If you move forward to the part where the sheriff loses his job and he is cooking breakfast, look in the top right hand corner as his wife enters the room. You can see the mic EXTREMELY clearly. Let me know what you guys think.
1. Sheriff Brody was never fired in Jaws, this happened in Jaws 2.
2. There is not a microphone in the scene, it appears to be a decoration on the wall behind Mrs. Brody that is way out of focus. If it were a microphone, it would have been between the two actors and in focus, not a blurry thing on the wall. I say this is not a slip-up at all.