In April 2008, biologists at Rachel Carson National Wildlife Refuge surveyed several vernal pools located on refuge property.  Vernal pools are depressions that contain water for a few months in the spring and early summer, but are generally dry by late summer.  A vernal pool, because of its periodic drying, does not support breeding populations of fish.  This is advantageous to those organisms that have evolved to use this temporary wetland to breed, as their offspring will not be eaten by fish.  These organisms are called “obligate” vernal pool species because they must use a vernal pool for various parts of their life cycle. 

This is the third year that biologists have monitored ten vernal pools at Rachel Carson NWR.  The U.S. Fish and Wildlife Service considers a vernal pool to have significance if it meets any of the following criteria: presence of particular organisms such as fairy shrimp; contains 40 or more wood frog egg masses; 20 or more spotted salamander egg masses; or 10 or more blue spotted salamander egg masses.  Biologists focused on counting egg masses of the tree frog, spotted salamander, and blue spotted salamander.  Out of the ten vernal pools surveyed, seven of them met the requirements needed to be considered significant.  We intend to monitor these pools each year in order to protect and maintain this precious and rare habitat.