Great Barrier Reef

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Great Barrier Reef

• Threats and Sustainable Management

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Great Barrier Reef - Facts

• Located off coast of Queensland, Australia
• Largest collection of reefs in the world
• Home to wide variety of fish, seagrasses, coral
  and other invertebrate species
• GBR World Heritage Area is the largest in the
  world
• Covers 30 million hectares

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GBR - Threats

• Sedimentation and nutrient run-off
• Commercial shipping
• Commercial fishing
• Crown of Thorns starfish
• Global warming and coral bleaching

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GBR - Management

• To preserve environment asset, reef must be
  carefully managed!
• Sustainable Management
• The use of components of biological diversity in
  a way and at a rate that does not lead to the
  long term decline of biological diversity,
  thereby maintaining its potential to meet the
  needs and aspirations of present and future
  generations (Reichelt 2005, p. 7)

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Ningaloo Reef vs. GBR

• Located off coast of Western Australia, near
  Exmouth
• Extends over 260 kilometers
• Are management plans from the GBR transferable to
  Ningaloo Reef?

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Terrestrial Inputs

• Increased sedimentation is a result of human
  activity - land clearing, agriculture, urban
  development and industry
• Riverine discharge dominated by flood events
  resulting from cyclones and monsoons
• Estimated 15-28 tons of sediment deposited into
  the lagoon annually (Haynes 2001)
• Largest discharges originate from the Burdekin
  and Fitzroy catchments

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The Great Barrier Reef and its
catchments (Productivity Commission 2003)
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Terrestrial Inputs Croplands and Grazing

• Croplands responsible for the greatest impacts on
  sediment yield
• Major crops sugarcane, mangoes, bananas,
  lychees, tomatoes and cotton sugarcane being the
  largest
• Nitrogen and phosphorus are associated with
  fertiliser use, much of which is not absorbed and
  reaches the lagoon
• Elevated nutrient levels promote phytoplankton
  growth, encourage macro algae blooms, and results
  in weakened coral skeletons
• Cattle grazing - largest single use of land
• Woodland and vegetation clearing contribute to
  run-off, overgrazing worsens erosion

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Terrestrial InputsTurbidity and Flood Plumes

• Turbidity smothers corals and reduces light
  availability - adversely affects algae symbionts
  and seagrass beds
• Freshwater plumes lower salinity causing stress
  on coral resulting in excessive mucous release
  and loss of zooxanthellae
• Agricultural and urban storm and waste water
  carry unnatural quantities of heavy metals into
  lagoon
• Potentially toxic and can cause growth and
  reproductive problems

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Terrestrial InputsLand Management

• Avoid further clearing of coastal wetlands and
  riparian vegetation
• Maintain fringing vegetation along stream and
  river banks
• Improved farming and grazing practices will lead
  to improved water quality

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Terrestrial InputsLand Management

• CANEGROWERS Code of Practice for Sustainable Cane
  Growing
• Fertiliser application, soil management, native
  vegetation, irrigation and drainage
• Green cane harvesting/trash blanketing - used by
  majority of cane growers in GBR catchment
• Grazing
• Spelling -Rotation of grazing pastures in order
  to maintain adequate ground cover

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Terrestrial InputsNingaloo

• Not currently under the same pressure as the GBR
  due to sparsely populated coastline
• Unless restrictions are established, development
  of the coastal region and increases in population
  will lead Ningaloo to face similar threats

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Shipping in the GBR

• Several major international shipping routes
  intersect the region
• Cargo includes bauxite, alumina, manganese, iron
  ore, general container freight and oil
• 2500 ships transit the GBR every year
• (Hugget et al. 2001)

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GBRWHA Principal Shipping Routes (Great Barrier
Reef Marine Park Authority 1998)
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Impact of Shipping in the GBR

• Accidental Pollutants
• result from grounding, collision or structural
  failure
• oil or other noxious chemical
• potential to cause serious environmental damage
• Operational Pollutants
• result from day-to-day operation
• waste products
• e.g. oil, sewage, garbage and greenhouse
  emissions
• antifoulants from hull paints
• toxic to many marine organisms
• introduce marine pests from ballast water

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Management of GBR Shipping

• implemented through International Maritime
  Organisation (IMO)
• MARPOL (73/78)
• world's first Particularly Sensitive Sea Area in
  1990
• compulsory pilotage
• mandatory vessel reporting system (REEFREP)
• REEFPLAN

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Future of GBR Shipping

• grounding MV Carola, MV Peacock and MV New Reach
  demonstrate grounding potential is not eliminated
• areas deemed high risk remote from established
  stockpiles of response equipment

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Ningaloo vs. GBR Shipping Density
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Fisheries at the GBR

• There are many important recreational and
  commercial fisheries at the GBR
• Fisheries at the GBR
• Prawns, scallops, reef fish, rock lobster and sea
  cucumber

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Environmental Impacts of Fisheries

• Fishing affects coral reefs directly and
  indirectly
• Directly
• Reduces abundances of target and non-target
  species
• Trawling and dredging destroy benthos
• Indirectly
• Impacts on biological interactions
• Affects the whole ecosystem

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Management of Fisheries in GBR

• Management based on input restrictions eg. gear
  specifications, bag limits
• Queensland DPIF has effectively reduced fishing
  effort while maintaining catch levels
• Zoning is used
• 6 different zones are used
• 33 of the GBRMP is no-take areas
• This management was introduced to help depleted
  species recover

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Management of Fisheries in GBR

• Sustainable management is currently occurring
• Further improvements could be to change the focus
  from single species management to ecosystem
  based approaches

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Crown of Thorns Starfish

• COTS widespread throughout GBR
• Reddish brown echinoderm
• Only venemous seastar
• Typically 1ft. in diameter
• Feeds on live hard coral mainly branching
  tubular and staghorn coral (Aeropora)
• Prefers to live in deep water along reef fronts

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How COTS Affect GBR

• Individual COTS consumes 2-6 sq. m coral/year
• Populations can grow faster then coral growth
  leads to extensive loss of coral
• Indirectly affects other organisms
• Substantial coral deaths in the GBR since 1960s
• Since then many outbreaks have occurred as COTS
  have spread southwards along the coast via
  currents

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What causes COTS Outbreaks

• Not known what the major cause of COT growth
• Nutrients released via land runoff from human
  activities increase phytoplankton (important COTS
  food source)
• Fishing and shell collecting has decreased COTS
  predators

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What is Being Done?

• Extensive surveying of COTS have occurred in many
  sections of the GBR since 1985
• Most tourism sites have control systems in place
  for COTS
• Divers inject deadly Soduim Sulphate solutions
  into COTS tissues
• -doesnt affect other species
• COTS exist in natural numbers in Ningaloo off
  Dampier may be a threat in the future

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Global Warming - Threat

• Elevated levels of greenhouse gases in the
  atmosphere ? global climate change
• The worlds oceans are a sink for atmospheric CO2
• GBR ? elevated sea surface temperatures, caused
  by El Niño Southern Oscillation events

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Global Warming - Impact

• Increased CO2 in water ? dissolution and
  weakening of coral skeleton
• Elevated SSTs ? corals become stressed, expel
  some zooxanthellae, and are bleached
• 1998 worldwide mass coral bleaching event
• - Approximately 87 of the inshore reefs of the
  GBR were affected
• - Pacific, Indian Ocean, Red Sea, Persian Gulf,
  Mediterranean, Caribbean regions AND Ningaloo Reef

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Global Warming - Management

• Cannot be managed on site GBR
• Global problem global responsibility
• Coral bleaching canary to the coal mine is
  the destruction of coral reefs an indication of
  the damage that could be caused by global climate
  change in the future?

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GBR - Review
Prioritised Threat GBR Impacts Is the problem transferable to Ningaloo?
1. Terrestrial Inputs Much of the GBR area, particularly the inner fringing reefs are under threat Not at this stage, as the land adjacent to the reef is very sparsely populated and underdeveloped
2. Shipping and boating Localised damage, and has the potential to harm a large area in the event of an accident, but is being well managed Yes, but shipping density around Ningaloo is low in comparison with the GBR
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3. Fishing Over-removal of certain species and altering of the dynamics between marine species Yes, although the tourism industry is not as developed for Ningaloo
4. Crown of Thorns Starfish Can cause irreversible damage but is localised Yes, as although COTS exist at Ningaloo in natural numbers currently, outbreak is possible
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5. Global Warming Risk of coral bleaching wiping out population. Rates lowest due to it being a worldwide problem its management cannot be handled exclusively at the GBR. Yes, problem is being faced internationally. Consequences are applicable at Ningaloo as well.
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Conclusions

• Extremely important environmental feature under
  threat
• Needs to be better managed
• Possible with better administration and tougher
  legislation
• Sustaining of the reef is a viable future!