Throat pumps are one of the great tools of stillwater fly fishing. When used correctly, they do not harm the fish at all and allow you to see exactly what was on the recent menu. They become very effective during a chironomid hatch, as what’s in the throat pump can give you a great idea how deep you should be fishing.
When a chironomid pupa transforms from a larva and ascends the water column, they will build up a gas inside of their abdomen. This is what gives them the silvery sheen that is often referred to as a “chromie”. Seeing this silvery chironomid pupa in a throat sample is a great indication that fish may not be feeding all that close to bottom. Typically, fish that are stuffed with shiny chironomid pupa are actually suspended in the water column. Using a depth sounder to pick up fish will give you confirmation of this.
On the other hand, if you are finding that a majority of your throat samples are showing darker bugs in black, brown, maroon or dark green with no sign of silver sheen then fish are likely feeding close to bottom. Darker bugs, especially those with red accents towards the back end of the fly have not had a chance to take on the same shiny appearance.
Next time you pump a fish, take a closer look at the colour of the chironomid found in the sample and use it to your advantage. If you have any questions regarding this topic or want to book some time on the water this spring, fill out the form below and I’ll be happy to get back to you!