Anyone have experience in determining optimal use of anesthetizing agents on fish larvae. We use MS-222 regularly on juveniles and adults but larvae seem to have great difficulty recovering. We want to set an experiment to determine what exposure is required to anesthetize larvae without killing them.

Anyone have experience in determining optimal use of anesthetizing agents on fish larvae. We use MS-222 regularly on juveniles and adults but larvae seem to have great difficulty recovering. We want to set an experiment to determine what exposure is required to anesthetize larvae without killing them.

I haven't any experience in anesthetizing larvae, but have killed some very small juvenile pompano (Trachinotus carolinus) at 50 mg/l. When I lived on the coast I would routinely use 10-50 mg/l (buffered 2:1 with sodium bicarb) to mildly sedate juvenile pompano during shipping to reduce the build-up of metabolites and keep DO a little higher, but found the real little guys (<10 mm TL) couldn't even tolerate the full 50 mg/l for 10-20 minutes while I was preparing to bag them up. But of course that is only one species, I should think it near impossible to predict the outcome of anesthetizing any larval fishes without a little trial and error...

On a bit of a tangent- there have been some quite interesting findings coming out of the veterinary literature which would seem to suggest that MS-222 is a bit harsher than has been previously assumed, I would assume any negative effects would be magnified in larvae...

...for what it's worth,
-BC