Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Coorong Fish Hedge Their Bets for Survival


Analysis of the ear bones of the River Murray estuarine fish black bream has revealed how these fish ‘hedge their bets’ for population survival.

Published in the journal Biology Letters, University of Adelaide research has shown that within this single species of fish there are some individuals which migrate to different parts of the Coorong in South Australia, and some that generally stay in the one location. Black bream are important for recreational and commercial fishing.

Image by Zoe Doubleday, University of Adelaide. Permission to use with this story only.

A sectioned ear bone of black bream showing its growth rings.

“When we consider animal migration, we tend to think of large seasonal migrations of species like the humpback whale or the Arctic tern. We don’t often think of migratory behaviour that varies within populations,” says Professor Bronwyn Gillanders, from the University’s School of Biological Sciences and Environment Institute.

“But it appears that within the black bream Coorong population there is a ‘bet-hedging strategy’ that allows the fish to survive and persist in the Coorong over good times and bad.

“Migration to another area may be more favourable under drought conditions when the water becomes more saline and, conversely, when there is lots of fresh water coming in and there is lots of food readily available, it would be more beneficial for the fish to stay in the location. This probably helps to make the species more resistant to both climate and human-related change.”

The researchers used the ear bones of fish collected throughout the estuary to construct their findings. Fish ear bones provide much information through analysis of the trace elements they contain and the width of their growth rings.

“Like tree growth rings, the ear bones reveal the age of the fish and growth periods which correlate with the growth of the fish itself,” says Professor Gillanders. “When we measure the width of the growth increments, we can trace back to see how fast the fish was growing at a particular time and year.

“The bones can also tell us whether the fish is migratory or ‘resident’ by mapping the ratios of barium against calcium. The higher levels of barium indicate when the fish was in fresher water.”

Professor Gillanders found that 62% of the fish were resident and 38% were migratory. Models were used to investigate differences in annual growth between the two groups and construct a growth time series.

“Throughout the late 1990s and early 2000s resident fish had increased growth compared with migrant fish but this changed around 2005 when growth of migrant fish increases,” says Professor Gillanders. “This is likely to be a result of the deteriorating conditions in the Coorong and reflects the ability of the migratory fish to find more favourable conditions and source more food.”

This research was in collaboration with the South Australian Research and Development Institute (SARDI.

Media Contact:
Professor Bronwyn Gillanders
Southern Seas Ecology Laboratories
School of Biological Sciences and Environment Institute
The University of Adelaide
Phone: +61 8 8313 6235
Mobile: +61 417 036 235

Robyn Mills
Media and Communications Officer
The University of Adelaide
Phone: +61 8 8313 6341
Mobile: +61 410 689 084

Robyn Mills | newswise
Further information:

More articles from Ecology, The Environment and Conservation:

nachricht Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide

nachricht Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Innovative technique for shaping light could solve bandwidth crunch

20.10.2016 | Physics and Astronomy

Finding the lightest superdeformed triaxial atomic nucleus

20.10.2016 | Physics and Astronomy

NASA's MAVEN mission observes ups and downs of water escape from Mars

20.10.2016 | Physics and Astronomy

More VideoLinks >>>