What type of impact can a single great blue heron have on a 1.5 acre pond managed for trophy bass? What size and quantity of fish can one of those consume? Should the activity be "discouraged"?

Not a lot IMHO. If it bothers you there are nonlethal measures you can take such as a few inconspicuous mono lines mounted to stakes around the pond to keep the bird out of the water. I do this every year in my four ponds.

Just because i'm curious. If they are benign, why keep them out?

My ponds aren't recreational ponds. They are part of my living and two of them are for intense fingerling production which a heron could make a dent in.

If my ponds were purely recreational I wouldn't have much of a concern at all.

gotcha

Do they only eat small fish?

They only eat what they can swallow in one gulp. BUT, they will also stab larger fish that they perceive as a threat to their food supply if one comes close.

One a year ago stabbed and killed a 14" RBT in my pond.

They are federally protected, but they can be "removed" if you have a permit.

Or if you have enough land to bury one without the neighbors knowing it!

Or the game warden .....

I never thought of it that way. I assumed they just were instinctively spearing anything that moved.

I've seen a video of cormorants eating some pretty darn big fish which causes my concern.

Cormorants will eat until they drop. Herons will eat and fly off. Herons will also eat snakes. Cormorants outnumber herons 100 to 1. I get along with the herons, but will light up the corms.

You've seen cormorants on your pond?

I've been lucky; haven't seen one yet. Did have two ospreys show up one morning at daybreak and just stand on my pier as if they were resting after a long flight. They soon took off again. I didn't observe them after any fish.

I do dye my big pond to reduce visibility (otherwise you can see all the way to the bottom) and feel this helps dissuade diving birds.

I haven't seen those on my pond, I saw them eating large fish on a fishing program. Hope they stay away, but I am aware of some in my area.

My state is reintroducing them along with the otters. I have families of both within a few miles. I have nonlethal ways of dealing with the Ospreys if need be. Not so sure about the otters.

Cecil, your ponds would be perfect for an electric fence install to keep otters out.

Anyone know if blue herons and cormorants coexist? Does one run the other away? If given a choice, I would prefer the heron.

Yeah I forgot about the electric fence option Scott. I think I will be putting one up next year when I start raising brookies again. I did kill a mink a couple of years ago. Too valuable of a crop to lose any. If all goes well the next brook trout crop should pay for a pole barn.

The herons are territorial. A resident heron will run another new heron off. The cormorants only respect hollow points.

This only runs the otters off to another pond.

True, but they're protected in Indiana. Big no-no if caught shooting one.

The electric fence works 24/7 while the hollow points only work when you are at the pond (and can see).

Key word is "caught". Luckily I haven't seen any near my pond, and I don't expect to since I'm a ways away from any other surface water.

Wouldn't a pond have to be pretty small for a fence to be feasible?

No, but it'd be hard to fence if it had a lot of brush and marginal plants growing around it. Cecil's are manacured up to the waters edge, and they drop off quickly at the water line.

For otters, the fence could be strung up outside of the marginals, and as long as it had a couple of strands near the ground so the otter couldn't slide thru/under it, it would work fine.

I've seen fence controllers for 25 miles of fencing.......

Heron isn't the greatest evil but...
If you find only single bird today, it doesn't mean you won't find 3 of them after a month. I would try to get rid of them - how to do that, it is up to you.

I have a seven acre pond and have not had more than one. He/she has been here at least five years.

Lucky you.
At first only one heron visited my pond (~1,2 acre) but in the end of summer there were at least 4 of them. 3 young ones and 1 of parents (who knows, maybe even both of them).
2 were successfully eliminated.