1

People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.

2

Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution

3

Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

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Researchers have found that when water temperatures heat up for corals, fish ‘tempers’ cool down, providing the first clear evidence of coral bleaching serving as a trigger for rapid change in reef fish behaviour.

Publishing in Nature Climate Change this week, researchers from Lancaster University and collaborating institutes including the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at James Cook University show how the iconic butterflyfish, considered to be sensitive indicators of reef health, can offer an early warning sign that reef fish populations are in trouble.

The international team of researchers spent more than 600 hours underwater observing butterflyfish over a two-year period encompassing the unprecedented mass coral bleaching event of 2016.

Led by Dr. Sally Keith of Lancaster University, previously Center for Macroecology, Evolution and Climate, the team examined 17 reefs across the central Indo-Pacific in Japan, the Philippines, Indonesia and Christmas Island (Indian Ocean).

During the initial data collection, the researchers were unaware that the catastrophic bleaching event was on the horizon. Once underway, the researchers realised that this serendipitous ‘natural experiment’ placed them in a unique position to see how fish changed their behaviour in response to large-scale bleaching disturbance.

The team sprang into action to repeat their field observations, collecting a total of 5,259 encounters between individuals of 38 different butterflyfish species. Within a year after the bleaching event it was clear that, although the same number of butterflyfishes continued to reside on the reefs, they were behaving very differently.

“We observed that aggressive behaviour had decreased in butterflyfish by an average of two thirds, with the biggest drops observed on reefs where bleaching had killed off the most coral,” said Dr Keith. “We think this is because the most nutritious coral was also the most susceptible to bleaching, so the fish moved from a well-rounded diet to the equivalent of eating only lettuce leaves – it was only enough to survive rather than to thrive.”

Such changes in behaviour may well be the driver behind more obvious changes such as declining numbers of fish individuals and species. The finding has the potential to help explain the mechanism behind population declines in similarly disrupted ecosystems around the world.

Co-author Dr. Erika Woolsey of Stanford University said: “By monitoring behaviour, we might get an early warning sign of bigger things to come.”

“Our work highlights that animals can adjust to catastrophic events in the short term through flexible behaviour, but these changes may not be sustainable in the longer-term,” added co-author Prof Andrew Baird of Coral CoE at James Cook University.

The paper “Synchronous behavioural shifts  in reef fishes linked to mass coral bleaching” is available online here.

Citation: Keith, SA, Baird, AH, Hobbs, J-PA, Woolsey, ES, Hoey, AS, Fadli, N, Sanders, NJ (2018) Synchronous behavioural shifts in reef fishes linked to mass coral bleaching. Nature Climate Change 8:986-991

Visuals available here.

Video abstract here.

 

CONTACTS

Sally A. Keith, PhD (UNITED KINGDOM)
Lancaster University
E: sally.keith@lancaster.ac.uk
Twitter: @Sal_Keith

Beth Broomby, Head of Press Office
Lancaster University
O: +44 (0) 1524 593719
M: +44 (0) 7881813831

Prof Andrew Baird (AUSTRALIA) – available for comment from 29 October
ARC Centre of Excellence for Coral Reef Studies
James Cook University
E: andrew.baird@jcu.edu.au

Catherine Naum, Communications Manager
ARC Centre of Excellence for Coral Reef Studies
E: catherine.naum1@jcu.edu.au

 

Thanks to mom and dad, baby reef fish may have what it takes to adjust to hotter oceans.

In a rapidly changing climate, the decline of animal populations is a very real concern. Today, an international team of researchers report new evidence of reef fish adjusting to global warming conditions at the genetic level.

For the first time, researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) and the King Abdullah University of Science & Technology (KAUST), have found that reef fish can inherit from their parents the genetic tools to adjust to ocean warming.

“When parents are exposed to an increase in water temperature, we found that their offspring improved their performance in these otherwise stressful conditions by selectively modifying their epigenome,” said senior author Prof Philip Munday of Coral CoE at James Cook University.

Epigenetic change refers to chemical modifications in the DNA that signals genes to be switched on or off. A range of factors, including disease, famine, or in the case of this research, heat stress, can stimulate these subtle changes.

In this study, when both parent and offspring experienced the same elevated water temperatures, responsive changes in their epigenome, via selective DNA methylation, were observed that enhanced the next generation’s ability to cope with the new, warmer temperatures.

“We reared spiny chromis damselfish, a common Indo-Pacific reef fish, for two generations under three different water temperatures, up to 3 degrees Celsius warmer than current-day ocean temperatures,” explained co-author Prof Timothy Ravasi of KAUST.

“The next generation appeared to be advantaged by parental exposure to elevated temperatures. The offspring’s altered gene expression, also referred to as ‘acclimation,’ allowed them to maximise oxygen consumption and energy use.”

“Acclimation may buffer populations against the impacts of rapid environmental change and provide time for genetic adaptation to catch up over the longer term,” said Prof Munday.

The authors of the study note that while this is good news for reef fish, the decline of their coral habitat, as a result of climate change, will continue to be an overriding concern for their survival.

The paper “The epigenetic landscape of transgenerational acclimation to ocean warming” is published in Nature Climate Change.

Citation: Ryu, T, Veilleux, H, Donelson, JM, Munday, PL, and Ravasi, T (2018). The epigenetic landscape of transgenerational acclimation to ocean warming. Nature Climate Change. DOI: 10.1038/s41558-018-0159-0

Images must carry credits as listed in Dropbox folder.

 

CONTACTS

Prof Philip Munday

Coral CoE

Phone: +61 (0) 0408 714 794, +61 (0)7 4781 5341 (AEST)

Email: philip.munday@jcu.edu.au

 

Prof Timothy Ravasi

KAUST

Phone: +61 491 333 697 (AEST)

Email: timothy.ravasi@kaust.edu.sa

 

FOR MORE INFORMATION

 

Ms Catherine Naum

Communications Manager

ARC Centre of Excellence for Coral Reef Studies

Phone: +61 (0) 0428 785 895, +61 (0)7 4781 6067 (AEST)

Email: Catherine.Naum1@jcu.edu.au

 

New research into the impact of climate change has found that warming oceans will cause profound changes in the global distribution of marine biodiversity.

In a study published in the journal Nature Climate Change an international research team modelled the impacts of a changing climate on the distribution of almost 13 thousand marine species, more than twelve times as many species as previously studied.

The study found that a rapidly warming climate would cause many species to expand into new regions, which would impact on native species, while others with restricted ranges, particularly those around the tropics, are more likely to face extinction.

Professor John Pandolfi from the ARC Centre of Excellence for Coral Reef Studies at the University of Queensland says global patterns of species richness will change significantly, with considerable regional variability.

“This study was particularly useful because it not only gave us hope that species have the potential to track and follow changing climates but it also gave us cause for concern, particularly in the tropics, where strong biodiversity losses were predicted,” says Professor Pandolfi.

“This is especially worrying, and highly germane to Australia’s coral reefs, because complementary studies have shown high levels of extinction risk in tropical biotas, where localized human impacts as well as climate change have resulted in substantial degradation.”

To model the projected impact of climate change on marine biodiversity, the researchers used climate-velocity trajectories, a measurement which combines the rate and direction of movement of ocean temperature bands over time, together with information about thermal tolerance and habitat preference.

They say the analysis provides the simplest expectation for the future distribution of marine biodiversity, showing recurring spatial patterns of high rates of species invasions coupled with local extinctions.

Professor Elvira Poloczanska from CSIRO says, “This study shows how climate change will mix up biodiversity patterns in the ocean. Ecological communities which are currently distinct, will become more similar to each other in many regions by the end of the century”

Dr David Schoeman from the University of the Sunshine Coast says the model suggests that there is still time to act to prevent major climate-related extinctions outside of the topics.

“Results under a scenario in which we start actively mitigating climate change over the next few decades indicates substantially fewer extinctions than results from a business-as-usual scenario,” Dr Schoeman says.

“Possibly more worrying, though, is the imminent development of novel biotic assemblages. We have little idea of how these new combinations of species in ocean systems around the world will affect ecosystem services, like fisheries. We should be prioritising ecological research aimed specifically at addressing this question.”

Professor Pandolfi warns the resultant novel combinations of resident and migrant species will present unprecedented challenges for conservation planning.

“Above all, this study shows the broad geographic connections of the effects of climate change – conservation efforts need to be facilitated by cooperation among countries to have any real chance of combating the potentially severe biodiversity losses that a changing climate might impose.”

 ~~~

Paper

The paper, Climate velocity and the future of global redistribution of marine biodiversity by Jorge Garcia Molinos, Benjamin S. Halpern, David S. Schoeman, Christopher J. Brown, Wolfgang Kiessling, Pippa J. Moore, John M. Pandolfi, Elvira S. Poloczanska, Anthony J. Richardson and Michael T. Burrows is published in the journal Nature Climate Change http://dx.doi.org/10.1038/nclimate2769

Contact
Professor John Pandolfi, j.pandolfi@uq.edu.au, +61 (0) 400 982 301
Professor Elvira Poloczanska, Elvira.poloczanska@csiro.au, +61 (0) 428 741 328
Dr David Schoeman, dschoema@usc.edu.au, +61 (0) 423 982 898
Eleanor Gregory (media), eleanor.gregory@jcu.edu.au

Scientists in Queensland have used historic media to measure the decline in Queensland’s pink snapper fishery, highlighting a drop of almost 90 per cent in catch rates since the 19th Century.

Researchers from the ARC Centre of Excellence for Coral Reef Studies (Coral CoE) at the University of Queensland and the Department of Agriculture Fisheries and Forestry examined thousands of newspaper articles dating back to1870 to reveal the historic catch rates for the iconic Queensland fishery.

“We found that 19th century recreational fishers would regularly catch hundreds of fish off the coast of Queensland, often in just a few hours of fishing,” says Dr Ruth Thurstan, a Research Fellow from the Coral CoE.

Combining historical data with statistical analyses allowed the researchers to calculate catch rates, which are the number of fish caught per hour fishing per day, for nearly 300 fishing trips between 1871 and 1939.

When the researchers compared the findings to contemporary fishing trips, they found that recent catch rates averaged just one-ninth of historical levels.

The old news articles have given researchers unparalleled insights into the history of the Queensland snapper fishery.

“When we searched through these old newspapers we were amazed by the level of detail they provided,” Dr Thurstan says.

“They give us a much better understanding of just how rich and productive this fishery used to be, as well as providing us with some fascinating insights into the development of offshore recreational fishing in Queensland.”

“Crucially, these newspaper articles place the modern day fishery into a longer-term perspective that isn’t available using only official records. This helps us understand the changes that have occurred in the fishery over time, and provides an additional piece of the puzzle for those managing this fishery today,” Dr Thurstan says.

Study co-author, Professor John Pandolfi, also from Coral CoE agrees.

“This is one of the most comprehensive perspectives on historical trends in catch rates for Australian fisheries ever compiled,” Professor Pandolfi says.

“We expect similar trends to be uncovered for other Australian fisheries.”

 

Paper

‘Nineteenth century narratives reveal historic catch rates for Australian snapper (Pagrus auratus)’ by Ruth H Thurstan, Alexander B Campbell and John M Pandolfi is published in the journal Fish and Fisheries.

http://onlinelibrary.wiley.com/doi/10.1111/faf.12103/abstract

 Contacts

Dr Ruth Thurstan: +61 (0) 450 586 263 or r.thurstan@uq.edu.au;

Professor John Pandolfi: + 61 (0)7 3365 3050 or j.pandolfi@uq.edu.au

Eleanor Gregory, Communications Manager: +61 (0)7 47816067, +61 (0)428 785 895 or eleanor.gregory@jcu.edu.au

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Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au