[Coral-List] Potential effects from using MS.222 (tricaine methanesulfonate) on coral reefs (Taratau Kirata)
Rob Hilliard, imco
rhilliard at imco.com.au
Tue Dec 2 22:14:36 EST 2008
I would be surprised if expensive MS.222 (Sandoz) would be a popular
choice for using in open reef waters by the live reef fish food trade to
catch large wrasse and groupers - either for slowing them down (it's not
quick acting on large fish) or for keeping them under sedation/ narcotic
state for long periods (it precipitates out and decomposes into
non-effective and more toxic compounds relatively quickly - especially
The speed and level of anaesthesia achieved by MS.222 varies
considerably (3 to +30 minutes) with water temperature, salinity, DO2
and, most importantly, with fish size/biomass and particular species.
If MS.222 were to be used heavily and irresponsibly on a patch reef
during, say, the low water slack, you can predict the most potentially
immediate side-effect will be substantial mortality losses to the
damsels, humbugs, gobies, etc, because it is the smallest fish that are
almost always the most sensitive. Note the point made below that
MS.222 in seawater becomes toxic when exposed to sunlight. Very high
doses (20% concentrations) of MS.222 are reported to be required to
achieve narcosis in invertebrates such as annelid worms.
Our fish lab stopped using MS.222 as a fish anesthetic back in 1979 - it
was quite expensive and a reported carcinogen - although there are some
contrary claims, e.g
We switched to the much cheaper benzocaine (which needs to be
pre-dissolved in a little ethyl alcohol before using). MS.222 breaks
down quicker and into potentially more toxic compounds than benzocaine
(which is a common topical pain killer, e.g. powerful throat
lozenges). You may be interested in the following snippets I trawled
from Googling "MS 222"
A LABORATORY COMPANION FOR GENERAL AND COMPARATIVE PHYSIOLOGY - 2nd
editon by Hoar & Hickman.
"There is a very wide latitude in the permissible dosage, and
recommended amounts vary from 1:5,000 to 1:20,000. In practice, a
solution of about 1:10,000 is usually found satisfactory; animals are
placed in the solution until the desired level of narcosis is attained
and then removed to their natural water for injection or operation.
The sustaining dose for prolonged anesthesia (added to the water flowing
over the gills) should be much more dilute (1:45,000). Solutions of
MS-222 gradually lose their activity but a 10% solution will remain
fully active if stored in a brown bottle for up to three days.
Solutions in seawater will become toxic if exposed to light."
Ohr, E.A. 1976. Tricaine methanesulfonate--I. pH and its effects on
anesthetic potency. Comp. Biochem. Physiol. 54C:13-17.
In a nutshell: Start with 0.01% in distilled water (pH will be about
3.7 but if using in seawater there's no need to titrate this back to pH
7-8 with NaOH). A working stock solution is not possible - both MS.222
and benzocaine tend to precipitate out. Induction times take around 5
minutes for 2-5 g fish. Recovery is about 4 minutes after returning to
Cheers and hope this helps,
InterMarine Consulting Pty Ltd
Mob: +61 427 855 485
Office: +61 8 6394 0606;
Fax: +61 8 9255 4668
*rhilliard at imco.com.au*
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