Responses to Extremely Low Frequency Electromagnetic Fields by a Dragonfly Naiad (Ophiogomphus colubrinus) in a Northern Michigan Stream: A Five Year Study

ABSTRACT

Movement patterns of dragonfly naiads in a small northern Michigan stream were followed from 1985 through 1989 to determine if Extremely Low Frequency (ELF) electromagnetic fields affected movements for this predator. ELF lines were activated in 1986 and increased in amperage and duration from that time until the system went to full power in 1989. Mark-recaptures at two sites, an experimental and a reference site on the Ford River, showed that Ophiogomphus colubrinus only moved in a downstream direction and travelled relatively short distances. Distances the animals travelled were related to discharge rather than to ELF antenna cumulative exposures.