I have periodic problems with otters. They like to kill for fun. You can always tell when they are around. You will find the largest fish from your pond with a big hole chewed out of their heads and lying on the bank. If they were killing and eating I wouldn't have a problem with them, but they don't just kill to eat.

I'll start treating my wife as good as my dog when she starts retrieving ducks.
http://geocities.com/h20fwlkillr/