The Louisiana Department of Wildlife and Fisheries is charged with the responsibility of managing and protecting Louisiana's abundant natural resources.


Damage

Vegetative damage caused by nutria has been documented in at least 11 Coastal Wetlands Planning Protection and Restoration Act (CWPPRA) project sites in the Barataria-Terrebonne Basins. The estimate of 80,000 acres of marsh damaged was conservative because only the worse (most obvious) can be detected from aerial surveys. The number of acres being impacted was certainly higher. Since the introduction of the Coastwide Nutria Control Program in 2002, the number of impacted acres has dropped to 4,181 acres. Over grazing by nutria removes vegetation from the surface of the marsh, which results in the very fragile organic soils becoming exposed to erosion through tidal action. If damaged areas do not revegetate quickly, they will become open water as tidal scour removes soil and thus lowers elevation. Frequently, nutria grazing damages the plant's root systems, making recovery through vegetative regeneration very slow.


The first coast wide nutria herbivory survey was flown in 1998 and continued through 2001, as part of the Nutria Harvest and Wetland Demonstration Program.  The Coastwide Nutria Control Program began in 2002.  Below are the total number of nutria damage sites and the number of acres documented for each year.

 

Year 

Total # Damaged

Sites Observed 

Total # Damaged

Acres Observed 

Estimated # Damaged

Acres Coastwide * 

1998

170

23,960

89,850

1999

15

27,356

102,585

2000

132

25,939

97,271

2001

124

22,139

83,021

2002

94

21,185

79,444

2003

84

21,888

82,080

2004

69

16,906

63,398

2005

49

14,260

53,475

2006

21

14,868

55,755

2007

23

9,244

34,665

2008

23

6,171

23,141

2009

19

5,422

20,333

2010

11

2,260

8,475

2011

10

1,679

6,296

2012

11

1,129

4,233

2013

12

1,266

4,624

2014

11

1,115

4,181

2015

12

1,602

6,008

 2016

11

1,732

6,496

 2017

16

1,564 

5,866

* Coastwide damage estimated by formula: damaged acres observed x 3.75.  The 3.75 multiplication factor comes from the area not visible from the transect lines flown in aerial surveys.

Click on images to see wetland damage caused by nutria.