Fish diet heats up marine biodiversity hotspot
Scientists have discovered a never-before-seen biodiversity pattern of coral reef fishes that suggests some fishes might be exceptionally vulnerable to environmental change. A new study shows plank
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
To effectively manage fisheries worldwide, we first need to understand exactly why people fish. And the reasons are many.
In Australia, 96% of recreational fishers cited a connection to the environment as their reason for fishing. Other personal reasons included:Using interviews, researchers from and the ARC Centre of Excellence for Coral Reef Studies Matthew Young, Simon Foale and David Bellwood explored the motivations of two fisher groups: subsistence/artisanal fishers in the Solomon Islands, and experienced recreational fishers in Australia.
In the Solomon Islands, the most common motivations for fishing were food (100%) and income (93%). However, many fishers said they would continue fishing even if they had alternative income, and many of their motivations overlapped with recreational fishers.
* physical fitness and exercise
* benefits to mental health through escapism
* stress release and relaxation
* the health properties of seafood
* social interactions and bonding with friends and family
* the ability to be outdoors and satisfy their hunter-gatherer instinct
“Fishing provides social benefits to the community through camaraderie, fishing clubs and the sharing of a common interest,” said one Australian fisher. “It also contributes to social cohesion as it crosses social boundaries and encourages unification.”
Article:
Young MAL, Foale S, and Bellwood DR (2016) Why do fishers fish? A cross-cultural examination of the motivations for fishing. Marine Policy, 66: 114‒123 (April 2016).
Image:
Michael Dawes/Flickr (CC BY-NC 2.0) https://flic.kr/p/9VEAgv
Marine scientists are calling for a re-think of how marine protected areas (MPAs) are planned and coordinated, following a global assessment of the conservation of tropical corals and fishes.
Researchers from the Australian Research Council Centre of Excellence for Coral Reef Studies (Coral CoE), at James Cook University in Townsville, analysed the extent to which the evolutionary histories of corals and fishes are protected, rather than looking at individual species.
“Our interest was in evolutionary branches of the tree of life, rather than the traditional focus on rare, threatened or endemic species,” said Professor David Bellwood from the Coral CoE.
“In particular we were interested in the longer branches, which represent the greater proportion of evolutionary history.
“When we looked at tropical Marine Protected Areas from that perspective, we found that protection of corals and fishes falls significantly short of the minimum conservation target of protecting 10 per cent of their geographic ranges.
“Just one sixteenth of hard corals species are afforded that minimum level of protection, and for fishes – the wrasses – less than a quarter reach minimum protection levels.”
Professor Bellwood said that while it was still useful to focus on the conservation of rare, threatened and endemic species, planning protected areas around evolutionary history helped provide a deeper perspective.
“In effect, we are looking at protecting the reef equivalent of cultural heritage, the critically important history of living organisms,” he said.
“It is not just species that need protection but the genetic history that they contain. In a changing world this evolutionary diversity is likely to be increasingly important, as reefs respond to new challenges.
The researchers found that the shortfall in protection for corals was greatest in the Atlantic and the Eastern Pacific.
For fishes, the highest concentrations of poor protection are in the Western Indian Ocean and the Central Pacific.
“Even though our estimates are highly conservative, the inescapable conclusion is that most evolutionary branches of the tree of life on coral reefs are inadequately protected by the current system of Marine Protected Areas,” Professor Bellwood said.
Around 830,000 multi-cellular species call the world’s threatened coral reefs home, and half a billion people rely on the reefs for ecosystem services including food security, income and protection against natural hazards.
“MPAs continue to provide important and essential protection to certain species and habitats, but the bigger evolutionary picture needs to be considered in planning and coordinating the choice and location of future protected areas,” Professor Bellwood said.
“This is especially important in light of chronic decline due to deteriorating water quality and periodic damage by coral bleaching and cyclones.”
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Paper
Global marine protected areas do not secure the evolutionary history of tropical corals and fishes by D. Mouillot, V. Parravicini, D.R. Bellwood, F. Leprieur, D. Huang, P.F. Cowman, C. Albouy, T.P. Hughes, W. Thuiller and F. Guilhaumon is published in the journal Nature Communications.
Photo credit: João Paulo Krajewski
Contacts
When it comes to catching elusive prey, many fishes rely on a special trick: protruding jaws that quickly extend their reach to snap up that next meal. Now, researchers have found a clever way to trace the evolution of jaw protrusion in fishes over many millions of years.
The evidence suggests that fishes’ jaw protrusion skill is relatively new, appearing only in the last 100 million years of their 400-million-year history.
“We take it for granted that all fishes can snap up elusive prey,” says David Bellwood from the ARC Centre of Excellence for Coral Reef Studies at James Cook University. “But it wasn’t like that millions of years ago.”
Based on a careful analysis of the jaws of 60 living fish species, the researchers developed a method to predict a fish’s jaw protrusion ability based on a simple anatomical measurement. It was suddenly possible to predict jaw protrusion in long-lost fishes of the ancient past.
“We knew that most [modern] fishes could protrude their jaws,” explains Christopher Goatley, co-author of the study, also at James Cook University. “The question was, when did this ability arise, and what anatomical features were required for protrusion?”
The researchers discovered that “one simple measurement of one jawbone explained almost everything. With this we could predict how fishes feed today and how they are likely to have fed in the past, over the last 400 million years.”
Once protruding jaws did arise, they took off. The researchers’ analyses show an increase in both the average and maximum jaw protrusion over the last 100 million years, making fish more venerable predators over time. At first, the increase in jaw protrusion mostly came from an increase in the proportion of fishes with that ability, as spiny-rayed fishes won out over other groups. Then the extent of jaw protrusion in those spiny-rayed fishes continued to increase.
The findings suggest that this characteristic may have played an important role in the success of the spiny-rayed fishes—now the dominant fish clade in modern oceans, the researchers say. Those extendable, protruding jaws also made prey species more vulnerable to attack. That might explain why many crustaceans today are so small.
“We think [that] over evolutionary time this drove prey to hide by becoming smaller, nocturnal, or hiding in holes,” Bellwood says. “Today the average crustacean on a coral reef is less than a millimeter long. This may be a consequence of increasing predation pressure.”
Bellwood says this is just the beginning of an in-depth look into fish feeding and the dynamics between fish and their prey in a changing environment.
“There have been major changes in the abilities of fish to feed over time,” Bellwood says. “The key to understanding this history is in the workings of a fish’s head.”
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Paper
Current Biology, Bellwood et al.: “The Rise of Jaw Protrusion in Spiny-Rayed Fishes Closes the Gap on Elusive Prey” http://dx.doi.org/10.1016/j.cub.2015.08.058
Contact
David Bellwood, David.bellwood@jcu.edu.au, mobile +33 7 5224 5044, office +61 (0)7 4781 4447
Eleanor Gregory (Communications Manager), eleanor.gregory@jcu.edu.au, +61 (0) 428 785 895
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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