AUTECOLOGY OF AN INTERTIDAL ALASKAN HARPACTICOID COPEPOD APOLETHON SP

The life history and ecology of a harpacticoid copepod, Apolethon sp., were investigated for one year in the intertidal zone of a subarctic bay in southeastern Alaska. Core samples were collected biweekly at th e 0 m tidal level from March, 1992 through March, 1993; zonation and v ertical distribution were determined from additional samples. Large se asonal variations in density of Apolethon sp. parallelled that of the total harpacticoid community, with highest densities (124.3+/-12.5 10 cm-2; mean +/- standard error) in March and lowest densities in May an d October (7.6+/-4.5). The sex ratio of Apolethon sp. varied directly with population density, varying from <0.1 to 1.2 (male:female) during the study period. The species was restricted to a relatively narrow v ertical band within the intertidal zone, having its greatest density a t - 1 m and being rare above + 1 m tidal height. Adult Apolethon sp. b ear conspicuous ovoid mucin structures located laterally on the genita l double-somite. The mucin structures are unique to the species; sever al putative functions are discussed.