Mix of marine zones matters most for prey fish

August 17, 2016, James Cook University
Coral trout. Credit: James Cook University

In a first-of-its-kind study, James Cook University scientists have discovered a mosaic mix of marine zones could benefit populations of prey fishes.

The research, conducted by JCU's Dr April Hall and Professor Michael Kingsford, looked at whether fishing of on the Great Barrier Reef had effects on the reproductive dynamics of their prey.

Dr Hall said it was the first study to demonstrate that the depletion of predators can cause cascading ecological effects, and impact prey species at a biological level.

The scientists collected a prey species - the bridled monocle bream - from two management in the Palm Island group: , which are protected from fishing, and open zones, which are heavily fished.

Predators such as coral trout, snapper, and emperor fish are popular fishing targets on the Great Barrier Reef, and play a vital role in coral reef food webs.

"We predicted that in marine reserves, where predators were abundant, prey would allocate more energy to predator avoidance compared to fished zones with fewer predators, and that this would affect their growth and reproduction," said Dr Hall.

The team found that in the predator-rich marine reserves, the bream had reduced growth, poorer body condition, and a reduced capacity to reproduce compared to fished areas.

In fished areas, depletion of predators meant grew faster, and had a greater reproductive capacity.

Dr Hall said that the study emphasises the importance of long-term protection of predators in marine reserves.

"It's important to recognise that this pattern of predators influencing prey is a natural process, and marine reserves are the best way to ensure that this process continues."

Professor Kingsford says the research has potential implications for understanding the connectivity of fish populations across management zones. "One of the things we now understand is that the reproductive effort of prey fish outside protected areas can flow back into reserves. This suggests that a mixture of zones is important for the health of fish populations."

Dr Hall said it's likely that the patchy mosaic design of fished zones and marine reserves around the Palm Islands enables this process. "This is significant, and provides support for the multi-zone system of the Great Barrier Reef Marine Park," she said.

Explore further: Marine reserves are critical for coral reef resilience

More information: A. E. Hall et al, Variation in the population demographics of Scolopsis bilineatus in response to predators, Coral Reefs (2016). DOI: 10.1007/s00338-016-1486-0

Related Stories

Marine reserves are critical for coral reef resilience

April 7, 2016

Researchers who studied the effects of various disturbances on reef communities of coral and fish found that those in 'no-take' marine reserves are less impacted and recover faster than those in reefs that are not located ...

Sharks more abundant on healthy coral reefs

September 10, 2014

Sharks in no-fishing zones in the Great Barrier Reef (GBR) Marine Park are more abundant when the coral is healthy, according to a study published September 10, 2014 in the open-access journal PLOS ONE by Mario Espinoza from ...

Twice the coral trout in Great Barrier Reef protected zones

March 26, 2015

Coral trout in protected 'green zones' are not only bigger and more abundant than those in fished 'blue zones' of the Great Barrier Reef Marine Park, but they are also better able to cope with cyclone damage, according to ...

Decade of benefits for the Great Barrier Reef

July 3, 2014

With this week marking the tenth anniversary of the rezoning of the Great Barrier Reef Marine Park, prominent marine scientists from around the world have gathered in Canberra to discuss its successes - both expected and ...

Recommended for you

Sea slug study illuminates how mitochondria move

January 17, 2019

Your cells have an amazing ability—they can build their own energy factories, called mitochondria. Once built, mitochondria must move where needed in the cell. Defects in mitochondrial transport are a suspected cause of ...

60 percent of coffee varieties face 'extinction risk'

January 16, 2019

Three in five species of wild coffee are at risk of extinction as a deadly mix of climate change, disease and deforestation puts the future of the world's favourite beverage in jeopardy, new research warned Wednesday.

How stem cells self-organize in the developing embryo

January 16, 2019

Embryonic development is a process of profound physical transformation, one that has challenged researchers for centuries. How do genes and molecules control forces and tissue stiffness to orchestrate the emergence of form ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.