U.S. Department of the Interior U.S. Geological Survey
Identifying an optimal anesthetic for juvenile Pacific lampreys
Helena E. Christiansen, Lisa P. Gee, and Matthew G. Mesa Columbia River Research Laboratory
Why study Pacific lamprey?
©Michael Durham
When is anesthesia necessary?
Handling issues
• Reaction to high concentrations of MS-222 • Fungus
Objectives
1. Identify an effective anesthetic
2. Identify a safe anesthetic
Anesthetic efficacy trials • Tested time to handleable and time to recovery for 4 anesthetics at 12°C
MS-222 BENZOAK (20% benzocaine) AQUI-S 20E (10% eugenol) Aquacalm (metomidate hydrochloride) • 3 concentrations per anesthetic
• 15 fish per concentration
MS-222
0
5
10
15
20
Tim
e to
han
dlea
ble
(min
)
50 100 2000
2
4
6
8
10
Concentration (mg/L)
Tim
e to
reco
very
(min
)
A
B B
B
AA
Anesthetic efficacy
3:53
2:22
3:47
5:55
Anesthetic efficacy
6:10
6:03
Aquacalm
0
5
10
15
20
25
Tim
e to
han
dlea
ble
(min
)
50 75 1000
5
10
15
20
Concentration (mg/L)
Tim
e to
reco
very
(min
)
B
BA
Anesthetics: Health and survival • Treated 45 lampreys with each anesthetic until handleable
MS-222: 100 mg/L BENZOAK : 60 mg/L AQUI-S 20E: 100 mg/L • 15 lampreys per aquarium, 3 aquaria per anesthetic
• Monitored health and survival for 30 d
Health—Fungal infections Control
0 5 10 15 20 25 3005
1015202530354045
Days post-exposure
# of
fish
MS-222
0 5 10 15 20 25 3005
1015202530354045
Days post-exposure
# of
fish
BENZOAK
0 5 10 15 20 25 3005
1015202530354045
Days post-exposure
# of
fish
AQUI-S 20E
0 5 10 15 20 25 3005
1015202530354045
Days post-exposure
# of
fish
Control
0 10 20 300
20
40
60
80
100
Days post-exposure
Perc
ent s
urvi
val
MS-222
0 10 20 300
20
40
60
80
100
Days post-exposure
Perc
ent s
urvi
val
BENZOAK
0 10 20 300
20
40
60
80
100
Days post-exposure
Per
cent
sur
vival
AQUI-S 20E
0 10 20 300
20
40
60
80
100
Days post-exposure
Perc
ent s
urvi
val
Survival
Summary
• MS-222 and BENZOAK are effective anesthetics for juvenile lampreys • AQUI-S 20E and Aquacalm are poor anesthetics for juvenile lampreys
• BENZOAK may reduce fungal infections?
Future questions
• Refine dose needed
• Temperature effects
• Use of anesthetics in field studies
Thanks
Greg Kovalchuk & staff: PSMFC
Ken Lujan: USFWS—Willard FHO Sean Tackley & Natalie Richards: USACE Lisa Weiland: USGS
