Blinding Nemo: Young clownfish living closest to the shore die FASTER than those further out because they’re being exposed to artificial lighting, study warns
- Clownfish living closest to shore die faster than those further out, a study warns
- This is because of exposure to artificial light from streetlights, piers and ports
- The reef-dwellers feed by day and need period of inactivity at night to recharge
- But when this is interrupted it causes higher mortality and slower rate of growth
Young clownfish living closest to the shore die faster than those further out because they are being exposed to artificial lighting from streetlights, piers and ports, a new study has warned.
Made famous by ‘Finding Nemo’, the iconic reef-dwellers feed, reproduce, defend their territories and interact with other fish during the day before sleeping at night.
Like humans, this period of inactivity is crucial for their well-being because they need it to recharge, researchers said.
But when the down time is interrupted by artificial light the effect on clownfish can be catastrophic.
In need of sleep: Young clownfish living closest to the shore die faster than those further out because they are being exposed to artificial lighting from piers and ports, a study has warned
Clownfish were monitored for almost two years in the reefs around Moorea in French Polynesia
A team of international scientists from France, the UK, Chile and Australia found that young clownfish had higher rates of death when exposed to light pollution close to the coast.
This is because of the harmful effects it has on the physiology of the fish, as well as the potential for artificial light to attract natural predators.
The juvenile clownfish also grew 44 per cent slower than those in natural lighting conditions.
‘The impacts of light pollution found here are probably underestimated and mitigation measures and policy changes are urgently required,’ said marine ecology expert Stephen Swearer.
The clownfish were monitored for almost two years in the reefs around Moorea in French Polynesia.
Professor Swearer, from the University of Melbourne, said researchers exposed 42 clownfish in their host anemones to either artificial light at night (ALAN) or natural light in the lagoon.
‘Thirty six per cent of the clownfish exposed to light pollution were more likely to die than fish under natural light cycles,’ said lead author, Jules Schligler, from the École Pratique des Hautes Études PSL Université Paris.
He said clownfish can be found in shallow coastal waters and are easily impacted by light at night from streetlights, piers or ports because they are highly sedentary living in anemones.
In the research paper, the scientists said that ‘even those fish that survived didn’t entirely escape the effects of artificial light at night as they grew less than fish from the control group.’
Reef-dwellers: Researchers exposed 42 clownfish to either artificial light or natural moonlight
The study from the University of Melbourne produced this graphic to summarise its findings
‘This is the first time that the impacts of ALAN have been tested on a coral reef fish in the wild and over such a long time,’ said Daphne Cortese, a post-doctoral fellow at the University of Glasgow.
‘As 12 per cent of all coral reef fish live in close association with another sedentary species, such as a coral or anemone, light pollution could already be having severe negative impacts on a fifth of fringing reef fish populations.’
Scientists hope the research will help raise awareness of the impacts of ALAN on coastal marine ecosystems.
‘Many marine protected areas are impacted by light pollution at night, and authorities are not taking this pollution into account,’ said Ricardo Beldade, associate professor at the Pontificia Universidad Católica de Chile.
‘We hope that policymakers take this threat much more seriously for future management strategies.’
The study is published by the University of Melbourne in the journal Proceedings of the Royal Society B.