19 August: A fish's first "words"

Researchers at the Australian Institute of Marine Science have been studying the unique communication methods of baby coral reef fish to try and understand more about how animals "talk" to each other.

Combining laboratory and field-based experiments, scientists from the Australian Institute of Marine Science (AIMS), the University of Western Australia (UWA) and the University of Queensland (UQ) explored when and under what conditions young coral reef fish develop ultraviolet (UV) facial patterns used to communicate vital information to each other while remaining undetected by potential predators.

“These baby fish are under tremendous pressure from predators so their first “words” are most likely going to be important ones, ones that enhance survival” said AIMS scientist Dr Martial Depczynski.

“Consequently, we expected that all fish would develop these UV markings at an early pre-determined age and that their development was genetically “hard-wired”, but to our surprise we found that these markings did not develop at all in our lab fish. There is something about their natural reef environment which triggers the need to rapidly develop this communication channel”.

Funded by an Australian Research Council Grant and published in the high impact scientific journal Scientific Reports, the study was carried out on the Great Barrier Reef at the Australian Museum’s Lizard Island Research Station.

“We put our lab-based fishes under a whole range of different feeding and social conditions to exclude everything else that is important to a young fish at this critical stage of their lives” said Associate Professor Monica Gagliano from UWA.

“The next obvious study is to see if exposure to predators in a lab-based environment is enough to trigger the markings”.

“Understanding what and how much animals are able to communicate to each other is one of science’s most intriguing mysteries” Dr Depczynski said.

“Because there are so many predators on a coral reef and life is so risky for baby fish, the ability to communicate danger is the most likely candidate to explain the absence of UV markings in our lab fishes and why they need to develop them so quickly on the reef”.

The research has major implications for the way in which we see the role of structural colouration in animals.

“Traditionally, UV markings have been studied in the context of attracting mates but these fish are not only sexually immature, but they are also all born female suggesting that these colours have a completely different function at this early stage in life, one that maybe changes as fish get older”, said Dr Depczynski.

“Regardless, it seems that UV signalling may convey a whole range of different information and we are just touching the tip of the iceberg with this research”.

The paper - Gagliano, M. et al. Facing the environment: onset and development of UV markings in young fish. Sci. Rep. 5, 13193; doi: 10.1038/srep13193 (2015) - available here.

For interviews please contact:

Martial Depczynski, Australian Institute of Marine Science, 08 6369 4025

Monica Gagliano, UWA, School of Animal Biology, 08 6488 1361

Ulrike Siebeck, University of Queensland, 07 3365 4070