Among possible food sources for the sea cucumbers, fish feed and
settling OM were analyzed for their isotopic compositions. Assuming
that the δ13C and δ15N values of the sea cucumbers sampled in June reflect
only the isotopic compositions of the diets for the three months
prior to the collection due to their rapid growth, the mean (±SD)
δ13C and δ15N values of fish feed and settling OM were calculated to
be −20.1±0.4‰ (n=15) and 9.5±0.5‰ (n=15) for the former,
and −22.3±0.9‰ (n=36) and 8.2±1.3‰ (n=36) at the fish farm
station and−20.4±0.7‰(n=34) and 6.6±1.2‰(n=33) at the control
station for the latter, respectively.