Bluegills and channel catfish were exposed to four applications of malathion at two concentrations in ponds over an 11-week summer period. Fish losses ranged from 8 to 44 percent but could not be correlated to treatment levels. Neither acute nor chronic pathology developed, nor were depressions in the brain cholinesterase activity significant or reproducible. The total number of aquatic insects from plate sampling the low-treated ponds was not significantly lower than that from the untreated ponds, but the number of organisms from the high-treated ponds was significantly lower than that from either the low-treated or untreated ponds. Chironomidae was the dominant family of aquatic insects, and formed about 70 percent of the total benthos. This group showed a significant reduction in numbers in both low- and high-treated ponds after the third application of malathion.

A bibliography comprising annotated citations of 2037 scientific and technical publications from ten series issued by the U.S. Fish and Wildlife Service. Includes a six-page introduction containing a history of the Service and a description of the research and development series.