• Dube, Norman R.
  University of Maine
  

The potential effect of insecticide spraying of forests for spruce budworm control on reproduction of smallmouth bass was studied in two lakes in Maine. A test lake adjacent to a spray area that received a single aerial application of Dylox was compared to a similar control lake located upstream in the same watershed. Insecticide residues for water from the test lake ranged from 0.25 to 0.91 µm/l and Dylox was not detected in water from the control lake. Acetylcholinesterase in the brain of smallmouth bass from the test lake was not significantly different between fish obtained before and after the spraying; levels also were stable in control fish. Fluctuations in zooplankton abundance apparently were independent of the spray application and utilization of zooplankton by larval bass was not altered.