It's still $5 a tail for every one you get over 7" (the tail)
http://www.nutria.com/site10.php
The Coastwide Nutria Control Program consists of an economic incentive payment of $5 per nutria tail delivered by registered participants to collection centers established in coastal Louisiana. The goal of the Program is to encourage the harvest of up to 400,000 nutria annually from coastal Louisiana. This program is funded by Coastal Wetlands Planning Protection and Restoration Act through Louisiana Department of Natural Resources and Natural Resources Conservation Service.
Participant Application Process
1. Participants must acquire a valid Louisiana Trapping License.
2. Participants must obtain permission to trap/hunt in the Program Area from an appropriate private, state, or federal landowner.
3. Participants are required to submit a COMPLETE, legal property description for each property to be trapped / hunted. Participants are also required to send a map outlining each property to be trapped / hunted.
4. Participants are required to submit a completed W-9 Federal Tax Form with the Coastwide Nutria Control Program Application.
5. Applications submitted to the department or its contractor by October 1 shall be processed by the opening of trapping season (Nov. 20 – Mar.31). Applications submitted to the department or its contractor after October 1 shall be processed in the order received.
6. Applications listing only waterbodies, without signature of adjacent landowner(s) or designated representative(s), shall be considered incomplete and will be returned to the applicant.
7. For applications determined to be complete and valid, the participant shall be notified by mail and provided a Nutria Control Program Registration Number.
Edit:
During my formative years in TX, I used to take them with a .22, but a .22 Mag or even a .17 wouldn't hurt.