I've been looking for a 10,000 watt model, 2 or 3 slow passes over the Crappie hole and they'll float to the top already microwaved! Just lift the skin off, salt and pepper to taste, and enjoy!!!
Actually, all sonars will spook fish in shallow water. You will do better if you KNOW fish are holding in a certain to turn off all of your electronics and fish the area quietly.