Navigation Links
Baby fish 'smell their way home'

Marine scientists working on Australia's Great Barrier Reef have uncovered evidence that baby fish, only millimetres long, manage to find their way to their home coral reef across miles of open sea by using their sense of smell.

Remarkable in itself, the discovery by a team including Professor Mike Kingsford of the ARC Centre of Excellence for Coral Reef Studies and James Cook University and colleagues from Woods Hole, USA, also shines a new light on how the breathtaking diversity of fish on coral reefs has arisen. This has major implications for how reefs are managed.

"The babies of many coral fish species are swept off their home reef by ocean currents within days of hatching. Ordinarily you'd expect them to be thoroughly mixed up and this would mean the population of one reef would be pretty much the same, genetically, as another," he says.

"But that is not the case. There are major genetic differences between fish of the same species on reefs only a few kilometres or even hundreds of metres apart."

This diversity between populations of the same fish species is what drives evolution on the Reef and underpins the spectacular richness of its sea life, Prof. Kingsford says. "This genetic separation between reefs may be what gives rise to so many different species in coral reef systems."

The researchers were intrigued how tiny damsel and cardinal fish, born on one reef, managed to find their way back home to preserve such remarkable population differences, braving strong currents and ferocious predators in their 20 days at sea ?all when only a centimeter or so in size.

"We tested several ideas, but the most attractive seemed to be that they could smell the unique trace of their home reef ?rather like salmon can smell the home river.

"We know these late stage fish larvae, generally between about 9 and 14mm long, already have developed noses ?but the question was whether they could use them to recogni se what the home reef smelt like, when they left it only a day or so after hatching."

The team exposed tiny fish larvae in a tank to pure streams of water from four different reefs. To their amazement, within minutes a surprisingly high percentage of baby fish had congregated in the water flow from their home reef.

"It was a lot more than you'd expect to happen by pure chance ?and it applied, in differing degrees, across several species of fish," Mike says.

The fish could also be responding to other stimuli, including distant noise off a reef and the behaviour of other fish, but the team concluded that smell was probably the dominant factor leading the babies home.

"Every reef gives off its own unique chemical signature, a rich mixture of the proteins and amino acids emitted by corals, all the plankton and mucus from its life. We think baby fish can pick this up and distinguish it from other reefs.

"We think some fishes then choose currents that smell like 'home' and swim up them. The ones that cannot do this perish. The ones that get home preserve the unique 'ethnic' make-up of their tribe ?and so continue the process of evolving into separate new species."

How the fish learn the unique smell of home is a mystery still. The researchers theorise that it is imprinted on them either when they are an egg inside their mothers, a fertilised egg swept around on the bottom, or new-hatched fry loose in the stream or brooded in their parents' mouths.

"An egg, even a fry, hasn't a fully developed sense of smell, but it may have a way of absorbing the local molecules and then recognizing their signature as "home" when it grows up a bit and is ready to settle," Mike says.

"This evidence that individual coral reefs play such a key role in the emergence of new species is a fresh reason to take even greater care in how we look after them."


Source:James Cook University

Related biology news :

1. Priming embryonic stem cells to fulfill their promise
2. Protein offers way to stop microscopic parasites in their tracks
3. Flocking together: Study shows how animal groups find their way
4. Where bacteria get their genes
5. Chickadees can help humans get their bearings
6. Bacteria use hosts immune response to their competitive advantage
7. Structures of marine toxins provide insight into their effectiveness as cancer drugs
8. Beauty queens urge girls not to sacrifice their bones
9. Researchers learn how blood vessel cells cope with their pressure-packed job
10. Stem cells electric abilities might help their safe clinical use
11. Multiple genes permit closely related fish species to mix and match their color vision
Post Your Comments:

(Date:10/8/2015)... Oktober 2015 Die Track Group, ... des Bereiches Tracking, hat heute bekannt gegeben, ... Virginias (Department of Corrections – DOC) unterzeichnet ... alle Strafen geliefert werden, die der Behörde ... für den Amerikanischen Kontinent der Track Group. ...
(Date:10/6/2015)... 2015 Track Group, Inc. (OTCQX: TRCK), a ... signed a contract with the Virginia Department of Corrections ... of sentences under the Department,s oversight. Derek ... contract with the Virginia DOC will expand our footprint ... our position as a trusted leader in offender electronic ...
(Date:10/1/2015)... Oct. 1, 2015  Biometrics includes diverse set ... body characteristics, such as fingerprints, eye retinas, facial ... of biometrics technology has been constantly increasing in ... five years. In addition to the most prominent ... recognition, other means of biometric authentication are rapidly ...
Breaking Biology News(10 mins):
(Date:10/13/2015)... , ... October 13, 2015 , ... ... recombinant antibodies, today announced that it has received a Phase I Small Business ... by the National Institute of General Medical Sciences (NIGMS), will fund the development ...
(Date:10/13/2015)... , October 13, 2015 ... and development company, has entered into a strategic relationship ... and Paris, France ... --> --> This collaborative arrangement gives ... respected scientific advisory team as well as long established ...
(Date:10/13/2015)... , Oct. 13, 2015  According to Kalorama ... will reach $102 billion by the end of ... the health industry, as it is estimated that ... of laboratory tests. In addition to diagnosing patients, ... evaluate disease progression, monitor drug treatment and conditions, ...
(Date:10/13/2015)... ... October 13, 2015 , ... ... of automation systems, material handling solutions and components, is opening its latest Parker ... State Street, the facility is Exotic’s second major expansion in Metropolitan Detroit in ...
Breaking Biology Technology: