Filleting Sturgeon

I've had a problem filleting sturgeon. I hope this is the right group
to ask this question.

In short, they seem to take a *really* long time to die and I hate
cutting into something that's still moving. The last time I tried
to clean one it had been out of the water an hour, had been gutted,
had the spinal cord removed, had no head, and it would still wiggle
around every time I put my blade into it.

Is there something I can do to avoid this problem? This is a
serious question and I'd appreciate any advice.

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Reg email: RegForte (at) (that free MS email service) (dot) com