ECOLOGICAL AND FISHERY BENEFITS OF

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ECOLOGICAL AND FISHERY BENEFITS
OF NO-TAKE MARINE RESERVES
By Dr. Roger Grace
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FOUR MAIN THREATS TO THE MARINE ENVIRONMENT
Effects of fishing - depletion of fish
- damage to
habitats
Pollution - sedimentation from land
- nutrient enrichment
Climate change
Introduction of new organisms
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Marine Reserves protect all the species in a
functioning ecosystem
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• Because everything
• is linked, only total
• protection can
• guarantee restoration
• to as natural
• a state
• as possible

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Yield curve for fished stock
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Many stocks are overfished
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A better way less impact and similar yield
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Reserves as management tools

• NZ fisheries act requires that essential fish
  habitat be managed sustainably
• MFish should set up many Marine Reserves as
  controls for their giant manipulative
  experiment which is fishing

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Kina havechewedout the kelp forestover large
areas
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Kina barrens are now extensive
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Kina keep the rock bare by chewing at the surface
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Zonation at Goat Island
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Pa Point 1950 - 2003
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Snapper increased rapidly at the Poor Knights
after full protection
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Rapid increase in snapper following total
protection at Poor Knights. Compare with fished
areas, and partial protection at
Mimiwhangata. Denny et al. (2002) N. Z. J. Mar.
Freshwater. Res
Mimiwhangata
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Snapper population structure in exploited versus
protected stocks.
Comparative age-structures of fish produced by
the individual-based model for the Leigh Reserve,
the adjacent exploited reefs, and for the no
fishing (F0) scenario. Babcock, Egli Attwood
2002
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Acknowledgements For some graphics, ideas and
data Vince Kerr, Bill Ballantine, Nick Shears,
Russ Babcock, Dan Egli, Tim Langlois, Chris
Denny, Debbie Freeman, Chris Wild, Glen Edney,
Alison MacDiarmid, Greenpeace.
Roger Grace Nga Maunga ki te Moana Conservation
Trust 2006