Tuesday, June 07, 2005

Green Drakes

The Eastern Green Drake is a large yellow-green mayfly that has been common to the upper Credit River as long as I can remember. However, all is not well with this insect in the Credit. While healthy in the West Credit, it appears that it is in severe decline in the main stem. A group of fly fishers and other interested parties are taking part in a survey of this insect. It only emerges for a few days each year, typically in early June. The hatch is on now, so I will be at the river Wednesday evening to count duns and spinners. The dun is the adult form of the bug, and the spinner is the egg-layer.....when the drake reaches this stage in its lifecycle, it transforms to a white insect with long tails. We call them coffin flies. Mike was at the Forks tonight and counted quite a few spinners but no duns at all. As more is discovered about the plight of this insect, I will report. This is apparently the second mayfly to decline on the Credit. The first has disappeared completely from the stream. This is an indicator that something bad is happening on the river. The question is just what exactly is causing the problem.

4 comments:

mister anchovy said...

I counted drakes below and above stuck-truck pool on the upper Credit tonight. It wasn't hard to count. I only saw two of the bugs. Very discouraging.

greatwhitebear said...

that's a a shame! Are they water temp sensitive? I know some of our hatches have been bothered by high temps and low water.

mister anchovy said...

I don't think the problem is water temperature in this case. I suspect some kind of nasty shit has been deposited in the substrate. When more is known, I will report.

greatwhitebear said...

I hope you track down the cause and or perpetrators!