Karen,
      An interesting question, and not one most isotope geochemists are
used to dealing with.  In my opinion, I would not take any chance of using
MS-222.  Why not simply use CO2?  It can be bubbled into solution from
a tank or, perhaps more crudely, alka seltzer does a wonderful job.  I've
put down fish about 3 inches long myself by gradually dropping in about
6-8 alka seltzer tablets into a liter or 2 of water (the smaller the volume the
fewer tablets needed).  CO2 is supposed to have an anesthetizing affect,
which I can't attest to.  But I can say that the fish go down within a few
minutes and usually with very little struggling.  I believe that CO2 is an
accepted humane way for euthanizing fish.  Use of CO2 would have absolutely
no isotope effects on tissue samples
Best of luck,
Nathaniel Ostrom


At 11:58 AM 3/14/2003 -0700, you wrote:
>Hello, everyone.
>
>Has anyone out there used MS-222 (C9H11O2N + CH3SO3H) to euthanise fish
>before taking tissue samples for isotope analysis?  The Animal Care and
>Use Committee at my university wants me to use this method instead of
>freezing my tiny fish on dry ice.
>
>I'd just as soon use the least traumatic method possible for the little
>guys, of course, but I haven't seen any references to using MS-222 for
>euthanasia in the SIA literature.
>
>If you've used this stuff with great success, *or* know for sure that its
>use would mess up the isotope ratios (which I suspect), would you please
>let me know ASAP so that I can satisfy the powers that be?
>
>Thanks for your help!
>
>      Karen Gaines.
>
>  =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|= =|=
>
>Karen H. Gaines               "The Libella [dragonflies] do set forth
>Doctoral Candidate        Nature's elegancy beyond the expression of Art."
>University of New Mexico              - Tho. Mouffet, 1658
>Department of Biology                 The Theater of Insects
>MSCO3 2020
>1 University of New Mexico
>Albuquerque, NM 87131-0001  U.S.A.
>Phone: (505) 277-4969, FAX: 277-0304
>E-mail: [log in to unmask]

Nathaniel E. Ostrom, Ph.D.
Professor
Dept. of Geological Sciences
206 Natural Sciences Building
Michigan State University
East Lansing MI 48824-1115
517-355-4661