I haven't spent as much time running a shock boat as some of the guys on the forum, but I've done enough to know a couple things:

1) catfish are best shocked at a different setting (pulse frequency) than works best for most other fish. If you were mostly interested in catfish they might have been able to specifically electrofish for them.

2) Crappie (other than during the spawning season) are pretty tough to get with a shock boat. They generally hang out in open water deeper than the shock boat is effective or if they do get shocked the water is not clear enough to see to scoop them.

Fish definitely spook ahead of the shock boat. The vibration of a generator in a jon boat has to be deafening to them. Thats why shocking works better if there is cover for them to hide in, they think its safe until its too late. In a lake with little cover the fish tend to run more from the boat, which makes it tougher but can possibly be countered with some fancy boat herding/driving.

A gas motor on a lake with fish that have never experienced one can also cause the fish to go nuts. I did lake water quality surveys a couple summers for the state and we had special permission to use a gas motor on "electric only" or "no boat" lakes and occasionally common carp would respond to the motor like the newly invasive asian carps by jumping 3 or 4 feet in the air. There was also a lake with northern pike and every trip to it we would get a couple of them airborne too.

The other important thing to remember is that electrofishing is not the magic bullet most people think it will be. If your water conductivity was not right it could have made electrofishing very tough.

Too bad they didn't give you a little more thorough sampling. Electrofishing can definitely teach a lot about a body of water in a short amount of time.

Every person should have an interest in life - I think I'll go fishing. ~ Thoreau