Two hermaphroditic alewives from Lake Michigan

Hermaphroditism has been reported frequently among many of the Clupeidae, but only one account of hermaphroditism has been published for the alewife, Alosa pseudoharengus. Rothschild discovered four hermaphroditic alewives among 444 fish he examined from Cayuga Lake, New York. We recently collected two hermaphroditic alewives from Lake Michigan. Both fish were normal in external appearance but were easily identified as hermaphrodites by gross examination of their gonads. The first hermaphrodite (177 mm T.L.) was discovered among several hundred normal adult alewives captured in early July 1965 in the Kalamazoo River about one mile upstream from Lake Michigan. The second hermaphroditic alewife (152 mm T.L.) was obtained from a sample of 160 adult alewives captured in Lake Michigan near the mouth of the Kalamazoo River in mid-April 1966.