Ecology and Life History of the Brown Water Snake, Nerodia taxispilota
Mark S. Mills
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I
am in the final stages of my doctoral research on the ecology and life
history of the brown water snake, Nerodia taxispilota. This study
encompasses several aspects of the natural history of this large, semi-aquatic
snake, including: movement patterns, habitat use, diet, population ecology,
reproduction, and growth. This project
consists of two basic sampling programs: a mark-recapture effort begun
in 1991 by several students at SREL and continued by me, and a radiotelemetry
study of more than 20 individuals over a two-year period.
As of the spring of 1997, I have PIT-tagged over 1000 individuals in several habitats (primarily the Savannah River and Upper Three Runs Creek). This species seems to prefer deeper, fast-water areas of the creek and river and occurs in relatively high densities. In fact, I would venture so far as to say that in some aquatic habitats in this area (e.g., the Savannah River), it is probably the most common non-fish vertebrate.
They
are relatively long-lived snakes. Males reach sexual maturity in about
3 years and females in their 4th or 5th year. I have captured individuals
that may be 15 years old or more, and I suspect, based on growth curves
and size, that there are individuals that are at least 20 years old. They
are piscivores, primarily feeding on catfish. Because of their densities,
ease of capture, semiaquatic habitat, and diet (benthic feeding fish),
I believe that N. taxispilota is a potentially good candidate for
monitoring toxins in aquatic systems.