How to Use a Stomach Pump

Taking stomach samples from the trout you catch can be a highly effective way to get a handle on what fly patterns you should be using. Many anglers own stomach pumps, but not everyone knows how to use them properly. Make sure you discard the little metal clip that comes attached to the tube of many pumps. This clip can damage a fish's gills or throat. The key is to totally fill the pump with water. Turn the fish upside down and tilt his head at a slight downward angle. This tends to "freeze" the fish - the loss of equilibrium causes the fish to stiffen up and cease wiggling. This works about 90% of the time. Once this is accomplished, insert the stomach pump into the fish's mouth, being careful not to touch the gills. When you feel the pump enter the throat area, proceed slowly. Resistance will decrease as the pump enters the stomach cavity. Squeeze the pump in order to inject a small amount of water into the stomach. This will loosen the stomach contents and you can suck the organisms into the pump. Withdraw the pump carefully. Keep in mind, there are times when trout have little in their stomach, or they have consumed larger organisms like minnows and crayfish. In these cases, it is difficult to extract any sample; but on a river like the Bighorn where most of the food items are small, you'll often end up with a pump full of insects and crustaceans.

Steve Hilbers-Bighorn Trout Shop