Fishing chironomids on BC lakes

Ask an interior BC stillwater angler which insect matters most and the answer is almost always the chironomid. It is a non-biting midge, a small relative of the mosquito without the bite, and on a productive lake its larvae can carpet the mud by the thousand in a square metre. Trout eat them all year, and during the big spring hatches they can eat little else.

The life cycle, and why it matters

The larva lives in the bottom sediment, often a deep red from the haemoglobin that lets it breathe in low oxygen, which is where the name bloodworm comes from. When it is ready it seals itself into a pupa, and the pupa rises slowly to the surface, hangs in the film, splits and releases the adult midge. That slow rise is the part that matters to an angler. For a trout it is an easy meal that cannot escape, and for most of a hatch the fish feed on pupae well below the surface rather than on adults on top. A rising fish is often taking a pupa just under the film.

When the hatches come

Chironomids start soon after ice-off and turnover, and the heaviest hatches run through late spring into early summer. The exact weeks move with elevation: a low lake can be in full swing while a plateau lake is still frozen. Hatches carry on through summer, often in the early morning or at dusk and deeper, and return in fall. Look for the empty pupal shucks floating in the film, swallows working low over the water, and adults resting on your boat. A calm, overcast day after a stable spell of weather is the classic hatch day.

Where to anchor

Chironomids come from the mud, so the fish hunt the flat shoals and the edges of the drop-off, usually in three to eight metres of water, where larvae are thickest and the light reaches the bottom. A depth chart is the fastest way to find those shelves on a new lake; the guide to reading a depth chart shows how. Anchor at both ends so the boat does not swing, on the shoal just above the drop, and fish down the slope as well as on the flat.

Under an indicator

The common method is a pupa suspended under a strike indicator. The key is depth: the fly should hang just above the bottom, where the pupae start their rise. Measure the depth with a forceps clipped to the fly and lowered until it touches, then set the indicator so the fly sits a little above that. Most days that is all it takes. Watch the indicator for the smallest dip or pause; a trout takes a pupa gently. If nothing happens, move the fly up in steps until you find the level the fish are feeding at.

On a long leader

Without an indicator, a floating line and a long leader let the fly sink straight down, then a very slow hand twist retrieve brings it back up as a real pupa would rise. It takes more patience and more feel, and it covers the whole water column. On deep shoals some anglers use a slow sinking or clear intermediate line instead.

Choosing the fly

Match the size first, then the colour. Pupae run from tiny to more than two centimetres, and a hatch is usually one size.
Black, olive, maroon and brown are the workhorses, with thin bright ribbing to suggest the segmented body and a white bead or tuft for the gills.
Scoop a trout that is being kept, or a sample from the surface film, and look at what is in it. The fish will tell you what they are eating.
A bloodworm pattern fished just off the bottom works before and between hatches.

Picking the day

Chironomid fishing is anchored, still water fishing, and a gusting wind that swings the boat and drags the indicator ruins it. That is why wind carries the largest share of the score on every lake's forecast, scaled to how much open water that lake gives the wind. Open the lake, look for the calm morning, and go.

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