Fisheries Implications of Freshwater Diversions

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Fisheries Implications of Freshwater Diversions
Coastal Wetland Planning, Preservation, and
Restoration Act (CWPPRA) Outreach Committee Topic
Series December 2001
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Floods, Fisheries, and Diversions?

1. What does history have to say about floods and
   fisheries? Levees and landings?

• What is a Freshwater Diversion and
  how does it affect fisheries?
• Case Study Caernarvon

1. What is the situation regarding land loss
   in coastal Louisiana?

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Floods and Fisheries

• LA leads lower 48 in fisheries landings

• Salt water ? fish !

• Location, location, location

• Alluvial fertilization

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a crevasse in reality results in the
restoration of our wetlands the effect of a
crevasse is akin to the cultivation and
fertilization of farm lands and might be termed
wholesale aquaculture. Percy Viosca, Jr.
(1927) American Fisheries Society
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The Great Flood of 1927
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Fortification of Levee System
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160-200 million metric tons a year
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Net Result?

• Louisiana has lost 1000 square miles of coastal
  wetlands in the past century.

• 25-30 square miles per year

• 1 acre of land every 24 minutes

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Whats at stake?
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How have our fisheries been affected by all this
land loss?
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Who needs habitat? Louisiana Commercial Fisheries
Landings
(million pounds)
1930
1940
1950
1960
1970
1980
1990
1935
1945
1955
1965
1975
1995
1985
Year
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Land-Water Interface Length for
Coastal Louisiana
(Source Browder et al.1985, 1989)
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Will the fishing always be great?

• What is sustaining Las
• coastal fisheries
  
• Alluviation or Deterioration?

• Are we consuming
• interest or principle?

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Coast 2050
Toward a Sustainable Coastal
Louisiana

• Local, state, federal consensus effort 1997-98

• 77 ecosystem restoration strategies

• Restore 500,000 acres over next 50 years

• Estimated price tag 14 Billion

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Coast 2050
Toward a Sustainable Coastal
Louisiana
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Caernarvon

• Construction 1988 - 1991

• Enhancement of marsh vegetation, fisheries
  enhancement, and reduction of marsh loss

• 26 million in construction costs (25 state)

• Post Construction Monitoring 1991-94

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Intermediate to Brackish Marsh Boundary
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Finfish
Post-diversion
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