An Australian study reveals that survival isn’t easy for young fish
living on the Great Barrier Reef (GBR) - and may be even harder under
climate change.
Environmental differences experienced early in life not only have
immediate consequences for survival of baby fish, but also profoundly
influence their chances of success later in life.
This is the finding of research by Dr Monica Gagliano and Dr Mark
McCormick of the ARC Centre of Excellence for Coral Reef Studies (CoECRS)
and James Cook University (JCU), and colleague Dr Mark Meekan from the
Australian Institute of Marine Science (AIMS).
The team have studied hundreds of Ambon damselfish from egg to
adulthood to establish the extent to which parental quality and
environmental rearing conditions shape the survival of these fishes.
"Even long before spawning, mothers mould the quality of their
babies, thereby influencing their chances of survival," Dr Gagliano
says, "however, the mother’s effort isn’t the only thing that
influences their survival."
The team’s research at Lizard Island on the northern GBR showed
that elevated temperatures experienced during development of the young
fish have devastating consequences for the future survival of baby
fish.
"Survival of fish embryos was dramatically compromised at 31°C,
which is not uncommon at this location during summer" Dr Gagliano
says.
"There is no doubt that the quality of parents and the early
environment experienced by fish as they develop have major effects on
who will survive."
"For the first time, we have been able to establish the fate of
young fishes in their natural environment by following them through
time, from leaving their parents up to months after settling back on
the reef," she says.
The team’s findings, recently published in prestigious science
journals including Oecologia, Journal of Animal Ecology
and Proceedings of the Royal Society: Biological Science,
showed that the effects mothers have on young fish and the environment
encountered during their early life, have long-lasting consequences in
determining who survives to repopulate the reef into the future.
The team’s detailed look at the struggles of growing up on the GBR
and their findings help us understand how these, and other reef fish,
can be managed and protected so that they can survive through the
threats of climate change.
"While a privileged upbringing of good quality parents and a high
quality environment can significantly define an individual’s success
in life, the major environmental changes taking place today may well
undermine these prerequisites for survival"
Our ability to understand what shapes the life of these fish is
pivotal to our success in predicting their responses to today’s
rapidly changing environment," Dr Gagliano says.
As reef environments may experience dramatic shifts in the face of
climate change, understanding the complex lives of reef fish becomes
essential to ensuring they survive into the future, since the
colourful damselfish, along with the many other species of reef fish
on the GBR, are all of vital importance to the area’s environment –
and part of the attraction that drawn $4.5 billion’s worth of tourism
to the region.
Together with her colleagues from CoECRS, JCU and the AIMS, Dr
Gagliano now aims to investigate how the impact of environmental
changes occurring today will be translated in the future.
"The possibility that stressful conditions experienced by today’s
fish may be transmitted on through successive generations of offspring
remains largely unexplored, but it seems very likely in light of our
recent findings," says Dr Gagliano.
More information:
www.coralcoe.org.au
AIMS
- reef monitoring
