A $5 bounty is paid by the state for each tail and 338,512 have been turned in, officials ssaid.
That's about 24 percent down from last year's record of 445,963, but very close to the average since a bounty was first put on nutria in 2002, according to analysis of figures at the Coastwide Nutria Control Program website.
The buck-toothed rodents reproduce faster than rabbits and eat roots, stems and leaves of the grasses that hold marshland together. When the bounty program started, officials estimated that killing at least 400,000 a year could keep them under control and avoid wholesale destruction of marshland.
Last year's November-to-June harvest was the first to meet the 400,000 goal - and marsh acreage destroyed by nutria was 58 percent less than the previous year's estimated total. The damage total estimated in a 2009 survey was 20,332 acres; last year, it was 8,475.
Higher water levels in late 2009 and early 2010 let hunters get into more nutria habitat and bring in bigger catches, Edmond Mouton, a biologist program manager with the state Department of Wildlife and Fisheries, told The Courier.
The year-to-year acreage drop before and after 2010 has ranged from 12 percent to 33 percent.
The smallest number of tails brought in since the program began was 168,843 in 2005-06. The bounty was boosted from $4 to $5, and the tail count bounced back up to 375,683.
The market for nutria fur was enough to keep the critters under control until the 1990s. Hunters bagged an average of 1.5 million nutria a year in the 1970s and 790,000 a year in the 1980s. But as fur fell out of fashion, the catch plummeted to an average of 190,000 a year in the 1990s, and to fewer than 30,000 a year by 2000.
A 2001 survey estimated that nutria had eaten out more than 83,000 acres of marshland. That was probably low, since only severe damage can be seen from airplanes, biologists said.