Status of the Ozark Hellbender (Cryptobranchus Alleganiensis Bishopi): a Long-Term Assessment
A global decline in amphibian populations has been noted by biologists since the early 1970's. There are two problems with documenting the decline of amphibian populations: natural fluctuations in population numbers and lack of long-term data. I censused populations of the long-lived Ozark hellbender, Cryptobranchus alleganiensis bishopi, in three rivers in Missouri, and compared the 1998 data to data from previous studies from the 1970's and 1980's. Ozark hellbenders appear to have declined in numbers. This decline is characterized by an increase in average body size, due to an apparent lack of recruitment of young into the population. Hellbenders from at least one of the rivers tended to be in better condition in the 1998 samples than they were in the past. It is not known whether the population decline for hellbenders has a single cause or whether each population has experienced independent declines.
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