Please select your home edition
Edition
KZRaceFurlers

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

Wildwind 2016 660x82Ancasta Botin Fast40 660x82Mariners Museum 660x82

Related Articles

A Few Rays – Moisturising, Anti-Aging Action …
Consistent moisturising sun protection has an anti-aging action Consistent moisturising sun protection has an anti-aging action Out on a boat, sailors are exposed to extreme conditions for their skin. There are UV rays from the sun, hopefully some wind if you are a sailor, and the drying effects from wet and dry cycles during the course of your day
Posted today at 9:39 am
BoatUS looks at accuracy of 22 Years of hurricane season predictions
BoatUS Seaworthy Program, which helps BoatUS members avoid injuries and boat damage by analyzing insurance claims data With most 2017 storm forecasts now predicting average to above-average storm activity for the 2017 Atlantic Hurricane Season (June 1 – November 30), just how accurate are these predictions, and do boaters need to adjust their hurricane prep plans this year?
Posted on 13 Jun
Caffari to lead a team with sustainability message in Volvo Ocean Race
Sixth confirmed team out of a possible eight for the upcoming edition will amplify United Nations Environment’s campaign Caffari’s ambition is to build a multi-national, 50-50 male/female squad, with the majority under 30 years of age. As part of the sustainability focus, the messages around diversity in age and gender will be strong themes of a campaign that in sporting terms may not start as a favourite, but could easily surprise on the water.
Posted on 13 Jun
A Few Rays - What is Broad Spectrum Protection?
What is Broad Spectrum sunscreen? Ultraviolet rays only make up a small proportion of all of the sun’s rays. What is Broad Spectrum sunscreen? Ultraviolet rays (UVA, UVB and UVC) only make up a small proportion of all of the sun’s rays. UVA and UVB sun-rays are however the biggest contributors to skin damage from sun.
Posted on 19 Apr
Frigid flying – Coast Guard aircrews take on New England Winter
Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. At Air Station Cape Cod, aviation maintenance and electronic technicians work around the clock to ensure the MH-60 Jayhawk helicopters are prepared and ready to launch. There is one thing the maintenance crews and pilots cannot control: winter weather.
Posted on 9 Feb
When whales meet sails
CAMPER helmsman Roberto ‘Chuny’ Bermudez found himself nearly face to face with whale in middle of North Atlantic Ocean. Currently the database for marine mammal strikes is very sparse. We are requesting sailors and boaters help to submit information on current and past incidents, however long ago that may be. By giving a location, date, identification if possible, and any other relevant information you can help scientists better understand where marine mammals are at risk for strikes
Posted on 8 Jan
Vendée Globe – Uncertainty about weather condition in North Atlantic
Alex Thomson and Armel le Cléac'h are probably looking closely at the wind models for the North Atlantic. Alex Thomson and Armel le Cléac'h are probably looking closely at the wind models for the North Atlantic. It does not seem to be easy.
Posted on 4 Jan
10,000 metric tons of plastic enter Great Lakes every year
A new study inventories and tracks high concentrations of plastic in Great Lakes could help inform cleanup efforts A new study by Rochester Institute of Technology that inventories and tracks high concentrations of plastic in the Great Lakes could help inform cleanup efforts and target pollution prevention.Researchers found that nearly 10,000 metric tons—or 22 million pounds—of plastic debris enter the Great Lakes every year from the United States and Canada.
Posted on 2 Jan
The Deepwater Horizon aftermath
Researchers analyze 125 compounds from oil spilled in Gulf of Mexico to determine their longevity at different levels. Researchers analyze 125 compounds from oil spilled in the Gulf of Mexico to determine their longevity at different contamination levels. The oil discharged into the Gulf of Mexico following the explosion and sinking of the Deepwater Horizon (DWH) rig in 2010 contaminated more than 1,000 square miles of seafloor.
Posted on 1 Jan
What happened to Deepwater Horizon Oil?
What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Six years after the Deepwater Horizon oil spill, we are continually asked two questions. What happened to the 160 million gallons of oil that gushed for 87 days into the Gulf of Mexico in 2010? Was discharging 1.67 million gallons of chemicals into the ocean to disperse the oil a good or bad idea?
Posted on 24 Dec 2016