My project investigated the effects of the Crown of Thorns Starfish on the Great Barrier Reef. The starfish causes major damage to coral during outbreaks, which are linked to human and environmental factors. A 2012 study found that 50% of coral on the GBR has been lost in the past 27 years. Researchers are working to develop effective control methods like sodium bisulphate injection to limit further damage as the reef recovers from severe storms. Public awareness and support of reef conservation efforts are also important to protect this vital ecosystem.

1. Presentation outline:
Here is my problem:
• Outbreaks of the cots result in a decline in coral coverage on the GBR
• Study completed in 2012 states that over the past 27 years, 50% of coral has been lost on GBR
• Scientists not 100% sure of reason for outbreaks but think result of human and environmental
factors
• Cots have very few predators
• Reef can take 10/15 yrs to recover where outbreaks can occur in this time or storms can strike
This is what I have learnt
• Many control methods tried-injection method most effective
• Cots one of main reasons for coral decline
• No specific explanation for cots outbreak
• Can grow to 80cm diameter
• Up to 21 poisonous arms
• Approx 1.5 mill covering GBR
• Outbreak defined as more than 200 starfish/hectare
• Have been 3 recorded recorded: 1962-1976, 1978-1991 and 1993-2005
• Cots feeds on coral until it turns white
• Reduction in coral affects sea life as animals rely on it for food shelter and nesting
This is what we or others can do to solve the problem:
• It is important to raise awareness of this issue to prevent further outbreaks
• Those who work on projects near the coastline involving fertilizers should take care in
preventing its spread into the ocean as this has been linked to outbreaks
• Can take care not to overfish as this reduces cots predators
• We can make small donations to institutions working closely alongside the GBR,
particularly aims so they can facilitate the resources they need and further there work
• Injection methods can be expensive so donations can be useful
• The variety of resources and statistics reassure is that we can prevent further
outbreaks occurring
My project investigated the effects of the Crown of Thorns Starfish on Coral in the Great
Barrier Reef. The Crown of Thorns Starfish is most dangerous to the reef when an
outbreak occurs as they feed on the coral excessively until it eventually dies. The
population of the starfish rapidly increases during an outbreak and has very few predators
making it difficult to control their numbers. Researchers are unsure of the exact causes of
an outbreak but have made links to human and environmental factors. A study conducted
in 2012 stated that over the past 27 years, 50% of the coral has been lost in the GBR and
a further 50% could disappear in coming years if the reef is not protected. The Crown of
Thorns Starfish is currently the second key cause for the reduction of coral in the Great
Barrier Reef next to cyclones and storms. Reefs can take between 10 and 15 years to
recover from an outbreak and within this time another outbreak can occur or storms and
cyclones strike, resulting in a continuous cycle of destruction.
The Crown of Thorns Starfish is scientifically referred to as the Acanthaster Planci and
occurs naturally on reefs throughout the indo-pacific region. The starfish can grow to 80cm
in diameter and has up to 21 arms covered in thick spines filled with poisonous toxins. It
eats the coral extra orally by pushing its stomach through its mouth to feed.
When an outbreak occurs, the population exceeds 200 starfish per hectare, which sees
the thousands of starfish feed on coral until particular areas are completely wiped out.
Human factors related to outbreaks include fertilizers from coastal developments leaking
into the ocean, which increases nutrients in the water allowing the starfish to grow and

2. reproduce at a faster rate. Overfishing is also a potential cause as the very few predators
of the COTS, such as the starry puffer fish and sweetlips emperor, are removed from the
ocean. Natural causes have been linked to an increase in phytoplankton, one of the
COTS food sources as there is evidence that the population of COTS increases when
phytoplankton is readily available.
There have been three recorded outbreaks of the COTS on the GBR, in 1962-1976, 1978-
1991 and 1993-2005. However, researchers note that other outbreaks could have
occurred that were not recorded.
Various studies outline that the main effects of a decline in coral are on sea life that inhabit
the GBR. Some animals rely on coral for food, shelter, oxygen and nesting. The fish then
either die as they lack coral for survival or move to a different area where there is enough
for them to survive.
Coral is more important to our society than many of us realize. It protects our coastline
from the effects of storms and is currently being trialed for medical purposes such as
treatment for cancer and HIV.
Researchers have tested many control methods but the most successful so far is the
sodium bisulphate injection. Divers inject the solution into the tissue resulting in the death
of the cots after at least 24 hours. This is the most environmentally friendly and efficient
method as it does not disturb other marine life. The success of this method is reassuring
researchers that they have the resources and ability to prevent another outbreak.
In speaking with Ian Miller, a staff member at the Australian Institute of Marine Science, he
stated that the reef is doing well but currently recuperating from the effects of some severe
cyclones so it is important to prevent another outbreak as the GBR is currently very
vulnerable.
This issue is significant to our generation and future generations as a reduction in coral
has vast effects on our environment and ecosystem. It is the responsibility of this
generation to protect the coral and maintain the sea life in order to ensure we preserve our
environment for those in the future.
With alarming statistics including the possibility of a further decline of 50% of coral
coverage over coming years, researchers are working alongside the GBR to continue
developing more efficient control methods and conducting surveys to keep track of the
population of COTS. As we are not located near the GBR there is little we can do directly
to protect the reef however we can use our understanding of the importance of coral to our
environment and the ecosystem to ensure we care for reefs local to us by taking small
steps such as not overfishing. Simply raising awareness of this issue is important as many
do not realize the COTS is still problematic as there has not been an outbreak since 2005.