Nemo can't go home

Aug 20, 2013

Round the planet the loveable clownfish Nemo may be losing his home, a new scientific study has revealed.

Research by an international team of has found that , which provide shelter for clownfish and 27 other , are facing the same worldwide threat as and loss due to temperatures.

"Our study showed that at least seven of the ten anemone species suffer from bleaching when get too high," says Dr Ashley Frisch of the ARC Centre of Excellence for Coral Reef Studies at James Cook University, a co-author of the report which has highlighted a potential crisis for two of the world's most popular .

"Importantly, we found bleaching of anemones occurring wherever we looked – from the Red Sea and Indian Ocean to the Indo-Australian region and the Pacific. Sometimes it was on a ."

The bleaching appears to be due to the same cause as coral bleaching – loss of the anemone's symbiotic algae, which supply an important part of its nourishment. This happens when the surrounding water becomes too warm.

But it also involves the loss of the brightly coloured fishes which the anemone protects – and which in turn protect it. The result is a collapse in the delicate three-way partnership between algae, anemone and fish.

"Anemones are naturally tough and live for many years. As a result their rates of reproduction are slow – and when they are hit by a killer bleaching event, it can result in their complete loss from an area over a period of time. It appears they cannot reproduce fast enough to make good the loss, especially if the fish are also gone," Dr Frisch explains.

"Bleaching causes the loss of anemonefish, like nemos, which have nowhere to hide and without the anemones to protect them are quickly gobbled up by predators.

"Also, because the fish appear to perform useful services for the anemone like protecting them from grazing fish, it may also be that the loss of anemonefishes following a bleaching event means the anemones themselves are much less likely to recover."

The researchers, from Australia, Saudi Arabia and the USA surveyed nearly 14000 anemones worldwide and found 4 per cent were bleached. However bleaching rates ranged from 20-100 per cent, following five major bleaching episodes.

They conclude that in some areas, anemone "population viability will be severely compromised if anemones and their symbionts cannot acclimat(is)e or adapt to rising sea temperatures.

"Anemone bleaching also has negative effects to other species… including reductions in abundance and reproductive output of anemonefishes.

"Therefore, the future of these iconic and commercially valuable coral reef fishes is inextricably linked to the ability of host anemones to cope with rising sea temperatures associated with climate change."

The study concludes "If host anemones (and their ) cannot acclimate or adapt to rising sea temperatures, then populations of host anemones and associated anemonefishes are anticipated to decline significantly."

Dr Frisch says that apart from their roles in coral ecosystems, anemones and their fish are of economic importance to both tourism and the aquarium trade, and many poor coastal communities depend on the income they bring.

The report "Taxonomic, Spatial and Temporal Patterns of Bleaching in Anemones Inhabited by Anemonefishes' by Jean-Paul A. Hobbs, Ashley J. Frisch, Benjamin M. Ford, Michele Thums, Pablo Saenz-Agudelo, Kathryn A. Furby and Michael L. Berumen appears in the journal PLOS One.

Explore further: The right amount of grazing builds diverse forest ecosystems

add to favorites email to friend print save as pdf

Related Stories

Nemo helps anemone partner breath by fanning with his fins

Feb 27, 2013

Setting up home in the stinging tentacles of a sea anemone might seem like a risky option, but anemonefish – also known as clownfish and popularised in the movie Finding Nemo – are perfectly content in their unlikely ...

Cloud brightening to cool seas can protect coral reefs

Jul 10, 2013

The seeding of marine clouds to cool sea surface temperatures could protect threatened coral reefs from being bleached by warming oceans. Research, published in Atmospheric Science Letters, proposes that a targeted versio ...

Corals can sense what's coming

Nov 18, 2011

Australian scientists have thrown new light on the mechanism behind the mass death of corals worldwide as the Earth's climate warms.

Recommended for you

Seeds keep vital much longer when stored without oxygen

17 hours ago

If seed breeding companies, gene banks and the Svalbard Global Seed Vault on Spitsbergen should store plant seeds under oxygen-poor conditions, it would be possible to store them for much longer while still ...

Native species may be hindering fox control efforts

17 hours ago

Native species interfering with ground distributed baits used to control red foxes in south west Western Australia may mean the baits are not available to the target species, a Murdoch University study has ...

Giant anteaters kill two hunters in Brazil

Jul 26, 2014

Giant anteaters in Brazil have killed two hunters in separate incidents, raising concerns about the animals' loss of habitat and the growing risk of dangerous encounters with people, researchers said.

User comments : 0