Use of Biological Control in Aquatic Systems

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Use of Biological Control in Aquatic Systems

• What is Biological Control?
• Controlling invasive species by intentional
  release of native/non-native
• Herbivores/Predators
• Parasites
• Diseases
• Pesticides (most common)
• Mechanical Removal

• USES
• Reduce Common Pests
• Dinoflagellates reduce mortality of fish,
  invertebrates, grass beds, increase toxins in
  shellfish
• Red Algae degrade coral reefs
• Jellyfish powerful sting, decrease fish and
  zooplankton
• Bivalves spread mortal diseases, reduce
  phytoplankton, alter diets of fish and birds,
  replace other suspension/filter feeders
• Sea urchins destroy kelp beds, decrease fish
  stocks
• Burrowing shrimps disturb sediments and
  filter/suspension feeders
• Crabs EUROPEAN GREEN CRAB, Carcinus maenas
• Burrows into banks, causes erosion
• Only control is Nermertean egg predator
• Other crabs (China) can be hosts for flukes
• Fishes replace native fish

• What determines a Biological control?
• Respond to repeated host outbreaks
• Able to survive in target area
• Host specific

• Use of Native Species
• More effectively track pests
• Evolve with pests
• Less time consuming and expensive
• Not quarentined

IS A PEST, A PEST?

• RISKS
• Predation, Parasitism, Herbivory of Non-Target
  Species
• Any predator or herbivore maintained at high
  densities can potentially drive a rare non-target
  species to extinction. (Simberloff 1966)
• Competition with Native Species
• Effects within Community and Ecosystem
• Non-native species that destroys a keystone
  species or becomes a dominant structural element,
  might be expected to have a huge impact, not
  easily predicted. (Simberloff 1967)
• Aquatic environments openoffspring disperse
  quickly, easily, do not stay with parents
• Makes pest removal very difficult
• Aquatic pests eradicated modestly/low levels to
  reduce effects
• How much control is needed to reduce impact of
  pest?
• Environmental Safety

References Lafferty, Kevin D, Armand M. Kuris.
Biological Control of Marine Pests. Ecology,
Vol. 77, No. 7. Oct, 1996. 1989-2000. Sheldon,
Sallie P, Robert P. Creed Jr. Use of Native
Insect as a Biological Control for an Introduced
Weed. Ecological Applications, Vol. 5, No. 4.
Nov, 1995. 1122-1132. Simberloff, Daniel, Peter
Stiling. How Risky is Biological Control.
Ecology, Vol. 77, No. 7. Oct, 1996. 1965-1974.