I've experienced the fish loss problem,
but the answer was obvious - herons and
water turkeys. What they didn't eat, they
speared and wounded. But, these birds are
not discriminating, they will go after
all types of fish - not just bass. Also,
you should see evidence of bird predatation,
ie, partial eaten fish, skeletal remains,etc.
Curiously, I'm wondering how Meadowlark has
managed to control the bird problem.