Population dynamics of bloaters Coregonus hoyi in Lake Huron, 1980-1998

I investigated population dynamics of bloaters Coregonus hoyi in Lake Huron using data collected during 1980-1998 from fixed-site trawl surveys. Bloaters were uncommon in 1980, but abundance increased during 1980-1992 through a series of strong year classes. High adult abundance appeared to suppress recruitment after 1992, and the population subsequently declined. Growth was similar between sexes up to age-5, thereafter females grew faster than males. Both sexes lived to age-9, but females tended to live longer than males. A Ricker least-squares stock-recruitment relationship defined the relationship between adults and age-3 recruits, and may have been due to egg predation by adult bloaters. Higher female survival and shift in age structure toward older ages after 1990 led to female predominance in the population during 1995-1998. Female predominance appeared to be a consequence and not a cause of the observed population cycle.