

cheers fnq

[billfisher]

Probably the same reason that critiques of the "Fish stocks to collapse in fifty years" report didn't get much publicity, same goes for the UBC's devastating review of the "Empty nets - Empty oceans" report written by a conservation group regarding NSW fisheries.

[BigE]

best we catch them before they starve ............. it's the only green/humane thing to do. i'll help do my bit.

E

[Matthias]

Hey Billfisher. Is there a site where I can download the report/note you posted up on coral bleaching?

Pete.

[Brett1907]

Global warming! Starving fish?

Have these scientists forgotten that there were once dinosaurs and the earth went through an ice age? It is nature at work. Unfortunately we are aggravating nature and she is getting angry.

Brett