I have an issue with garter snakes invading my FHM pond and hauling out many, many, many adult FHM.
If I throw a baited trap in and wait an hour I can pull trap out and have 4-6-8-10 drown snakes in it but quite a few regurgitated minnows as well.. This is the only pond I have issues with snakes-guessing a predator thing.
I hate trapping that many adults (removed from spawning process) to catch snakes, but maybe that's what I need to keep doing. I was wondering about putting 2-3 Male Tilapia in there to snip the snakes to maybe deter them. I know they will eat a few minnows but I'm also feeding pellets twice a day there.
Any grand ideas?

Snipe,

I am hoping there is a limited number of Garter snakes in your neck of the woods and that drowning them eventually eliminates the problem. The TP, if they reproduce, will compromise the production of minnows. They may not be a big deterrent to the snakes. Hope this resolves for you and with less impact each year.

In my experience, snakes will disappear when they have no cover.
Mow grass and weeds down tight, as close to the water as you can.
Then nature will take it's course, as Hawks and Eagles will take up residence over looking the area.

I'm having difficulty imagining enough garter snakes that would noticeably damage a FHM population given the FHM have ample structure for laying their eggs. BUT, trapping up to ten at a pop sounds like alot of snakes. What have you totaled so far in the trap? Either way, an hour of trapping that produces that many snakes is worth doing and I would continue those efforts as the catch rate will diminish as the snake population is reduced. That will be your tell-tale sign that your FHM losses are being positively affected and the sacrificial FHM's for bait will pay off in the long run.

As JM says, keeping the terrestrial growth to a minimum will help along with the lack of rock piles and fallen timber.

Are you in the market for a new dog? (short story - thanks for the trip down memory lane) I had an Airedale Terrier once that was H@11 on snakes. It didn't mater what kind, she would whip them back and forth in her mouth until limp...dead snakes everywhere, lol. As a youth, I would collect snakes and, one time, I had about 20 gathered up in trash cans, buckets, and boxes...Old Maggie got in the garage and upended every container and put every one to rest. That was the end of my snake collecting in the gargage (which made Mom rather happy I might add). A terrier is the only snake predator that I can think of that would not have an impact on your FHM's aside from nature's raptors.

I've drowned close to a dozen diamond back water snakes in the Z trap so far this season.
Had two in it one day last week. I don't know how many are left, but it wouldn't hurt me if every one of em drowned.
I've got a batch of RES caged up for pellet training and the snakes know it...

These are my 3 new ponds.. there is NO ground cover yet-as-in plain bare, but these dudes have figured it out.
I have drown about 50 now I'd guess, most are in that 18-24" range but got one yesterday about 35".
Guess I'll keep trapping, seems to remedy the issue at hand I guess but the other ponds that have BG, YP, Tilapia..I don't see any snakes in those even though there's FHM in those also.

jpsdad, I was thinking just 2-3 male only tilapia.. they seem to mess with anything that moves in the water..thought they might deter the snakes from entering if they get picked on.

Put a 18"-20" LMB in there.