What's Hatching on Stauffer Creek

This past long weekend was a great opportunity to get out and enjoy a day on the water. Temperatures were warm enough to stir things up but not so warm as to cause excessive run-off (at least not where I was). The trout were active, the bugs were active, and there was good fishing to be had. And yes, even the odd fish rising.

Winter stonefly hatches on Stauffer Creek are on again with both Utacapnia trava and Zapada cinctipes emerging in reasonable numbers. These are the first two stonefly species to emerge on most central Alberta trout streams and although they look very similar, and can be imitated with the same fly patterns, they are easy to tell apart if you look closely.

Utacapnia trava is in the family Capniidae and is characterized (in part) by longer tails with more than 4 segments. On the winged females the tails can be seen extending past the wing tips. The wings are rather plain looking and other than venation, they lack any distinctive pattern. The males will also have long tails but they have reduced wings and are often mistaken for nymphs crawling on the snow.



Utacapnia trava (adult female)

Utacapnia trava (adult male)

Zapada cinctipes, in the family Nemouridae, have short stubby tails that are hidden by the wings – both males and females have fully developed wings. The wings of both sexes exhibit some faint patterning. If you have a small hand lens you may also see branched gill remnants in the ventral neck region of both male and female adults.



Zapada cinctipes (adult male)

Another thing to watch for are adults that are light brown to tan in colour; these are teneral adults that have just emerged – they will darken as their exoskeleton hardens.

Utacapnia trava (teneral female)

Things will get more complicated in a few weeks as more winter stonefly species start to emerge, but for now this at-a-glance identification on Stauffer Creek is relatively reliable.

Temperatures look to be a little cooler for the coming weekend but this could be more of a blessing – with the heavy snow-pack, a slower melt should keep streams in fishable condition.