MALFORMED
FROG MONITORING |
|
 For
the second year in a row, Long Lake NWR Complex served as North Dakota’s
sole cooperator for malformed amphibian monitoring on FWS fee title lands.
Two WPAs previously surveyed in 2001 were also selected in 2002: Schiermeister
and Sisco-Fallgatter. Schiermeister was again deemed the “contaminant’ site
because the one acre semipermanent wetland that contained tadpoles was
flow-through in nature (part of Horsehead Creek) which increases the
site’s potential for receiving agricultural runoff (e.g., pesticides,
nutrients). Additionally, in previous growing seasons FWS personnel have
sprayed Tordon to control noxious weeds in close proximity to the study
wetland. Sisco-Fallgatter served as a reference site because the study
wetlands are closed basins, and little history of pesticide use exists
on the property. At Schiermeister in 2002, tadpoles were found in one
large impounded wetland, located just NE of the wetland that contained
tadpoles in 2001. Tadpoles were again found in one of the same Sisco-Fallgatter
wetlands from which they were sampled in 2001. |
| |
 Surveys,
sampling, and data collection were performed according to Standard Operating
Procedures developed by the FWS Chesapeake Bay Field Office. Sampling
was conducted by Refuge staff and volunteers at Schiermeister on July
17. Although tadpole growth was monitored weekly at Sisco-Fallgatter,
the wetland containing the tadpoles dried up completely sometime between
July 15-19. During the final Sisco-Fallgatter age determination survey,
the majority of tadpoles were between 38-42 Gossner Stage, so they were
not at the stage of metamorphosis when the wetland went dry. Several
other wetlands on the WPA were searched for tadpoles, and surrounding
uplands for metamorphs, but none were found. Below are the survey results
for Schiermeister WPA. |
| |
| Malformation
Survey - Schiermeister WPA |
| |
 A
total of 293 N. leopard frog metamorphs were collected (166 in the aforementioned
impounded wetland and 127 from the small semipermanent wetland which
contained tadpoles in 2001). Because tadpoles were only found in the
large impounded wetland in 2002, it is likely that the metamorphs collected
from the second smaller wetland had simply migrated there from the nearby
impounded wetland. Unlike 2001 when 5 of 100 sample frogs were deemed “abnormal”,
only one frog in 2002 was deemed abnormal and preserved for further examination.
This metamorph (weight = 3.8g, snout-to-vent length = 34mm) had a small
protrusion on its back, left of the spine and just a few millimeters
behind its left from leg. The protrusion was slightly larger than the
head of a pin. Water quality parameters for the small semipermanent wetland
were collected on June 3 and are as follows: Temperature = 19?C, DO =
5.02mg/l, Conductivity = 2741 uS, pH = 8.02. |
| |
| Parasite
Study |
| |
 Because
much speculation exists concerning the cause of amphibian malformations
nationwide, Refuge staff worked with scientists from the USDA - Agricultural
Research Service, Fargo, ND, to help determine whether the malformations
are resulting from parasites and/or environmental contaminants. Specifically,
the USDA was interested in obtaining live frog specimens to be analyzed
for the parasite Ribeiroia, which has been linked to malformed Pacific
tree frogs in the Pacific NW and also found at some Minnesota malformed
frog sites. Refuge staff collected 10 N. leopard frog metamorphs at
Schiermeister WPA for dissection by USDA scientists. It should be noted
that none of these frogs were malformed. Similar to the 13 “normal” metamorphs
examined in 2001, none of the frogs contained the parasite Ribeiroia;
therefore, USDA scientists are tentatively classifying the sites as “chemically
driven.” Using water and sediment samples collected from Schiermeister
WPA in the fall of 2001 and late spring of 2002, they plan to conduct
other studies in the near future through mineral analysis and estrogenicity
tests. Below are preliminary findings of the USDA parasite examination. |
| |
Species |
Sex |
Weight
|
Length |
Parasite |
Parasite |
Type
of Parasite |
Site |
|
| |
|
|
(g) |
(mm) |
(Y/N) |
# |
(Genus) |
|
|
| |
R. pipiens |
male |
4.58 |
41 |
N |
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
| |
R. pipiens |
female |
3.48 |
38 |
Y |
10 |
Manodistimum |
tail resorption site |
|
| |
|
|
|
|
|
8 |
Alaria |
hips |
|
| |
|
|
|
|
|
12 |
Alaria |
leg muscle |
|
| |
R. pipiens |
female |
3.30 |
32 |
N |
|
|
|
|
| |
R. pipiens |
female |
4.50 |
45 |
Y |
12 |
Alaria |
leg muscle |
|
| |
R. pipiens |
female |
3.14 |
34 |
N |
|
|
|
|
| |
R. pipiens |
female |
3.30 |
34 |
Y |
2 |
Apharyngostrigea |
lower jaw |
|
| |
R. pipiens |
female |
3.54 |
35 |
Y |
10 |
Manodistimum |
tail resorption site |
|
| |
|
|
|
|
|
10 |
Apharyngostrigea |
coelomic cavity |
|
| |
R. pipiens |
female |
3.66 |
37 |
Y |
15 |
Manodistimum |
tail resorption site |
|
| |
|
|
|
|
|
10 |
Fibricula |
leg muscle |
|
| |
|
|
|
|
|
2 |
Echinostomes |
kidneys |
| |
R. pipiens |
male |
3.22 |
33 |
Y |
10 |
Apharyngostrigea |
coelomic cavity |
| |
R. pipiens |
female |
3.07 |
34 |
Y |
2 |
Manodistimum |
tail resorption site |
|
|
|
| Developmental
Variability Monitoring |
| |
| The impetus
for this project came out of the WMDs 2001 malformation surveys. In 2002,
seven N. leopard frog metamorphs with fully developed mouths and retained
tails ranging from 16-42 mm in length were collected. According to the
FWSs 2001 Malformed Frog Sampling Protocol “any tail > 2 mm
in length is considered retained if the frog’s mouth is fully developed”,
and retained tails are considered abnormalities/malformations. These
seven frogs were recorded as abnormal/malformed, euthanized, and preserved
according to protocol. Subsequently, Long Lake National Wildlife Refuge
Complex staff’s curiosity was piqued regarding these “tailed
metamorphs.” |
| |
 Complex
staff initiated an investigation into whether frogs having a mouth developed
beyond their eye (Gossner stage #45) and having a retained tail > 2
mm in length are abnormal/malformed, or simply a product of developmental
variability (i.e., some frogs resorb their tail at a different rate than
others). Complex staff decided all metamorphs meeting the above criteria
that were captured during the 2002 malformed frog survey would be kept
in captivity to monitor their continued development. This project allowed
us to see if, given adequate time, frogs captured during the late stages
of metamorphosis (i.e., the mouth is developed beyond the eye) and still
having a tail > 2 mm in length, would eventually resorb their tail.
All frogs that were captured during the malformation survey and that
met the above criteria were transported to the Refuge headquarters and
placed in aquariums. Toe clipping was used to differentiate the frogs
from one another (e.g., frog #1 had its fifth toe on its left front foot
clipped, frog # 14 had its first toe on its right hind foot clipped).
No more than one toe was clipped per individual. Tails were measured
every three days with measurements taken between tail tip and vent. |
| |
| Researchers
with the USDA provided information on protocol for keeping frogs alive
in captivity. Frogs were kept in two 10-gallon aquariums (frogs # 1-7
in one and frogs # 8-15 in another) filled with de-ionized water. Both
wetland and upland habitats were provided in each aquarium. Because the
frogs were at the critical transformation (metamorphosis) stage, they
were fed both 4 to10 day-old crickets and tadpole food to ensure that
their nutritional needs were met. Water in aquariums was kept aerated
using standard aerators, plastic tubing and air stones. |
| |
| Fifteen
N. leopard frogs were captured at Schiermeister WPA having fully developed
mouths and tails ranging from 3-12.5 mm (note that these lengths are
substantially shorter than those observed in 2001 surveys). None of the
fifteen captive frogs retained any portion of a tail six days after capture,
and all but four had completely resorbed their tails after only a three-day
period. Below are developmental monitoring results for individual frogs. |
| |
-Frog |
Toe Clipped |
Initial Tail Length |
Day 3 Tail Length |
Day 6 Tail Length |
|
| |
-# |
|
(to 0.5mm) |
(to 0.5mm) |
(to 0.5mm) |
|
| |
|
|
|
|
|
|
| |
01 |
Left Front #5 |
12.5 |
3.0 |
Gone |
|
| |
02 |
Left Front #4 |
05.5 |
Gone |
- |
|
| |
03 |
Left Front #3 |
03.5 |
Gone |
- |
|
| |
04 |
Left Front #2 |
03.0 |
Gone |
- |
|
| |
05 |
Right Front #5 |
03.0 |
Gone |
- |
|
| |
06 |
Right Front #4 |
03.0 |
Gone |
- |
|
| |
07 |
Right Front #3 |
04.5 |
Gone |
- |
|
| |
08 |
Right Front #2 |
05.5 |
1.0 |
Gone |
|
| |
09 |
Left Hind #1 |
05.0 |
2.0 |
Gone |
|
| |
10 |
Left Hind #2 |
03.0 |
Gone |
- |
|
| |
11 |
Left Hind #3 |
03.5 |
Gone |
- |
|
| |
12 |
Left Hind #4 |
03.0 |
Gone |
- |
|
| |
13 |
Left Hind #5 |
04.5 |
Gone |
- |
|
| |
14 |
Right Hind #1 |
04.5 |
Gone |
- |
|
| |
15 |
Right Hind #3 |
09.0 |
2.0 |
Gone |
|
|
|
| |
|
Please direct questions
and comments to:
Long Lake
National Wildlife Refuge
U.S. Fish and Wildlife Service
12000 353rd St. SE
Moffit, North Dakota 58560-9704
Phone: 701-387-4397
E-mail: longlake@fws.gov
|
For
the second year in a row, Long Lake NWR Complex served as North Dakota’s
sole cooperator for malformed amphibian monitoring on FWS fee title lands.
Two WPAs previously surveyed in 2001 were also selected in 2002: Schiermeister
and Sisco-Fallgatter. Schiermeister was again deemed the “contaminant’ site
because the one acre semipermanent wetland that contained tadpoles was
flow-through in nature (part of Horsehead Creek) which increases the
site’s potential for receiving agricultural runoff (e.g., pesticides,
nutrients). Additionally, in previous growing seasons FWS personnel have
sprayed Tordon to control noxious weeds in close proximity to the study
wetland. Sisco-Fallgatter served as a reference site because the study
wetlands are closed basins, and little history of pesticide use exists
on the property. At Schiermeister in 2002, tadpoles were found in one
large impounded wetland, located just NE of the wetland that contained
tadpoles in 2001. Tadpoles were again found in one of the same Sisco-Fallgatter
wetlands from which they were sampled in 2001.
Surveys,
sampling, and data collection were performed according to Standard Operating
Procedures developed by the FWS Chesapeake Bay Field Office. Sampling
was conducted by Refuge staff and volunteers at Schiermeister on July
17. Although tadpole growth was monitored weekly at Sisco-Fallgatter,
the wetland containing the tadpoles dried up completely sometime between
July 15-19. During the final Sisco-Fallgatter age determination survey,
the majority of tadpoles were between 38-42 Gossner Stage, so they were
not at the stage of metamorphosis when the wetland went dry. Several
other wetlands on the WPA were searched for tadpoles, and surrounding
uplands for metamorphs, but none were found. Below are the survey results
for Schiermeister WPA.
A
total of 293 N. leopard frog metamorphs were collected (166 in the aforementioned
impounded wetland and 127 from the small semipermanent wetland which
contained tadpoles in 2001). Because tadpoles were only found in the
large impounded wetland in 2002, it is likely that the metamorphs collected
from the second smaller wetland had simply migrated there from the nearby
impounded wetland. Unlike 2001 when 5 of 100 sample frogs were deemed “abnormal”,
only one frog in 2002 was deemed abnormal and preserved for further examination.
This metamorph (weight = 3.8g, snout-to-vent length = 34mm) had a small
protrusion on its back, left of the spine and just a few millimeters
behind its left from leg. The protrusion was slightly larger than the
head of a pin. Water quality parameters for the small semipermanent wetland
were collected on June 3 and are as follows: Temperature = 19?C, DO =
5.02mg/l, Conductivity = 2741 uS, pH = 8.02.
Because
much speculation exists concerning the cause of amphibian malformations
nationwide, Refuge staff worked with scientists from the USDA - Agricultural
Research Service, Fargo, ND, to help determine whether the malformations
are resulting from parasites and/or environmental contaminants. Specifically,
the USDA was interested in obtaining live frog specimens to be analyzed
for the parasite Ribeiroia, which has been linked to malformed Pacific
tree frogs in the Pacific NW and also found at some Minnesota malformed
frog sites. Refuge staff collected 10 N. leopard frog metamorphs at
Schiermeister WPA for dissection by USDA scientists. It should be noted
that none of these frogs were malformed. Similar to the 13 “normal” metamorphs
examined in 2001, none of the frogs contained the parasite Ribeiroia;
therefore, USDA scientists are tentatively classifying the sites as “chemically
driven.” Using water and sediment samples collected from Schiermeister
WPA in the fall of 2001 and late spring of 2002, they plan to conduct
other studies in the near future through mineral analysis and estrogenicity
tests. Below are preliminary findings of the USDA parasite examination.
Complex
staff initiated an investigation into whether frogs having a mouth developed
beyond their eye (Gossner stage #45) and having a retained tail > 2
mm in length are abnormal/malformed, or simply a product of developmental
variability (i.e., some frogs resorb their tail at a different rate than
others). Complex staff decided all metamorphs meeting the above criteria
that were captured during the 2002 malformed frog survey would be kept
in captivity to monitor their continued development. This project allowed
us to see if, given adequate time, frogs captured during the late stages
of metamorphosis (i.e., the mouth is developed beyond the eye) and still
having a tail > 2 mm in length, would eventually resorb their tail.
All frogs that were captured during the malformation survey and that
met the above criteria were transported to the Refuge headquarters and
placed in aquariums. Toe clipping was used to differentiate the frogs
from one another (e.g., frog #1 had its fifth toe on its left front foot
clipped, frog # 14 had its first toe on its right hind foot clipped).
No more than one toe was clipped per individual. Tails were measured
every three days with measurements taken between tail tip and vent. 