Here's the report with chart;
LOUISIANA DEPARTMENT OF WILDLIFE & FISHERIES
POST OFFICE BOX 98000
BATON ROUGE, LA 70898-9000
Waterfowl Population Estimates
Date:
Coastal Zone: Sept. 10-12, 2012 in Louisiana’s Coastal Zone
Catahoula Lake: Sept. 12, 2012
U.S. Highway 90 and on Catahoula Lake
Reported By: L. Reynolds, J. Olszak and B. Davis
September 13, 2012
Pilot: B. Dorsa
Estimates made from Aircraft
COMMENTS:
The 189,000 blue-winged teal estimated on this survey is 12% higher than last year’s estimate of 169,000 but 21% below the long-term average of 240,000. All regions were different from 2011 with a 21% increase in southwest Louisiana, an increase from 4,000 to 18,000 at Catahoula Lake, and a decline from 30,000 to 7,000 in southeast Louisiana. The 164,000 estimated in southwest Louisiana is higher than the prior 3 September survey estimates but remains about 10% below the most recent 5-year average which includes the very large estimate (444,000) in 2008. The largest concentrations in southwest Louisiana were seen in the marsh south of the East Cove Unit of Cameron Prairie NWR, and in shallow-flooded agricultural fields northwest of Gueydan and off the survey transects north of Welsh. There were no concentrations of teal on southeast Louisiana transects, and the 7,000 estimated in that region is the lowest on record. With the 11,000 in 2010, 18,000 in 2009, and 13,000 in 2008, the 4 lowest blue-winged teal estimates for southeast Louisiana have come during the last 5 September surveys.
The estimated 19,000 mottled ducks is down 30% from the 27,000 last year and is the lowest September estimate on record for this species. The 14,000 in southwest is the lowest since 2002, when only 11,000 were estimated in the region and the total estimate was only 20,000 coastwide. The 5,000 mottled ducks in southeast Louisiana is the lowest estimate on record for that region.
Survey results may have been affected by hurricane Isaac in southeast Louisiana and high water levels in the marshes of southwest Louisiana. Isaac’s storm surge removed almost all of the submerged aquatic vegetation in Jefferson, Plaquemines, and St. Bernard Parishes, and water levels were still very high in those marshes, creating conditions that were not conducive to attracting and holding early-season migrants. High water levels in southwest Louisiana marshes appeared to be responsible for a shift in mottled ducks northward into the agricultural region seen during the April breeding survey, and water levels were higher than normal over much of southwest Louisiana during this survey. Agricultural areas north of I-10 are not included in the fall surveys. Water levels were also a concern at Catahoula Lake where managers drained the lake 6 feet below management target in preparation for hurricane Isaac, followed by flooding to 3 feet above management target by rainfall and runoff, and then rapid de-watering over the past week. Water level was near the 27.5 foot target at the time of this survey, and nearly all of the ducks counted were in one flock at the north end of the lake.
Habitat conditions in southwest Louisiana are much improved over the drought conditions seen in 2011 despite the higher-than-optimum water levels. Only average production of moist-soil vegetation was noted, but very good submerged aquatic growth was seen in most habitats. In addition to managed water, some shallow flooding from recent rainfall was noted in agricultural areas. In southeast Louisiana, habitat quality was reduced markedly by the hurricane, especially the food resources provided by SAV. However, those effects were not evident further west in the Terrebonne Parish marshes and the Atchafalaya Delta where very good habitat conditions await migrating ducks. Prior to the flooding from hurricane Isaac, growth of seed-producing annual vegetation was expanding after a late drawdown at Catahoula Lake, and foraging habitat appeared to be better than last year. The impact of the extreme water-level fluctuation on forage production is unknown, but it will likely be similar to 2011, which was considered below-average.
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