Boats and ships leave baby reef fish vulnerable to predators

Date:
July 23, 2020
Source:
ARC Centre of Excellence for Coral Reef Studies
Summary:
Scientists say the noise from boats and ships slows down the
activity of baby fish on coral reefs, which leaves them more
vulnerable to their predators.



FULL STORY ========================================================================== Juvenile fishes have one of the highest mortality rates compared to
other life stages. Within two days of settling into a reef almost 60
percent are consumed by predators. Our recent study found noisy boats
and ships can also affect the prey response of these young fishes.


==========================================================================
When exposed to the noise of vessels, juvenile fishes decreased their
activity, which reduced their swimming distance. Previous research found
more active fishes learn faster about their environment and potential predators, which results in a higher chance of survival.

We also found juveniles exposed to boat and ship noise were slower
to escape when exposed to a simulated predator attack. This is highly
relevant as the timing of the escape response to a predator is critical
for success -- a slower fish is more likely to get eaten.

Noise pollution is mostly concentrated in coastal areas. The higher
the human population the higher the incidence of recreational boating activities such as diving and recreational fishing. More than 250,000
boats are registered in the Great Barrier Reef region and this number
is projected to increase 500 percent by 2040. This means vessel noise is
not only already widespread, but increasing along the Great Barrier Reef.

Our results suggest boat and ship noise could increase the mortality of juvenile fishes during their critical period of growth (and remember,
~60 percent already die within two days). In areas such as the Great
Barrier Reef, fishes are likely exposed to recreational boats and ships multiple times throughout their life. An increase in the mortality rate
could have implications for population structure and community dynamics.

Human-made noise is easier to manage compared to other pollutants,
which provides an opportunity to mitigate its effects on coral reef communities. The main goal of our research is to investigate the effects
of noise on reef fishes in order to provide governmental institutions
with information for its management and regulation. Future research
will investigate the long-term effects of noise pollution on fishes and
whether there are interactive effects with other stressors.


========================================================================== Story Source: Materials provided by ARC_Centre_of_Excellence_for_Coral_Reef_Studies. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Laura Velasquez Jimenez, Eric P. Fakan, Mark I. McCormick. Vessel
noise
affects routine swimming and escape response of a
coral reef fish. PLOS ONE, 2020; 15 (7): e0235742 DOI:
10.1371/journal.pone.0235742 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200723143718.htm

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