The Great Barrier Reef: Threats and Management

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The Great Barrier Reef Threats and Management

• Rhys Murray, Anthea Shedley, Lucya Roncevich,
  Colin Hedderwick, Luke Sullivan and Adam Bartle

2
Introduction

• Threats and Prioritisation
• Issues Explained
• Management
• Recommendations

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Threats and Prioritisation
Note Consequence classified using scale of 1?5
Where 1 complete extinction, 3 local
irreversible damage, 5 Minor Damage.
4
Water Quality

• The Burdekin catchment is a major source of Water
  Quality pollutants and is ranked as the most
  significant risk are in the total GBR catchment.
• Contributes 6 x 106 tonnes of sediment per
  annum (approximately 40 of total GBR catchment
  input)
• Contributes 40,000 tonnes on Nitrogen and
  15,000 tonnes of Phosphorus per annum

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Causes.
6

• Sediment Impacts on the Great Barrier Reef
• Smothering by settlement
• Turbidity inhibiting photosynthesis and growth
• However a natural turbidity gradient exists
  some corals are more resilient than others

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Nutrient Impacts on the Great Barrier Reef

• Increased phytoplankton growth (leads to an
  increase in filter feeders and bivalves, which
  compete for space)
• Macro-algae blooms (overgrow coral and shade them
  out)
• Faster Coral Growth (less dense and weaker
  skeletons are more prone to storm damage)
• Inhibition of Fertility rates

8
Fishing

• The GBR sustains a 250 million fishing industry
• Trawling (8,200 tonnes)
• Reef-line (Commercial 3000 4000 tonnes,
  Recreational estimated at 2000 tonnes)

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Shipping

• The GBRMP facilitates Australias major
  commercial trading routes, and contains five out
  of six of Queenslands major ports
• Approximately 6000 ships greater than 50m length
  pass through the reef per year
• Damage is done to the reef through fire,
  grounding, sinking and spills
• Oil spills pose the greatest risk for
  point-source pollution from boating

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Coral Bleaching
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Coral Bleaching

• Causes
• - Elevated Sea Temperatures
• - High Light Intensity
• - Low Salinity
• - Pollutants
• In recent years high sea temperatures have been
  the major cause of coral bleaching

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Crown of Thorns
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Crown of Thorns

• Is it a problem????

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Current Management

• Many regulatory bodies involved in the management
  of the GBR i.e. Commonwealth Government, GBR
  Marine Park Authority, Australian Fisheries
  Management Authority etc.
• Consequently, management policies often overlap
  or leave out important threats to the GBR in the
  current statutes.

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Current Management

• Current management fails to adequately address
  the issue of water quality.
• Zoning aims to balance reasonable human use with
  the maintenance of natural and cultural integrity
• Mandatory pilotage of vessels through
  navigationally hazardous areas and reducing
  traffic through high risk areas

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Current Management

• No current polices to prevent coral bleaching
• To hard to manage due to the fact that global
  management is required to prevent rising sea
  temperatures.
• Crown of thorns is hard to manage and its effect
  on the reef is unsure in the longterm

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Recommendations

• Agriculture in the GBR catchment should be
  managed as a source of diffuse pollutants,
  particularly in relation to controlling
  agricultural practice in the sugarcane and beef
  grazing industry.
• Trash blanketing
• Ground cover
• Certain areas should have certain practices made
  mandatory, not voluntary, with cost incentives
  for encouragement as 90 of pollutants come from
  30 of the GBR catchment area.

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Recommendations

• Fishing is currently regulated fairly
  effectively.
• Improvements to the system could be made
• Detailed stock analysis in different areas
• Valid logbook catch recording system
• Analysis of mortality rates from trawling
• Spatial partitioning to reduce over fishing
  certain areas

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Recommendations

• Shipping is already highly monitored.
• Improvements to the system could be made
• Reducing total boating hours within the reef
• Upgrading navigational charts
• Restricting the size of boats using high risk
  areas
• Improve education of recreational boat users
• about, ballast water, sewerage, and litter

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Recommendations

• Improve public awareness on the impacts of global
  warming with respect to coral bleaching on the
  GBR
• every little bit helps
• Continue crown of thorns starfish research and
  monitoring

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Application to Ningaloo
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Application to Ningaloo

• Ningaloo is a completely different system to the
  GBR
• Existing threats are different
• Leads to different management policies

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Application to Ningaloo

• Water Quality pollution is limited to point
  sources, such as effluent waste, as there is no
  significant river system leading to the diffuse
  leaching of sediment and nutrients into the reef
  environment.
• Over fishing and shipping are believed to have
  greater effect on the reef as the reef is
  restricted to small localised patches. Over
  fishing and localised boating pollution can hence
  play a significant role in reducing reef
  biodiversity.

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Application to Ningaloo

• Bleaching is potentially more disastrous, as
  reefs are isolated limiting regrowth after
  bleaching events.
• Crown of Thorns is present in small patches but
  is effect is once again unknown.

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Conclusion

• Thanks for Listening