If he's in cormorant territory, could he get a permit to permantly remove them? A friend of mine that has ponds about 80 miles East of Dallas has a permit and when I was there in early May, I helped him get over the 200 mark. The 17HMR really works well on them.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).