Please select your home edition
Edition
Barz Optics - Kids range

Rising carbon dioxide levels alter fish behaviour

by ARC Centre of Excellence for Coral Reef Studies on 3 Feb 2012
Clown fish pair - Photo courtesy of Dr Simon Foale ARC Centre of Excellence Coral Reef Studies © http://www.coralcoe.org.au/
An international scientific team has found that rising human carbon dioxide emissions may be affecting the brains and central nervous system of sea fishes with serious consequences for their survival.

Carbon dioxide concentrations predicted to occur in the ocean by the end of this century will interfere with fishes’ ability to hear, smell, turn and evade predators, says Professor Philip Munday of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.

'For several years our team have been testing the performance of baby coral fishes in sea water containing higher levels of dissolved CO2 – and it is now pretty clear that they sustain significant disruption to their central nervous system, which is likely to impair their chances of survival,' Prof. Munday says.

In their latest paper, published in the journal Nature Climate Change, Prof. Munday and colleagues report world-first evidence that high CO2 levels in sea water disrupts a key brain receptor in fish, causing marked changes in their behaviour and sensory ability.

'We’ve found that elevated CO2 in the oceans can directly interfere with fish neurotransmitter functions, which poses a direct and previously unknown threat to sea life,' Prof. Munday says.


Prof. Munday and his colleagues began by studying how baby clown and damsel fishes performed alongside their predators in CO2-enriched water. They found that, while the predators were somewhat affected, the baby fish suffered much higher rates of attrition.

'Our early work showed that the sense of smell of baby fish was harmed by higher CO2 in the water – meaning they found it harder to locate a reef to settle on or detect the warning smell of a predator fish. But we suspected there was much more to it than the loss of ability to smell.'

The team then examined whether fishes’ sense of hearing – used to locate and home in on reefs at night, and avoid them during the day – was affected. 'The answer is, yes it was. They were confused and no longer avoided reef sounds during the day. Being attracted to reefs during daylight would make them easy meat for predators.'

Other work showed the fish also tended to lose their natural instinct to turn left or right – an important factor in schooling behaviour which also makes them more vulnerable, as lone fish are easily eaten by predators.

'All this led us to suspect it wasn’t simply damage to their individual senses that was going on – but rather, that higher levels of carbon dioxide were affecting their whole central nervous system.'

The team’s latest research shows that high CO2 directly stimulates a receptor in the fish brain called GABA-A, leading to a reversal in its normal function and over-excitement of certain nerve signals.

While most animals with brains have GABA-A receptors, the team considers the effects of elevated CO2 are likely to be most felt by those living in water, as they have lower blood CO2 levels normally. The main impact is likely to be felt by some crustaceans and by most fishes, especially those which use a lot of oxygen.

Prof. Munday said that around 2.3 billion tonnes of human CO2 emissions dissolve into the world’s oceans every year, causing changes in the chemical environment of the water in which fish and other species live.

'We’ve now established it isn’t simply the acidification of the oceans that is causing disruption – as is the case with shellfish and plankton with chalky skeletons – but the actual dissolved CO2 itself is damaging the fishes’ nervous systems.'
The work shows that fish with high oxygen consumption are likely to be most affected, suggesting the effects of high CO2 may impair some species worse than others – possibly including important species targeted by the world’s fishing industries.

The team’s latest paper Near-future CO2 levels alter fish behaviour by interfering with neurotransmitter function by Göran E. Nilsson, Danielle L. Dixson, Paolo Domenici, Mark I. McCormick, Christina Sørensen, Sue-Ann Watson, and Philip L. Munday appears in the journal Nature Climate ARC Centre of Excellence for Coral Reef Studies website

Bakewell-White Yacht DesignNorth Technology - Southern SparsBarz Optics - San Juan Worlds Best Eyewear

Related Articles

Terry Kohler, driving force of North Technology dies at 82
Terry Kohler who purchased North Sails was the driving force behind the North Technology Group, has died aged 82 Terry Kohler who purchased North Sails from Lowell North over 30 years ago and was the driving force behind the North Technology Group, has died aged 82. With the combined company of North sails and Southern Spars, Kohler created the 'Engine above the Deck' concept which married the technology used to build the sails and spars to be designed and work as an integral unit.
Posted on 21 Sep
'Grate Art' in Hong Kong
Hong Kong charity pioneers environmental awareness through innovative storm grate installations In an effort to help Hong Kongers play their part in protecting the world’s ocean, Ocean Recovery Alliance is raising awareness through a unique public art installation called ‘Grate Art’. Hong Kong’s drainage system is one of the main sources for debris outflow into the ocean, and Ocean Recovery Alliance is tackling this problem upstream through an initiative that uses “art for awareness”.
Posted on 14 Sep
Zhik sailors win 17 sailing medals at 2016 Olympic Regatta
The 2016 Olympic games are over and what a Games they have been - Zhik sailors dominated Zhik sailors won almost 60% of the medals contested at Rio de Janeiro. It was a regatta which tested sailors and gear - with one day being the most severe conditions ever experienced at an Olympic regatta. For the Zhik team riders on the waters of Rio, four years and more of hard work and dedication have paid off for many.
Posted on 29 Aug
Rio official murdered ten months before the Olympics
Rio de Janeiro is a troubled city and a reeling Olympic host, but it will always have beautiful Guanabara Bay. Does an unsolved murder of an official in Rio in charge of cleaning up Guanabara Bay say a lot about the state of platy in the magical city? Priscilla Pereira was murdered 10 months ago and the thinking is that she was murdered in relation to her work
Posted on 31 Jul
WHO statement on Zika virus
The third meeting of the EC convened by the Director-General under IHR 2005 regarding microcephaly and Zika virus The third meeting of the Emergency Committee (EC) convened by the Director-General under the International Health Regulations (2005) (IHR 2005) regarding microcephaly, other neurological disorders and Zika virus was held by teleconference on 14 June 2016, from 13:00 to 17:15 Central European Time.
Posted on 16 Jun
Atlantic Cup 2016 - a race with an environmental commitment
The Atlantic Cup continues to further its mission for the 2016 race by examining the global economic impact of the ocean The Atlantic Cup continues to further its mission for the 2016 race by examining the global economic impact of the ocean and how an unhealthy ocean can affect the economy.
Posted on 7 Apr
Zika virus situation report
From 1 January 2007 to 16 March 2016, Zika virus transmission was documented in a total of 59 countries and territories. From 1 January 2007 to 16 March 2016, Zika virus transmission was documented in a total of 59 countries and territories. Cuba and Dominica are the latest to report autochthonous (local) transmission of Zika virus on 14 and 15 March, respectively. Five of these countries and territories reported a Zika virus outbreak that is now over.
Posted on 2 Apr
Have Norway scientists solved the Bermuda Triangle mystery?
The Bermuda Triangle has been said to have claimed numerous ships and aircraft over the years The Bermuda Triangle has been said to have claimed numerous ships and aircraft over the years, and everything from aliens to remnants from the lost island of Atlantis have been fingered as the culprits.
Posted on 15 Mar
Cyclone Winston Relief Fund – Help the people of Fiji
Sea Mercy is sending volunteer fleet of small and large vessels, loaded with shelter, food and medical supplies to Fiji. Sea Mercy is once again sending our volunteer fleet of small and large vessels, loaded with shelter, food, water and medical supplies and teams to Fiji.
Posted on 27 Feb
Flying Scot Atlantic Coast Champs - Hanson Medals awarded for rescues
US Sailing Safety at Sea Committee awarded the Arthur B. Hanson Rescue Medals to eight boats for their heroic efforts The US Sailing Safety at Sea Committee awarded the Arthur B. Hanson Rescue Medals to eight boats for their heroic efforts when a microburst storm hit the 2015 Flying Scot Atlantic Coast Championship, hosted by the Blackbeard Sailing Club, in New Bern, NC on September 12.
Posted on 2 Feb