Please select your home edition
Edition
RS Sailing 728x90 AUS

Scientific research finds that small prey fish can grow a bigger 'eye'

by ARC Centre of Excellence on 25 Sep 2013
Tiny fish make ‘eyes’ at their killer Arc Centre of excellence for coral reef studies
New scientific research has found that small prey fish can grow a bigger ‘eye’ on their rear fins as a way of distracting predators and dramatically boosting their chances of survival.

Researchers from Australia’s ARC Centre of Excellence for Coral Reef Studies (CoECRS) have made a world-first discovery that, when constantly threatened with being eaten, small damsel fish not only grow a larger false ‘eye spot’ near their tail – but also reduce the size of their real eyes.

The result is a fish that looks like it is heading in the opposite direction – potentially confusing predatory fish with plans to gobble them up, says Oona Lönnstedt, a graduate student at CoECRS and James Cook University.

For decades scientists have debated whether false eyespots, or dark circular marks on less vulnerable regions of the bodies of prey animals, played an important role in protecting them from predators – or were simply a fortuitous evolutionary accident.

The CoECRS team has found the first clear evidence that fish can change the size of both the misleading spot and their real eye to maximise their chances of survival when under threat.

'It’s an amazing feat of cunning for a tiny fish,' Ms Lonnstedt says. 'Young damsel fish are pale yellow in colour and have this distinctive black circular ‘eye’ marking towards their tail, which fades as they mature. We figured it must serve an important purpose when they are young.'

'We found that when young damsel fish were placed in a specially built tank where they could see and smell predatory fish without being attacked, they automatically began to grow a bigger eye spot, and their real eye became relatively smaller, compared with damsels exposed only to herbivorous fish, or isolated ones.

'We believe this is the first study to document predator-induced changes in the size of eyes and eye-spots in prey animals.'

When the researchers investigated what happens in nature on a coral reef with lots of predators, they found that juvenile damsel fish with enlarged eye spots had an amazing five times the survival rate of fish with a normal-sized spot.

'This was dramatic proof that eyespots work – and give young fish a hugely increased chance of not being eaten.

'We think the eyespots not only cause the predator to attack the wrong end of the fish, enabling it to escape by accelerating in the opposite direction, but also reduce the risk of fatal injury to the head,' she explains.

The team also noted that when placed in proximity to a predator the young damsel fish also adopted other protective behaviours and features, including reducing activity levels, taking refuge more often and developing a chunkier body shape less easy for a predator to swallow.

'It all goes to show that even a very young, tiny fish a few millimetres long have evolved quite a range of clever strategies for survival which they can deploy when a threatening situation demands,' Ms Lonnstedt says.

Their paper 'Predator-induced changes in the growth of eyes and false eyespots' by Oona M. Lonnstedt, Mark I. McCormick and Douglas P. Chivers appears in the latest issue of the journal Scientific Reports.

For more information visit ARC Centre of Excellence Website
Jeanneau Sunfast 660x82Sail Exchange 660x82 Used SailsC-Tech Emirates TNZ

Related Articles

New rules to better protect and enable access to the Whitsundays
Great Barrier Reef Marine Park Authority Chairman Russell Reichelt said it was vital to protect the area’s values The updates to the Whitsunday Plan of Management — an area-specific plan that manages use in this highly visited region in addition to Reef-wide zoning — follows extensive consultation.
Posted on 10 Aug
Brisbane Boat Show – 18 days to go
The Brisbane Boat Show opens in less than three weeks, capturing all the Queensland boating lifestyle has to offer. There will be a huge clearance of fishing tackle and show only deals. If you love boats, fishing and water sports you don’t want to miss the Brisbane Boat Show.
Posted on 7 Aug
VMR Whitsundays celebrate the arrival of their new rescue vessel
In a ceremony hosted at Abell Point Marina last week, VMR Whitsundays announced the arrival of their new rescue vessel. In a ceremony hosted at Abell Point Marina last week, VMR Whitsundays delightedly announced the arrival of their new rescue vessel. Abell Point Marina VMR 1, as it has been named, has been 10 years in the making and certainly a labour of love for the VMR committee.
Posted on 24 Jul
Marine Notice - Official Nautical Charts
Marine Notice draw attention to importance of using only official nautical charts to comply with flag State requirements This Marine Notice draws attention to the importance of using only official nautical charts to comply with flag State requirements, which implement the relevant regulations of Chapter V of the International Convention for the Safety of Life at Sea (SOLAS), as amended.
Posted on 23 Jul
Marine Notice - VHF marine radios - Automatic channel switching
This Notice provides information on how VHF channel switching may interfere with safe operation of vessel communications This Marine Notice provides information on how automatic VHF channel switching may interfere with the safe operation of vessel communications.
Posted on 23 Jul
The four-year treasure hunt for the hoodwinker sunfish
Sunfish are famous for looking odd. They are the largest bony fish in the world, can grow to over 3 metres in length Sunfish are famous for looking odd. They are the largest bony fish in the world, can grow to over 3 metres in length, weigh up to 2 tonnes, and look a little bit like a suitcase with wings.
Posted on 22 Jul
Four weeks until 50th Sydney International Boat Show opens
The show returns fully to Darling Harbour coinciding with the completion of the new International Conference Centre. In what will be a special year, the show returns fully to Darling Harbour coinciding with the completion of the new, purpose built International Conference Centre-Sydney facility.
Posted on 6 Jul
Celebrate the opening of the Adelaide Boat Show
Purchase an Adult ticket between 10 am and 12 noon on the opening day, Friday 30 June and bring a friend in for free. In effect that allows two people in for the price of one. But remember, this offer is only available from 10 am until 12 noon on Friday 30 June. This ticket is only available at the door.
Posted on 27 Jun
Save on GO XSE during Simrad® Just GO! Promotion
You can fit boat with an all-in-one navigation product for cruising, fishing and keep more of your money where you want You can fit your boat with an all-in-one navigation product for cruising, fishing and watersports and keep more of your money where you want it – in your wallet.
Posted on 6 Apr
Navionics announces functionality available for Navico Brands
Navico have collaborated to make several new features available to customers using Navionics charts. Navico, a leading provider of marine electronics under the Lowrance, Simrad and B&G brands, and Navionics, the leader in content and location-based services for the recreational boating and outdoor markets, have collaborated to make several new features available to customers using Navionics charts. The NOS56 software update released for a wide range of new and existing models adds compatibility
Posted on 5 Apr