Amphibian malformations have been increasingly found and reported over the
past decade. Malformed amphibians have been documented in all states within
the Northeast region. Based on North
American Reporting Center for Amphibian Malformations (NARCAM) data, hotspots
for malformations in the Northeast (i.e., states with the greatest number
of positive reports of malformations) include Vermont, New Hampshire, Massachusetts,
and upstate New York. However,
this may simply represent more extensive sampling in these states compared
to others. Malformations may be environmentally-induced by exposure to parasites
(trematodes), xenobiotic chemicals such as pesticides and/or metabolites,
naturally-occurring chemicals, ultraviolet radiation, temperature extremes,
disease, or may be determined genetically.
Surveys for malformed amphibians typically target early life stages (larvae/tadpoles
and recent metamorphs), as it is thought that severely malformed adults would
have a reduced probability of survival and hence would be harder to find.
Anyone who finds malformed amphibians is encouraged to enter their observations
into the NARCAM database.
What we have found
At one site at the USDA Beltsville Agricultural Research Center in 2001,
we documented malformation rates of 2% for green frog metamorphs (14 malformed
of 706 total examined) and 4% for spotted salamander adults (17 malformed
of 435 total examined). Extreme malformations included missing lower jaws
and holes in lower jaws (see pictures).
What we are doing
NE ARMI personnel enter amphibian malformation data into NARCAM and ARMI
databases and send severely malformed amphibians to the USGS
National Wildlife Health Center in Madison, WI, where Dr. David E. Green
examines and diagnoses the malformed amphibians. At sites where extreme or
high incidences of malformations have been documented, we are working with
Drs. Carol Meteyer and Linda Trueb to determine how the malformation develops
and which factors may influence its development.
What you can do
The most important data to collect is a detailed description of the malformed
amphibian (documentation using photography is recommended) and to record how
many normal individuals of the species you encountered at the site compared
to the number of malformed individuals (malformation rate). It is important
to report this information to the NARCAM web site,
which provides useful information on amphibian species identification and
types of malformations encountered in the field. If an amphibian malformation
is severe (e.g., multiple limbs, missing jaws or holes in throat) or
if you find a high percentage of malformed amphibians at a site (e.g.,
> 5% of at least 40 amphibians examined at a site), this might signal an environmental
problem that should be reported to local or state wildlife health specialists.
National Wildlife Health Center
and the Global Decline of Amphibians
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