Predatory fish play an important role in coral reefs. Last week, we wrote about how fish pee (particularly large, predatory fish pee) is important to reefs, but the presence or absence of these big fish can also have a big impact on their prey.
A new study from James Cook University (JCU) examined whether or not the fishing of predators had an effect on the reproductive capabilities of their prey.
The researchers studied bridled monocle bream in two different areas: marine reserves where no fishing occurs and open zones, which are heavily fished.
“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,” lead author Dr. April Hall explained in a news release.
They found just that. In the marine reserve where predators were abundant, the bream had reduced growth, poorer body condition, and reduced reproductive capacity. In fished areas, the lack of predators resulted in faster-growing bream with increased reproductive capacity.
“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,” Dr. Hall said.
The authors also note that a mix of different management zones is important because fish populations in different areas are still connected.
This finding “provides support for the multi-zone system of the Great Barrier Reef Marine Park,” Dr. Hall said.
To learn more:
- Read the JCU news release: Mix of marine zones matters most for prey fish
- Read the full study: Variation in the population demographics of Scolopsis bilineatus in response to predators
Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.