Iowa DNR
River & Stream Biological Monitoring
Fish and Benthic Macroinvertebrate Surveys
Physical Habitat Assessments

Fish Health

When fish are collected, they are externally examined for the presence of external abnormalities such as skeletal deformities, eroded fins, lesions, and tumors (DELTs).

The presence of DELTs is used as an indicator for poor water quality conditions. If the number of DELTs within a sampled population passes a percentage threshold, the Fish Index of Biotic Integrity score can be lowered.

This page was created 3/14/2013 12:59:50 PM and was last updated 11/12/2013 9:56:51 AM