Newly hatched stage I-II nauplii of Balanus improvisus (Darwin) were 'totally starved' (until death) or 'partially starved' for the first 48 h and 96 h of their development. Daily mortality and molting were monitored throughout larval development in both starved and fed control groups. Fed control animals exhibited a largely synchronous molting pattern with instars of equal duration. Total starvation suppressed molting beyond stage II; 50% mortality occurred in 4 days at both 15 and 21C, while longest survival time was 7 days at 15C and 6 days at 21C. At 15C, partially starved nauplii retained the ability to complete naupliar development but at a slower overall rate and with increased mortality relative to controls. These effects were more pronounced in the 96-h group. Increased mortality of stage VI nauplii was evident in both partially starved groups (u.1% for 48h, 18.8% for 96h) relative to unstarved controls (3.1%). Stage II nauplii exhibited little resistance to starvation and survival potential may have decreased as soon as 24h.