Virginia Institute of Marine Science
MARINE ECOLOGY PROGRESS SERIES
Survival and growth of newly settled oysters were measured at sub- and intertidal treatment levels during the first month of post-settlement life in the York River, Virginia, USA. Controlled settlement of hatchery-reared larvae in the laboratory and image analysis techniques allowed for individual oysters grown in the field to be tracked through time. High mortality occurred within 1 wk postsettlement at ah tidal heights in 3 experiments which spanned the natural recruitment period. This initial mortality strongly influenced later abundance, as weekly mortality rates decreased sharply after 2 wk. Additionally, all recruits were eliminated from the mid-intertidal zone and above (>25% aerial exposure) during high temperature periods. Only in autumn did recruitment occur in the intertidal area occupied by natural oyster populations. In contrast, low intertidal and subtidal populations persisted through the month long experiments where adult oysters were rare. Growth (shell area) of intertidal oysters exposed >25% was reduced relative to more immersed oysters. Density-dependent growth was not observed. While the natural oyster population appeared to be relegated to the suboptimum intertidal, successful recruitment to this zone was limited on a seasonal basis by lethal air temperatures >30 degrees C. The mortality agents which structure the intertidal population affect recently settled and juvenile oysters.
OYSTER; RECRUITMENT; GROWTH; JUVENILE; INTERTIDAL ZONATION
Roegner, GC and Mann, Roger L., Early recruitment and growth of the American oyster Crassostrea virginica (Bivalvia: Ostreidae) with respect to tidal zonation and season (1995). MARINE ECOLOGY PROGRESS SERIES, 117, 91-101.