Back in August I was on driffield beck. As dusk set in a large grayling started doing this strange whirly dance. Just under the surface it would turn on its side, rapidly swimming in a circle fanning its tail while flowing back with the current. It did this a few times, then sat motionless on the streambed before starting again! Being august I'd discounted some strange form of sexual selection.

Any one else seen this or know about it?

Whirling Disease (Myxobolus cerebralis). Common and dangerous in North America, but also present in Europe

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Game fish are too valuable to be caught only once - Lee Wulff

I just had a read about it. Not good. I better email the bloke who runs the fishery. thanks shuck raider.

I presume, as you could clearly see the fish that it was not a juvenile/fingerling sized fish? In that case it is NOT whirling disease.

A big old grayling. Reading wikipedia it doesn't rule out older fish getting it, and european grayling unlike arctic grayling are susceptible...but yes, it would seem to be less than certain that its whirling disease.

Who can tell though? Sounds like spawning behaviour but seems highly unlikely.

I (and many others) did however, observe dozens of bright fresh salmon (not kelts) cutting redds in March this year.

It's a dangerous assumption to think it's Whirling Disease. Worth mentioning it to the keeper, but there are other possible explanations.

There's a chance that the fish is trying to remove parasites - perhaps leaches. Less common on fish in the Summer, but not impossible. Thy will try a splash against the surface to dislodge them. Sometimes they will flick their flanks over the gravel.

Cheers,
Dave.

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Dave Wiltshire

River Fly Box