Ocean acidification to devastate commercial fisheries

December 17, 2009

Rising carbon emissions could hit fish stocks around the world

Previous studies have focused on the impact of acidification on coral reefs but not other marine organisms

Commercial fishing in the northern hemisphere will be devastated by rising carbon emissions, according to the first major study into the impact of ocean acidification.

A report by the marine NGO Oceana, presented to delegates at the Copenhagen Climate talks this week, has highlighted how higher acidity disrupts all marine organisms abilities to grow, reproduce and respire.

The worst affected countries, based on current fish catches, consumption, the importance of coral reefs and projected level of acidification in their coastal waters, are expected to be Japan, France and the UK. The United States and China are also expected to suffer.

Population collapse

‘Its not far fetched to talk about really dramatic physiological effects as a result of acidification’ said Mike Hirshfield, Oceana’s Chief Scientist and the report’s author.

‘The evidence isn’t all in the impact on fish, but everyday we get a new piece of information that suggests we could see population collapse as a result of acidification,’ he said.

Hirshfield presented his findings at Copenhagen alongside a group of commercial fishermen.

‘They are not our usual allies but they are concerned about the effect that acidification might have on their livelihoods.’

Erling Skaar, a Bering Sea Crab fisherman from Alaska said: ‘We could be facing a question of having resources or having no resources in a very few years if they keep dumping more carbon in the oceans.’

‘We don’t know the time line, but we don’t want to find out that it’s too late,’ he said.

Carbon emissions

The report says that atmospheric carbon dioxide levels would need to be stabilised at 350ppm to protect the oceans from rising carbon dioxide levels. According to the Intergovernmental Panel on Climate Change, this would entail an 85 per cent reduction in emissions below 2000 levels by 2050.

‘We are already seeing real problems now at 380ppm; we know that 450ppm is definitely too high,’ Hirshfield said.

Dr. Rajenda Pachauri, chairman of the IPCC, highlighted ocean acidification as a serious consequence of CO2 emissions in his opening remarks in Copenhagen.

However a 180-page draft negotiating text only contained the word ‘acidification’ once and the word ‘ocean’ nine times.

‘Land based effects of climate change often take priority over the oceans but we need to get the message out about acidification,’ said Hirshfield.

‘For a lot of people who may be sceptical about the weather and warming issues, acidification is a completely separate line of evidence. It’s simple chemistry,’ he said.

Source: Ecologist

Posted in Uncategorized