Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Coorong Fish Hedge Their Bets for Survival

27.03.2015

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
bronwyn.gillanders@adelaide.edu.au

Robyn Mills
Media and Communications Officer
The University of Adelaide
Phone: +61 8 8313 6341
Mobile: +61 410 689 084
robyn.mills@adelaide.edu.au

Robyn Mills | newswise
Further information:
http://www.adelaide.edu.au

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>