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Minke Whales and Krill: An Ecosystem Approach

Minke Whales and Krill: An Ecosystem Approach. By Alice Chen. Opening Remarks. Explanation of food web Complexity All ecosystems tends towards equilibrium. The Equilibrium Principle. There is never a surplus of one species More prey = more energy The human factor. Two Arguments.

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Minke Whales and Krill: An Ecosystem Approach

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  1. Minke Whales and Krill: An Ecosystem Approach By Alice Chen

  2. Opening Remarks • Explanation of food web • Complexity • All ecosystems tends towards equilibrium

  3. The Equilibrium Principle • There is never a surplus of one species • More prey = more energy • The human factor

  4. Two Arguments • First, krill fisheries damage the marine ecosystem. • Model • Antarctic Fur Seals • Second, does the Minke whaling quota set by Norway ultimately benefit the surrounding aquatic ecosystem • Models • Adelie Penguins • Murphy’s Model

  5. Krill Fisheries • Background • Expansion in the Antarctic • Numbers • CCAMLR sets a catch limit • Fishing operations overlap with feeding grounds • Ultimately, detrimental to aquatic ecosystems.

  6. Thomson, Butterworth, Boyd, & Coxall (2000) • Antarctic Fur Seals in South Georgia • Seal pup survival rates decreased • Less food • Forage • Less energy • Overcrowding

  7. Population Size Predator Survival Rate

  8. Norway’s Minke whaling policy • Background • IWC moratorium • Norway sets quota based on IWC’s method • Highest obtainable yield from a stock, but at the same time not endangering that species • Positive impact

  9. Ainley, Ballard, & Duggar (2006) • Adelie Penguins • Diet’s changed when there was an influx in whales • Foraging distance increased • When, Minke populations shrunk, penguin once again ate krill

  10. Murphy (1995) • 1st model • Krill population increased by almost 50% • 2nd model • Antarctic Fur seals and Adelie Penguins reached carrying capacity

  11. Arguments against Norway • Iron depletion • Taking away natural resources • Moral and ethical issues • When is enough, enough? • However, Norway keeps an eye on these issues

  12. Recap • Equilibrium • Krill fisheries • Depleting resources • Norway’s Policy • Allowing krill to thrive

  13. Closing Remarks • We are part of this ecosystem equilibrium • Most intelligent species • We have a choice to make • Choose not to act • We attempt to take what we think is a responsible approach

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