Alewife,rainbow smelt and native fishes in Lake Michigan: competition or predation?

Synopsis Several native fish species in Lake Michigan became rare or locally extinct during the increase of rainbow smelt (1930s) and alewife (1950s–1960s). These particular native species have pelagic eggs or larvae which were large relative to the zooplankton and which co-occurred with feeding alewife, smelt or both. Alewife, smelt and most of the other planktivores in the lake probably consumed eggs, and at least alewife and smelt are known to consume larvae. For each species, I comment on the probable role of predation on early life history stages in their decline. Several species which currently co-exist with alewife and smelt have shown large scale declines during the increase of the exotics. Recruitment declines were often dramatic and the probability of predation on these species during their early life history is evaluated.