The tidal exchange of Callianassa californiensis larvae between the ocean and the Salmon River estuary, Oregon

Graduation date: 1981During the Callianassa californiensis larval release period, weekly zooplankton samples were taken through daylight tidal cycles near the mouth of a small, fast flushing estuary on the Central Oregon coast. Although C. californiensis adults are confined to estuaries and embayments, stage I zoeal larvae were shown to be exported from the Salmon River estuary to the nearshore ocean. Physical features of the Salmon River estuarine environment appear to dominate any Callianassa larval behavior that would lead to retention within the estuary. Larval recruits to the adult population at the Salmon River must come from the nearshore region which probably contains Callianassa larvae flushed from estuaries all along the coast. The relative effects of temperature, salinity, spring/neap tide series, tidal position, the number of days elapsed from January 1, 1979, upwelling, and river discharge on larval density were examined using correlation and multiple regression techniques. The results supported the contention that larvae were exported to the nearshore ocean and the hypothesis that larvae would be retained in the nearshore ocean despite upwelling if they remained below the surface Ekman layer