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

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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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James Cook University researchers have found brightly coloured fish are becoming increasingly rare as coral declines, with the phenomenon likely to get worse in the future.

Christopher Hemingson, a recent PhD graduate at JCU’s Centre of Excellence for Coral Reef Studies, led the research. He said over the past 30 years, human-induced stressors have caused profound changes to reefs – typically from the loss of corals.

“Reefs these days are becoming increasingly defined by non-coral substrates, especially turf algae. We wanted to investigate what effect this had on the kind of brightly-coloured fish people like and that attract tourists and visitors,” said Dr Hemingson.

The scientists used a new community-level measure of fish colouration and then explored the links between fish community colouration and the environment.

“We found that as the cover of structurally complex corals increases on a reef, so does the diversity and range of colours present on fishes living in and around them. But, as the cover of turf algae and dead coral rubble increases, the diversity of colours declines to a more generalised, uniform appearance,” said Dr Hemingson.

He said it was notable that fish community colouration declined significantly in the years following the 1998 global coral bleaching event – likely driven by the loss of branching corals.

“We found the structure of the sea floor appears to be very important in shaping fish colouration; more so than its composition (that is, its live coral cover). Having places to hide from predators may have allowed reef fishes to evolve unique colourations due to a reduced reliance on camouflage to avoid being eaten.

“Unfortunately, the types of corals most capable of surviving the immediate impacts of climate change (massive and boulder corals) are unlikely to provide these refuges. Fish communities on future reefs may very well be a duller version of their previous configurations, even if coral cover remains high,” said Dr Hemingson.

He said the loss of colourful fishes may not have a huge impact if assessing reefs through a strictly functional or ecological lens.

“But in a human context, loss of these colourful species may trigger a broad range of human responses, including grief.”

VIDEO ABSTRACT




PAPER

Hemingson CR, Mihalitsis M, Bellwood DR 2022. ‘Are fish communities on coral reefs becoming less colourful?’. Global Change Biology. DOI: 10.1111/gcb.16095

IMAGES

A selection of images can be used for media stories with credit to the photographer as stated in the file name. Please note these are for single use with this story only, not for any other story. No archival permissions are granted.

CONTACT

Dr. Christopher Hemingson (Townsville, AEST)
P: +61 (0) 450 848 901
E: christopher.hemingson@my.jcu.edu.au

Scientists have solved the mystery of why some closely-related species of an iconic reef fish have vastly different colour patterns, while others look very similar.

Innovative research led by scientists at the ARC Centre of Excellence for Coral Reef Studies based at James Cook University, examined the differences in appearance of 42 species of the butterflyfish.

They found that on reefs where closely related butterflyfish species ranges overlap, the differences in colour patterns between the two were most pronounced.

The team used high-resolution digital colour photographs to quantify colour patterns and explore how they were influenced by evolutionary processes.

“Our results show that, over millions of years, butterflyfishes have evolved the greatest diversity of visual markings when they live in the same area as other, closely related species,” said lead author and PhD student Christopher Hemingson.

“Crucially, we also found that this only happens when both species have ranges that are of similar sizes,” said Mr Hemingson.

“We were surprised to find that when one species’ range is a lot larger than the neighbouring species, the pattern is reversed – with the colour pattern of overlapping species found to be less different,” said co-author Dr Peter Cowman.

Professor David Bellwood, a co-author and senior investigator, noted that this is the first time geographic range dynamics have been shown to be an important predictor of colour differences among marine fish species.

“This research is the first of its kind to quantify colour and pattern differences simultaneously among butterflyfish species. It showed us that colour pattern differences can evolve very quickly among species (within 300,000 years) but then remain stable over millions of years,” said Professor Bellwood.

“Colour is far more complicated than just looking different from other species,” said Mr Hemingson.

“These colour patterns also depend specifically on what other species are also present. It is an interesting piece to the puzzle and may help explain why reef fishes are so colourful.”

The paper “Colour pattern divergence in reef fish species is rapid and driven by both range overlap and symmetry” is published in the journal Ecology Letters.

Citation: Hemingson, RF, Cowman, PF, Hodge, JR &  Bellwood, DR (2018). Colour pattern divergence in reef fish species is rapid and driven by both range overlap and symmetry. Ecology Letters DOI: 10.1111/ele.13180

Images available here. Please attribute as indicated.

Contact

Mr Christopher Hemingson
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Email: christopher.hemingson@my.jcu.edu.au

Dr Peter Cowman
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Office: +61 7 4781 3194
Email: peter.cowman@jcu.edu.au

Prof. David Bellwood
ARC Centre of Excellence for Coral Reef Studies
James Cook University, Townsville, QLD, 4811, Australia
Office: +61 7 4781 4447
Email: david.bellwood@jcu.edu.au

For More Information

Catherine Naum
Communications Manager
ARC Centre of Excellence for Coral Reef Studies
T: +61 (7) 4781 6067
M: +61 (0) 428 785 895
E: catherine.naum1@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