Proportion of Individuals as Trout
Proportion of Individuals as Piscivores (Top Carnivores)
Streams with slight or moderate water quality impairment generally contain several top
predator fish species. In cold water streams of New Jersey, predator fish such as bass and
pickerel are depauperate and typically replaced by trout. Thus, a metric is required which
measures both groups of top carnivores. A metric fulfilling this requirement is currently
used on Vermont streams (Langdon 1992) and has been adopted for use in New Jersey.
American eels are excluded from use in this metric. The ubiquity of American eels in streams
that have a wide range of water quality and habitat conditions limits their use as an indicator
of aquatic health.